Ecology and management of a forested landscape: fifty years on the Savannah River Site

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FORESTS / ECOLOGICAL RESTORATION

Advance praise for Ecology and Management of a Forested Landscape

“Ecology and Management of a Forested Landscape is a unique chronicle of the successful ecological rehabilitation and restoration of a degraded, formerly agriculture-dominated system, starting with research and moving through adaptive natural resource management. With a case-study approach containing applications and concepts extending beyond the southeastern United States, this book is invaluable to all ecologists—from the academic to the practicing land manager.” —W. Mark Ford, research wildlife biologist, USDA Forest Service, Northeastern Research Station, West Virginia “The Savannah River Site is a priceless model of ecological recovery and restoration. It provides hard evidence of how a mutually beneficial relationship between humankind and natural systems might develop. This book’s clearly stated goals and objectives are admirably supported by data that cover large temporal and spatial spans.” —John Cairns Jr., University Distinguished Professor of Environmental Biology Emeritus, Virginia Polytechnic Institute and State University JOHN C. KILGO is research wildlife biologist, USDA Forest Service, Southern Research Station, Center for Forested Wetlands Research. JOHN I. BLAKE is assistant manager of the research program with the USDA Forest Service, Savannah River.

Washington • Covelo • London www.islandpress.org

Ecology and Management of a Forested Landscape

“The history of ecological research at the Savannah River Site is testimony to the power of long-term studies, interdisciplinary collaboration, and the application of basic science to land management challenges. This volume wonderfully documents that history and provides a comprehensive review of our current understanding of the dynamics and functioning of this diverse landscape.” —Norman L. Christensen Jr., professor of ecology and founding dean, Nicholas School of the Environment and Earth Sciences, Duke University, North Carolina

KILGO BLAKE

Ecology and Management of a Forested Landscape Fifty Years on the Savannah River Site

Edited by John C. Kilgo and John I. Blake

All Island Press books are printed on recycled, acid-free paper. Cover design: Amy Stirnkorb Cover photo: John Kilgo

Foreword by H. Ronald Pulliam

About Island Press Island Press is the only nonprofit organization in the United States whose principal purpose is the publication of books on environmental issues and natural resource management. We provide solutions-oriented information to professionals, public officials, business and community leaders, and concerned citizens who are shaping responses to environmental problems. In 2005, Island Press celebrates its twenty-first anniversary as the leading provider of timely and practical books that take a multidisciplinary approach to critical environmental concerns. Our growing list of titles reflects our commitment to bringing the best of an expanding body of literature to the environmental community throughout North America and the world. Support for Island Press is provided by the Agua Fund, The Geraldine R. Dodge Foundation, Doris Duke Charitable Foundation, Ford Foundation, The George Gund Foundation, The William and Flora Hewlett Foundation, Kendeda Sustainability Fund of the Tides Foundation, The Henry Luce Foundation, The John D. and Catherine T. MacArthur Foundation, The Andrew W. Mellon Foundation, The Curtis and Edith Munson Foundation, The New-Land Foundation, The New York Community Trust, Oak Foundation, The Overbrook Foundation, The David and Lucile Packard Foundation, The Winslow Foundation, and other generous donors. The opinions expressed in this book are those of the author(s) and do not necessarily reflect the views of these foundations.

Ecology and Management of a Forested Landscape

Ecology and Management of a Forested Landscape

r

Fifty Years on the Savannah River Site

Edited by John C. Kilgo and John I. Blake

r Foreword by H. Ronald Pulliam

Washington • Covelo • London

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Copyright (c) 2005 Island Press All rights reserved under International and Pan-American Copyright Conventions. No part of this book may be reproduced in any form or by any means without permission in writing from the publisher: Island Press, 1718 Connecticut Ave., Suite 300, NW, Washington, DC 20009. ISLAND PRESS is a trademark of The Center for Resource Economics. Copyright is claimed in the work of I. Lehr Brisbin Jr., Kurt A. Buhlmann, William D. Carlisle, Michael B. Caudell, Brent J. Danielson, J. Whitfield Gibbons, Judith L. Greene, Nick M. Haddad, Charles H. Hunter Jr., Paul. E. Johns, Robert A. Kennamer, Yale Leiden, Barton C. Marcy Jr., John J. Mayer, Tony M. Mills, William F. Moore, Eric A. Nelson, Sean Poppy, Travis J. Ryan, David E. Scott, Barbara E. Taylor, Tracey D. Tuberville, Lynn D. Wike, Christopher T. Winne, in the foreword, and the index to the Island Press edition. In accordance with Federal law and U.S. Department of Agriculture policy, this institution is prohibited from discriminating on the basis of race, color, national origin, sex, age, or disability. To file a complaint of discrimination, write USDA, Director, Office of Civil Rights, Room 326-W, Whitten Building, 1400 Independence Avenue, SW, Washington, DC 20250-9410 or call (202) 7205964 (voice and TDD). USDA is an equal opportunity provider and employer. Product or trade names may be registered trademarks, and are given only to identify materials used. Mention of specific products or trade names should not be considered an endorsement or recommendation by the authors. No claim to copyright can be made for original works produced by U.S. government employees as part of official duties. Original works by the U.S. government are in the public domain. Library of Congress Cataloging-in-Publication data. Ecology and management of a forested landscape : fifty years on the Savannah River Site / edited by John C. Kilgo and John I. Blake ; foreword by H. Ronald Pulliam. p. cm. Includes bibliographical references and index. ISBN 1-59726-010-X (cloth : alk. paper) — ISBN 1-59726-011-8 (pbk. : alk. paper) 1. Forest ecology—South Carolina—Savannah River Site. 2. Restoration ecology—South Carolina—Savannah River Site. I. Kilgo, John C. ( John Carlisle), 1967– II. Blake, John Irvin. QH105.S6E28 2005 333.75′153′097577—dc22 2004025494 British Cataloguing-in-Publication data available. Printed on recycled, acid-free paper Design by Paul Hotvedt Manufactured in the United States of America 10 9 8 7 6 5 4 3 2 1

Contents List of Figures and Tables ix Foreword xvii Preface xx Acknowledgments xxii

Chapter 1 The Savannah River Site, Past and Land-Use History 2 Industrial Operations and Current Land Use 12 Chapter 2 The Physical Environment Climate and Air Quality 20 Soils and Geology 30 Water Resources 41

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Chapter 3 SRS Forest Management 57 Silviculture and Harvesting Activities 59 Prescribed Fire Management 75 Ecological Restoration 84 Chapter 4 Biotic Communities Plant Communities 106 Aquatic Invertebrates 161 Butterflies 175 Fishes 184 Amphibians and Reptiles 203 Nongame Birds 223 Nongame Mammals 253

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Present 1

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Contents

Chapter 5 Threatened and Endangered Smooth Purple Coneflower 266 Sensitive Plants 275 Shortnose Sturgeon 282 American Alligator 285 Wood Stork 289 Bald Eagle 295 Red-Cockaded Woodpecker 301 Sensitive Animals 312

Species

Chapter 6 Harvestable Natural Resources Minerals 325 Commercial Forest Products 328 Fishery of the Savannah River 338 Small Game 341 Waterfowl 347 Wild Turkey 359 Furbearers 366 Wild Hog 374 White-Tailed Deer 380 Chapter 7

Conclusion

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390

Appendix: Habitat Suitability Matrix for SRS Plants 401 Literature Cited 436 List of Reviewers 466 About the Authors 467 Index 469

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List of Figures and Tables Figures Figure A. At the time of government acquisition, all towns and buildings were removed or demolished. xxi Figure 1.1. Streams and physiography of the Savannah River Site. 3 Figure 1.2. Pine savannas probably dominated most of the uplands in the area prior to European settlement. 4 Figure 1.3. Bottomland hardwood forests occurred on the floodplains of larger streams and rivers. 5 Figure 1.4. Pre-European vegetation types of the Savannah River Site. Color insert Figure 1.5. Cut-over condition of much of the Savannah River Site at the time of government acquisition. 11 Figure 1.6. Land use on the Savannah River Site in 1951. Color insert Figure 1.7. Satellite image of the Savannah River Site and surrounding region, March 1999. Color insert Figure 1.8. Land-use areas of the Savannah River Site. Color insert Figure 1.9. Aerial view of a developed area and surrounding forest on the Savannah River Site. 14 Figure 1.10. Size of the workforce on the Savannah River Site, 1987–2003. 16 Figure 2.1. Topographic relief on the Savannah River Site. 32 Figure 2.2. Geological stratigraphy and groundwater systems of the Savannah River Site. 34 Figure 2.3. General soil map of the Savannah River Site. Color insert Figure 2.4. Major streams, wetlands, and larger lakes of the Savannah River Site. 42 Figure 2.5. Relative mean monthly discharge for major streams on the Savannah River Site. 48 Figure 2.6. During reactor operations, the high flow rates and temperatures of reactor cooling water destroyed riparian vegetation in Fourmile Branch, Pen Branch, and Steel Creek. 51

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List of Figures and Tables

Figure 2.7. Aerial view of Ellenton Bay, a large Carolina bay bisected by a utility right-of-way. 55 Figure 2.8. Hydroperiods for fifty-six Carolina bays on the Savannah River Site. 56 Figure 3.1. Longleaf pine planted in an old field on the Savannah River Site, early 1950s. 61 Figure 3.2. Net number of acres planted 1953–2003 or seeded successfully 1960–1971 at the Savannah River Site for slash pine, loblolly pine, longleaf pine, and various hardwood species including cypress. 62 Figure 3.3. Longleaf pine planted in cutover scrub oak on the Savannah River Site, early 1950s. 63 Figure 3.4. Changes in silviculture and harvesting practices on the Savannah River Site 1952–2001. 71 Figure 3.5. Number of wildfires and average area per fire 1954–2002 on the Savannah River Site. 77 Figure 3.6. Trends in prescribed burning at the Savannah River Site, 1952–2002. 79 Figure 3.7. Under proper conditions, smoke from prescribed burning is carried upward and away from sensitive areas. 83 Figure 3.8. Locations of restoration projects on the Savannah River Site. 88 Figure 3.9. Aerial view of the Pen Branch corridor and delta on the Savannah River Site during reactor operations. 90 Figure 3.10. Degraded wetland areas of the Pen Branch corridor and delta on the Savannah River Site that were impacted by thermal releases from reactors and later restored as part of the mitigation effort. 91 Figure 3.11. Planting trees in the Pen Branch corridor on the Savannah River Site, 1993. 92 Figure 3.12. A drainage ditch from a Carolina bay on the Savannah River Site. 94 Figure 3.13. Aerial view of restored Carolina bays on the Savannah River Site. 98 Figure 3.14. Distribution of remnant and degraded savanna plant communities in relation to land-use and fire exclusion history, mapped for potential savanna restoration on a representative section of the Savannah River Site. 100 Figure 4.1. Forest land-use associations of the Savannah River Site. Color insert Figure 4.2. Potential vegetation types of the Savannah River Site. Color insert Figure 4.3. Pine savanna. 115 Figure 4.4. Sandhill woodland. 116 Figure 4.5. Forested Carolina bay. 123 Figure 4.6. Herbaceous Carolina bay. 126

List of Figures and Tables

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Figure 4.7. Longleaf pine plantation, two to three years old, with welldeveloped shrub-scrub understory. 128 Figure 4.8. Loblolly pine stand on an old-field site (“old-field pine”). 129 Figure 4.9. Mature loblolly pine stand with some understory development. 130 Figure 4.10. Mature slash pine stand with little understory but a hardwood midstory. 130 Figure 4.11. Upland hardwood forest. 131 Figure 4.12. Flooded swamp. 142 Figure 4.13. Bottomland hardwood forest with herbaceous understory. 149 Figure 4.14. Bottomland hardwood forest with switchcane understory. 150 Figure 4.15. Old-field conditions typical of rights-of-way and other open areas. 158 Figure 4.16. First-order (headwater) stream. 189 Figure 4.17. Third-order stream. 190 Figure 4.18. Terrestrial snakes associated with xeric upland habitats and mesic floodplain habitats on the Savannah River Site. 212 Figure 4.19. Aquatic snakes associated with stream systems and Carolina bays on the Savannah River Site. 213 Figure 4.20. Salamanders and frogs associated with Carolina bays on the Savannah River Site. 214 Figure 4.21. Turtles associated with Carolina bay wetlands on the Savannah River Site. 216 Figure 4.22. Locations of terrestrial refugia for wetland turtles in uplands surrounding Dry Bay on the Savannah River Site during autumn-winter, 1994–1997. Color insert Figure 4.23. Abundance of strong- and weak-excavating cavity-nesting birds and total bird species richness on plots with all coarse woody debris removed and with none removed on the Savannah River Site. 230 Figure 4.24. Abundance, species richness, and diversity of birds in three successional stages of bottomland hardwood forest on the Savannah River Site. 234 Figure 4.25. Probabilities of occurrence of four area-sensitive birds in bottomland hardwood forests of various widths on the Savannah River Site. 236 Figure 4.26. Number of shrub-successional bird species and total number of bird species in clear-cuts of various sizes on the Savannah River Site. 237 Figure 4.27. Densities of Bachman’s sparrows in clear-cuts isolated by various distances from areas with source populations on the Savannah River Site. 238 Figure 4.28. Number of small mammals captured in longleaf pine stands of various ages on the Savannah River Site. 257

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List of Figures and Tables

Figure 4.29. Number of cotton mice captured on plots where tornado damage created a pulse of dead wood in 1989 on the Savannah River Site. 261 Figure 4.30. Diversity and species richness of small mammals in three sizes of clear-cuts on the Savannah River Site. 262 Figure 5.1. Locations of smooth purple coneflower populations on the Savannah River Site. 269 Figure 5.2. The response of individual smooth purple coneflower plants to burning and cutting treatments at the Burma Road population area, Savannah River Site. 271 Figure 5.3. Flowering patterns of smooth purple coneflower following burning and cutting treatments at the Burma Road population area, Savannah River Site. 271 Figure 5.4. Potential shortnose sturgeon spawning habitat in the Savannah River adjacent to the Savannah River Site. 284 Figure 5.5. Population growth of American alligators in Par Pond on the Savannah River Site, 1972–1988. 287 Figure 5.6. Seasonal use of the Savannah River swamp system by wood storks, 1983–2002. 290 Figure 5.7. Average numbers of wood storks observed per aerial survey of the Savannah River swamp system, 1983–2002. 293 Figure 5.8. Locations of bald eagle nest sites and management areas on the Savannah River Site. 296 Figure 5.9. Number of groups and size of post-breeding-season population of red-cockaded woodpeckers on the Savannah River Site, 1975–2003. 304 Figure 5.10. Location of active and inactive red-cockaded woodpecker groups and recruitment stands within habitat management areas during 2001 on the Savannah River Site. 306 Figure 5.11. Artificial cavity inserts, developed at SRS, have become a critical tool in red-cockaded woodpecker recovery efforts rangewide. 307 Figure 5.12. A red-cockaded woodpecker cavity tree with an encroaching midstory below. 308 Figure 6.1. Volume of wood in softwoods and hardwoods sold on the Savannah River Site, 1955–2003. 335 Figure 6.2. Total value of wood sold for all species on the Savannah River Site, 1955–2000, and the average unit price of the wood sold during each year. 336 Figure 6.3. Habitats used by waterfowl and locations of nest boxes for breeding wood ducks and hooded mergansers on the Savannah River Site. 351 Figure 6.4. Population parameter estimates for female wood ducks using nest boxes on the Savannah River Site, 1979–1995. 354

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Figure 6.5. Maximum numbers of ring-necked ducks, lesser scaup, buffleheads, and ruddy ducks observed per year during aerial surveys of Par Pond and L Lake on the Savannah River Site, 1982–2003. 358 Figure 6.6. Hunter recovery locations in the eastern United States of 594 ring-necked ducks originally banded on the Savannah River Site, 1985–2002. 359 Figure 6.7. Wild turkey observations recorded during South Carolina Department of Natural Resources summer brood surveys 1974–2003 on the Savannah River Site. 363 Figure 6.8. Number of Virginia opossum, raccoon, and striped skunk captured per year during the Small Furbearer Survey, Savannah River Site, 1954–1982. 367 Figure 6.9. Number of red fox, gray fox, and bobcat captured per year during the Small Furbearer Survey, Savannah River Site, 1954–1982. 370 Figure 6.10. Expansion of wild hog distribution on the Savannah River Site. 375 Figure 6.11. Estimated size of the deer population and number of deer harvested on the Savannah River Site, 1965–2003. 383 Figure 6.12. Relationship between the number of deer-vehicle accidents and (a) the estimated size of the deer population and (b) the size of the workforce on the Savannah River Site. 387

Tables Table 2.1. Mean monthly rainfall and extremes for the 773-A area at the Savannah River Site for the period 1952–2001. 22 Table 2.2. Predicted extreme precipitation recurrence estimates by accumulation period and observed extreme total precipitation received in the Savannah River Site region, August 1948–December 1995. 23 Table 2.3. Ranges for monthly mean, monthly high, and monthly low temperature and monthly mean, maximum, and minimum relative humidity, 1964–2001, from A Area at the Savannah River Site. 24 Table 2.4. Historical average pan evaporation at the Edisto Experiment Station, Blackville, South Carolina, 1963–1992. 25 Table 2.5. Monthly occurrences of tornadoes, hurricanes, thunderstorms, and snow or ice in the Savannah River Site region. 27 Table 2.6. Chemical characteristics of selected upland soils, by depth, on the Savannah River Site. 40 Table 2.7. Hydrologic characteristics of major streams on the Savannah River Site. 46 Table 2.8. Chemical characteristics of major streams on the Savannah River Site. 49

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List of Figures and Tables

Table 3.1. Acreage treated by various silvicultural practices at the Savannah River Site 1952–2001. 65 Table 3.2. Pre- and postburn fuel loading and total fuel reduction. 80 Table 3.3. Observed annual mean twenty-four-hour PM10 values from three counties near the Savannah River Site. 84 Table 3.4. General ecological impacts from post-European settlement in the Central Savannah River Area and strategies for ecological restoration. 86 Table 3.5. Species richness for taxa in Pen Branch compared with disturbed post-thermal and late-successional forested reference sites at the Savannah River Site. 93 Table 3.6. Level of disturbance to surface hydrology by drainage ditches in isolated depression wetlands at the Savannah River Site in 2002. 95 Table 3.7. Effects of burning, harvesting, and harvesting plus burning on the average herbaceous species richness and percent wetland species occurring in Bay 93 on the Savannah River Site before and after closing the drainage ditch in 1994. 96 Table 3.8. Savanna grasses, composites, and legumes selected for experimental introduction to old-field pine sites at the Savannah River Site to establish founder populations. 101 Table 4.1. Extent of forest cover types on the Savannah River Site. 111 Table 4.2. Extent of vegetation types on the Savannah River Site. 114 Table 4.3. Percent basal area for species associated with sandhill woodland and remnant pine savanna communities on the Savannah River Site. 118 Table 4.4. Percent basal area for species associated with Carolina bay forests and savanna communities on the Savannah River Site. 124 Table 4.5. Percent basal area for species associated with upland oak-pine woodland and pine-hardwood forest communities on the Savannah River Site. 134 Table 4.6. Percent basal area for species associated with upland slope and hardwood communities on the Savannah River Site. 138 Table 4.7. Percent basal area for species associated with swamp communities on the Savannah River Site. 144 Table 4.8. Percent basal area for species associated with river and large stream bottom habitats on the Savannah River Site. 146 Table 4.9. Percent basal area for species associated with stream bottom communities on the Savannah River Site. 152 Table 4.10. Habitats of aquatic insects on the Savannah River Site. 162 Table 4.11. Habitats of aquatic arthropods on the Savannah River Site. 165 Table 4.12. Habitats of other aquatic invertebrates on the Savannah River Site. 166 Table 4.13. Conservation status of aquatic invertebrates of the Savannah River Site. 172

List of Figures and Tables

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Table 4.14. Butterfly species of the Savannah River Site, organized by family, with month and habitat of occurrence. 176 Table 4.15. Number of butterfly species on the Savannah River Site, by family. 183 Table 4.16. Fish species confirmed at the Savannah River Site. 185 Table 4.17. Relative density of fish in streams recovering from thermal impacts and in undisturbed streams on the Savannah River Site. 193 Table 4.18. Percent composition of fishes from Par Pond on the Savannah River Site, 1969–1980. 199 Table 4.19. Number of fish (and percent composition) captured in two studies of Carolina bays and isolated depression wetlands on the Savannah River Site. 201 Table 4.20. Habitat characterizations and rarity rankings of amphibians and reptiles of the Savannah River Site. 205 Table 4.21. A typology of species rankings for amphibians and reptiles on the Savannah River Site based on geographic range, habitat specificity, and local population size. 210 Table 4.22. Bird-habitat matrix for the Savannah River Site, South Carolina. 240 Table 4.23. Typical avian communities associated with six common habitats on the Savannah River Site. 228 Table 4.24. Taxonomic listing and conservation status of the mammals of the Savannah River Site. 254 Table 4.25. Primary habitats of nongame mammals of the Savannah River Site. 258 Table 4.26. Levels of foraging bat activity over nine habitats on the Savannah River Site. 260 Table 5.1. Number of ramets for three smooth purple coneflower populations on the Savannah River Site, 1988–2003. 270 Table 5.2. Sensitive plants occurring on the Savannah River Site, with their global and state ranking and number of populations for each species in 1990, 1995, and 2000. 276 Table 5.3. The Nature Conservancy and South Carolina Department of Natural Resources rarity and vulnerability rankings used on the Savannah River Site. 278 Table 5.4. Estimated population size and sex ratios of American alligators in Par Pond on the Savannah River Site 1972–1974 and 1986–1988. 286 Table 5.5. Wood stork use of the Savannah River swamp system, 1983–2000. 292 Table 5.6. Number of nestlings fledged by bald eagle nesting pairs on the Savannah River Site, 1986–2000. 299 Table 5.7. Numbers of red-cockaded woodpecker fledglings and groups on the Savannah River Site, 1990–2003. 304

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List of Figures and Tables

Table 5.8. Acreage receiving midstory control and prescribed burning for red-cockaded woodpecker management on the Savannah River Site, 1990–2003. 309 Table 5.9. Number of red-cockaded woodpeckers translocated to the Savannah River Site, 1986–2000. 310 Table 5.10. Number of southern flying squirrels removed from redcockaded woodpecker cavities on the Savannah River Site, 1986–2003. 312 Table 6.1. Chemical formulas of minerals occurring at the Savannah River Site. 327 Table 6.2. Standing volume of pine and hardwood at the Savannah River Site at intervals, 1952 to 2001. 330 Table 6.3. Approximate distribution of the total forest area by stand age class and major commercial forest type using the Savannah River Site periodic stand mapping database. 331 Table 6.4. Estimated total number of trees by species and diameter class on the forested land area on the 2001 Savannah River Site in 1992. 333 Table 6.5. Comparative volume, value, and revenue sold from selected clear-cut or regeneration sales versus thinning or partial-cut sales 1987–1996 on the Savannah River Site. 336 Table 6.6. Area raked, total sales revenue, and unit value per acre for pine straw harvest at the Savannah River Site, 1991–2000. 337 Table 6.7. Estimate of percentage of fish species harvested from New Savannah Bluff Lock and Dam on the Savannah River during the 1999 access creel census. 340 Table 6.8. Christmas Bird Count data for small game birds at the Savannah River Site, 1979–2002. 342 Table 6.9. Small game harvest at Crackerneck Wildlife Management Area and Ecological Reserve, Savannah River Site, 1984–2003. 344 Table 6.10. Locations on the Savannah River Site where waterfowl and other selected aquatic birds have been observed, 1952–1997. 349 Table 6.11. Number of wild turkeys trapped on the Savannah River Site by the South Carolina Department of Natural Resources for off-site restocking programs, 1978–2000. 361 Table 6.12. Wild turkey harvest data recorded on Crackerneck Wildlife Management Area and Ecological Reserve, 1983–2003. 362 Table 6.13. Causes of mortality among 132 radio-instrumented wild turkeys on the Savannah River Site and the Crackerneck Wildlife Management Area and Ecological Reserve, 1998–2001. 363 Table 6.14. Annual number of beaver trapped on the Savannah River Site, 1983–2003. 369 Table 6.15. Number of wild hogs removed annually from the Savannah River Site, 1965–2003. 377

Foreword In 1539, Hernando de Soto and his band of six hundred soldiers, gold seekers, and Indian guides set out to explore the interior of what is now the southeastern United States. De Soto and his men traveled north and east from Florida and across the upper coastal plain of Georgia before crossing the middle Savannah River into South Carolina. Although their exact route is unknown, they would have passed through a heavily forested landscape, perhaps following Indian trails and sticking, as much as possible, to the open, sandhill scrub forest and longleaf pine–dominated uplands, avoiding the more difficult terrain of the tupelo-cypress swamps and bay forests of the bottomland floodplains. Though no doubt grand by modern-day standards and magnificent to behold, the forests encountered by De Soto had already been modified for centuries by Indians seeking to improve their hunting grounds and increase the abundance of edible berries and other wild foods. But the changes wrought by Native Americans were relatively minor compared to what was to come. Four hundred years after De Soto’s travels, the uplands of the upper coastal plain had been almost entirely cleared for intensive agriculture, and even much of the swampy lowlands had been drained and cleared. These dry, infertile lands provided a farmer little yield and a difficult life, however, so by the mid-twentieth century, many farmers had left, leaving the patchwork of abandoned farms and secondgrowth forests still seen throughout most of the upper coastal plain today. Can land degraded by centuries of poor agricultural practices be restored to something approaching its original productivity and diversity? This book tells the remarkable story of fifty years of natural resource management and restoration of the forested landscape of the Savannah River Site (SRS). In 1950, the Atomic Energy Commission began purchasing land and relocating thousands of descendants of the original European settlers who had cleared the land and tried to eek out a living from it. xvii

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Shortly afterward, researchers from the Universities of Georgia and South Carolina and the Philadelphia Academy of Sciences were invited to work on the site, and the USDA Forest Service began an aggressive program to replant and restore the forests. As a result of these efforts, the Savannah River Site is one of the best-studied ecological research sites in North America, and an amazing diversity of native flora and fauna exist in what was once corn and cotton fields, pastures, and degraded and poorly managed forests. Editors John Kilgo and John Blake have assembled a talented group of authors, all of whom are intimately familiar with the subject matter of their chapters. Some authors are university faculty who for years have traveled back and forth from schools across the country to work at the Savannah River Site because of the unique research environment the site offers. Others are permanent residents working on site at Westinghouse, the U.S. Forest Service, or the University of Georgia’s Savannah River Ecology Laboratory. Their collective knowledge of the history, ecology, and management of the Savannah River Site is itself a unique resource, and this book serves to make their knowledge and experience available to others. Today, most of the original forest traversed by De Soto is gone. In 1989, in “Longleaf pine and wiregrass: Keystone components of an endangered ecosystem” (Nat. Areas J. 9:211–213), Reed F. Noss estimated that less than 30 percent of bottomland and riparian forests and only 14 percent of longleaf forests remain in the Southeast and only 3 percent of longleaf habitat survives as old growth. Some of the unique species of the southeastern forests (e.g., Carolina parakeet, ivory-billed woodpecker, and Bachman’s warbler) are gone forever, but—though many of the remaining species are threatened or endangered—much of the original diversity of the region has survived. Our ability to ensure the long-term viability of the region’s biological diversity depends on three critical steps: (1) inventorying the existing diversity of native species, (2) determining the habitat requirements of the threatened species, and (3) restoring habitats and managing them to provide for the habitat requirements of native flora and fauna. In summarizing fifty years of research into the biotic communities and native species of the Savannah River Site, this book provides a comprehensive overview of the forest management practices that can support long-term forest recovery and restoration of native habitats. The success of the management efforts at SRS is attested to by the 103 species of reptiles and amphibians, 87 fish species, 69 species of dragonflies and damselflies,

Foreword

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99 species of butterflies, 64 rotifer species, and literally thousands of other species that still exist there. Not only the presence of species but also their habitat requirements have been documented in detail, even for often ignored groups such as aquatic invertebrates. As a result of reintroducing or regenerating appropriate native species, restoring natural hydrological cycles in the lowlands and regular burning in the uplands, controlling non-native invasive species, and carefully regulating hunting and fishing, the native flora and fauna of the Savannah River Site is flourishing. Our ability to preserve the native biological diversity of the southeastern United States, or any other region of the world, over the next thousand, or even hundred, years is still uncertain. There are those who feel we have done too little too late, and the loss of habitat and poor management practices of the past combined with our ignorance and greed in the future will inevitably lead to massive losses of biological diversity. This book stands as a counterargument to that bleak and gloomy view of the future and provides a concrete example of the role that good science combined with good management can play in ensuring that our descendants will be able to enjoy the splendors of nature that have delighted our own generation. H. Ronald Pulliam Regents Professor of Ecology University of Georgia August 12, 2004

Preface In 1950, the United States Department of Energy (then the U.S. Atomic Energy Commission) began purchasing the land that became the present Savannah River Site (SRS). All residents were removed (figure A), and in 1951 the government closed the site to the public to begin work on production of nuclear weapons materials. At the time, abandoned agricultural fields dominated upland areas, and the SRS and the USDA Forest Service initiated an aggressive reforestation program. Concurrently, the primary site contractor at the time, E.I. DuPont de Nemours Co., subcontracted researchers from the University of South Carolina, the Philadelphia Academy of Sciences, and the University of Georgia (which would eventually establish the Savannah River Ecology Laboratory) to initiate baseline ecological surveys of the site. Since that time, researchers from those organizations and many others have intensively studied and monitored the natural resources of the SRS. The initial inventory of the fauna and flora established both a baseline for future comparison and a philosophy of stewardship for resources that persists today. Although management objectives have changed, the SRS goal for stewardship has remained focused upon innovative leadership in resource management through sound scientific and technical strategies. In 1972, the Department of Energy designated the SRS as the nation’s first National Environmental Research Park, a place where the effects of human impacts on the environment could be studied. The SRS has provided excellent opportunities for research within that concept. The comprehensive nature and scope of information on the ecology of the site and its resources is unparalleled. The SRS has made this information available to the public through numerous professional journals, reports, and publications by the Savannah River Ecology Laboratory, the Savannah River Technology Center, the South Carolina Archeology Research Program, the U.S. Forest Service, xx

Preface

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Figure A. At the time of government acquisition, all towns and buildings were removed or demolished (J. Kilgo).

cooperating universities, and other agencies. The SRS has periodically published overviews of the natural resources in various formats. However, no publication has integrated information on ecology, natural resources, and management practices, and various public groups have expressed a desire to obtain that relevant scientific and technical information about the site in a single document. This book tells the story of the fifty-year period after human residents moved from that 310-square-mile tract of land in the South Carolina coastal plain. Human impact has continued, to be sure. The SRS workforce approached twenty-five thousand at its peak in 1991. Nuclear reactors and related facilities have been constructed, as well as several large cooling reservoirs, and environmental contamination has occurred (there are sites on SRS designated under the provisions of the Resource Conservation and Recovery Act and the Comprehensive Environmental Response, Compensation, and Liability Act). These impacts have generally been localized within the site, however; industrial development (not including rights-of-way and reservoirs) constitutes less than 3 percent of the site’s area, and surface contamination exists in only 0.6 percent of the area. The SRS manages its forests on a far longer rotation length than most managed lands in the Southeast. Thus, the vast majority of the land area of SRS has suffered relatively minimal human impact in the past fifty years. We hope that this book will provide its readers with a better understanding of the plant and animal populations and communities present on the SRS and the effect on them of fifty years of land management by the Department of Energy.

Acknowledgments This work was supported by the U.S. Department of Energy–Savannah River Operations Office through the U.S. Forest Service–Savannah River (USFS-SR) under Interagency Agreement No. DE-AI09-00SR22188, which also supported authors from USFS-SR. Authors from the Savannah River Ecology Laboratory (SREL) were supported by the Environmental Remediation Sciences Division of the Office of Biological and Environmental Research, U.S. Department of Energy, through Financial Assistance Award No. DE-FC09-96SR18546 to the University of Georgia Research Foundation. Authors from Westinghouse Savannah River Company were supported by the U.S. Department of Energy under contract DE-AC0996SR18500. Authors from the U.S. Forest Service Southern Research Station (USFS-SRS) were supported by that agency. Many individuals generously contributed their time, efforts, and ideas to make this book possible. Elizabeth LeMaster, formerly of USFS-SR, was instrumental in the original conception of the book. Special thanks are offered to Dumitru Salajanu and Andrew Thompson (USFS-SR) for creating most of the maps used herein, to David Scott for providing many of the photographs, and to Kim Hale for support in putting it all together. Donald Von Blaricom (Strom Thurmond Institute, Clemson University, South Carolina) provided figure 1.3 and associated image analysis. Deno Karapatakis (SREL) provided figure 1.4. Dean Fletcher (SREL) provided the list of SRS fishes in chapter 4. Kay Franzreb and Chuck Daschelet (USFS-SRS) collected much of the unpublished red-cockaded woodpecker data in chapter 5. The late Tom Lloyd provided invaluable assistance with the forest inventory data in chapter 6. Finally, we wish to thank the multitude of land management professionals, from many organizations, whose diligent work during the past fifty years has resulted in the unique resource that is the Savannah River Site.

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The Savannah River Site, Past and Present Land-Use History David L. White

Industrial Operations and Current Land Use John I. Blake, John J. Mayer, and John C. Kilgo

The land area now owned by the U.S. Department of Energy and known as the Savannah River Site (SRS) has been occupied by humans for about 11,500 years. In the section titled “Land-Use History,” David White describes the vegetation of the area prior to European settlement and then provides a brief overview of the area’s long and varied history, with an emphasis on the impacts of humans upon the landscape. Native Americans influenced the landscape through their use of fire and agriculture. Around 1700, Savannah Town was established as the first European settlement in inland South Carolina, approximately 20 km north of the present SRS. Although residents grazed cattle and hogs in the woodlands and began to affect native wildlife populations, agriculture was not well established until the late 1700s, after which, land clearing increased dramatically. Timber and cotton became the dominant products of the area. By 1950, when the government acquired the land, much of the site had been cut repeatedly and most of the uplands were in agricultural fields or bare ground. The SRS contracted the U.S. Forest Service to reforest the site in 1951. Today, the SRS is almost completely forested 1

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Ecology and Management of a Forested Landscape

and contrasts greatly with the surrounding landscape, which is dominated by agriculture and suburban development. (The material in this section was condensed and summarized from White and Gaines, 2000.) In “Industrial Operations and Current Land Use,” John Blake et al. first outline in general terms the primary missions, activities, and infrastructure of SRS. They then describe the land-use zones, including habitat management areas for the endangered red-cockaded woodpecker (a primary habitat management area, a supplemental habitat management area, and an other-use area), the Crackerneck Wildlife Management Area and Ecological Reserve (managed cooperatively by the South Carolina Department of Natural Resources), and the research set-aside areas. Collectively, these areas form the framework within which SRS land management is conducted.

Land-Use History David L. White Creation of the 80,267-ha (198,344-ac or 310-mi2) Savannah River Site (SRS) by the U.S. Department of Energy (DOE, formerly the Atomic Energy Commission, AEC) in 1951 set the stage for a dramatic change in land use. Construction of nuclear production facilities and the reforestation of abandoned farmland and cutover forests affected SRS ecosystems in profound ways. The construction and operation of nuclear facilities from 1953 to 1988 directly impacted about 4,000 ha (9,884 ac) of land, created almost 2,000 ha (4,942 ac) of cooling reservoirs, and released thermal effluent in all but one major SRS stream (Upper Three Runs). Nuclear facilities now on the site include five deactivated reactors, as well as facilities for nuclear materials processing, tritium extraction and purification, waste management, solid waste disposal, and power plants for steam generation and production of electric power (Noah 1995). This section describes the land that became the SRS and the historical uses of that land, focusing on agricultural and natural resource uses of the area. The SRS is located on the Upper Coastal Plain and Sandhills physiographic provinces, 30 km south of the Piedmont Plateau (figure 1.1). It is south of Aiken, South Carolina, and includes portions of Aiken, Barnwell, and Allendale Counties. Kolka et al. describe the soils and physiography of the SRS in chapter 2.

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Figure 1.1. Streams and physiography of the Savannah River Site.

Pre-European Settlement Vegetation For the past ten thousand years, oak and pine forests have dominated the SRS area. Pine species probably have dominated the uplands of the area for the past four to five thousand years (Watts 1971, 1980; Delcourt and Delcourt 1987). Views of pre- or early-settlement forests in the Central Savannah River Area (CSRA) and adjacent regions from the 1700 and 1800s help characterize the distribution of plant communities in the region (Von

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Ecology and Management of a Forested Landscape

Figure 1.2. Pine savannas probably dominated most of the uplands in the area prior to European settlement (J. Kilgo).

Reck 1733; Michaux 1805; Mills 1826; Lieber 1860; Sargent 1884; Cordle 1939; Bartram 1942; Bartram 1958; Lawson 1967; Drayton 1996). Generally, longleaf pine dominated the uplands (figure 1.2), while hardwoods, ranging from oak-hickory to cypress-tupelo forests, dominated the “clay land,” terraces, and flood plains (figure 1.3). Canebrakes in adjacent regions (Logan 1858; Lawson 1967) and the existence of remnant patches within the SRS suggest that these communities were common. Frost (1997) described composition and distribution of eleven presettlement vegetation types (figure 1.4, in color insert). He defined community types from soils, historical data, and remnant vegetation. Longleaf pine was dominant on 63 percent of SRS forests (80 percent of non-wetland areas). Swamps, bottomland, and bay forests occupied 22 percent of the site. Estimates of fire-return intervals ranged from one to three years on the Aiken Plateau to seven to twelve years on more fire-sheltered sites.

Land Use before 1950 The SRS area was used extensively by people prior to the establishment of the Site in 1951. I consider three broad time periods prior to 1951: preEuropean settlement, settlement to 1865, and 1865–1950.

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Figure 1.3. Bottomland hardwood forests occurred on the floodplains of larger streams and rivers (J. Kilgo).

Pre-European Settlement Aboriginal people entered the SRS area about 11,500 years before the present (BP), though early use was sporadic and transient and probably concentrated along bottomlands and terraces adjacent to streams (Sassaman et al. 1990; Sassaman 1993). Sustained seasonal habitation of the area began between 9,800 and 8,000 years BP, with winter residential bases along the first terrace of the Savannah River near the mouths of major tributaries. Although use of the region may have declined between 8,000 and 6,000 years BP with a warming and drying climate, aboriginal populations began to increase again around 6,000 years BP. By 3,000 years BP, hunting parties used the Aiken Plateau at least seasonally (Sassaman 1993), and between 3,000 and 2,500 years BP, occupation of the Aiken Plateau became more intensive and perennial. Population density apparently fluctuated until the mid-1400s, when a significant portion of the aboriginal population is thought to have abandoned the CSRA, probably as a result of political actions of chiefdoms outside the immediate area (Sassaman et al. 1990; Anderson 1994). A severe drought in the mid1400s also may have affected the distribution of aboriginal populations (Stahle and Cleaveland 1992; Anderson 1994). When Hernando de Soto passed through the middle Savannah River valley in 1541, he found no

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Ecology and Management of a Forested Landscape

people in five days of travel from present-day Greensboro, Georgia, to the Savannah River and beyond, further supporting the contention that significant aboriginal populations were absent in the CSRA during the two centuries preceding European settlement. Native Americans had significant impacts on the southeastern landscape through their use of fire and agriculture. They used fire extensively for hunting and land clearing, although the extent of its historical use at the SRS is not known. In contrast to fires ignited by lightning strikes, which are most frequent during the spring and summer, Native Americans set fires during the fall, winter, and spring. Alteration of fire season and frequency, especially on the more mesic part of the landscape, may represent the largest-scale impact on the landscape by Native Americans in the region (White 2004). Native American agriculture apparently did not begin in the CSRA until approximately 800 years BP (Sassaman et al. 1990), later than elsewhere in the Southeast, and its extent is not known. Areas along streams were used most extensively, corn, beans, and squash being the main crops. Land clearing involved various ways of killing trees followed by burning. Native Americans practiced field rotation but not crop rotation. Generally, aboriginal agricultural techniques were much less erosive and damaging to the soil than those associated with Europeans after settlement (Herndon 1967; Trimble 1974). The population declines during the 1400s and 1500s probably had a significant impact on fire dynamics, the area cleared for cultivation, and the level of hunting pressure, but the degree of impact is not known. Thus, the CSRA landscape first described by explorers and settlers in the late 1600s resulted from a combination of natural disturbance patterns and, to a lesser extent, those brought about by Native Americans.

Settlement to 1865 Savannah Town, 20 km (13 mi) northwest of the current SRS boundary and just south of Augusta, Georgia, became the first inland settlement in South Carolina around 1700 and served as an important trading post. Whether the proximity to Savannah Town directly affected the SRS area is not known. The earliest land plats on the present-day SRS date from the 1730s (Brooks and Crass 1991), but settlement of the area did not occur until the 1760s (Brooks 1988). Woodland cattle grazing probably occurred in the SRS between the 1730s and the 1760s, but the dates and extent are not known (Brown 1894; Meriwether 1940; Brooks 1988). The

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predominant land use before 1780 was woodland cattle grazing and scattered small-scale farming. Crop cultivation and timber cutting prior to 1780 was limited and occurred primarily along streams and terraces (Brown 1894). Planters grew rice and indigo to an unknown extent. Cowpens were common in the SRS area in the 1700s (Brown 1894; Bartram 1942). They were mostly 40 to 160-ha (100–395-ac) cleared areas with enclosures for cattle, horses, and hogs and buildings for the cowpen keepers (Dunbar 1961). Cattle also grazed the uncleared upland forests, bays, and bottomlands along streams. They used savannas in summer and cane swamps in winter. The widespread abundance of cattle likely impacted native grazers, cane and other forage plants (see the appendix for scientific names of plants), and soil erosion and water quality along streams and near cowpens. Hogs were abundant in the region (Schoepf 1911; Frost 1993), but their abundance in the CSRA was not documented until 1825 (Mills 1826). Cattle and hog abundance peaked in 1850. Hogs directly impacted the regeneration and survival of longleaf pine (Schoepf 1911) and competed with species that were dependent on hardwood mast. Several local (Mills 1826; Brown 1894) and regional (Ashe 1682; Von Reck 1733; Logan 1858; Chapman 1897; Bartram 1958; Lawson 1967) references cite an abundance of gray (Canis lupus) and red wolves (Canis rufus), panthers (cougar, Felis concolor), and “wild cats” (bobcat, Lynx rufus), as well as game species, notably white-tailed deer (Odocoileus virginianus) and wild turkey (Meleagris gallopavo). Bison (Bison bison) were also probably abundant based on their numbers above (Logan 1858) and below (Von Reck 1733) the SRS. Tarleton Brown (1894), who lived near the SRS in 1769 and later along Lower Three Runs, and Mills (1826) describe the abundance of certain predator and game species and the constant effort to eliminate the former. Logan (1858) characterized the dynamic relationship between the decline of the native fauna, the process of settlement, and the extensive peltry trade with Native Americans in the South Carolina upcountry (Piedmont). Much of this information is relevant to the SRS area. South Carolina passed laws to control or eliminate predators from 1695 to 1786 (Heaton 1972). Bison and the large predators were the first species eliminated, largely before 1800. White-tailed deer, black bear (Ursus americanus), beaver (Castor canadensis), and other species were reduced dramatically before 1800; other species such as the raccoon (Procyon lotor), opossum (Didelphis virginiana), muskrat (Ondatra zibethicus), and squirrel (Sciurus spp.) suffered declines throughout the 1800s. By 1900, the Carolina parakeet (Conuropsis carolinensis) and the passenger pigeon (Ectopistes migratorius) were extinct or

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Ecology and Management of a Forested Landscape

near extinction (Salley 1911), as was the ivory-billed woodpecker (Campephilus principalis), though due to habitat destruction as opposed to direct harvest. Establishment of grain and sawmills on SRS streams increased in the late 1700s. From 1780 to 1865, there was a dramatic increase in cotton farming, and by 1825 cotton and lumber were the primary staples in the CSRA. From 1825 to 1860, the amount of improved land (defined in the 1850 census as “only such as produces crops, or in some manner adds to the productions of the farmer”) increased from 4 percent to 31 percent of the total, so that in 1860, about 70 percent of the land on farms was woodland. Though many swamps, bays, and creek bottoms of the Upper Coastal Plain were cleared, drained, and cultivated between 1845 and 1860 (Hammond 1883), SRS swamp forests along the Savannah River in the 1840s were relatively intact, with only patchy human disturbance (Ruffin 1992). However, timber and fuelwood harvests in the upland forests were substantial before 1865. Sawmills were abundant on SRS streams (Brooks and Crass 1991; Ruffin 1992). Lumbermen released floodgates on SRS streams to facilitate transport of rafts of lumber to Savannah. The 1840 census indicates that forests within the Barnwell district were used more than those in surrounding counties, or in many areas of the southeastern United States. Demands on forests included the 1833 construction and operation of the Charleston to Hamburg (North Augusta) Railroad, Savannah River steamboats, and domestic fuelwood use.

1865–1950 Following the Civil War, a cycle of poverty, cotton dependence, and land abuse developed in the South and persisted for most of the period from 1865 to 1950. Increased pressures on the land for production of cotton and other crops, naval stores (tar, pitch, and turpentine), fuelwood, and timber left only scattered patches of relatively untouched land. A significant shift in settlement toward the upland sandhills and an increasing trend away from watercourses occurred in the SRS after 1865 (Brooks and Crass 1991), corresponding to an increased emphasis on cotton production and a decrease in available farmland. Within the CSRA, land-use intensity peaked in the 1920s with the peak in cotton production and following extensive forest cutting. Approximately 30 percent and 45 percent of Aiken and Barnwell Counties, respectively, was improved land (mostly cultivated) during

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most of the period from 1900 to 1950, with cotton and corn production accounting for the majority of cultivated land. “Shifting agriculture,” the abandonment of “worn out” land for “new” land, prevailed in the nineteenth and twentieth centuries. The abandoned land eventually reverted to forest. As a result, estimates of land under cultivation at any time mask or underrepresent the cumulative impacts of cultivation on the landscape. During this period, most of the SRS consisted of relatively small, dispersed farms, largely related to the increase in tenant farming after 1865. Tenancy peaked in 1925, and erosional land use increased with tenancy (Trimble 1974). Mechanization of southern agriculture did not occur until the 1930s and came even later to most of the farms of the SRS (Cabak and Inkrot 1996). While soil erosion increased after 1870, it was probably not extensive until after 1900. However, based on local soil descriptions for the SRS area (Carter et al. 1914; H. H. Bennett 1928; Rogers 1990), severe erosion was not common, and even moderate erosion was not extensive. Drainage and cultivation of upland depressions and bays in Barnwell County were uncommon before 1912 (Carter et al. 1914) but increased rapidly after 1930. An estimated two thirds of depression wetlands on the SRS ultimately were drained, primarily for agricultural purposes (see chapter 3). Agricultural chemical use in the SRS area increased significantly in the late 1800s with the dramatic increase in fertilizer use (South Carolina Department of Agriculture, Commerce and Industries and Clemson College 1927). With the arrival of the boll weevil in South Carolina in 1917, farmers initiated applications of calcium arsenate, and by the 1930s most CSRA farmers were “mopping” cotton crops with calcium arsenate, water, and molasses (Brunson 1930; South Carolina Extension Service 1940, 1946; A. Barker, Allendale, S. C., pers. comm.). This mixture was the predominant pesticide used in the area until the late 1940s, when farmers began using DDT and other organic pesticides for a variety of cotton pests (Boylston, Nettles, and Sparks 1948; South Carolina Extension Service 1951). Forest use, in the form of land clearing, logging, and turpentining, increased dramatically between 1865 and 1950. U.S. Census records and other records (Frothingham and Nelson 1944) suggest that naval stores production peaked in CSRA counties between 1880 and 1890 after the statewide peak in 1879. Statewide production fell sharply after 1890 but increased again after 1920. Longleaf pine was still quite prevalent in CSRA forests in the 1880s (Anonymous 1867; Hammond 1883), and loggers did not cut much of

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Ecology and Management of a Forested Landscape

the river swamp until about 1900 (Fetters 1990). Between 1910 and the early 1930s, extensive railroad logging occurred within the SRS. At least nine companies logged the SRS with at least 22 km (14 mi) of rail line along the swamp, 40 km (25 mi) along Upper Three Runs, and unknown amounts along other streams. Between 1880 and 1925, the area of woodland on farms decreased from 65 percent to 33 percent. By 1938, logging had impacted 70 percent of the Savannah River swamp with additional operations occurring between 1938 and 1950 (Mackey and Irwin 1994). In the late 1940s, sawtimber and pulpwood harvests throughout Aiken and Barnwell Counties were extensive (McCormack 1948). Other significant drains on forest resources included harvests for fencing, fuelwood, and the railroads. Use of the yellow pines and other species as fuelwood continued until the 1890s, but nationally and regionally the railroads’ impact peaked in the 1880s. Initial clearing for construction alone yielded an estimated 3 to 12 ha of cleared line per kilometer of rail (11–48 ac per mile; derived from Derrick 1930). Within the SRS, rail lines were built after the Civil War. The railroads brought increased use of longleaf pine and swamp forests, creating new land for crops and eventually creating settlements and towns, from which many agricultural and timber products flowed. The rather rapid decline of longleaf pine during the late nineteenth and early twentieth centuries resulted from a combination of factors, including hogs, destructive wildfires, and naval stores activities (Ashe 1894). Hog saturation densities in Barnwell County were high enough between 1840 and 1900 to severely impact longleaf pine establishment (Frost 1993). A decline in fire frequency after 1880, related to passage of stock laws, further impacted establishment of longleaf pine. After 1880, pressures on the land from agriculture and wood use, coupled with fire suppression efforts of the 1930s, drastically reduced the once extensive longleaf pine forests in the SRS and throughout the rest of the South.

Land Condition in 1951 and 2001 After the Atomic Energy Commission acquired the SRS in 1951, it authorized the U.S. Forest Service to manage most of the land and to act as consultant to the AEC and the DuPont Company, the project contractor (Savannah River Operations Office 1959). Much of the site had been cut repeatedly, and the timber was of little value (figure 1.5). A 1951 forest inventory conducted for a real estate appraisal classified about 48,724 ha (120,400 ac) as forest land, including 25,643 ha (63,365 ac) as

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Figure 1.5. Cut-over condition of much of the Savannah River Site at the time of government acquisition (U.S. Forest Service files).

pine, 10,296 ha (25,443 ac) as hardwood, 11,021 ha (27,233 ac) as swamp, and 1,764 ha (4,358 ac) as plantation (U.S. Army Corps of Engineers 1951). The remaining 32,265 ha (79,727 ac) were in agricultural land. These figures include existing roads, buildings, and other infrastructure and therefore overestimate actual vegetated areas. Recent analysis (Sumerall and Lloyd 1995; White 2004) of an orthorectified mosaic of 1951 aerial photos (figure 1.6, in color insert) yielded results comparable to the inventory appraisal and estimates by the Savannah River Operations Office (1959). Agriculture accounted for 38 percent of SRS land. Most of this was cropland or recently plowed ground. The majority of the uplands were in agricultural fields and bare ground. The two forested land classes consisted of “forest,” which represented mostly intact forest, much of which was distributed along streams and the Savannah River (44 percent), and “regenerating forest,” which represented regenerating woody vegetation from abandoned agricultural land and cutover forests (18 percent). The initial focus of management was to reforest abandoned farmland, and by 1960, the Forest Service had planted 24,000 ha (59,304 ac; see chapter 3 for details). Forested land increased dramatically between 1951 and 1988 (White and Gaines 2000). In 2001, virtually all of the SRS was

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Ecology and Management of a Forested Landscape

forested; only 12 percent of the forest stands were less than ten years old, and 72 percent were more than thirty years old. Satellite imagery of the region illustrates the impacts of reforestation of the SRS (figure 1.7, in color insert). The green, forested SRS contrasts sharply with the surrounding landscape, dominated by agriculture and urbanization.

Industrial Operations and Current Land Use John I. Blake, John J. Mayer, and John C. Kilgo The management of natural resources at the Savannah River Site (SRS) has been variously executed over the years to meet conservation and restoration objectives, to provide research and educational opportunities, and to generate revenue from the sale of forest products. However, these management activities have been implemented under the constraints imposed by the Site’s nuclear mission and the objectives for which the SRS was established. This management challenge has been further complicated by the vast area encompassed by the Site, as well as the complex spatial mosaic of operational facilities and natural features. This section provides a general description of both the operational infrastructure and the land-use framework within which natural resource management activities occur.

SRS Background and Operations The SRS is one of several government-owned, contractor-operated sites within the U.S. Department of Energy’s nuclear defense complex. It is managed as a controlled area with limited public access. It was constructed during the 1950s to produce basic materials (e.g., plutonium-237 and tritium) used in nuclear weapons. Responsibility for these activities was initially assigned to the Atomic Energy Commission, whose mission was later assumed by the Department of Energy. Following the end of the Cold War, the Site’s mission changed to stewardship of the nation’s nuclear weapons stockpile, nuclear materials, and the environment (Mamatey 2004). Activities associated with the nuclear mission at SRS occur in several industrialized or developed areas located around the site. There are five nuclear production reactors; two chemical separations facilities; a heavy water extraction plant; a nuclear fuel and target fabrication facility; a tritium extraction facility; waste processing, storage, and disposal facilities;

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and various administrative support facilities. The production reactors, the heavy water extraction plant, and the nuclear fuel and target fabrication facility are no longer operational. The last reactor was shut down in 1988. Several of these latter facilities have been decommissioned, and the remainder are scheduled to be decommissioned by 2026 (Austin, Noah, and Nelson 2003). SRS facilities are located in twenty separate developed areas around the site, which encompass a total of 1,781 ha (4,403 ac). The administrative areas are situated around the periphery of the site, while the industrialized operations areas (e.g., nuclear reactors, separations and waste management facilities) are in the inner core of the 803-km2 (310-mi2) footprint, with sufficient buffer lands to protect both the surrounding communities and the security of these classified operations (figure 1.8, in color insert). Additionally, remote facilities, less than 1 to 2 ha (1–5 ac) in size, are scattered around the site. They include power substations, sanitary wastewater treatment facilities and lift stations, cooling water intake and pump stations, field laboratories, maintenance buildings, and various security facilities. Perimeter security barricades control personnel and vehicle access. The infrastructure necessary to support these various administrative and operations areas is massive. Site utilities provide electricity, steam, cooling water, domestic water, service water, and sanitary waste treatment. The SRS has an extensive internal transportation infrastructure, which consists of approximately 225 km (140 mi) of primary roads and 2,253 km (1,400 mi) of secondary roads (including logging roads and jeep trails). Recent traffic flow on primary roadways has been in the thousands of vehicles per hour during periods of worker shift change. The SRS has a railway system consisting of approximately 96 km (60 mi) of track. It also has used the Savannah River to transport large, heavy loads to the site. The various pipelines, transmission lines, roads, and railways all have maintained rights-of-way associated with them (Noah 1995). Buffer zones between industrialized areas and surrounding undeveloped habitats are minimal (figure 1.9). Most transitions are abrupt, with maintained lawns or parking lots ending at the forest edge. Due largely to the close proximity of industrialized and undeveloped areas, the industrialized areas are used by various wildlife species. The presence of a number of medium-sized species (e.g., opossum, eastern cottontail, gray fox, and raccoon) within facility areas demonstrates that perimeter fences do not effectively deter wildlife movement. Mayer and Wike (1997) documented 153 species in and around developed portions of the site. However, they considered most (58.3 percent) uncommon in these areas, and

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Ecology and Management of a Forested Landscape

Figure 1.9. Aerial view of a developed area and surrounding forest on the Savannah River Site (Westinghouse Savannah River Co. files).

introduced or invasive species made up 50 percent of the abundant species. Foraging and feeding were the most commonly observed activities. Of the eight subhabitats surveyed, landscaped areas away from buildings and structures were the most heavily used. Potential impacts to humans from such urban wildlife include contaminant transport, physical injury, disease transmission, and destruction of property. Potential impacts to wildlife in these areas include physical harm and contaminant exposure (Mayer and Wike 1997). In an effort to fulfill its nuclear operations in a safe, secure, and environmentally responsible manner, the SRS has operated an extensive environmental monitoring program since 1951. Both on-site and off-site locations and media are monitored for potential impacts. Monitoring programs cover a suite of potential contamination pathways, including surface water, groundwater, drinking water, ingestion, contact, and air.

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Annually, thousands of samples (air, water, soil, sediment, food, vegetation, and animal tissue) from both within and around the site are taken to support different analyses, and the potential human dose impacts are calculated for the different pathways. In 2003, the estimated dose to the maximally exposed individual from all pathways was 0.19 millirem (mrem; Mamatey 2004), which is 0.05 percent of the dose (360 mrem) received annually by people from natural and other manufactured sources of radiation (e.g., x-ray, television; Arnett and Mamatey 2000). Screening of both aquatic and terrestrial biota doses for 2003, the most recent year available, resulted in all sampled sites passing the pathway screening (Mamatey 2004). The SRS has significant social and economic effects on the area outside of its boundary. It contributes to South Carolina and Georgia through employment and purchasing and through educational, research, technology transfer, business development, and community assistance programs. The site is located in the Central Savannah River Area, consisting of eight counties in South Carolina and Georgia. The region contains eight county governments and thirty-eight incorporated municipalities. SRS employment has varied over the life of the Site, with a maximum of 38,582 employees during the peak construction period in 1952. During the early 1990s, the SRS was the largest single employer in South Carolina (Reed et al. 2002; Grewal and Noah 2004). However, employment has declined in recent years with the Site’s reduced post–Cold War missions (figure 1.10). Stewardship plans for the SRS have been developed for the next fifty years. In the near term, work will continue to improve environmental quality, clean up legacy waste sites, and manage any future waste produced from Site operations. This effort will include the construction of new facilities, retooling of existing Site facilities for new missions, and reconfiguration of the Site to a form that is more conducive to meeting mission requirements. In the decades ahead, SRS will consolidate its functions toward the center of the site. As new missions are funded, facilities will be placed near areas of current industrialization to minimize maintenance costs, infrastructure needs, and developmental and environmental impacts. Natural resource management is an integral component of the SRS Long Range Comprehensive Plan (U.S. Department of Energy 2000). Specifically, the plan defines three natural resource goals: demonstrate excellence in environmental stewardship; provide natural resource information critical to the Department of Energy’s science base; and provide cost-effective, flexible, and compatible programs to support SRS missions.

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Ecology and Management of a Forested Landscape

Figure 1.10. Size of the workforce on the Savannah River Site, 1987–2003.

Current cleanup efforts at many Department of Energy sites, including SRS, cannot restore those federal lands to acceptable levels for unrestricted public use. This is due in part to the nature of the contamination and the lack of proven cleanup and treatment technologies. Some hazards may require attention for many centuries. Consequently, long-term stewardship will be needed at those sites to ensure that the selected remedies will remain protective for future generations (U.S. Department of Energy 2000).

Natural Resource Management Because the SRS conducts natural resource management within the framework of several land-use areas (see figure 1.8), knowledge of the objectives for those areas is important in understanding SRS land management. The SRS Long Range Comprehensive Plan (U.S. Department of Energy 2000), the Land Use Baseline Report (Noah 1995), and the Natural Resource Management Plan (U.S. Department of Energy 2005) provide overviews of land-use conditions, strategies, and activities. More detailed information on specific management objectives and practices within particular zones can be found elsewhere (NUS 1984; Davis and Janecek 1997; Edwards et al. 2000; Caudell 2000). Here we provide general background information on natural resource management in the major land-use areas and the rationale for partitioning the site.

The Savannah River Site, Past and Present

17

The various programs and entities with land-use areas include the redcockaded woodpecker (Picoides borealis) management program, the Crackerneck Wildlife Management Area and Ecological Reserve, and the Department of Energy Set-Aside Program. Although other endangered and threatened species occur on SRS, the red-cockaded woodpecker recovery program influences the largest portion of the landscape (Edwards et al. 2000). About two thirds of the upland forest areas are managed for this species and for the associated fire-maintained savanna conditions that support a great diversity of species. In the mid-1980s, the first woodpecker management plan delineated the SRS roughly as a donut shape, with the outer perimeter as the recovery area and the core containing the industrial areas. In 1997, a new plan detailed the current red-cockaded woodpecker habitat management areas (see figure 1.8). Primary factors considered from a landscape perspective included minimizing smoke problems from prescribed burning, optimizing savanna restoration opportunities through compatibility with ecological land classification, increasing management flexibility, and retaining prime industrial development sites. The plan incorporated the Department of Defense concept of including a “supplemental habitat management area” where lower woodpecker population densities are accepted to achieve greater flexibility. The woodpecker management plan provides specific guidelines on the kind and amount of timber harvest, development, and other activity allowed in each zone (Edwards et al. 2000). Within the industrial core or “Other Use Area” (figure 1.8) are most of the original industrial facilities. Infrastructure developments that dissect the area heavily impact wildlife (Mayer and Wike 1997) and other natural resources. They include transportation, power, and communications facilities; monitoring equipment; soil and groundwater closure projects; and support facilities. In order to minimize mission conflicts, there is a need to maintain industrial management flexibility and to limit natural resource goals in this zone. However, at least one population of an endangered plant, numerous sensitive species, and considerable wetland habitat occur near the industrial facilities. The South Carolina Department of Natural Resources, in conjunction with the U.S. Department of Energy, manages the Crackerneck Wildlife Management Area and Ecological Reserve primarily as wildlife habitat to enhance recreational hunting, fishing, and nonconsumptive use (Caudell 2000). Objectives are similar to those on many state lands and wildlife management areas. The Crackerneck area encompasses about 4,450 ha (11,000 ac) of wetland and mesic land with predominately pine forest,

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Ecology and Management of a Forested Landscape

bottomland hardwood, and cypress-tupelo swamp habitats. Prior to SRS establishment, agriculture and logging activities heavily impacted this zone. No industrial facilities exist within it. Forest and wildlife management activities include traditional practices designed to enhance wildlife habitat for game species, such as frequent burning, maintenance of food plots, thinning of pine stands, creation of edge habitat, and protection of mast-producing oaks. The Savannah River swamp and the Lower Three Runs corridor are designated as separate zones. Resource management objectives are primarily wetland protection, access control, and minimization of contaminated sediment movement. Frequent flooding and wet soils limit access. Although logging impacted these areas prior to 1951 and reactor operations after 1951, limited timber harvesting or silviculture still occurs. Management activities that occur often include restoration programs, such as the Pen Branch restoration project (see chapter 3). The Department of Energy Set-Aside Program is implemented through designated land-use areas that cover about 5,665 ha (14,000 ac) in multiple parcels. Activities are restricted to nonmanipulative research and monitoring (Davis and Janecek 1997). A wide range of land uses, including logging, impacted the individual areas prior to 1951, but most have suffered relatively minimal disturbance since that period. The setaside areas cover a range of ecological conditions. They include unique ecological areas such as Carolina bays and major stream systems (e.g., Upper Three Runs and Meyers Branch), as well as old fields and experimental sites. The SRS began selecting set-aside areas in the 1950s for protection from land management. In addition to meeting research and monitoring objectives, these areas provide habitat for a number of sensitive plants and animals. The streams and wetlands frequently provide baseline data on metals, radioactive elements, and organic compounds on noncontaminated sites and serve as reference areas for assessing biological impacts from industrial facilities. Identification of SRS land-use area objectives and boundaries, as well as evaluation of activities compatible with those objectives, is a continually evolving process. Land management objectives must not compromise the evolving missions of the Site. In addition, land management activities on site, as elsewhere, are subject to applicable federal laws and regulations governing land use. While these varied objectives and constraints present a challenge to land management on SRS, they are designed to allow for compatibility between the primary SRS missions and the responsible stewardship of the vast natural resources of the site.

2

r

The Physical Environment Climate and Air Quality John I. Blake, Charles H. Hunter, Jr., and Bruce A. Bayle

Soils and Geology Randall K. Kolka, Gary Sick, and Bobby McGee

Water Resources Randall K. Kolka, Cliff G. Jones, Bobby McGee, and Eric A. Nelson

Climate, soils and topography, and water constitute the physical environment of any area and serve as the natural framework in which terrestrial and aquatic plants and animals must function. In the first section of this chapter, “Climate and Air Quality,” John Blake et al. describe the climate of the SRS as humid subtropical, with a mean annual temperature of 18°C (64°F) and a mean annual precipitation of 1,225 mm (48.2 in). They present trends and ranges in precipitation, temperature, and relative humidity and discuss conditions that create inversions or fog or affect atmospheric stability. Lightning, wind, storms, and other disturbances, as well as acid deposition and ground-level ozone concentrations, are considered for their impacts on natural resources. In the second section, Randall Kolka et al. describe the soils and geology of the SRS. The topography ranges from gently rolling to flat, and elevation ranges from 20 m to 130 m (66–427 ft) above sea level. Soils on the uplands are sandy. Intensive farming prior to SRS establishment significantly impacted 19

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Ecology and Management of a Forested Landscape

the soils of the area. Seven soil associations occur on the SRS: ChastainTawcaw-Shellbluff, Rembert-Hornsville, Blanton-Lakeland, Fuquay-BlantonDothan, Orangeburg, Vaucluse-Ailey, and Troup-Pickney-Lucy. The authors discuss the physical and chemical properties of upland and wetland soils and describe soil restoration and watershed maintenance efforts at SRS. Kolka et al. then describe the streams, waterbodies, and groundwater resources of the SRS in the third section, “Water Resources.” Wetlands and aquatic systems occupy more than 20 percent of the SRS, and nearly all drain to the Savannah River. After discussing general stream hydrology and chemistry, the authors describe characteristics of the major streams, impoundments, and isolated wetlands. Streams include the Upper Three Runs–Tinker Creek system, Beaver Dam Creek, Fourmile Branch, Pen Branch, and the Steel Creek–Meyers Branch system. Major impoundments include Par Pond and L Lake. Isolated wetlands include 343 Carolina bays and depression wetlands.

Climate and Air Quality John I. Blake, Charles H. Hunter, Jr., and Bruce A. Bayle The Savannah River Site (SRS) conducts intensive meteorological data collection, climate analysis, and modeling of the atmospheric transport of air pollutants to support safety, public health, and facilities design (Hunter 1999). This information and expertise provide resource managers and scientists with unparalleled capability. Climate is defined as the statistical weather characteristics of an area. These include such variables as average precipitation, frequency of extreme events, diurnal temperature range, number of frost-free days, and storm occurrence. In combination with soils and topography, climate establishes the natural environmental framework for both terrestrial and aquatic plants and animals. Resource management practices—whether aimed at conservation, restoration, research, exotic pest management, stream monitoring, harvesting, road construction, fire management, or erosion control—must take climatic factors into consideration when evaluating alternatives. Climate influences the physical range or geographical limit of many plant and animal species and associated communities (Barbour and Billings 1988). In part, those limits determined the natural assemblages of plants and animals prior to European settlement and now determine those species that can potentially be restored, managed, and sustained at the SRS. For example, slash pine (see appendix for scientific names) is no

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longer planted here because the natural northern limit for that species is south of the SRS. While it survived well initially, experience over the last fifty years has shown it to be more susceptible to ice storms and stem diseases than native species such as loblolly, longleaf, and shortleaf pine. In contrast, although the SRS is at the edge of the range of the American alligator and the gopher tortoise, it is within their historical ranges and should be able to support viable populations of those species.

General Description The climate of the SRS is humid subtropical with a mean annual temperature of 18°C (64°F) and a mean annual precipitation of 1,225 mm (48.2 in). Geographical position heavily influences the climate. The SRS is approximately 160 km (100 mi) from the Atlantic Coast and a similar distance from the mountains. It is south and east of the Appalachian Mountains, which provide protection from colder and drier polar air masses that penetrate the region. As a result, the SRS rarely experiences snow or icing conditions compared with areas farther north. Because the “Bermuda high” pressure (Atlantic subtropical anticyclone) system generally weakens in the fall and winter, air masses that dominate during that period are drier and cooler. During the summer and early fall, because of the proximity of the SRS to the coast, the persistent Bermuda high dominates weather conditions, and temperatures are often greater than 32°C (90°F) with high humidity. These warm, humid conditions result in frequent afternoon thunderstorms, lightning, and occasional tornadoes or tropical storms.

Precipitation Important precipitation variables include monthly mean precipitation and extremes, the maximum precipitation and its recurrence interval, and the spatial variability and distribution of precipitation events. While mean annual precipitation is approximately 1,225 mm (48.2 in), extreme droughts occurred in 1954 (732 mm, or 28.8 in) and 2001–2002 (915 mm, or 36.0 in), and extreme wet years occurred in 1964 (1,866 mm, or 73.5 in) and 1972 (1,625 mm, or 64.0 in). According to monthly precipitation characteristics from 1952 to 2001 (table 2.1), precipitation tends to be distributed somewhat evenly throughout the year at SRS, but April, May, October, and November are typically drier than other months. In contrast, coastal regions in the South tend to have peak precipitation

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Ecology and Management of a Forested Landscape

Table 2.1 Mean monthly rainfall (depth in equivalent mm) and extremes for the 773-A area at the Savannah River Site for the period 1952–2001 Max Month Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Total

Min

Mean

Depth

Year

Depth

111.8 110.5 124.0 82.6 93.7 115.8 130.8 123.7 103.6 73.9 66.3 88.1 1225

254.5 202.4 278.4 208.3 276.8 291.6 291.6 313.4 221.2 498.3 197.6 242.6 1866

1978 1995 1980 1961 1976 1973 1982 1964 1959 1990 1992 1981 1964

22.6 15.5 23.1 14.5 5.1 22.6 22.9 26.4 12.0 0.0 5.3 11.7 732

Year 1981 2000 1995 1972 2000 1990 1980 1963 1985 1963/2000 1958 1955 1954

Source: Savannah River Technology Center, Atmospheric Technologies Group.

periods during the summer and somewhat drier winters. The variability in monthly precipitation is equally important. Maximum precipitation is 2 to 2.5 times the mean, whereas the minimum is as little as 10 to 20 percent of the mean. October has a maximum of 498 mm (19.6 in) and a minimum of 0 mm. On average, about seventy-six rain events each year have precipitation above 2 mm (0.08 in), which is the estimated canopy retention capacity for forest vegetation surfaces. Precipitation events below that amount will generally not rewet the soil. Events greater than 20 mm (0.8 in) in a twenty-four-hour period are fairly common, occurring an average of twenty times per year, and rain greater than 50 mm (2.0 in) can be expected at least once a year. The SRS region has experienced at least one one-hundred-year precipitation event in the last fifty years (table 2.2). Precipitation events of more than 100 mm (3.9 in) per twenty-four-hour period can be expected every five to ten years. Spatial variability in precipitation is also an important climate characteristic. Spatial gradients of precipitation often exist in mountainous terrain. At SRS, no such gradient is evident, either in total rainfall or seasonal means, but there is tremendous spatial variation in precipitation from individual storms. For example, over a seven-year period, measure-

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Table 2.2 Predicted extreme precipitation recurrence estimates (mm) by accumulation period and observed extreme total precipitation received in the Savannah River Site region, August 1948–December 1995 Accumulation period

Predicted extremes Recurrence interval (yrs) 10 25 50 100 1000 Observed extremes Columbia, SC Augusta, GA SRS

3-hour

6-hour

24-hour

48-hour

83.8 101.6 116.8 129.5 188.0

91.4 111.8 127.0 144.8 210.8

127.0 154.9 175.3 198.1 292.1

165.1 200.7 218.4 238.8 NAa

127.8 108.0 132.1

134.4 114.3 147.3

194.6 217.7 187.7

NA 283.2 259.1

Source: Savannah River Technology Center, Atmospheric Technologies Group. a Not available.

ments at gauging stations on SRS had a mean precipitation of 6.8 mm (0.3 in) and an average standard deviation among locations of 4.4 mm (0.2 in), or approximately two thirds of the mean. Distance between locations and season determines reliability of individual storm precipitation measurements. Variability among measurements was less than 10 percent for observations within 0.5 to 1 km of each other during summer, but about 60 percent for measurements 2 to 5 km apart. In winter, comparable values were less than 5 percent and about 20 percent.

Temperature and Humidity The SRS experiences a range in average temperature, extreme high and extreme low temperatures, and corresponding minimum, maximum, and average humidity (table 2.3). Data over a thirty-seven-year period indicate climate ranges, but greater extremes are expected over longer periods of record. From June through September, extreme high temperature can exceed 40°C (104°F). Below-freezing temperatures can occur from late October through early April, but extreme low temperatures of –19.4°C (–3°F) and –13.9°C (7°F ) were observed in January and December, respectively. The pattern of humidity indicates the shift in air masses that

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Ecology and Management of a Forested Landscape

Table 2.3 Ranges for monthly mean, monthly high, and monthly low temperature and monthly mean, maximum, and minimum relative humidity, 1964–2001, from A Area at the Savannah River Site Temperature range in °C Month January February March April May June July August September October November December

Average

High

1.7–12.8 4.4–12.8 10.0–18.3 15.6–21.1 18.3–26.7 23.9–29.4 26.7–29.4 23.9–29.4 21.1–26.7 15.6–23.9 10.0–18.3 4.4–12.8

13.3–30.0 16.6–30.0 23.3–32.2 28.3–37.2 31.1–37.2 33.9–40.6 33.9–41.6 32.2–41.6 32.2–40.0 27.8–35.6 22.2–31.7 18.9–27.8

Low (–19.4)–0.6 (–11.1)–0.0 (–11.6)–4.4 (–1.7)–7.2 3.3–12.2 8.9–21.1 14.4–21.1 13.3–20.6 4.4–18.3 (–2.2)–7.8 (–7.8)–3.9 (–13.9)–(–1.7)

Percent humidity Average 70 65 71 56 63 75 75 78 78 74 70 70

Minimum Maximum 51 44 40 36 40 44 47 50 48 45 46 48

86 84 86 88 93 95 96 97 93 90 87 91

Source: Savannah River Technology Center, Atmospheric Technologies Group.

dominate the SRS over the year. Humidity is generally highest in midsummer; less humid periods in the spring and fall correspond to months with lower than average precipitation.

Evapotranspiration and Soil Water Deficits Evapotranspiration (ET) represents the combined amount of water lost to the atmosphere by surface evaporation from soils and transpiration from vegetation surfaces. It is important for terrestrial vegetation because it represents the amount of water that precipitation must replace during a given period to prevent a soil water deficit. A deficit period during a drought can reduce growth and cause mortality. This relationship is especially important for vegetation with poorly established roots systems, such as newly planted seedlings, or vegetation growing on very sandy soils with limited water-holding capacity. ET also regulates the seasonal cycle of wetting and drying in isolated wetlands, bottomland forests, and swamps. As it increases, soils dry and open water is reduced. The average monthly and daily open-pan evaporation for Blackville, South Carolina, provides an index of the potential ET (table 2.4). Total annual pan evaporation is approximately 1,448 mm (57 in), or slightly

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Table 2.4 Historical average pan evaporation at the Edisto Experiment Station, Blackville, South Carolina, 1963–1992 Pan evaporation (mm) Month January February March April May June July August September October November December

By month

By day

48 67 112 151 174 188 191 164 132 103 67 51

1.53 2.39 3.62 5.02 5.62 6.27 6.16 5.28 4.41 3.33 2.24 1.64

Note: No pan coefficient (e.g., 0.8) adjustment has been applied to these values.

more than the average rainfall of 1,225 mm (48.2 in). Pan evaporation in summer is two to three times the winter rate. In SRS forests, actual ET follows calculated ET, using the Priestly-Taylor method (Rebel 2004). Combining actual ET by closed forest vegetation with precipitation records and the water-holding capacity of a typical soil (Dothan) yields an estimate of the average soil water deficit at SRS. Although rainfall tends to be uniformly distributed throughout the year, the actual ET from April through September results in a seasonal deficit of about 485 mm (19 in). Measurable deficits also occur in the fall during extreme droughts such as in October and November of 2001.

Atmospheric Stability, Inversions, and Fog Atmospheric stability and the formation of inversions help predict dispersion of smoke from prescribed burning and occasional wildfires. The combination of fog and smoke produces extremely limited visibility and hazardous conditions on public roads. Augusta, Georgia had heavy fog about thirty days per year from 1951 to 1995. Fog occurred about three days per month in the fall and winter. Stable atmospheric conditions occur when the temperature change with elevation in the atmosphere is more than 0.1°C per 30 m (more than 1.8°F per 100 ft), with little wind.

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Ecology and Management of a Forested Landscape

Unstable conditions occur when the temperature change is less than –0.5°C per 30 m (less than 0.9°F per 100 ft), in moderate winds. The latter conditions favor the transport and dispersion of pollutants, like smoke, away from populated areas. Inversions occur when temperature increases with height above the ground, preventing mixing and dispersion of smoke or other emissions. Elevation at the base of the inversion in the atmosphere defines the mixing height. This elevation varies diurnally and seasonally. Annually, the average mixing height in the early morning is about 380 m (1,246 ft) and in the afternoon is about 1,500 m (4,921 ft). The elevation of the afternoon mixing height ranges from 1,100 m (3,609 ft) in winter to 2,000 m (6,562 ft) in summer, on average. In Georgia and South Carolina, inversions within 457 m (1,500 ft) of the ground happen on about 70 percent of the nights during the year (Langley and Marter 1973). This observation has been confirmed by meteorological studies with data from towers at SRS (Lavadas 1997).

Lightning, Wind, and Disturbance Natural disturbances linked to climatic phenomena are important factors controlling the ecology and management of natural resources (Pickett and White 1985). Design of the recovery efforts for the endangered redcockaded woodpecker must consider the occurrence of these events (Hooper and McAdie 1995). Wildfires, lightning, hail, tornadoes, hurricanes, strong winds, ice glazing, flooding, and catastrophic insect outbreaks all create early successional or open habitat. These events cause vegetation mortality that allows other plant and animal species to develop. Many species native to SRS depend on natural or anthropogenic disturbances to sustain their populations, most notably fire-maintained savanna communities (see chapter 4). Storm phenomena occur in every month at SRS (table 2.5). Thunderstorms are the most frequent recurring event, with a peak in midsummer. Lightning, high rainfall, hail, and strong winds disturb forested and wetland areas. Lightning frequently kills one or more trees directly, leading to bark beetle attacks that cause additional tree mortality (Outcalt 1999). These spots provide gaps in the forest canopy. Approximately 0.04 lightning strikes per hectare per year occur at SRS and cause mortality in mature longleaf pine of 0.2 trees per hectare per year, a significant mortality source in rotations of 80 to 120 years. High winds not associated with tornadoes or hurricanes can also cause significant blowdown and top

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Table 2.5 Monthly occurrences of tornadoes, hurricanes, thunderstorms, and snow or ice in the Savannah River Site (SRS) region

Month January February March April May June July August September October November December Total

Tornadoes (number)a 14 17 21 26 27 14 13 18 8 7 27 8 200

Hurricanes (number)b 0 0 0 0 0 1 2 11 18 4 0 0 36

Thunderstorms (days)c 0.8 1.7 2.6 3.9 6.3 9.7 13.1 10.0 3.5 1.3 0.8 0.7 54.4

Snow/ice (max depth, mm)d 66 (1992) 356 (1973) 28 (1980) 0 0 0 0 0 0 0 trace (1968) 25 (1993)

Source: Savannah River Technology Center, Atmospheric Technologies Group. a Includes all tornadoes (F-0 to F-5) in a 2-degree square centered on SRS, 1951–1996; 95 percent were between F-0 and F-2. b Includes all hurricanes observed in South Carolina, 1700–1992. c Average days per month for Augusta, Georgia, 1951–1995. d Maximum depth of snow and ice pellets observed in Augusta, Georgia, 1951–1995.

breakage in trees. In November 1995, high winds blew down the estimated equivalent of one million board feet of trees at SRS. Damage was most severe on old-field–planted pines, whose agricultural plow layer restricted taproot development (Kormanik, Sung, and Zarnoch 1998). Hail damage can also be significant. A hailstorm in 2002 seriously damaged a large stand of trees on SRS near Jackson, South Carolina. Nine tornadoes have been recorded in close proximity to SRS since operations began in 1951. In 1989, a tornado swept through the southern portion of SRS, creating a path 26 km (16 mi) long and destroying almost 500 ha (1,235 ac) of forest. Four F-2 tornadoes struck forested areas during March 1991. Tornadoes occur in all months, but most are in March, April, May, and November. Hurricanes also cause significant damage in South Carolina, but because the SRS is inland, winds associated with tropical weather systems usually diminish below hurricane force before reaching SRS. While snowfall is uncommon, ice glazing does occur, and the

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Ecology and Management of a Forested Landscape

loading on branches and stems causes significant damage to tree crowns. The weight of 1 cm (0.4 in) of ice, which has a recurrence frequency of ten to twenty-five years, is enough to cause severe tree breakage. Ice glaze leaves a legacy of forked trees and bent stems.

Air Quality Air quality can impact natural resources, including soils, vegetation, aquatic organisms, and surface waters at SRS. Of the six criteria pollutants established by the U.S. Environmental Protection Agency (EPA) under the Clean Air Act, four are of primary concern to natural resource managers because of their effect on terrestrial and aquatic ecosystems: sulfur dioxide (SO2 ), nitrogen oxides (NOx), ozone (O3), and particulate matter (PM). Air quality in the Central Savannah River Area is generally considered acceptable with respect to current levels and trends of these four pollutants. From 1995 to 2000, South Carolina and Georgia state monitors registered almost no exceedances of the National Ambient Air Quality Standards (NAAQS) within or near the SRS (Aiken, Allendale, and Barnwell Counties, South Carolina; and Richmond County, Georgia). The one exception was in Richmond County, which exceeded the NAAQS for the O3 one-hour standard once in 1995 (U.S. Environmental Protection Agency 2001a).

Acid Deposition Acidifying compounds that are suspended in the atmosphere, such as sulfates (SO4 ), nitrates (NO3), and ammonium (NH4), can be deposited on forests through precipitation and fog or simply by settling out of the atmosphere. Sulfur dioxide (SO2 ) and nitrogen oxides (NOx), the precursors to those acidic compounds, are emitted primarily from coal-fired power plants, industry, and the transportation sector. Acid deposition can adversely impact both soils and streams. Soils with a low buffering capacity can exhibit a depletion of calcium, magnesium, and potassium, a decrease in pH, and an increase in available aluminum (National Science and Technology Council 1998). Depletion of macronutrients can lead to growth reduction in vegetation. Soil pH levels below 4.5 can increase aluminum uptake by plants. Both low pH and aluminum are toxic to aquatic organisms and vegetation. Despite the negative impacts of NO3 deposition, that compound can benefit vegetation by providing nitrogen, an essential nutrient whose absence often limits vegetation growth

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in southeastern soils. The natural geologic parent materials, warm temperature, high rainfall, and long period of soil development in the Carolinas results in highly leached soils. In general, the upland soils of the SRS have low to moderate buffering capacity, naturally low cation exchange capacity (CEC), low pH, and low base saturation (calcium and magnesium as a percent of CEC), making them somewhat susceptible to acidification. Compared to most of the eastern United States, only moderate levels of sulfate and nitrate deposition occur within the upper coastal plain of South Carolina (National Atmospheric Deposition Program 2001). Emissions of SO2 and NOx, precursors to acidic compounds, originate primarily outside of South Carolina. Those precursors are transformed through atmospheric chemical reactions into secondary pollutants, sulfate and nitrate (SO4 and NO3), which can travel great distances from their point of origin. The SRS lies approximately midway between the closest monitoring sites at Santee National Wildlife Refuge, Clarendon County, South Carolina, and Bellville, Evans County, Georgia. The majority (43–49 percent) of both annual nitrate (7.9 kg per ha) and annual sulfate (10.7 kg per ha) deposition from rainfall occurs during summer (National Atmospheric Deposition Program 2001), coinciding with the peak for electric power demand. Sulfate deposition has been decreasing over the SRS area since approximately 1990 as a result of changes in the Clean Air Act. Nitrate deposition has remained constant since approximately 1990.

Ground-Level Ozone Ozone is a gaseous pollutant formed by a reaction between NOx and volatile organic compounds (VOC) in the presence of sunlight and warm temperatures. Ozone levels typically follow a diurnal pattern, being lowest during late night and early morning hours and highest during the afternoon. The trend in rural O3 has remained fairly constant since 1989 (U.S. Environmental Protection Agency 2001a), and the trend for the near future is expected to remain constant. NOx levels from vehicles and utilities have remained relatively constant over the past decade, and anthropogenic VOC levels have declined by 20 percent. The overwhelming majority of VOC emissions is from trees. Damage to sensitive vegetation occurs when hourly O3 exposures during the growing season are frequently above 0.05 ppm or when there are numerous hours in which O3 concentrations are greater than or equal to 0.10 ppm. However, other environmental conditions must be favorable

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Ecology and Management of a Forested Landscape

for O3 to enter a leaf. Soil moisture is perhaps the most important factor affecting O3 uptake by plants. During drought conditions, plants close their leaf stomata cells and prevent O3 from entering. Thus, damage to sensitive plants caused by O3 occurs most often during years with plentiful rainfall. The U.S. Forest Service Southern Forest Health Monitoring program annually assesses impacts of O3 to sensitive species in South Carolina. Visible symptoms do occur to varying degrees on sensitive species within the SRS. However, current research has been unable to establish that ambient O3 exposures are causing growth losses. Visible symptoms of O3 do not necessarily damage an individual species or the forest. Not all plant species have the same likelihood of damage when exposed to similar amounts of O3. For example, black cherry may suffer damage at lower O3 exposures than tulip poplar. Loblolly pine is normally considered very resistant to O3. At concentrations the SRS currently receives, we do not expect loblolly pine growth loss.

Soils and Geology Randall K. Kolka, Gary Sick, and Bobby McGee Knowledge of the soils and geology of the Savannah River Site (SRS) is critical to understanding the ecology and management of its natural resources. The geology of the site determines the topography and influences the water quality in various aquifers, as well as the transport of water, organic materials, ions, and metals to streams (Cooke 1936; Siple 1967). It is also the primary parent material for soil development. In combination with other environmental factors, soil properties influence vegetation composition and productivity (Row 1960; Whipple, Wellman, and Good 1981; Jones, Van Lear, and Cox 1984; Thompson and Lloyd 1995; Duncan and Peet 1996; Smith 2000); root disease (Witcher and Lane 1980); animal habitat; and management activities. Activities include planting and seeding, harvesting, vegetation control, fertilization, restoration, road construction, and prescribed burning (Hatcher 1957; Aydelott 1971; Wells et al. 1979; Bush et al. 1995). Various soil properties and topographic position affect the transport of nutrients, sediment, organic matter, and chemicals to wetlands and streams via surface runoff and subsurface flow (Dosskey and Bertsch 1994; Bush et al. 1995). The characteristic “blackwater” chemistry of SRS streams and isolated wet-

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lands is a consequence of the soil chemical and transport properties within the drainages (Meyer 1986).

Land-Use Impacts to Soil before 1951 Soils vary naturally across the SRS because of differences in parent material and the effects of topography, climate, organisms (plants and animals), and time ( Jenny 1941). However, a major factor affecting the soils is the recent human-induced landscape disturbance since European settlement, including a wide range of agriculture and related activities (Cabak and Inkrot 1997; White and Gaines 2000; White 2004). With the exception of narrow terraces and floodplains, SRS soils are generally poorly suited for productive farming. On the uplands, the sandy texture and low organic matter, nutrient status, pH, and cation exchange capacity limit productivity (Rogers 1990; Brooks and Crass 1991). Significant portions of the SRS are cypress-tupelo swamp and too wet for cultivation. Early farmers often practiced a form of slash-and-burn agriculture on the uplands, abandoning cleared forests after a few years (Cabak and Inkrot 1997). To improve productivity, farmers applied fertilizers such as lime, phosphates, and nitrogen to cash crops like cotton and corn. The residual effect of these practices was enhanced subsequent pine tree growth (Bennett 1956). However, because of the soil’s physical and chemical properties, surface erosion, and the reduction in organic matter during cultivation (e.g., Smith 2000), additional nutrients have been leached away or transported to subsurface clays (Odum, Pinder, and Christiansen 1982). On many sites, a residual plow layer at shallow depths of 0.5 to 0.8 m (1.6–2.6 ft) is compacted sufficiently to impede tree taproot development and enhance windthrow (P. Kormanik, U.S. Forest Service, pers. comm.). At SRS, erosion and stream sedimentation were not as serious as in the Piedmont and mountains. Caved stream banks and erosion channels, formed from concentrated runoff, contributed to stream sedimentation prior to SRS establishment (U.S. Department of Agriculture 1951), and they are still evident.

General Physiography and Geology The northern part of SRS is located within the Aiken Plateau of the Sandhills physiographic province. The southern part is within the Pleistocene coastal terraces of the Upper Coastal Plain (see figure 1.1). The topography is gently rolling to flat, and elevation ranges from 20 to 130 m (66 to 427

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Ecology and Management of a Forested Landscape

Figure 2.1. Topographic relief on the Savannah River Site. MSL = mean sea level.

ft) above sea level (figure 2.1). The Aiken Plateau has sandy soils deeply incised by stream channels. These soils range in age from 10 million to 50 million years. Slopes range from gentle (1–2 percent) to moderately steep (30–40 percent). Some upland areas, as well as bottomlands along the major streams, are nearly level. Strongly sloping areas are adjacent to major drainage ways and their headwaters. The Pleistocene coastal terraces are flat to gently rolling; the Brandywine, Sunderland, and Wicomico terraces that generally parallel the Savannah River represent successive recessions

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in sea level from ten thousand to one million years ago (Langley and Marter 1973). The oldest, Brandywine Terrace, is adjacent to the Aiken Plateau at 50 to 80 m (164–262 ft) elevation. The Sunderland Terrace lies between the Brandywine and Wicomico terraces at elevations ranging from 30 to 50 m (98–164 ft). The Wicomico comprises the current floodplain of the Savannah River at 20 to 30 m (66–98 ft) above sea level. Flat-bedded sedimentary deposits of Paleozoic, Mesozoic, and Cenozoic geologic formations underlie the SRS, but only Cenozoic-aged (Tertiary) deposits are at or near the surface (figure 2.2; Prowell 1996). The Tertiary formations are important aquifers for environmental management and environmental restoration activities, potable water supplies, and stream hydrology (Williams and Pinder 1990; Prowell 1996). Of these formations, only Paleocene deposits (65–54 million years BP) do not reach the surface at SRS, ranging from 30 to more than 90 m (98 to more than 295 ft) deep. Eocene deposits (54–38 million years BP) include the Huber and Congaree Formation (undivided), the McBean Formation, and the Barnwell Group. The Huber formation is fine to coarse, poorly sorted quartz in a matrix of white kaolin clay (Prowell 1996), whereas the Congaree formation is fine to coarse, moderately to well-sorted quartz sand in a matrix of gray kaolin clays. The Huber and Congaree Formation is approximately 15 to 30 m (49–98 ft) thick and is only at or near the surface along Upper Three Runs (Prowell 1996). The McBean Formation lies above the Huber and Congaree Formation with the basal part of the formation containing white to buff sandy limestone, calcareous sand, and dark olive-green marl deposits. Above the basal sediment, the formation contains moderately to well-sorted quartz sand and gravel. The McBean Formation is approximately 10 to 45 m (33–148 ft) thick and, like the Huber and Congaree Formation, is only at or near the surface along the Upper Three Runs drainage (Prowell 1996). The Barnwell Group, consisting of the Clinchfield Formation, Dry Branch Formation, and Tobacco Road Sand, lies above the McBean Formation. The Clinchfield Formation consists of sandy to calcareous clayey sand and is not present at the surface on the SRS. It ranges from 0 to 15 m (0–49 ft) thick and underlies other sedimentary deposits in the southeastern area of the SRS. The Dry Branch Formation contains well-sorted calcareous clays, kaolin clays, and sands and ranges from 0 to 30 m (0–98 ft) thick across the SRS, getting thicker toward the southeast. It is at or near the surface in all major SRS drainages (Prowell 1996). The Tobacco Road Sand consists of poorly to moderately sorted fine to very coarse sand and is 0 to 15 m (0–49 ft) thick, also becoming thicker toward the southeast.

Figure 2.2. Geological stratigraphy and groundwater systems of the Savannah River Site (U.S. Department of Energy 1998).

It is at or near the surface along all major drainages and extends into the uplands of the Aiken Plateau and Brandywine Terrace. Above the Eocene deposits are deposits of the Miocene (23–5 million years BP), Pliocene (5–1.8 million years BP) and Holocene periods (11,000 years BP to present; figure 2.2). Deposited during the Miocene, the Upland Unit has beds of gravel and poorly sorted sands, fine to coarse sand containing clays, and brightly colored (red, orange, yellow, or purple) massive sandy clay. From 0 to 25 m (82 ft) thick, the Upland unit is at or near the surface on most upland areas of the SRS, including portions of the Aiken Plateau and the Brandywine Terrace. Above the Upland Unit is dune sand of Pliocene age. The dune sands are eolian deposits consisting of moderately sorted medium sands devoid of clays. Dune sand deposits up to 10 m (33 ft) thick dot the landscape of SRS, becoming

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more defined in the northeast part of the site. Two alluvial deposits comprise the Holocene deposits on site. Both are fine to coarse sands intermixed in a sparse clay matrix and range in thickness from 0 to about 15 m (49 ft). The older, more highly weathered alluvial deposit is associated with the Sunderland Terrace. The younger deposit, which occurs on the Wicomico Terrace, is the current floodplain of the Savannah River.

Soil Associations Approximately fifty distinct soil types exist on the SRS. Soil scientists often combine them to develop general soil associations that show broad areas of distinctive soils, relief, and drainage. Typically, a soil association consists of one or more major soil types and several minor soils. Such associations (figure 2.3, in color insert) can be used to compare the suitability of large areas for general land uses. Seven soil associations occur on the SRS (Rogers 1990). The first two associations comprise most of the floodplain, wetlands, and bottomlands along stream terraces and the Savannah River. The last five comprise the associations of the upland Sandhills and Coastal Plain.

Chastain-Tawcaw-Shellbluff Association Located on floodplains along the larger streams, Chastain-TawcawShellbluff soils occur in depressions and remnant sloughs from old stream channels. Slopes are generally 0 to 1 percent. The association includes approximately 60 percent Chastain, 20 percent Tawcaw, 15 percent Shellbluff, and 5 percent other soils. Chastain soils are poorly drained and clayey to a depth of about 1 m (3.3 ft). Tawcaw soils are somewhat poorly drained, clayey in the upper part, and loamy in the lower profile. Shellbluff soils are well drained and loamy to a depth of about 1 m. This association constitutes about 6 percent of the SRS.

Rembert-Hornsville Association Rembert-Hornsville soils are located on stream terraces adjacent to floodplains. Slopes are generally 0 to 2 percent. The association has approximately 30 percent Rembert, 18 percent Hornsville, and 52 percent other soils. Rembert soils are poorly drained, and Hornsville soils are moderately well drained. This association constitutes about 7 percent of the SRS.

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Ecology and Management of a Forested Landscape

Blanton-Lakeland Association Blanton-Lakeland soils are located on the broad stream divides in the uplands. Slopes are generally 0 to 10 percent. The association has approximately 40 percent Blanton, 20 percent Lakeland, and 40 percent other soils. Blanton soils are somewhat excessively drained, have sandy surface and subsurfaces, and loamy subsoil 1 to 2 m (3–7 ft) below the surface. Lakeland soils are excessively drained and are sandy throughout. This association constitutes about 18 percent of the SRS.

Fuquay-Blanton-Dothan Association Fuquay-Blanton-Dothan soils are located on the broad upland ridges. Slopes are generally 0 to 10 percent. The association has approximately 20 percent Fuquay, 20 percent Blanton (see above), 12 percent Dothan, and 48 percent other soils. The soils are generally well drained to excessively well drained. Fuquay soils are well drained with a sandy surface and loamy subsoil that contains iron-rich nodules of plinthite. Dothan soils are well drained with loamy subsoil that contains iron-rich nodules of plinthite. This association constitutes about 47 percent of the SRS.

Orangeburg Association Orangeburg soils also are located on the broad upland ridges. Slopes are generally 0 to 10 percent. The association includes roughly 70 percent Orangeburg soils and 30 percent other soils. Orangeburg soils are well drained with friable loamy subsoil. These soils generally have the highest clay content and cation exchange capacity among the upland soils (Looney et al. 1990). This association constitutes about 2 percent of the SRS.

Vaucluse-Ailey Association Vaucluse-Ailey soils are located on the uplands in scattered areas around the head and sides of small drainage ways. Slopes are generally 6 to 15 percent. The association includes approximately 25 percent Vaucluse, 15 percent Ailey, and 60 percent other soils. Vaucluse soils have loamy surface and subsurface layers of less than 50 cm (20 in). Ailey soils have a moderately thick sandy surface and subsurface layer. Both soils are well drained and have a loamy subsoil with a brittle layer. This association constitutes about 10 percent of the SRS.

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Troup-Pickney-Lucy Association Troup-Pickney-Lucy soils are located on the steep slope uplands and on the floodplains along streams. Slopes range from 0 to 40 percent. The association has approximately 45 percent Troup, 10 percent Pickney, 10 percent Lucy, and 5 percent other soils. Troup soils are well drained, with a thick, sandy surface and loamy subsoil 1 to 2 m (3–7 ft) below the surface. Pickney soils are poorly drained with a thick black surface soil and are sandy throughout. Lucy soils are well drained with a moderately thick, sandy surface and subsurface layer, with loamy subsoil at a depth of 0.5 to 1 m (1.6–3.3 ft). This association constitutes about 10 percent of the SRS.

Soil Characteristics Because of the extent and importance of the wetlands on the SRS, we consider the distinct characteristics of wetland and upland soils.

Wetland Soils Wetland soils include typically flooded Fluvaquents along the Savannah River and deltas, as well as true organic soils (Medisaprists) in some of the Carolina bays and bottomland hardwood systems (Rogers 1990). The SRS contains approximately 16,000 ha (40,000 ac) of wetland or hydric soils. Carolina bays range in size from less than 0.1 ha (0.04 ac) to more than 50 ha (124 ac). Bay surface soils generally grade from well-drained sands on the exterior to sandy loams in the wetland center. A loamy to clayey horizon commonly underlies the sandy upper horizons. Bays with long hydroperiods may develop variable layers of peat on the surface (Schalles et al. 1989). Soils in bottomlands range from sandy well-drained soils at floodplain edges and in upper areas of watersheds to very poorly drained loamy and clayey soils in floodplains and stream deltas. Bottomlands with extended hydroperiods, commonly found in deltas and in some floodplains, may develop organic upper horizons of variable depth. Generally, past disturbance and the degree of flooding, inundation, and saturation of the soil dictate plant distribution and abundance more than physical or chemical properties (Whipple, Wellman, and Good 1981; De Steven and Toner 1997). On about 11,170 ha (28,000 ac) of the SRS, flooding is a hazard. Ecological (Whipple, Wellman, and Good 1981) and wetland (De Steven and Toner 1997) restoration studies have documented wetland soil properties at SRS. Dixon et al. (1997) and Schalles et al. (1989) measured

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Ecology and Management of a Forested Landscape

baseline chemical characteristics both on and off SRS. Wetland soils are highly variable, but the variables tend to align with major soil groups. In the surface, soil organic carbon ranges from 0.5 to 9.0 percent and pH ranges from 4 to 7.6. Nutrient status is generally high except in Carolina bays; for example, phosphorus ranges from 84 to 830 µg/g. Cation exchange capacity and the percent base saturation are also high, with the former ranging from 2 to 194 meq/100g. Nearly all chemical variables decrease with depth, except pH and in Carolina bays.

Upland Soils Most upland soils are Paleudults that are highly weathered, nutrient poor, and typically sandy. These soils are well drained to excessively well drained with a sandy surface layer of variable thickness over a loamy to clayey subsoil. The productivity of planted pines at SRS is directly related to the depth to the subsurface clay layer and the thickness of the surface organic horizon (Row 1960). In general, this relationship is also true for old-field vegetation (Odum 1960; Thompson and Lloyd 1995) and native communities ( Jones, Van Lear, and Cox 1984; Smith 2000). While water availability in the root zone is undoubtedly important, nutrition, particularly nitrogen, is the primary factor limiting growth on these sites (Birk 1983; McKee et al. 1986; Davis and Corey 1989; Allen, Albaugh, and Johnsen 2002). Several studies have measured physical properties of the upland soils. Surface soil texture ranges from 80 to 90 percent sand, with less than 5 percent silt and the balance in clay size particles (Odum 1960; Nutter 1979; Odum et al. 1982; Looney at al. 1990). At the lower limit of rooting for most trees, 1.5 to 2 m (4.9–6.6 ft), the clay content typically increases to 35 percent or more, with an additional 10 to 15 percent silt content, depending on the soil series (Nutter 1979). Bulk densities are normally low in the surface (1.1–1.4 g/cc) and rapidly increase to a depth of 1 m (1.6–1.8 g/cc; Davis and Corey 1989). Clays are primarily kaolinite (70–95 percent), with lesser amounts of vermiculite (1–30 percent) and minor quantities of illite (Looney et al. 1990). These soil textures generally result in very low water-holding capacity for plants during the summer. From the surface to a depth of 2 m (6.6 ft), the amount of water available to plants varies from 100 to 300 mm (3.9–11.8 in). As much variation in chemical properties exists within a given soil series as between soil series. In part, this variation comes from prior landuse history (Smith 2000), succession (Odum, Pinder, and Christiansen 1982), and amendments applied (Birk 1983; Davis and Corey 1989). In

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contrast to wetland soils, surface mineral soil has very low organic matter, which varies from less than 1.0 percent to 4.0 percent (Odum 1960; Smith 2000), or from less than 0.1 percent to 1.45 percent organic carbon (Looney et al. 1990). Similarly, pH ranges from around 4 to 6.5 at the surface with little relationship to soil series; the maximum values are less than the maximum pH in wetland soils. On the whole, cation exchange capacity (1.2–4.5 meq/100g), base saturation (0.12–0.88 percent), and most major nutrients are lower (table 2.6) than in wetland soils. However, phosphorus is high for forest sites, particularly in the subsoil, presumably due to prior agricultural fertilization (Nutter 1979; Odum et al. 1982).

Soil Restoration and Watershed Maintenance Since only 1.3 percent of the SRS drains into the Salkehatchie basin, the impacts of soil and watershed management activities at SRS largely affect the Savannah River. Watershed degradation in industrial areas is generally caused by unhealthy or poor vegetation cover (from improper maintenance) or by impermeable surfaces (rooftops, paved and gravel areas, sidewalks, and compacted areas), both of which increase storm water runoff. A forest with a fully developed overstory allows almost no storm water runoff (Williams and Pinder 1990) or sediment transport (Yoho 1980; Patric, Evans, and Helvey 1984). Replacement of forests with lawns, utility corridors, and roadsides doubles the amount of runoff. If such areas are converted to impermeable surfaces, runoff is about eleven times as great (Natural Resource Conservation Service 1986). Natural channels that carry runoff from the watershed can be overtaxed and fail. In forested areas, poor vegetation cover follows disturbances such as road construction, timber harvest, prescribed burning, and vegetation control. These activities can lead to short-term increases in stream flow, sediment, and nutrient transport (Binkley and Brown 1993). The SRS uses best management practices to minimize the impact of normal forest management activities (National Council for Air and Stream Improvement 1994). Mitigative harvesting practices such as helicopter logging, low ground pressure equipment, and restricting harvests during wet weather reduce rut formation, compaction, and erosion. The SRS has left buffer strips along streams since the mid-1970s and has reduced mechanical site preparation (see chapter 3). Managers have routinely seeded secondary roads to grass, and water bars have been installed since the 1970s (Swift 1988). The area in stabilized log-loading decks and forest roads is minimal relative to industrial sites.

Loamy sand Sandy clay loam Sandy clay loam Sandy clay loam Loamy sand Sandy clay loam Sandy clay loam Sandy clay loam Loamy sand Sandy clay loam Sandy clay loam Sandy clay loam Sandy clay loam Loamy sand Loamy sand Loamy sand

Soil texture

a

Source: Nutter 1979. CEC = cation exchange capacity.

0–23 24–81 82–117 118–152 Fuquay 0–30 31–74 75–117 118–165 Norfolk 0–18 19–53 54–89 90–114 115–170 Troup 0–25 26–75 77–257

Dothan

Series

Horizon depth (cm)

5.0 5.3 5.4 5.3 4.5 4.3 4.7 5.0 5.3 5.4 5.6 5.6 5.3 4.9 5.2 5.2

pH 1.45 0.40 0.21 0.18 0.76 0.38 0.25 0.20 0.65 0.40 0.30 0.20 0.09 1.15 0.15 0.12

Organic matter (%) 140 200 252 241 120 138 170 205 82 164 175 175 200 20 70 85

P 128 150 180 131 101 123 225 178 90 227 287 268 90 10 18 19

Ca 14 55 65 44 11 36 53 79 12 53 70 97 77 3 15 18

Mg

Total (µg/g)

Table 2.6 Chemical characteristics of selected upland soils, by depth, on the Savannah River Site

16 26 20 16 16 28 36 15 25 27 23 22 15 14 15 17

K 2.0 3.0 4.5 3.2 1.5 2.0 3.2 3.3 1.6 3.1 3.1 2.6 3.3 1.7 1.2 1.4

0.34 0.63 0.38 0.33 0.44 0.50 0.51 0.47 0.48 0.53 0.69 0.88 0.38 0.12 0.32 0.34

47 30 23 35 18 23 18 25 30 24 21 18 20 41 23 22

Total CECa % base Exchangeable (meq/100g) saturation Al (µg/g)

40 Ecology and Management of a Forested Landscape

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From a watershed perspective, forest and protected areas contribute a relatively minor amount of surface runoff and sediment compared to developed areas (National Council for Air and Stream Improvement 1994). In 1973, severely disturbed sites such as gravel pits, spoil piles, and borrow pits from construction occupied about 809 ha (2,000 ac) on SRS (Beavers et al. 1973). Although direct sedimentation impacts were localized, there were concerns that these poorly vegetated sites could cause additional erosion, channel degradation, and deposition in low areas (Aydelott 1971). Therefore, most early soil conservation efforts were aimed at revegetating these sites (Hollod and Christensen 1983). Establishment and growth of vegetation on these sites was inadequate unless the sites were ripped to reduce compaction and organic amendments such as municipal waste were applied (Berry and Marx 1980). In 1991, the restoration program shifted its focus to the legacy impacts of SRS operation and of facility developments where off-site storm water effects could not be controlled. After 1992, due to new regulations, new construction and development projects incorporated measures to manage storm water runoff, surface drainage, and vegetation cover along roads. Vegetation maintenance activities include liming, fertilization, seeding, mowing, and aeration. Annually, SRS restores about 60 ha (150 ac) and maintains about 457 ha (1,129 ac) of disturbed sites. Because of the need for rapid establishment of cover, SRS uses quick-germinating annual grasses (e.g., ryegrass, browntop millet; see the appendix for scientific names) in a mixture of seeds that includes warm-season perennials (e.g., Bahia grass, Bermuda grass) and legumes (e.g., Trifolium clovers, vetches, partridge pea). Efforts are currently underway to evaluate various native grasses.

Water Resources Randall K. Kolka, Cliff G. Jones, Bobby McGee, and Eric A. Nelson The Savannah River Site (SRS) has freshwater resources that support rich aquatic communities. Over 20 percent of the SRS consists of wetlands and aquatic systems (Bowers et al. 1997). With the exception of the far northeastern corner that drains to the Salkehatchie River (1.3 percent of SRS), all surface water on the SRS drains to the Savannah River (figure 2.4). The Savannah River watershed drains approximately 27,000 km2 (10,420 mi2), including western South Carolina, eastern Georgia, and a

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Ecology and Management of a Forested Landscape

Figure 2.4. Major streams, wetlands, and larger lakes of the Savannah River Site.

small portion of southwestern North Carolina. The SRS makes up about 3 percent of the Savannah River watershed. In its middle and lower portions, where a 27-km (17-mi) reach forms the SRS boundary, the Savannah River is broad with extensive floodplain swamps and numerous tributaries. Several groundwater aquifers exist in the Tertiary and Upper Cretaceous sedimentary deposits that underlay the site. Groundwater is an important source of flow to riparian zones, streams, and wetland depressions on SRS. Five major stream systems originate on or pass through

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the SRS (see figure 2.4). A smaller stream, Beaver Dam Creek, also originates on the SRS and ultimately drains to the Savannah River. Two large cooling water reservoirs, Par Pond and L Lake, are present in the southeastern portion of the site. A number of small artificial ponds ranging in surface area from 0.1 to 1.2 ha (0.04–0.5 ac) exist on the SRS. Some were farm ponds, constructed when the area was still under private ownership, whereas others resulted from cooling water canals or other SRS construction projects. More than three hundred isolated Carolina bays and wetland depressions (see chapter 3) exist at SRS, as well as numerous beaver ponds (Fitzgerald 1979; Snodgrass 1997). Bottomland hardwood and swamp wetlands are associated with the floodplains of the Savannah River and its tributaries.

Historical Impacts Prior to 1951 The historical impacts of post–European settlement land use on the natural streams, swamps, and isolated wetlands of the Southeast have been extensive (Mulholland and Lenat 1992). To promote navigation, several of the larger SRS streams, like Upper Three Runs, were cleared of debris in the 1850s. During the same period, numerous dams were constructed along major streams, including Upper Three Runs, Lower Three Runs, Fourmile Branch, Pen Branch, and Tinker Creek, to power sawmills and gristmills (Brooks and Crass 1991). Remnants of those dams still exist on SRS. About 162 ha (400 ac) of artificial ponds were present in 1951, generally at the headwaters of major tributaries. Logging occurred along all of the major streams and throughout the Savannah River swamp (Fetters 1990). The primary impacts of logging were altered drainage patterns that resulted from the construction of access roads, rail lines, and haul back lines, which often blocked natural channels or created new channels. Fur trapping reduced beaver populations and thereby the number of beaver ponds ( Jenkins and Provost 1964). Corralling of livestock adjacent to streams (e.g., Pen Branch) and farming in the uplands often resulted in loss of stream bank integrity and an increase in overland flow and sedimentation (Trimble 1975). Meyers Branch was dredged during the 1940s to improve drainage of the basin in an attempt to reduce habitat for malarial mosquitoes. Information about chemical inputs to these systems prior to 1951 is scarce, but DDT was used for mosquito control, arsenate insecticide was used for boll weevil control, and mercury from manufacturing facilities was discharged into the Savannah River (Gladden et al. 1985).

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Isolated wetlands were also impacted. Although the exact number is unknown, many Carolina bays were drained and farmed (Kirkman at al. 1996). Drainage reduced the hydroperiod of the bays, and farming altered the soil and vegetation. One of the largest impacts on the hydrology of SRS resulted from construction of the Strom Thurmond Reservoir on the Savannah River above Augusta, Georgia. The reservoir stabilized the flow of the river and altered the frequency, timing, depth, and duration of natural flooding of the swamp (Sharitz and Lee 1986).

Groundwater Groundwater resources of the SRS are described in detail by Clarke and West (1997, 1998). The SRS is underlain by the Atlantic Coastal Plain Hydrogeologic Province, which includes three major aquifer systems and three confining units, all underlain by the Appleton Confining System (see figure 2.2). The Appleton Confining System separates the Atlantic Coastal Plain Hydrogeologic Province from the underlying Piedmont Hydrogeologic Province. The Atlantic Coastal Plain Hydrogeologic Province consists of unconsolidated sediments of Late Cretaceous and Tertiary origin. The uppermost unconfined Floridan Aquifer System includes the Steed Pond, Upper Three Runs, and Gordon Aquifers and ranges from 0 to 40 m (0–131 ft) below the surface of SRS (U.S. Department of Energy 1999). It is the primary source of groundwater contributing to streams (U.S. Department of Energy 1999; Arnett and Mamatey 1996). All three Floridan Aquifers are recharged directly through precipitation where they are at or near the surface and through leakage from both underlying and overlying aquifers. The Floridan Aquifer System is generally not a source of domestic or production water on the SRS because deeper aquifers provide a more abundant supply of higher-quality water (U.S. Department of Energy 1995b). Below the Floridan Aquifer System is the Crouch Branch Confining Unit of the Meyers Branch Confining System that separates the above aquifers from the Crouch Branch Aquifer of the Dublin Aquifer System (see figure 2.2). Recharge of the Crouch Branch Aquifer is from both overlying and underlying aquifers. Groundwater from the Crouch Branch Aquifer is pumped for both domestic and industrial uses, although the majority of groundwater used on the SRS is from the deeper McQueen Branch Aquifer (U.S. Department of Energy 1995b).

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The McQueen Branch Confining Unit of the Allendale Confining System separates the Crouch Branch Aquifer from the McQueen Branch Aquifer (figure 2.2). Recharge of the McQueen Branch Aquifer is mainly from the overlying Crouch Branch Aquifer. The McQueen Branch Aquifer is the main production aquifer of the SRS. The SRS withdraws approximately 14.0 billion liters (3.7 billion gal) per year of groundwater for domestic and industrial uses (U.S. Department of Energy 1995b). Groundwater quality is strongly influenced by the mineralogy of aquifer geology. In general, groundwater from the aquifers on the SRS is low in dissolved solids and in some areas low in pH, which results in high corrosivity and dissolved iron concentrations (Arnett, Karapatakis, and Mamatey 1993). Solvents, metals, radionuclides, nutrients, and other chemicals generated during SRS operations contaminate groundwater at 5 to 10 percent of the site (U.S. Department of Energy 1995b). Generally, the contaminated areas underlie or are in the vicinity of facilities, and contaminants are the result of facility processing. Contamination is restricted to Floridan Aquifer System waters, with one exception where trichloroethylene and tetrachloroethylene have contaminated the Crouch Branch and McQueen Branch Aquifers in the northwest portion of the site (U.S. Department of Energy 1995b).

Streams The hydrology and chemistry of streams on SRS have important influences on stream ecology, and each stream has had a unique history.

Stream Hydrology The depths of perennial streams vary from less than 1 meter to several meters during nonstorm periods. SRS streams have numerous pools but few riffles. In general, they are shallow and have low gradients and very low perennial and intermittent drainage densities (see table 2.7). Low stream slopes are typical of the geomorphic nature of the Lower Coastal Plain and Sandhills region. Ephemeral streams (estimated at 5–25 percent of drainage) are not frequent at SRS due to its sandy soils and low relief. They occur primarily in low-lying areas or along steeper slopes associated with Vaucluse soils that border major streams. Flow rate, depth, width, submerged woody debris, sediment, and sunlight have significant effects on habitat and associated biological communities both on and off SRS

63,792 50.4 2.25

Upper Three Runs

None 0.64 0.28 0.67 0.42 2.0–3.7 2.9

13,342 77.3 1.22

Tinker Creek

1955–1985 0.69 0.29 0.93 0.41 1.3–34.0 15.3

5,865 100 7.64

Fourmile Branch

1954–1988 0.65 0.34 1.02 0.44 4.2–26.8 14.5

5,663 100 3.07

Pen Branch

1954–1968 0.47 0.13 1.70 0.46 3.4–17.0 11.2

9,339 100 1.63 (6.10)a

Steel Creek

47,326 32.8 0.50 (7.15)a 1958–1964 0.56 0.06 2.31 0.38 4.8–32.0 13.0

2.78 1952–1982 NAc NA 2.30 NA 27.1–64.2 35.3

Lower Three Runs

2,200 100

Beaver Dam Creek

Source: U.S. Geol. Surv. Reps. for South Carolina: http://sc.water.usgs.gov. Note: The last four variables were calculated using data from the lowest gauge on each watershed and thus do not represent the entire watershed. a Includes area impacted by L Lake, Par Pond, and Ponds 2, 5, B, and C. b Perennial and intermittent stream segments only. c Not available. d Perennial segments only. Portion below L Lake dam for Steel Creek and below Par Pond dam for Lower Three Runs. e Upper and Lower Three Runs (1975–2000), Steel Creek (1994–2000), Pen Branch (1993–2000), Fourmile Branch (1987–2000), and Tinker Creek. (1993–2000). Beaver Dam Creek (1976–2000) is still affected by power generating operations. f Ratio of mean annual stream flow to annual precipitation over area for period of record.

Thermal impacts (yrs) None Mean density (km/km2)b 0.32 Mean stream slope (%)d 0.17 Mean annual flow (m3/sec)e 6.82 Precipitation runoff ratiof 0.37 Range of peak discharge (m3/sec) 12.1–56.6 Median peak discharge (m3/sec) 21.4

Watershed area (ha) Amount of watershed on SRS (%) Industrialized area (% SRS)

Hydrologic characteristic

Table 2.7 Hydrologic characteristics of major streams on the Savannah River Site

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(e.g., Meffe and Sheldon 1988; Smock and Gilinsky 1992; Lakly and McArthur 2000; Fletcher et al. 2000). The percentage of the watershed area affected by industrial land use is greatest in the Fourmile Branch, Pen Branch, and Beaver Dam Creek watersheds. Average precipitation-runoff ratios in SRS streams range from 0.37 to 0.46 (table 2.7) and are typical for the fall line and Upper Coastal Plain/Sandhills region of South Carolina (Smock and Gilinsky 1992). Peak discharge is generally lower in that region than in other areas of South Carolina, particularly the Piedmont and mountain regions (Guimares and Bohman 1992). Because of channel characteristics, bed sediment and organic debris are readily resuspended and transported during storm flows. Though mean flow is greatest during winter (figure 2.5), catastrophic flooding and hence annual peak runoff can occur in any month. On streams not affected by industrial process water discharge, mean monthly flows typically are greatest in March but decline abruptly in April as evapotranspiration increases. As evapotranspiration declines in the fall and surface soils are recharged, mean flow increases. During reactor operations, about 10 percent (174,000 gal/min, or 658,662 l/min) of the flow of the Savannah River was used for cooling water (Dukes 1984). The impacts of this pumping on the streams and ponds are complex (U.S. Department of Energy 1997; Arnett and Mamatey 1999). Water pumped from the Savannah River was initially used to cool P, R, L, C, and K Reactors and was discharged directly to streams. Subsequently, water was directed to cooling ponds, such as Par Pond, constructed for that purpose. Water was later used in a recirculation system. Currently, river water is pumped to maintain reservoir levels in Par Pond and L Lake, thereby reducing exposure of contaminated sediment and maintaining the ecological benefits of these larger bodies of water.

Stream Chemistry The geology of the SRS region strongly influences water chemistry. The sedimentary material through which water flows and eventually reaches the surface consists primarily of acidic silica sands and kaolinitic clays. Flowing waters at SRS are characterized as blackwater streams. They typically have high dissolved organic matter and acidity and low buffer capacity and nutrient concentrations (Meyer 1986) compared to Piedmont streams or major streams draining the Gulf Coast (Smock and Gilinsky 1992). Bowers et al. (1997) summarized extensive stream chemistry and temperature data from SRS.

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Figure 2.5. Relative mean monthly discharge for major streams on the Savannah River Site: Upper Three Runs (UTR) and Lower Three Runs (LTR; 1975–2000); Tinker Creek (TC; 1993–1995, 1999–2000); Fourmile Branch (FM; 1987–2000); Pen Branch (PB; 1993–2000); Steel Creek (SC; 1993–2000); and Beaver Dam Creek (BDC; 1976–2000) (U.S. Geological Survey Reports. for South Carolina, http://sc.water.usgs.gov).

As in most stream systems, dissolved O2 decreases in periods of low flow and increased water temperature during summer and fall (table 2.8). Dissolved organic carbon, dissolved solids, and pH fall within normal ranges for blackwater streams (table 2.8; Smock and Gilinsky 1992). Phosphorous levels are lower in SRS streams than in the Savannah River. The alkalinity of SRS systems is typically lower than in whitewater systems, and sulfate provides the major anion contribution to the system. Because bicarbonate and calcium are low, heavy metals can be more toxic to certain organisms in these systems (Specht and Paller 1995). Elevated heavy metal concentrations have been observed in only a few locations close to contaminated seeps (Bowers et al. 1997).

Major Streams and Watersheds Major streams that drain the SRS include the Upper Three Runs–Tinker Creek system, Fourmile Branch, the Steel Creek–Meyers Branch system, Pen Branch, Lower Three Runs, and Beaver Dam Creek.

9.5–26.0 3.1–7.6 7.0–76 1.0–37 2.0–19 6.2–10 5.6–6.6 0.01–0.07 0.3–1.5 0.05–1.1 0.05–4.5 0.2–0.7

Temperature (°C) pH Conductivity (µS/cm) Alkalinity (mg CaCO3/l) Suspended solids (mg/l) Dissolved oxygen (mg/l) Total organic carbon (mg/l) Total phosphorous (mg/l) Sodium (mg/l) Total sulfate (mg/l) Total chloride (mg/l) Total calcium (mg/l)

7.1–24.4 5.2–8.0 17.0–40 2.0–6.0 1.0–69 5.0–12.5 1.0–12 NDi–0.16 0.3–5.6 1–5.6 1–13.8 1.2–2.3

Upper Three Runsb 17 5.2–7.7 30.0–135 6.0–17.0 <1–23 6.4–12.7 NA ND–0.13 4.7–11.0 3.0–8.1 2.4–10.7 2.6–4.2

Fourmile Branchc 18 6.0–8.6 2.0–170 10.0–21.0 2.8–28 6.3–14.8 4.4–13.2 ND–0.18 3.3–10.0 4.0–19.0 3.0–12.9 1.0–6.4

Pen Branchd 19 6.1–8.1 36.4–128 6.2–26.4 0.4–97.2 4.7–11.9 NA 0.01–0.18 1.6–15.7 1.1–13.4 2.3–27.4 2.6–6.7

Steel Creeke

Beaver Dam Creekg 25 4.9–10.9 50.2–103.7 10.5–21.8 2.0–60.8 2.0–10.3 5.7–6.8 0.01–0.2 2.6–11.5 2.9–19.0 2.9–7.9 2.7–12.7

Meyers Branchf NAh 6.0–8.3 30.4–72.4 3.8–26.9 0.3–17.2 5.1–12.4 NA 0.01–0.07 0.6–13.7 0.1–5.5 1.6–4.2 2.1–9.1

Source: Bowers et al. 1997. Note: The sampling years selected are recent periods in which the direct influence of cooling water pumped from the Savannah River was minimal or nonexistent, except Beaver Dam Creek, where temperature is still affected by power house operations. a Above SRS boundary near Hwy 278 (1987–1991). b Lower SRS boundary near Road A (1992–1995). c At Road A-13.2 (1992–1995). d At Road A-13.2 (1992–1995). e Above confluence with Meyers Branch (1983–1985). f Above confluence with Steel Creek (1983–1985). g Near confluence with Savannah River (1987–1991). h Not available. i Nondetectable levels.

Upper Three Runsa

Chemical characteristic

Table 2.8 Chemical characteristics of major streams on the Savannah River Site

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Ecology and Management of a Forested Landscape

Upper Three Runs The headwaters of Upper Three Runs are off SRS near Aiken, South Carolina; approximately half of the watershed originates on those rural agricultural, residential, and forest lands. Important tributaries of Upper Three Runs on the SRS include Tinker Creek, McQueen Branch, Crouch Branch, and Tims Branch, of which only Tinker Creek is not impacted by facilities. Upper Three Runs has not received thermal discharges, although it does receive surface runoff from several facilities. The relative reduction in stream flow associated with summer water deficits is much smaller for Upper Three Runs and its tributary Tinker Creek (monthly minimum/monthly maximum about 0.69) than for other SRS streams (about 0.5; figure 2.5), suggesting that groundwater flow from subsurface aquifers contributes substantially more to the base flow of Upper Three Runs than other streams at SRS. This relationship is also reflected in the lower ratio of median peak flow to average annual flow, indicating that relatively more precipitation from large storm events enters the groundwater prior to entering the stream. Although Upper Three Runs is a typical southeastern blackwater stream, the larger groundwater contribution results in lower dissolved solids, lower hardness, and lower pH (table 2.8; Bowers et al. 1997), which can increase the toxicity of heavy metals to certain organisms. However, though the overall diversity of fish (Paller 1992) is similar to that of most blackwater streams, the richness of macro-invertebrates is higher than in other streams in the region and the United States (Morse et al. 1980). This phenomenon appears to be due in part to channel heterogeneity, the presence of large macrophyte beds, and perhaps certain discharge characteristics (Smock and Gilinsky 1992).

Fourmile Branch Fourmile Branch has one major tributary, Castor Creek. Thermal effluents from C Reactor impacted Fourmile Branch from 1955 to 1985. During reactor operations, stream temperatures exceeded 60°C (140°F) with flows of approximately 11 m3/sec (388 ft3/sec), or ten times the normal flow (figure 2.6, table 2.7). Fourmile Branch still receives surface runoff from several SRS facilities, including the Solid Waste Disposal Facility, but that runoff is not a major contributor to flow (Williams and Pinder 1990). Because of the elevated flows during reactor operations, a delta formed near the outlet to the Savannah River, and the current riparian floodplain vegetation is in an early successional state dominated by species such as black willow (see appendix for scientific names), smooth alder, and wax

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Figure 2.6. During reactor operations, the high flow rates and temperatures of reactor cooling water destroyed riparian vegetation in Fourmile Branch, Pen Branch, and Steel Creek (W. Gibbons; reprinted by permission from Gibbons and Sharitz 1981, © 1981 by The American Institute of Biological Sciences).

myrtle (Giese et al. 2000). Groundwater flow from chemical waste seepage basins impacts water quality, which increases nitrate, heavy metal, and radionuclide inputs (Arnett and Mamatey 2000).

Pen Branch Pen Branch has one major tributary, Indian Grave Branch. Cooling waters from K Reactor influenced Pen Branch from 1954 to 1988, with stream temperatures of 40 to 50°C (104–122°F) and flows of approximately 11 m3/sec (388 ft3/sec), or ten times the normal volume (table 2.7). Similar to Fourmile Branch, the riparian floodplain vegetation was dramatically altered, and a delta developed as a result of sediment deposition from elevated flows. Efforts were begun in 1992 to accelerate the restoration of 236 ha (583 ac) of the Pen Branch riparian and delta forest by planting typical bottomland hardwood species (see chapter 3 and Nelson, Kolka et al. 2000 for review). Although the flora and fauna are recovering, the open canopy, altered stream morphology, and reduced volume of large woody debris has had a significant impact on species composition (Lakly and McArthur 2000; Buffington et al. 2000; Bowers et al. 2000; Paller et al. 2000). Currently, Pen Branch receives surface runoff from K Area, but there is no other significant impact on stream water quality (Bowers et al. 1997).

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Ecology and Management of a Forested Landscape

Steel Creek Steel Creek is dammed about 9 km (6 mi) south of its headwaters, creating L Lake. Water through the dam flows about 8 km (5 mi) before entering the Savannah River. Meyers Branch is the main tributary of Steel Creek and flows approximately 10 km (6 mi) before entering Steel Creek. Although Meyers Branch was dredged prior to 1951, it is relatively unimpacted. Steel Creek received thermal discharges from P and L Reactors from 1954 to 1968, prior to construction of the L Lake dam in 1984– 1985. Although no historic temperature information is available, stream temperatures were probably comparable to those in Fourmile Branch and Pen Branch during reactor operations. After construction of L Lake, flow included water pumped through L Canal from the reactor and water pumped directly from the Savannah River. Mean flow during that period was 4.5 m3/sec (160 ft3/sec), or about 2.5 times the flow since reactor shutdown (Bowers et al. 1997). As in Fourmile Branch and Pen Branch, a delta developed on the Savannah River floodplain as a result of sediment deposition from elevated flows. Approximately 20 percent (0.32 m3/sec, or 42 ft3/sec) of Steel Creek’s total flow originates from the Meyers Branch drainage (W. Stringfield, U.S. Geological Survey, pers. comm.). Meyers Branch has a closed forest canopy throughout its length, which provides large quantities of coarse woody debris as substrates for macro-invertebrates. Similar to Upper Three Runs, Meyers Branch also has low sediment and nutrient loading compared to the Steel Creek channel (table 2.8).

Lower Three Runs The majority of the drainage area of Lower Three Runs is outside the SRS boundary; only the riparian floodplain is inside the boundary (see figure 2.4). Major tributaries of Lower Three Runs include Mill Creek, Davis Branch, Bodiford Mill Creek, Patterson Branch, and Gannts Mill Creek. Lower Three Runs was dammed in 1958 to form Par Pond. Prior to the construction of Par Pond, thermal effluent from R Reactor was discharged into the stream. R Reactor was shut down in 1964, and P Reactor thermal discharges were diverted from Steel Creek to Par Pond and subsequently to Lower Three Runs (Bowers et al. 1997). P Reactor was shut down in 1988. As a result of the reservoir system, water temperatures and flows during reactor operation were not as severe as in other streams. However, flows from pumping and cooling are complex (U.S. Department of Energy 1997), and flow is currently maintained by water pumped from the Savannah River. Lower Three Runs currently receives no direct runoff

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from SRS facilities. Although mercury and radionuclides contaminate the sediment in Par Pond, water chemistry and biological systems do not appear to have been dramatically affected in Lower Three Runs beyond the immediate outfall from the dam. The waters of Lower Three Runs are notably lower in phosphorous than the Savannah River but have higher organic carbon than other SRS streams (Bowers et al. 1997). Stream temperature is several degrees higher than other streams on SRS. Otherwise, the stream chemistry is similar to other SRS streams.

Beaver Dam Creek Prior to SRS operations, Beaver Dam Creek was likely an intermittent or ephemeral stream. It was channelized to receive runoff from D Area (Bowers et al. 1997), and from 1952 to 1982, it received thermal discharges from heavy water production. No data are available on stream temperatures from that period. Since 1982, Beaver Dam Creek has continued to receive runoff from D Area, including the cooling water from a coal-fired power plant (see figure 2.5). This water is originally drawn from the Savannah River. Mean stream temperature is approximately 25°C (77°F), about 7 to 8°C (11–13°F) higher than that of other SRS streams, and the chemistry of the stream more closely parallels the chemistry of the Savannah River (see table 2.8). Runoff from D Area appears to have increased the concentrations of sulfate and several heavy metals in Beaver Dam Creek.

Surface Water Impoundments and Wetlands Surface water at SRS includes artificial impoundments, Carolina bay wetlands, and bottomland hardwood and swamp wetlands.

Impoundments Although several artificial impoundments exist, here we describe the two large reservoirs, L Lake and Par Pond.

L Lake L Lake was formed in 1985 by damming the headwaters of Steel Creek above the Meyers Branch confluence (figure 2.4). Maximum depth of L Lake is 19.8 m (65 ft), with a mean depth of about 8 m (26 ft; Bowers 1992). At a normal pool elevation of 58 m (190 ft) above sea level, the dam impounds about 31 million m3 (1.1 billion ft3) of water and covers about 418 ha (1,033 ac; U.S. Army Corps of Engineers 1987). The SRS pumps water from the Savannah River to maintain water levels. Groundwater

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discharges to L Lake in the upper third to half of the reservoir. Below the midpoint of the reservoir, L Lake recharges the groundwater system (R. Hiergesell, Westinghouse Savannah River Co., pers. comm.). L Lake received cooling water from L Reactor in a “once-through” system during various periods from 1985 to 1988. Water temperatures during that time were about 2°C (3.6°F) warmer than nonthermally impacted reservoirs in the Southeast (Bowers et al. 1997). Although sediment in L Lake is contaminated with heavy metals and radionuclides, it does not appear to be affecting reservoir water quality or the biotic community structure appreciably (Bowers 1992).

Par Pond The SRS created the 1,012-ha (2,500-ac) Par Pond cooling reservoir in 1958 by impounding Lower Three Runs. The Site constructed Par Pond to receive cooling water from P and R Reactors. Par Pond currently receives pumped water from the Savannah River (to maintain the reservoir) and surface discharges from Poplar Branch, Joyce Branch, and the upper reach of Lower Three Runs (Wilde and Tilly 1985). The SRS constructed several other ponds between the reactors and Par Pond to improve the cooling efficiency of the reactor effluent. Pond B is the largest and has an area of about 73 ha (180 ac). The maximum depth of Par Pond is 18 m (59 ft), with a mean depth of 6.2 m (20.3 ft; Bowers 1992) and a volume of 62 million m3 (2.2 billion ft3). Par Pond received thermal discharges from recirculation systems at R Reactor from 1958 to 1964 and P Reactor from 1961 to 1988. Mean annual water temperatures during reactor operations ranged from 21° to 31°C (71–88°F). Since reactor operations have ceased, mean water temperature has decreased to 18.1°C (64°F), which is similar to temperatures of other nonthermally impacted reservoirs in the Southeast (Bowers et al. 1997). Water pumped from the Savannah River and discharge from R and P Reactors have contaminated sediment in Par Pond with mercury and radionuclides, respectively (Paller and Wike 1996). Par Pond was drawn down in 1991 to repair the dam and was returned to normal pool in 1995.

Carolina Bays Carolina bays are isolated, natural, shallow depressions that are poorly drained and seasonally inundated (figure 2.7). They are oval or elliptical in shape. They occur throughout the Southeastern Coastal Plain, and 343 Carolina bays and baylike depressions occur on the SRS (see chapter 3).

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Figure 2.7. Aerial view of Ellenton Bay, a large Carolina bay bisected by a utility right-of-way (D. Scott).

Carolina bays on SRS range in size from 0.1 to 50 ha (0.04–124 ac), with a median size of 0.8 ha (2 ac). They tend to have relatively low pH (3.8–5.5) and are oligotrophic (Irwin et al. 1997) to mesotrophic (Taylor et al. 1999) in nature. Most Carolina bays were drained and farmed prior to SRS establishment (Irwin et al. 1997). These disturbed Carolina bays are in various hydrologic and vegetative conditions (see chapter 4). The source of water for recharge of most bays appears to be annual rainfall rather than groundwater from the Floridan aquifer (R. Hiergesell, Westinghouse Savannah River Co., pers. comm.), though periodic groundwater inflow may be important for a few bays (Lide et al. 1995). Maximum open water area of the bays usually occurs during March, following winter recharge of the soils (Schalles et al. 1989). Bays tend to have water levels and hydroperiods that fluctuate with annual rainfall and evapotranspiration (figure 2.8), though some bays are more sensitive than others to those processes. During extreme droughts (e.g., in 2002), over half of the bays may not fill, while during wet years (e.g., in 1997), less than a quarter actually dry. The complex hydrology of bays is reflected in lag effects from precipitation rates, which apparently carry over between years. Forested bays tend to have short hydroperiods (i.e., flashy) and perched water tables from clay layers in the soil, indicating that precipitation and subsurface runoff from upland origins are important water sources to forested Carolina bays. Marshy bays tend to have long

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Ecology and Management of a Forested Landscape

Figure 2.8. Hydroperiods for fifty-six Carolina bays on the Savannah River Site. Data is for monthly (1996–2000) and quarterly (2001–2002) intervals (R. Sharitz and R. Lide, Savannah River Ecology Lab, unpublished data analyzed by B. Taylor, Savannah River Ecology Lab).

hydroperiods and sandy soils, indicating that local groundwater influences the hydrology of those wetlands (Chmielewski 1996).

Bottomland Hardwood and Swamp Wetlands Approximately 20 percent of the SRS is composed of riparian systems occurring along the major drainages and the floodplain of the Savannah River (see figure 2.4). The vegetation of SRS riparian zones ranges from early successional systems created by disturbances, most notably thermal discharges, to mature bottomland hardwood or swamp forest. Imm and McLeod (chapter 4) describe those communities. Bottomland hardwood wetlands occupy mesic habitats where flooding is common but of limited depth and duration. The water source of bottomland hardwood systems is mainly upland-derived subsurface runoff, though groundwater also contributes. Riparian zones can be both groundwater recharge and discharge zones (Kolka et al. 2000). Swamp forest wetlands have water tables that are near or above the soil surface for all or most of the year (Workman and McLeod 1990). Water in the Savannah River swamp comes from the drainage of major streams, flooding of the Savannah River, and groundwater discharge.

3

r

SRS Forest Management Silviculture and Harvesting Activities John I. Blake

Prescribed Fire Management Daniel J. Shea and Bruce A. Bayle

Ecological Restoration Christopher D. Barton, John I. Blake, and Donald W. Imm

This chapter describes major land management activities on the SRS. Additional land management information appears in chapters 4 and 5, where sections on various wildlife species cover activities directed at enhancing habitat, occasionally including significant vegetation manipulation, as in the case of the red-cockaded woodpecker. In “Silviculture and Harvesting Activities,” the first section in this chapter, John Blake provides an analysis of the trends and extent of silviculture and harvesting practices at SRS over the last fifty years, revealing their dynamic and evolving nature. He shows that forest managers have adapted practices to changing public values, new scientific information and technical developments, and the changing structure and composition of the forest. In the 1950s and 1960s, forest management was directed at establishing forest cover on old fields and cutover areas. During the 1970s and 1980s, management emphasis shifted to the age distribution and composition of the forest, improvement of understocked scrub oak sites, and conversion of slash 57

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pine plantations to longleaf pine. In addition, with the advent of environmental legislation, a more holistic approach to forest management began to develop. Wildlife habitat improvement, particularly for the endangered red-cockaded woodpecker, took on a more important role. That trend has continued through the 1990s to the present, with less emphasis on productivity and management intensity. Although many standard forestry practices are used, SRS forests are not managed solely for wood products; the current extended rotation ages in the red-cockaded woodpecker zones and in hardwood stands are inconsistent with traditional even-aged sustained-yield and area-regulation concepts. Additional factors now considered include landscape structure, species diversity, and ecological restoration. As forest stands age, intermediate harvest and mortality occurs, creating opportunities for natural succession and regeneration to dominate the structure of those stands. The ultimate outcome depends on fire regime, soils, overstory stocking, and seed dispersal into those areas. New scientific information will likely further refine the application of traditional and current silviculture and harvesting practices. Rather than follow rigid standards and guidelines, SRS forest managers must integrate a broad set of tools and principles to guide stand-specific prescriptions in the future. Historically, fire has been a significant disturbance process shaping the natural landscape at SRS. In the second section, Daniel Shea and Bruce Bayle describe the historical and current management of fire on SRS. The SRS suppresses wildfire to protect facilities, infrastructure, personnel, and natural resources, and it uses prescribed fire as a tool to reduce wildfire hazard, prepare areas for planting, enhance wildlife habitat, and restore native communities. Prescribed burning occurs year round. Most areas are scheduled for burning on a three-to-five-year rotation, but weather, logistical, and regulatory constraints prevent the SRS from achieving that rotation. Current strategies include conducting smaller burns that produce less smoke, closing site roads to increase the number of available burn days, and mechanically removing fuels. As smoke management is a crucial limiting factor, research is investigating PM2.5 and PM10 smoke concentrations, monitoring smoke plume evolution, and improving meteorological predictions of dispersion. Although ecological restoration has been an integral component of natural resource stewardship at the SRS for fifty years, restoration activities increased dramatically in the 1990s. In the third section, Christopher Barton, John Blake, and Donald Imm describe the primary components of the SRS restoration program, noting that its general goal is to restore native species, their habitats, and key environmental processes, while retaining the integrity of the Site’s missions. The authors describe restoration of hardwoods, wet-

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lands, and pine savannas. Primary projects in this effort have included restoration of the bottomland hardwood forest in the Pen Branch floodplain, denuded by reactor effluent; restoration of several Carolina bay wetlands, drained prior to SRS establishment; and restoration of native understory plants in longleaf pine savannas, eliminated by the intensive agriculture that dominated the area during the nineteenth and early twentieth centuries.

Silviculture and Harvesting Activities John I. Blake The Savannah River Site (SRS) has a national defense and environmental management mission, a significant research role as a National Environmental Research Park, and a distinct land-use history and geographic location, all of which establish the framework for silviculture and harvesting there. The U.S. Department of Energy contracted SRS forest management activities to the U.S. Forest Service in 1951, and historical silvicultural activities at SRS were typical of that agency and common for the period. Current activities cover a broader range than those on national forest lands and are more adaptive to new information. The initial objective of the program was to establish selected tree species. This was accomplished by the early 1970s, and the focus shifted toward increasing the growth of pine and hardwood stands, controlling pests and diseases, and improving stand structure for wildlife. While these remain part of the current silviculture and harvesting program, the forest management program has designed more recent activities to enhance diversity and restore degraded communities. Silviculture and harvesting activities are those immediate actions designed to improve the structure, composition, and growth of a forest stand to meet diverse objectives. Activities such as thinning, partial cutting, and clear-cutting may generate revenue; other activities like site preparation, planting, competition control, disease control, fertilization, and snag creation may not. Sustainable natural resource objectives require that silviculture and harvesting alternatives track changes in public values. While available techniques and knowledge of the impact of current activities on future conditions have increased, environmental concerns and more complex biological objectives have created a challenging and dynamic environment. Because silviculture practices at SRS have changed so dramatically during the Site’s fifty-year history, those

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practices will be described separately for three periods: 1952–1971, 1972–1988, and 1989–2004.

Silviculture and Harvesting Practices: 1952–1971 The period between 1952 and 1971 covers the reforestation of the majority of the old-field and cutover forestland, the initial harvesting and timber stand improvement work, and the first inventory and management plan under the Atomic Energy Commission. The initial objective was to establish trees on old fields in order to prevent erosion, control dust, reduce noxious weeds, promote adequate ground cover to sustain the subsurface aquifer, improve existing timber stands, and provide a marketable crop of timber (Savannah River Operations Office 1959). Subsequently, the SRS modified those objectives to include developing a hardwood pulp market, controlling white-tailed deer and hogs (see table 4.24 and the appendix for scientific names), protecting valuable timberland, converting 11,736 ha (29,000 ac) of scrub oak to longleaf pine, and mapping the forestland (Gates et al. 1967). The early forest conditions (see chapter 1) and available technology determined the type of silviculture and harvesting activities undertaken. Because of the scale of the operations in relation to previous efforts, the SRS undertook a research program to improve reforestation practices and to develop new silviculture techniques for the Sandhills region (Shipman 1958).

Site Preparation Initially, forest managers planned no site preparation for the old-field areas. However, early research demonstrated that furrowing the soil with a fire plow or similar device could significantly improve survival (Shipman 1955). Furrows reduced herbaceous weed competition, increased moisture retention, and facilitated deep planting. Only 14 percent of the furrowed fields required replanting, compared to 25 percent of the unfurrowed fields (U.S. Forest Service 1957). To reduce soil compaction, forest managers also “ripped” the soil to a depth of 46 cm (18 in) on several thousand acres near construction sites. To control woody vegetation before longleaf pine seeding, they routinely applied herbicides. Methods were aerial or mist-blower application of 2,4,5-T or stem injection of 2,4-D amine or 2,4,5-TP (Silvex). However, spraying on cutover forest areas and scrub oak sites often resulted in incomplete control of turkey

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oak. During the late 1960s, foresters employed prescribed burning on a few hundred acres designated for natural regeneration of loblolly pine.

Planting and Seeding Because early observations indicated little natural regeneration of pine on the old fields, planting or seeding was essential (figure 3.1). Forest managers planted about 10 million seedlings each year obtained from nurseries in five states (Louisiana, Mississippi, Alabama, Georgia, and South Carolina; U.S. Forest Service 1954). Although not native to SRS, slash pine was preferred (figure 3.2) because of its high survival rate, good growth, and availability. Foresters also favored longleaf pine, but poor nursery stock quality, availability of seed supply, and low survival limited planting. The geographic source of seed for slash and loblolly ranged from Louisiana to South Carolina, whereas records indicate that foresters collected longleaf pine only locally in South Carolina or nearby Georgia for direct seeding operations from 1961 to 1971. Through research, the SRS developed and implemented an innovative procedure called “prescription planting” in 1955 (Hatcher 1957). The

Figure 3.1. Longleaf pine planted in an old field on the Savannah River Site, early 1950s (U.S. Forest Service files).

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Figure 3.2. Net number of acres planted 1953–2003 or seeded successfully 1960–1971 at the Savannah River Site for slash pine, loblolly pine, longleaf pine, and various hardwood species, including cypress. Longleaf pine planted 1974–1982 failed generally, and the areas were replanted with loblolly pine (U.S. Forest Service, unpublished data).

procedure involved grading pine seedlings by stem diameter and setting the tree spacing, or effective trees per acre, to correspond to the predicted survival for a given grade, species, and soil texture. This method proved more efficient and resulted in fewer replantings for all species. To achieve the same stocking after planting, foresters had to plant only 1,778 trees per ha (720 per ac) of slash pine using larger stock on furrowed sites with loam soils compared with 3,063 trees per ha (1,240 per ac) of the smallerdiameter stock on unfurrowed sites. The average cost per acre to establish pine on old fields by planting ranged from $11.12 to $15.12, exclusive of replanting costs. The area successfully planted from 1952 to 1971 appears in figure 3.2. The SRS wanted to reduce the cost of establishing longleaf on understocked scrub oak stands (figure 3.3) and the remaining old fields. However, prior to 1959, techniques and repellents to control seed predation by rodents, birds, and ants were unavailable or untested. The advent of several repellents (Arasan 42S and Endrin 50W), successful research trials, and the desire to reduce costs led to direct seeding (Tofte 1967). Foresters modified equipment to create furrows through residual scrub oak and to simultaneously place and cover seed (Hatcher 1967). Direct seeding of longleaf became operational in 1960. Of the 8,882 ha (21,948 ac) seeded by 1970, 3,186 ha (7,873 ac) were old fields, and the remaining were scrub oak sites. However, only 4,988 ha (12,326 ac, or 56

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Figure 3.3. Longleaf pine planted in cutover scrub oak on the Savannah River Site, early 1950s (U.S. Forest Service files).

percent of all seeded acres) were successfully seeded with two hundred or more longleaf pine trees per acre (U.S. Forest Service 1971). Longleaf pine was successfully established on less than half of the seeded scrub oak areas. The cost per acre to establish longleaf pine by seeding varied from $5.53 to $10.47, plus an additional $7.50 per acre for chemical release, exclusive of reseeding costs.

Post-Planting or Seeding Treatments The implementation of furrowing and prescription planting, coupled with the lack of overtopping woody vegetation in old fields, negated the need for post-planting vegetation treatments. However, an epidemic of white grubs (Phyllophaga prunnunculina) severely impacted the 1953–1954 planting. Forest managers successfully treated approximately 3,642 ha (9,000 ac) of that planting with aerial application of chlordane, heptachlor, aldrin, and dieldrin. Brown-spot disease (Scirrha acicola) on longleaf seedling foliage was also a problem. In the 1950s and 1960s, it was

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generally treated by burning 405 to 1,214 ha (1,000–3,000 ac) each year. In 1961–1962, approximately 809 ha (2,000 ac) were treated successfully with a mixture of hydrated lime and copper sulfate (bordeaux mixture). In the 1950s and 1960s, the priorities were natural regeneration and release of stream-bottom hardwood species like sweetgum and yellow poplar, along with release of naturally regenerating pine on scrub oak sites. Forest managers mechanically cut and stem-injected undesirable competing hardwoods with various herbicides (table 3.1), including 2,4-D amine, 2,4,5-TP, sodium arsenate, ammonium sulfamate (Ammate), and later picloram + 2,4-D (Tordon 101M). From 1952 to 1961, they treated 7,928 ha (19,591 ac) to release natural pine regeneration and desirable hardwood species. About 35 percent were hardwood sites and 65 percent scrub oak sites. From 1962 to 1971, they injected or sprayed undesirable hardwoods on 5,255 ha (12,986 ac) of the seeded longleaf in scrub oak sites (U.S. Forest Service 1971).

Commercial Harvesting and Regulation Harvesting generally was used to remove poor-quality stems or undesirable species. The remaining stems, mainly hardwoods, were injected with herbicides, as there was little market for hardwood pulp. Because of the poor forest conditions, silviculturists did not initially regulate harvesting. They later implemented an area-based regulation system (Gates et al. 1967) equivalent to a rotation age of forty to fifty years. Pine was harvested from residual or cutover longleaf stands, particularly for pulpwood. The 1,763 ha (4,358 ac) of pre-1951 slash pine plantations were thinned. Fire- and storm-damaged stands were salvaged, and selective cutting of hardwood sawtimber was conducted to improve the stands in the stream bottoms (Hatcher 1967). Commercial clear-cutting occurred in residual pine sites, salvage sales, and areas cleared for construction, such as the 1,133-ha (2,800-ac) Par Pond basin and dam.

Silviculture and Harvesting Practices: 1972–1988 During the 1970s, Congress enacted environmental laws and orders that changed harvesting and silviculture practices on federal lands. These included the Endangered Species Act, the National Environmental Policy Act, the Clean Water Act, the Clean Air Act, and Wetlands Assessment. In 1972, the Department of Energy designated the SRS a National Environmental Research Park to foster environmental and ecological research

Table 3.1 Acreage treated by various silvicultural practices at the Savannah River Site 1952–2001 Total acres treated in period Silvicultural treatment

1952–1971

1972–1988

1989–2001

Mechanical SPa Chemical spray SPb Chemical inject SPc Burning SPd Release or TSIe Brown spot burning Precommercial thinning

61,505 11,725 2,959 14,075 8,700 12,822 0 11,115 4,670 2,042 15,866 12,235 32,577 6,169 6,319 20,844 0 0 0 2,897 1,533 Average acres treated per year in period

Mechanical SP Chemical spray SP Chemical inject SP Burning SP Release or TSI Brown spot burning Precommercial thinning

3,065 690 228 704 512 986 No Data 654 259 102 933 941 1,629 363 37 1,042 0 0 0 170 118 Percent of planted acres treated in periodf

Mechanical SP Chemical spray SP Chemical inject SP Burning SP

81.6 18.8 No Data 2.7

37.4 27.8 35.5 50.6

16.1 69.5 25.3 66.4

Note: 1 ac = 0.405 ha. Treatments include preplanting or seeding site preparation (SP) and post-planting, seeding, or natural regeneration stand treatments (U.S. Forest Service 1960, 1972, 1983, 2001). No records of the area treated with borax for annosum root rot are available. a Mechanical SP includes furrowing, ripping, shearing-and-raking, piling, windrowing, and drum chopping. b Chemical SP includes aerial and ground spraying application of herbicides. c Chemical injection SP includes hand injection of various herbicides into undesirable hardwoods prior to planting. d Burning SP includes both chemically treated and untreated acres prior to planting. e Release and TSI (timber stand improvement) treatments include hand injection of various herbicides, aerial spraying, ground spraying, and some hand cutting of undesirable hardwoods following planting, longleaf seeding, or natural regeneration. f

Percentages do not total to 100 percent due to multiple treatments applied to the same area.

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and to provide for energy research and development activities. During 1972–1973, the SRS undertook an assessment of the natural resource program (Beavers et al. 1973) to identify progress, status, and new opportunities and to recommend harvesting levels and silviculture activities. The Land Use Plan subsequently established a goal to continue “forest management to produce forest products, enhance environmental diversity, protect endangered species, conserve other species, provide quality habitat for other wildlife, improve aesthetics, protect soil and watershed values, and provide a healthy forest for environmental research” (Energy Research and Development Agency–Savannah River Operations Office 1975). Considerations in silviculture and harvesting strategies during the 1970s included age distribution and composition of the forest, improvement of understocked scrub oak sites (estimated at 11,850 ha, or 29,282 ac), conversion of slash pine plantations to longleaf due to ice damage and disease, and wildlife habitat improvement (Thornton and Walker 1973). Wildlife habitat objectives focused on “featured species” management and key habitats like old house places and hardwood stream bottoms (Pitts 1976). Habitat management for the endangered red-cockaded woodpecker gradually dominated practices. The area affected by management for the red-cockaded woodpecker expanded from 4 percent of the total forestland in 1978 to 44 percent by 1988. A new soil survey and ecological classification map of the SRS also significantly influenced silviculture and harvesting practices during this period (U.S. Department of Energy 1979).

Site Preparation Forest managers used a variety of site preparation methods on clear-cut sites and no site preparation in hardwood stands and some pine sites. Practices depended on the postharvest conditions (i.e., vegetation competition, residual logging debris), soil conditions, method of planting, species, and long-term stand objectives. The relative proportion of the harvested area treated by various methods changed within the period. Burning alone or in combination with other methods increased from a few hundred acres per year to a maximum of 843 ha (2,083 ac) in 1987. Burning cleared debris to facilitate machine planting and reduced woody vegetation competition. Mechanical methods, preferred in the 1970s (U.S. Department of Energy 1979), gradually declined. Shear-and-rake was applied to 162 to 324 ha (400–800 ac) per year to convert an esti-

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mated 4,047 ha (10,000 ac) of understocked scrub oak stands and poorquality mixed pine hardwood stands to longleaf or loblolly pine (R. Pitts, U.S. Forest Service, retired, pers. comm.). A tractor-mounted KG blade sheared residual tree stems, and then another tractor with a root-rake blade piled the debris in rows, often moving surface soil in the process. The area treated in this manner was reduced by 1988 because of excessive soil disturbance, the increased effectiveness of burning and herbicides, and a desire to retain some scrub oak habitat. Forest managers used drum chopping in combination with herbicides or burning in 1987–1988 on several hundred acres. The use of herbicides for site preparation increased from 1972 to 1988 as available chemicals and their efficacy increased. In the 1970s, 2,4-D amine and picloram + 2,4-D (Tordon 101M, 101R) were applied by stem injection. During the 1980s, this procedure was replaced by aerial or ground application of hexazinone (Velpar L, Pronone 10G, 5G) and injection or foliar application of triclopyr (Garlon 4, 3A). Herbicides were more effective long term in controlling competing vegetation, both woody and herbaceous, than previous mechanical treatments. Herbicides also created less soil disturbance than furrowing, discing, chopping, ripping, or shear-and-rake. A combination of burning, herbicide, and mechanical treatments eventually became the preferred approach. For example, burning combined with herbicides like hexazinone, triclopyr, and picloram effectively controlled competing vegetation for several years after planting. Pre-harvest herbicide treatment of competing vegetation also was implemented. To reduce unwanted hardwoods, herbicides like hexazinone were broadcast and picloram + 2,4-D or triclopyr was injected prior to harvest.

Planting and Seeding A goal of the Timber Management Plan (U.S. Department of Energy 1979) was to increase pine and hardwood areas regenerated from 465 to 931 ha (1,150–2,300 ac) per year in order to regulate the age-class distribution and increase the annual harvest. Though forest managers depended on natural reseeding or resprouting for regeneration of hardwoods, they generally planted pine. Machine planting, the primary method, required areas to be clear of debris. In the early 1980s, a small V-blade attached to the tree planter allowed the planter to clear a small area in front of the planting coulter. This method reduced the area requiring mechanical site preparation. Loblolly pine was planted on 80 to 90 percent of the total

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Ecology and Management of a Forested Landscape

planted acreage from 1972 to 1988 (see figure 3.2). It had higher survival rates than longleaf because of improved site preparation techniques, better seedling quality, and greater availability of nursery stock. Loblolly pine also demonstrated superior growth over longleaf. It was planted on an 8×8-foot spacing (1,683 trees per ha, or 681 per ac). Seed was either collected locally or occasionally purchased. Purchased seed was probably genetically improved. Between 1971 and 1981, the establishment of new longleaf pine stands by planting was unsuccessful because of poor nursery stock quality; difficulty in storing, handling, and planting; and site preparation needs on deep sands. Though forest managers planted longleaf on 81 to 121 ha (200–300 ac) per year, they inevitably replanted those areas with loblolly pine. In 1982, they made a concerted effort to successfully plant longleaf. By the mid-1980s, longleaf researchers had improved nursery cultural techniques, seedling uniformity to match mechanical planter requirements, storage survival, site preparation, and contract planting standards (Hatchell and Muse 1990; Cram, Mexal, and Souter 1999). From 1982 to 1986, forest managers successfully planted several hundred acres per year, and by 1987, the number was over 202 ha (500 ac). A 6×8foot spacing (2,241 trees per ha, or 907 per ac) was standard (U.S. Forest Service 1986) to compensate for expected mortality. From 1984 to 1988, third-year survival varied from 54 to 88 percent and often resulted in overstocked stands. In general, seed was collected locally in South Carolina or nearby Georgia and was not genetically improved.

Post-Planting Treatments Post-planting practices changed significantly when compared with the prior period. Timber stand improvement on thousands of acres was gradually reduced to a few hundred acres annually. In part, this reduction resulted from more effective site preparation. Release treatments changed from stem injections of 2,4-D amine or picloram + 2,4-D in the 1970s and early 1980s to triclopyr or broadcast application of hexazinone pellets in the mid to late 1980s. The latter treatment was much more effective on scrub oak sites than previously used herbicides. It was used extensively to release longleaf pine on previously regenerated (natural, seeded, or planted) areas. Mechanical or chain-saw slashing was limited to a few hardwood stands. The SRS initiated precommercial thinning to reduce overstocked pine stands in 1982. From 1982 to 1988, 1,172 ha (2,897 ac) were thinned to improve growth. During the same period, a few hundred

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acres were fertilized with ammonium phosphate to stimulate growth, but that practice was discontinued.

Commercial Harvesting and Regulation During this period, silviculturists employed a distinct rotation age or the equivalent even-aged area regulation method to achieve an equal distribution of area within each age class. They set rotation age at sixty years for pine groups and eighty years for hardwood and red-cockaded woodpecker management groups. The area clear-cut annually ranged from about 465 ha (1,150 ac) in 1972 to 931 ha (2,300 ac) by the early 1980s. A goal was set to convert the remaining slash pine to longleaf or loblolly in thirty years and to reforest remaining understocked and poor-quality upland hardwoods. Those stands accounted for most of the clear-cut area during the period. The total volume harvested between 1971 and 1976 increased from 98,000 to almost 168,000 m3 (3.5–6 million ft3) and then declined to slightly less than 112,000 m3 (4 million ft3). Most of the volume initially came from thinning or clear-cutting small pine, but there was a gradual increase in pine sawtimber removals through the period as the planted stands developed (see chapter 6). Cordell and Landgraf (1969) reported that both Heterobasidium annosum root rot and fusiform rust (Cronartium fusiforme) stem canker were common in slash pine and loblolly pine stands at SRS. Numerous annosum root infection centers were observed on SRS. Fusiform rust–infected trees were removed during the first thinning as a means of mitigating the disease impact. However, the deep sandy soils were especially prone to annosum root rot, and the only known control was to clear-cut heavily infected stands. In 1980, Witcher and Lane (1980) demonstrated that annosum could be controlled by applying borax to the cut stump immediately following thinning, and that was subsequently done in thinned loblolly pine stands. Thinning also removed ice-damaged slash and loblolly trees damaged by storms in 1972–1973. The area thinned during the 1970s ranged from 2,428 to 3,237 ha (6,000–8,000 ac) annually but declined gradually to less than 809 ha (2,000 ac) annually during the 1980s. Thinned stands provided about two thirds of the total volume harvested during the 1970s, including an estimated 72 percent of the pulpwood and about 25 percent of the sawtimber, whereas clear-cut stands provided the majority of the wood in the 1980s. The wildlife habitat management methods associated with “featured species,” such as northern bobwhite (Colinus virginianus), wild turkey

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Ecology and Management of a Forested Landscape

(Meleagris gallopavo), fox squirrel, and red-cockaded woodpecker, reflected common wildlife management approaches at the time. Thinning coupled with burning increased habitat quality for fox squirrels and northern bobwhite. The limit for clear-cut size was a maximum of 40 ha (100 ac). Creating small or irregular cuts increased the amount of edge habitat. Wildlife biologists recommended clear-cut harvesting of hardwood stands to provide early-succession habitat for certain species. Forest managers retained old-house-place vegetation and hedgerows, especially those containing mast-producing oaks, and released them from encroaching pine. They made a limited attempt to protect soft fruit species like dogwood. The SRS increased rotation ages in red-cockaded woodpecker areas to provide cavity trees, and it set a goal to maintain 15 to 25 percent of each 607 to 809-ha (1,500–2,000-ac) block as hardwood habitat, which reduced conversion of remaining scrub oak stands to pine.

Silviculture and Harvesting Practices: 1989–2004 In the late 1980s, the Department of Energy (DOE) implemented a Natural Resource Management Plan for the SRS (U.S. Department of Energy 1991). While the plan did not detail practices, subsequent operations plans outlined strategies and standards for harvesting and silviculture (U.S. Forest Service 1992). The plan supports DOE’s industrial missions, environmental research, and a sustainable wood supply. As well, complex management for landscape structure, species diversity, ecological restoration, and threatened-endangered-sensitive species required significant changes in practices (figure 3.4). New vegetation and animal surveys, as well as research on the relationship between disturbance, patch structure, landscape patterns, and habitat use, have facilitated those changes. The SRS revised the red-cockaded woodpecker management plan in 1992 to include longer rotations for longleaf and loblolly pine, restrictions on clear-cut harvesting, and limits on residual stocking in thinned stands. A subsequent plan (Edwards et al. 2000) restructured the recovery areas (designating primary and secondary areas) and incorporated more emphasis on plant community conservation and restoration. While commercial silviculture techniques have expanded, the decrease in management intensity, the deemphasis of productivity, and the reduced harvest level have resulted in the application of few new technologies. Exceptions occur where practices have been aimed at creating a particular habitat structure or implementing conservation or restoration projects.

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Figure 3.4. Changes in silviculture and harvesting practices on the Savannah River Site 1952–2001, with the exception of planting and seeding. Arrows indicate general time frame when SRS initiated and ended specific practices (U.S. Forest Service, unpublished data).

Site Preparation During the early 1990s, the total area harvested and site-prepared declined (see table 3.1). Mechanical site preparation methods declined substantially. Forest managers last used shear-and-rake or shear-and-pile in 1993. Drum chopping occurred significantly only during 1989–1991 for a total of 853 ha (2,109 ac). The increase in wood utilization, use of the V-blade planter, efficacy of herbicides and burning, and selective hand planting essentially have eliminated the need for mechanical treatments. Occasional piling of residual logging debris occurs on a few sites. A slight increase in mechanical site preparation occurred in 1990–1991 to clear debris remaining after a tornado destroyed over 405 ha (1,000 ac) of longleaf pine in 1989. The common method of site preparation on harvested areas in recent years has been a post-harvest application of herbicide. Primarily, forest managers use imazapyr (Arsenal AC), triclopyr (Garlon 4), or hexazinone (Velpar L) and stem injection with triclopyr (Garlon 3A), followed by

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Ecology and Management of a Forested Landscape

broadcast burning of the logging residues. Miller and Chapman (1995) demonstrated that a complex plant community results, sufficient to support a large assemblage of early-successional wildlife species. These treatments, coupled with retention of logging debris and creation of snags, establish longleaf pine and provide a habitat structure that supports a rich avian savanna community (Krementz and Christie 1999). Remaining fragments of natural ground cover vegetation are now being mapped, and research is refining herbicide and mechanical site preparation treatments to enhance native savanna flora.

Planting and Seeding Both the greatest and lowest area planted per year over the last thirty years occurred during this period (see figure 3.2). Forest managers planted about 1,093 ha (2,700 ac) in 1989 and only 150 ha (370 ac) in 1998. The decline in area planted follows the 1991 recovery plan for the redcockaded woodpecker, which emphasized thinning and partial cutting because of the extended rotation ages. In contrast, a small surge in hardwood planting on old-field pine (pine stands grown on old-field sites; see chapter 4) and mixed hardwood sites has occurred since 1992. Many of the areas planted are part of specific ecological restoration projects. While natural regeneration is still preferred in hardwood stands, white and southern red oak are added in enrichment plantings using seed from an SRS seed orchard. As with longleaf, the success of the hardwood program corresponds to general improvements in seed availability, nursery stock, planting methods, and site preparation practices. Beginning in 1991, longleaf pine became the dominant species planted on most regeneration sites. With improved nursery practices, effective competition control, and mechanical planting, survival of bareroot longleaf pine seedlings has been adequate to establish this species. Survival three years after planting was 51 to 90 percent during this period. Longleaf pine is currently type-mapped on about 16,187 ha (40,000 ac). During the 1970s and 1980s, reclassification of forest types and harvesting of understocked or mature longleaf stands, excluding the redcockaded woodpecker management areas, resulted in a fairly stable percentage of the longleaf type despite the additional planting. In 1989, forest managers changed the planting density or spacing to 6.5×10 ft (1,656 trees per ha, or 670 per ac). However, both economic (Teeter, Somers, and Nepal 1998) and ecological studies (Harrington and Edwards 1999) suggest that lower densities may be desirable.

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For a reliable source of longleaf pine seed, SRS established two seed production areas in 1993. On part of the original 1950s old-field plantings, 129 ha (320 ac) were heavily thinned, burned, and fertilized to stimulate cone production. The seed source of the trees is unknown, but their health and appearance suggest well-adapted sources.

Post-Planting Treatments Release of planted pine and hardwood stands using herbicides to control overtopping vegetation continued to be a major silviculture practice until 1998. The primary herbicides used from 1989 to 2000 were hexazinone, imazapyr, triclopyr, and glyphosate. Except in the Pen Branch restoration project, these materials were applied using a ground sprayer. Release treatments peaked in 1996–1997 at approximately 283 ha (700 ac) and declined after the reintroduction of prescribed burning in young longleaf. In 1997–1998, forest managers conducted prescribed burning in young longleaf pine plantings two years or older to control hardwood encroachment. Combined with effective site preparation, burning reduced the need to release longleaf pine with herbicides and facilitated the maintenance or restoration of the native savanna community (see figure 3.4). Release treatments using spot and stem application of herbicide continue in hardwood plantings but only occasionally in loblolly plantings due to the faster growth of that species. Snag creation for cavity-nesting species and perching raptors is currently a post-planting practice. In general, between two and seven residual hardwood or pine trees (more than 30 cm, or 12 in, in diameter) per hectare (between one and three per acre) are killed by applying triclopyr (1989–1994), dicamba (Banvel CST; 1994– 1997), or picloram (Pathway; 2000) to cut stem surfaces. Almost 2,833 ha (7,000 ac) have been treated to create snags on regeneration areas. Improvements in the post and pulp markets that use small-diameter stems and stocking control have reduced the need to thin precommercially. Precommercial thinning activities peaked in 1993 at about 283 ha (700 ac), for a total of 620 ha (1,533 ac) during the period. The SRS commercially thins to eliminate damaged trees and incipient disease or insect infestations, and to reduce the incidence of southern pine beetle attack. Recent studies (Cram 1994) have established that longleaf pine, as well as slash and loblolly, is susceptible to annosum root rot. Selective use of borax treatments in longleaf pine during thinning operations may control the disease in high value red-cockaded woodpecker recruitment stands (Karsky and Cram 1998).

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Ecology and Management of a Forested Landscape

Commercial Harvesting and Regulation The maximum clear-cut harvest area varies from 4 to 40 ha (10–100 ac) and averages less than 16 ha (40 ac) outside the primary red-cockaded woodpecker management area and 4 to 16 ha (10–40 ac; average less than 10 ha, or 25 ac) within the woodpecker zone. Conversion of off-site and sparse stands of slash and loblolly to longleaf pine represents the primary harvest, in addition to a limited number of mixed pine-hardwood stands and new construction sites. Midstory mechanical control in woodpecker stands often stimulates natural regeneration, as well. Managers retain relict pines as nesting trees and hardwoods for den-trees and mast production in regeneration stands in the woodpecker areas. These practices create a partial cut that resembles a traditional seed tree or shelterwood cut, and though the stands are intended to regenerate to longleaf, the residual overstory often controls the subsequent stand composition and development. Thinning in pine-dominated stands has become increasingly important in the last decade, both for generating revenue and for maintaining stand structure and health. Thinning currently generates about half of the wood harvested and 30 to 40 percent of the revenue annually (see chapter 6). The SRS prescribes residual tree basal areas at 16 m2 per ha (70 ft2 per ac) for pole timber and 14 to 18 m2 per ha (60–80 ft2 per ac) for sawtimber. However, both stand growth dynamics (Teeter et al. 1998) and ecological studies have shown that a lower residual stocking is essential to balance growth and mortality and enhance understory fire savanna restoration. Over the last several decades, SRS has gradually reduced the area of forestland available for harvesting to approximately 60,703 ha (150,000 ac) or 82 percent of the total forest area. Approximately 53 percent of the total forest area and 62 percent of the harvestable stands are within the primary or supplemental red-cockaded woodpecker management areas. In 2000, SRS designated an additional 4,452 ha (11,000 ac) as the Crackerneck Wildlife Management Area and Ecological Reserve, managed by the South Carolina Department of Natural Resources. Rotation ages for hardwood were extended sitewide to one hundred years from the previous eighty years, and additional nonharvest buffer restrictions were established for Carolina bays and streams. The SRS still manages pine forests outside the primary red-cockaded woodpecker management area on a fifty-year rotation (Edwards et al. 2000). The smaller area in which harvesting can occur, combined with longer rotation ages (120 years for

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longleaf and 100 years for loblolly pine), has led to a lower even-aged regeneration harvest. The SRS currently harvests about 202 to 324 ha (500–800 ac) of a potential 726 ha (1,800 ac), each year as even-aged regeneration areas. Harvesting continues to be a major wildlife and plant community management tool to shape the landscape patterns, alter stand structure, and facilitate habitat restoration. However, complex management objectives, diverse stand conditions, and prior land use require flexible methods and dynamic guidelines.

Prescribed Fire Management Daniel J. Shea and Bruce A. Bayle Fire as a natural disturbance process has affected the landscape of the Savannah River Site (SRS) for thousands of years (Frost 1997). Prior to European settlement, Native Americans used fire extensively to manage game habitat and clear land for agriculture (White 2004; chapter 1). Lightning ignited fires that burned for many days or even weeks during dry summers. As a result, fire strongly influenced the vegetation structure and composition of most of the SRS uplands and a significant portion of the wetlands (Duncan and Peet 1996; chapter 4). Many native plant and animal communities have adapted (Stout and Marion 1993) to depend on periodic fires. Frost (1997) reconstructed presettlement vegetation and natural fire regimes at SRS. Using historical records, survey plats from 1730 to 1810, topography, and remnant natural vegetation, he estimated that fires influenced the structure and composition of 80 percent of the SRS landscape. March through early June were the months in which both natural and human-caused fires spread across significant portions of the SRS uplands due to continuous fuel loading, favorable weather (chapter 2), and few natural firebreaks. The recurrence interval on these areas was roughly one to three years. In moist locations, around bays and canebrake swamps, and in xeric longleaf-turkey oak stands with limited fuel (see appendix for scientific names), the recurrence interval was probably three to five years. Early European settlers also set fires intentionally to eliminate undergrowth and improve foraging for game and cattle. Those fires set in winter probably burned smaller areas due to cooler temperatures and higher fuel moisture conditions. After 1820, land clearing, farms, roads, and buildings fragmented the natural burning compartments, and human-caused ignition declined due to potential

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economic loss to landowners. Systematic forest fire suppression began in the 1940s in South Carolina (Ware, Frost, and Doerr 1993).

Wildfires Because SRS contains critical facilities interspersed with large expanses of forests, it does not allow wildfires to burn unchecked. Both facilities and personnel are susceptible to smoke and fire (Los Alamos National Laboratory 2000). In addition, uncontrolled fires could destroy a large number of research studies and cultural resources. Economic damage to adjacent landowners could occur if wildfires spread. The potential damage to SRS natural resources depends on fire intensity, season, and age and composition of the stand (Wade and Johansen 1986). While many stands tolerate fire, and natural savanna vegetation benefits from it, more intense fires kill or damage young loblolly pine, hardwoods, and shrubs (White, Waldrop, and Jones 1990). Wildfire occurrences have decreased since 1954 (figure 3.5), reaching the current low level of about ten to fifteen per year in the 1980s. Fewer arson and accidental fires occur on site, and annual burning of the CNX railroad bed area has eliminated flammable fuels. During a six-year period from 1967 to 1972, railroad-caused fires alone accounted for 57 percent of all wildfires at SRS (Beavers et al. 1973). Lightning accounted for only 10 percent. The remaining fires were caused by smokers and burning of debris. From 1990 to 2000, the proportion of human-caused fires from all sources declined to about 73 percent of the total. The total area burned and the average area per fire declined initially but has since remained relatively stable (see figure 3.5). In sixteen of the past twenty-five years, less than 40 ha (99 ac) burned; otherwise, between 41 and 178 ha (101 and 440 ac) burned with the peak during the drought of 2001–2002. Compared with the adjacent states, SRS has about one tenth the number of wildfires per unit area (Georgia Forestry Commission 2001; South Carolina Forestry Commission 2001). In Georgia and South Carolina, 95 to 98 percent are caused by humans. From 1992 to 2001, the average area per fire at SRS (2.1 ha, or 5.2 ac) was similar to that of both Georgia (1.7 ha, or 4.2 ac) and South Carolina (2.2 ha, or 5.5 ac). The single natural cause of wildfires at SRS is lightning. Based on regional estimates (see chapter 2), about 0.04 lightning strikes per hectare per year (0.1 strikes per acre per year), or more than 3,000 strikes annually, occur on SRS. Annual and seasonal variation is enormous and cor-

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Figure 3.5. Number of wildfires and average area per fire (ha) 1954–2002 (calendar years) on the Savannah River Site (U.S. Forest Service, unpublished data).

relates with thunderstorm frequency. Hundreds of strikes can occur during a single thunderstorm, but none will cause a fire if significant rain falls with the lightning or if the fuels are otherwise moist. If precipitation exceeds 6 to 7 mm (0.25 in), lightning rarely causes wildfires. From 1990 to 2000, an average of 2.7 lightning-caused fires occurred each year. During 2000 and 2002, lightning caused 14 and 9 fires, respectively.

Prescribed Fire The term prescribed fire refers to fire applied in a knowledgeable manner to forest fuels on a specific land area under selected weather conditions to accomplish predetermined, well-defined management objectives (Wade 1988). Strategies may vary the timing, frequency, and intensity of fire. Wildland fire is innately neither destructive nor constructive; it is simply a natural disturbance that causes change. In the South, managers prescribe fire to improve habitat for game species (Landers 1987), to enhance plant diversity and habitat for endangered species (Conner, Rudolph, and Walters 2001), to remove understory vegetation, to reduce fuel loading and the occurrence of catastrophic wildfires (Davis and Cooper 1963), to prepare areas for planting or natural seeding, to sustain and enhance range lands (Brockway and Lewis 1997), and to control certain diseases (Wahlenberg 1946).

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Trends at SRS At the SRS, objectives for prescribed burning are specific to each treated area. The purposes have shifted since prescribed burning began in the 1950s (figure 3.6). Burning from 1952 to 1969 primarily targeted brownspot control in young longleaf plantations. From 1970 to 1979, burning prepared areas for planting and reduced fuels, particularly on railroad rights-of-way. Beginning in 1980, burning was also conducted to improve wildlife habitat, both to control the midstory for the endangered redcockaded woodpecker and to stimulate browse for white-tailed deer (Odocoileus virginianus) and wild turkey (Meleagris gallopavo). More recently, limited burning for research has enhanced plant diversity and restoration. Over the last ten years, 58 percent of the burning was for wildlife habitat improvement, 36 percent for fuel reduction, 5 percent for planting site preparation, and 1 percent for research. While the primary objective controls the prescription for the burn, other resources may also benefit. For example, any burn will assist in fuel reduction. Much research has examined burning conditions that maximize benefits and minimize damage (e.g., Wade and Johansen 1986; White et al. 1990; Sullivan et al. 2003); however, applying that standard to large areas can be difficult. Because of smoke dispersion conditions, weather, fuel moisture, availability of personnel, and resource damage constraints, only fifty to seventy-five days per year are suitable for burning at SRS. Managers must use every suitable day to achieve prescribed burning goals. These constraints are reflected in variations in the total area burned each year (see figure 3.6). The area burned tripled from 1977 to 1980 due to more aggressive management but immediately declined after new South Carolina smoke management restrictions were enacted. It increased again in 1992 to 6,000 to 8,000 ha per year (14,826–19,816 ac per year) when aerial ignition allowed large areas to be burned in a single day. The area burned declined sharply in fiscal year 2002 because the extremely dry weather increased wildfire hazard.

Characteristics of Prescribed Fires at SRS Burning at SRS is typical of burning on other forestlands in the Southeast, particularly in national forests. Similarities include ignition methods, size of burns, recurrence intervals, seasons, weather and fuel moisture parameters (Wade 1988), burning indices (Burgan 1988), and fuel loading and consumption. Differences exist primarily due to the more re-

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Figure 3.6. Trends in prescribed burning at the Savannah River Site, 1952–2002 (fiscal years, October 1–September 30). Shaded area for each type of burn represents the proportion of total acreage. RCW = red-cockaded woodpecker. “Other” includes brown spot control 1952–1970 and research burns 1995–2002 (U.S. Forest Service, unpublished data).

strictive smoke management standards in South Carolina (South Carolina Forestry Commission 1998) and the complexity of burning around industrial facilities and special-use areas. Prescribed fires are ignited by hand or by aerial means. Hand burns range in size from 2 to 200 ha (5–494 ac) and aerial ignition burns from 80 to 1,300 ha (198–3,212 ac). Burns are planned to recur on most areas every three to five years, both to maintain low fuel loading and to eliminate woody vegetation. However, due to smoke management constraints and fuel conditions, lands near facilities and certain public roads may not be retreated for ten years or more. The primary recovery area for the red-cockaded woodpecker receives priority and is designed to minimize smoke management constraints and to optimize ecological attributes. The SRS conducts prescribed burning during all seasons. Site preparation burning for new planting areas normally occurs during the fall. Historically, prescribed burning in the forest understory occurred from December through late March, ending in time to avoid potential impacts on wild turkey nesting and to reduce damage to standing timber during the period of new growth. In the early 1990s, burning extended into the growing season, from mid-May through the end of July, to increase fuel

3.56 2.52 10.91 11.95 6.59 13.01 23.04 5.81 1.91 1.06 0.61 1.68 2.23

1 2 3 4 5 6 7 8 SC4 SC5 SC6 SC8 SC9

3.29 2.50 12.11 14.90 8.48 12.40 18.72 5.45 1.93 1.32 0.39 0.88 1.29

Postburn 0.36 1.22 0.29 0.29 2.43 4.57 1.91 1.13 0.29 0.04 0.72 0.53 0.78

Preburn 0.32 0.47 0.54 0.59 1.31 0.34 1.62 1.80 0.20 0.00 0.09 0.14 0.09

Postburn

Live vegetationc

10.76 11.48 12.33 13.30 10.10 6.14 11.21 7.00 25.44 12.96 21.43 3.64 4.82

Preburn 4.10 2.50 6.50 6.80 3.87 2.34 4.46 3.76 13.46 6.13 3.06 1.24 1.87

Postburn

Forest floord

6.98 9.95 4.41 3.24 5.49 9.27 11.34 4.05 12.04 6.61 19.21 3.60 4.58

Total fuel reduction

Source: Scholl and Waldrop 1999; W. Hao et al., unpublished data. Note: 1 metric ton/ha = 0.367 tons/ac. a Reference no. refers to fuel complexes (1–8) in Scholl and Waldrop or burn number (SC4–SC9) of Hao et al. b Woody debris refers to dead branches, stems, and logs on the forest floor. Scholl and Waldrop include all fuel classes (1-hr, 10-hr, 100-hr, and 1,000-hr), but Hao et al. include only 1-hr and 10-hr. c Live vegetation refers to grasses, herbaceous plants, vines, and small trees. d Forest floor refers to freshly fallen leaf material and older organic layers.

Preburn

Reference no.a

Woody debrisb

Table 3.2 Pre- and postburn fuel loading (metric tons/ha) and total fuel reduction

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reduction, woody vegetation control, and herbaceous plant response. Growing-season burns range in size from 4 to 60 ha (10–148 ac) compared to the 80 to 1,300-ha (198–3,212-ac) burns during the dormant season. The annual area of growing-season burns is less than 1,000 ha (2,471 ac) and is concentrated in red-cockaded woodpecker recovery areas. During the past several years, prescribed fire in young longleaf pine within two years after planting has reduced hardwood competition and sustained fire-dependent savanna species (Harrington and Edwards 1999). Controlling fire-intolerant species reduces herbicide use, and stands are conditioned to future burning by the reduction in fuel load. Fuel loading and fuel consumption are important indicators of burning impacts on natural resources. Fire managers consider live and dead fuels separately. Live materials include grasses and herbaceous vegetation, low shrubs and vines, and small trees. Dead fuels include fresh litter, surface organic layers, and woody material less than 6.5 mm (0.25 in) in diameter (1-hour fuels), 6.5 to 25 mm (0.25–1 in; 10-hour fuels), 25 to 75 mm (1–3 in; 100-hour fuels), and more than 75 mm (3 in; 1,000-hour fuels). Both dead and live materials contribute to wildfire spread, suppress desirable vegetation, and discourage red-cockaded woodpeckers from nesting. Low-intensity, less severe fires consume only litter, grasses, and woody material less than 25 mm (1 in) in diameter. Fires of greater intensity and severity consume more material and kill live woody vegetation partially or completely. Several studies at SRS have examined fuel loading and consumption in clear-cuts and forests. Total fuel loading on several clear-cuts ranged from 21.8 to 46.6 metric tons/ha (8–17.1 tons/ac), and fuel consumption ranged from 24 to 27 percent, largely litter and small deadwood components (McNab, Ach, and Shimel 1976). Available fuel loading in forest stands ranged from 14.6 to 36.2 metric tons/ha (5.4–13.3 tons/ac; table 3.2), and total fuel consumption averaged about 6.8 metric tons/ha (2.5 tons/ac) or 32 percent (Scholl and Waldrop 1999). In these low-intensity and low-severity burns, nearly all the consumed fuel came from the forest floor and live vegetation. W. Hao et al. (U.S. Forest Service, unpublished data) examined emissions from prescribed burning in forest stands and monitored fuel reduction on five prescribed burns at SRS. Total fuel loading ranged from 5.8 to 27.6 metric tons/ha (2.1–10.1 tons/ac; table 3.2). Fuel reduction varied from 39 to 85 percent of the initial loading, nearly all of which was derived from the forest floor and live vegetation. These differences demonstrate the range in consumption due to weather, season, fuel moisture, fuel loading, and ignition methods.

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Air Quality Impacts Burning releases a large amount of particulate matter (PM) and gases (W. Hao et al., unpublished data; U.S Environmental Protection Agency 2001a). The greatest impact of smoke on air quality results primarily from PM that is less than either 2.5 (PM2.5) or 10 (PM10) microns in diameter (U.S Environmental Protection Agency 2000a). Particles that are 2.5 microns or less present the greatest health risk to humans. Smoke is also a safety hazard and a nuisance near roads, facilities, and homes, regardless of health concerns. The standards established for PM10 require that average concentrations be below 150 µg/m3 over a twenty-four-hour period, and the annual mean must be less than 50 µg/m3. For PM2.5, the average concentrations must be less than 65 µg/m3 over a twenty-four-hour period and less than 15 µg/m3 annually (two days in one hundred). While the impacts from prescribed burning are important, the largest mass of PM2.5 in the Southeast comes from sulfates produced by electric utilities; prescribed burning contributes only a small percentage of the total PM2.5. Concerns were raised about radiological emissions from both wildfire and prescribed burning after wildfires during 2000 at Department of Energy facilities in Los Alamos, New Mexico; Hanford, Washington; and the National Engineering Lab, Idaho. However, monitoring at those facilities and statewide demonstrated that the radiological emissions in smoke are naturally occurring elements from the decay of radon gas ( Jacobson 2001). In South Carolina, the South Carolina Forestry Commission develops and implements management guidelines to minimize smoke impacts from burning vegetative debris (South Carolina Forestry Commission 1998). The main objective is to ensure that the smoke column rises above ground level away from sensitive areas and disperses in the upper atmosphere, keeping ground-level concentrations from exceeding air quality standards (figure 3.7). For prescribed burning, South Carolina assigns each day a classification from 1 to 5 to limit the combination of area and amount of fuel consumed, as well as the hours of ignition and termination. The classification varies with weather conditions such as predicted wind speed and direction, mixing height and stability, relative humidity and temperature, and rainfall. Current guidelines severely limit burning after dark because inversions, which trap smoke near the ground, routinely occur at night (Lavadas 1997). Research at SRS is currently monitoring PM10 and PM2.5 emissions from smoke and smoke plume dispersion. Equation (1) yields an estimate

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Figure 3.7. Under proper conditions, smoke from prescribed burning is carried upward and away from sensitive areas (L. Naeher).

of the average annual PM10 production from SRS based on the average area burned from 1993 to 2002 (see figure 3.6), fuel consumption (see table 3.2), and an emission factor (AP-42 table, in U.S. Environmental Protection Agency 2001b): Area (5,646 ha/yr) × Fuel (8,295 kg/ha) × Factor (0.0188 kg/kg) = PM10 (880,471 kg/yr)

(1)

Equation (2) yields a similar estimate for PM2.5 using an emissions factor derived from five burns at SRS in 1996 (W. Hao et al., unpublished data). Area (5,646 ha/yr) × Fuel (8,295 kg/ha) × Factor (0.0128 kg/kg) = PM2.5 (599,470 kg/yr)

(2)

These estimated particulate emissions represent 4 percent of total inventoried PM10 emissions and 7 percent of the inventoried PM2.5 emissions in the three counties near SRS (PM10 = 21,646,335 kg/yr, PM2.5 = 8,451,333 kg/yr for area and point sources within Aiken, Barnwell, and Richmond Counties; Environmental Protection Agency 2000b).

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Table 3.3 Observed annual mean 24-hour PM10 values (µg/m3) from three counties near the Savannah River Site County

1995

1996

1997

1998

1999

2000

Aiken, SC Barnwell, SC

19 16

19 17

21 19

23 19

21 19

21 23

Richmond, GA

NAa

24

26

28

24

23

Source: U.S. Environmental Protection Agency 2001a. a NA = Not available

While official PM2.5 monitoring data for South Carolina are not available, unpublished data indicate that emissions at rural sites exceed the annual PM2.5 concentration standard of 15 µg/m3 from April to September each year. The possibility that PM2.5 standards might be exceeded near the forest-urban interface could restrict burning in the future. In contrast, PM10 concentrations seldom approached half of the annual mean standard of 50 µg/m3 (table 3.3).

Ecological Restoration Christopher D. Barton, John I. Blake, and Donald W. Imm The long history of human settlement, agriculture, and industry at the Savannah River Site (SRS) has created extensive opportunities for ecological restoration. Two hundred years of farming, drainage, dam construction, stream channeling, fire protection, subsistence hunting and fishing, exotic animal and plant introduction, and selective timber harvesting have caused major changes in the SRS landscape (table 3.4). These activities degraded the native plant and animal communities by removing species for commercial use (e.g., longleaf pine, white oaks; see appendix for scientific names of plants) or subsistence needs (e.g., white-tailed deer, wild turkey [Meleagris gallopavo]; see table 4.24 for scientific names of mammals). Tillage eliminated native vegetation locally, and exotics (e.g., kudzu, hogs, and cattle) competed with or damaged native species. Activities also altered natural hydrologic and wildfire regimes essential to the maintenance of native communities. Baseline surveys of the flora and fauna at SRS in the 1950s provide a measure of the degree of human impact (e.g., Batson and Kelley 1953; Freeman 1954; Freeman 1955).

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Since the establishment of SRS, certain activities have also directly or indirectly affected native plant and animal communities. Industrial operations, such as the discharge of thermal effluent to streams (Halverson et al. 1997) and construction of facilities (Mayer and Wike 1997), caused contamination and habitat loss. The planting of non-native slash pine on old fields, harvesting of older trees in remnant forests, and site preparation for planting altered vegetation composition. Management activities that contributed to ecological restoration of the SRS occurred regularly during the first several decades of the Site’s operation. These include planting and seeding of longleaf pine, initiation of prescribed burning, draining of impoundment areas, reintroduction of the eastern wild turkey, and restoration of red-cockaded woodpecker habitat. The single most important restoration activity was probably the establishment of the buffer zone (unoccupied by human residents) to isolate the SRS facilities (Baker and Chesser 2000). This action allowed some native species to recover without further intervention (Beavers et al. 1973; Jenkins and Provost 1964). Those species included the American alligator, white-tailed deer, beaver, bobcat, and many reptiles and amphibians (see chapter 4). Similarly, certain silvicultural activities such as planting, harvesting, and burning have accelerated natural plant succession and expansion of native savanna plants (Smith 2000) and increased the abundance of important wildlife food plants (McCarty et al. 2002). In addition, protection of unique communities for research allowed recovery of local populations of aquatic species (Davis and Janecek 1997).

Current Ecological Restoration Strategies and Activities Restoration efforts have expanded in the last decade as knowledge of presettlement conditions (Frost 1997), current community distributions (chapter 4), and restoration techniques have increased. In general, the goal of ecological restoration at SRS is to restore native species, their habitats, and key environmental processes while retaining the integrity of the Site’s missions.

Hardwoods Early survey plats show a dominance of pine, but white oaks (e.g., Quercus alba, Q. stellata, Q. michauxii) were a common hardwood species two hundred years ago (Frost 1997), occupying the most fertile soils. These hardwood forests represent the preferred habitat for many wildlife species

Construction of mill dams, impoundments, and channeling streams Isolations and reductions in size of native vegetation areas

Drainage and farming of seasonal wetlands such as Carolina bays

Farming activities involving intensive tillage, chemicals

Loss of seasonal wetlanddependent species of plants and animals Altered stream structure and associated fish, plants, and invertebrates Fragmentation of the communities, limiting dispersal and densities

Loss of tree species and critical habitat for dependent species Dominance of woody shrubs and trees, loss of grass and herbaceous plants Loss of or reductions in major vertebrate species Competition with and predation on natives, and destruction of rare plants Local destruction of vegetation, stream sedimentation

Selective harvesting of commercial pines and hardwoods Forest fire prevention, limiting the spread of natural fires

Subsistence hunting, fishing, and predator control Introduction of exotic plants and animals not native to SRS

General ecological impacts

Post-European settlement activity

Replant or regenerate species on appropriate sites Thin stands and establish regular burning regimes during winter and summer Regulate hunting and fishing and selectively reintroduce species Direct control of non-natives where problems are localized

Restoration strategies

Tillage impacted 75% of SRS, with Revegetate old fields and bare widespread use of arsenic, areas, stabilize streamside areas nitrogen, phosphorus fertilizer Most wet depression meadows Restore hydrology, reintroduce farmed, >50% drained by ditching selected native wetland vegetation Probably >20 small dams and Break down water-holding ponds on streams at SRS structures to reestablish in 1951 natural flow Farming estimated to directly Reestablish native vegetation and impact 75% of SRS, about 60% large blocks of specific types forested in 1951

Longleaf pine, white oaks, bald cypress, swamp tupelo Loss of savanna herbs and grasses on remnant sites and associated animals Bison, black bear, red wolf, cougar, sturgeon, gopher tortoise Feral hogs, dogs, fire ants, kudzu

Examples specific to SRS

Table 3.4 General ecological impacts from post-European settlement in the Central Savannah River Area and strategies for ecological restoration

86 Ecology and Management of a Forested Landscape

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(chapter 4). Although the approximate area and distribution of hardwood stands is similar to that of pre-European settlement (Frost 1997), human activities have drastically altered the composition. Colonial settlers preferred oaks for barrels, furniture, and fuelwood. As a result, oaks declined to the point that they are no longer dominant in most hardwood stands on SRS. Certain red oak (e.g., Q. falcata) and hickory (e.g., Carya pallida) species sustained less dramatic reductions. Hardwood stands currently occur along stream corridors, near the Savannah River swamp on nontillable soils, and on sandhill soils too poor to farm. Upland stands often occur in small isolated remnants that escaped fire, in fencerows, and in stringers leading from stream corridors through the uplands. The current management objective is to maintain the existing percentage of land area in hardwood, mixed pine-hardwood, and bottomland swamp forest stands. Some area reduction within the primary red-cockaded woodpecker recovery zone (see chapter 1) may be offset by increases in the other zones through conversion of old-field pine to mixed hardwood-pine on mesic or wet soils. Restoration goals are to improve the quality of the species mixture in stands, particularly increasing white and red oaks, dogwood, holly, and other species that are soft fruit–producing. Experimental planting of various hardwood species in existing hardwood and old-field stands has occurred since the mid-1960s. However, poor stock quality, competition, and inappropriate site selections limited success. Since 1993, the SRS has planted 157 ha (388 ac) of hardwood on moist sites with a mixture of cherrybark oak, swamp chestnut oak, willow oak, green ash, white oak, and sycamore (figure 3.8a). Limited seed and seedling availability is a major constraint to planting more white and red oaks on suitable sites. Methods for restoring hardwoods include harvesting, usually clear-cutting small blocks of either pine or previously high-graded hardwood stands, followed by site preparation, which may include burning and herbicides. Enrichment planting of various oaks and other species is followed by competition release using mechanical cutting or spot treatment with herbicide. Natural regeneration of oaks is often unreliable due to previous removals, irregular acorn crops, and high acorn consumption by animals. The SRS developed a cooperative seed orchard to help supply southern red and white oak seed. Because size and root development of the bare-root stock is critical to long-term survival and growth (Kormanik, Sung, and Kormanik 1994), nursery managers carefully select the stock. Root competition and shading from overstory trees result in poor growth of species planted in the

Figure 3.8. Locations of restoration projects on the Savannah River Site: (a) mixed hardwood stands restored since 1993; (b) Carolina bays with restoration activity since 1989 (bays not labeled are the nineteen bays in the mitigation bank); (c) red-cockaded woodpecker habitat restored since 1983 by midstory removal and prescribed burning; and (d) sites selected for establishment of savanna plant populations in old-field pine stands. RCW = red-cockaded woodpecker (U.S. Forest Service, unpublished data).

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understory (R. H. Jones, Virginia Polytechnic Institute, unpublished data), so planting in newly cleared areas free of competition is preferable.

Bottomlands and Riparian Zones: Pen Branch The SRS has a “no net loss” wetlands policy and a wetlands banking program to mitigate potential loss of wetlands on the site. Several wetland mitigation projects involving the creation, restoration, or enhancement of wetlands have been performed on SRS (Irwin et al. 1997). The Pen Branch restoration, required for the continued operation of K Reactor (U.S. Department of Energy 1991), exemplifies the mitigation process at SRS. The Savannah River swamp is a 3,020-ha (7,462-ac) forested wetland on the floodplain of the Savannah River at the SRS (see figure 2.4). Historically the swamp consisted of approximately 50 percent bald cypress–water tupelo stands, 40 percent mixed bottomland hardwood stands, and 10 percent shrub, marsh, and open water (Nelson, Dulohery et al. 2000). Major impacts to the swamp hydrology and vegetation occurred with the completion of nuclear production reactors in the early 1950s. Water was pumped from the Savannah River through secondary heat exchangers of the reactors and discharged into tributary streams that flowed into the swamp. From 1954 to 1988, SRS discharged hightemperature effluents in excess of 65° C (149°F) into one of the tributaries, Pen Branch, at rates often twenty to forty times greater than normal flow. The sustained increases in water volume resulted in overflow of the stream banks, erosion of the original stream corridor, and deposition of a deep silt layer at the confluence of Pen Branch and the river floodplain. The nearly continuous flooding of the swamp, the thermal load of the water, and the heavy silting resulted in complete mortality of the original vegetation in the Pen Branch corridor and in large areas of the river floodplain (figure 3.9). Once SRS reduced the pumping, natural reestablishment of early successional species like cattail, bulrush, buttonbush, pokeweed, blackberry, and black willow occurred in the affected areas. However, few volunteer seedlings of bottomland hardwoods or bald cypress were evident. Therefore, a mitigation action plan was formulated to guide the restoration of the degraded Pen Branch wetlands. The successful completion of the mitigation entails three strategies: (1) the rehabilitation of the Pen Branch corridor and delta by natural succession, (2) the reforestation of the corridor and delta by planting, and (3) the compensatory mitigation of other

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Figure 3.9. Aerial view of the Pen Branch corridor and delta on the Savannah River Site during reactor operations (U.S. Forest Service files).

impacted areas on the SRS pending evaluation of the success of the first two approaches. From 1993 to 1995, the SRS planted approximately 75 percent of the affected Pen Branch floodplain area in bottomland hardwood tree species, keeping the remaining area (25 percent) unplanted for experimental purposes (figure 3.10). Three restoration approaches were formulated to address the differing conditions of the impacted floodplain. Approximately 8,700 seedlings were planted in the lower corridor (15 ha, or 37 ac) without any site preparation, and the delta (12 ha, or 30 ac) was planted after herbicide application in the absence of burning (figure 3.11). The upper corridor (24 ha, or 60 ac) was planted after the application of herbicide and a prescribed burn. Herbicide application and prescribed burning were performed to control a dense black willow overstory and to clear brush and vines from the planting area. Tree species included in the plantings were overcup oak, swamp chestnut oak, nuttall oak, willow oak, cherrybark oak, water hickory, persimmon, green ash, sycamore, swamp black gum, water tupelo, and bald cypress (Dulohery et al. 1995). While the stream structure and aquatic communities were not manipulated, the trees were expected to alter light, temperature, and organic debris (logs, leaf litter) in the stream favorably for fish and invertebrates. In

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Figure 3.10. Degraded wetland areas of the Pen Branch corridor and delta on the Savannah River Site that were impacted by thermal releases from reactors and later restored as part of the mitigation effort.

addition, several areas of open water in the delta were left unplanted with cypress or tupelo to benefit wading birds, waterfowl, and alligators. The SRS developed an extensive research program to examine the restoration ecology of the Pen Branch system. A special edition of Ecological Engineering (Nelson, Kolka et al. 2000) outlines many of these studies. Tree seedling studies indicated that many site preparation techniques (burning, herbicides, thinning) did not significantly impact early growth or survival (Dulohery, Kolka, and McKevlin 2000). However, tree shelters

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Figure 3.11. Planting trees in the Pen Branch corridor on the Savannah River Site, 1993 (U.S. Forest Service files).

and root pruning were effective silvicultural techniques that enhanced survivability in areas prone to stress from herbivory and competition (Conner, Inabinette, and Brantley 2000). A 1997 survey showed that water tupelo, green ash, sycamore, and persimmon had the highest survival in the upper corridor, while bald cypress survived best in the wetter lower corridor and river delta areas (Kolka et al. 1998). Although species abundance and, in some cases, diversity are higher in the Pen Branch floodplain than in the reference systems (table 3.5), the composition of plant and animal communities and key energy sources such as soil carbon and nutrients indicate that the Pen Branch floodplain remains an immature, early successional system but is moving toward recovery (Giese et al. 2000; Wigginton, Lockaby, and Trettin 2000). Pen Branch is currently functioning as a viable early successional wetland. Kolka et al. (2000, 2002) used measurements of hydrology, soils, vegetation, carbon and nutrient cycling, and animal communities to predict wetland function in response to the restoration. As a consequence, SRS wetland restoration research will serve as a template for future wetland restorations on site and elsewhere.

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Table 3.5 Species richness, calculated as either total number of species observed or average number, for taxa in Pen Branch compared with disturbed post-thermal (20–30 years) and late successional forested reference sites at the Savannah River Site

vegetationa

Fourmile Branch Meyers Branch and Steel Creek and Tinker Creek

Pen Branch

Pen Branch

(unplanted)

(planted)

(post-thermal)

(reference)

81 2.35 22.4

79 2.86 NA

68 2.23 NA

63 2.96 17.6

44.4 8.2 21

44.2 9.7 18

NA 16.3 15

NA 19.1 12.5

Total Herbaceous speciesa Macroinvertebrate ordersb Herpetofaunal speciesc Avian speciesd Fish speciese a Giese

et al. 2000. and McArthur 2000. c Bowers et al. 2000. d Buffington et al. 1997. e Paller et al. 2000. b Lakly

Carolina Bays The SRS has several hundred Carolina bays or baylike depression wetlands, ranging from small (less than 0.1 ha or 0.25 ac) ephemeral bays to large (larger than 50 ha or 124 ac) bays that retain water for most of the year (chapter 2; Schalles et al. 1989). They serve as habitat for a wide range of rare plants and many vertebrates. The adjacent uplands also provide nesting sites for turtles and birds, as well as niches for facultative wetland plants. Although bays share some common plant and animal associates, the variability in composition between bays with similar soil, hydrology, and geomorphic conditions suggests that periodic rainfall, fire, and chance colonization also influence the observed flora and fauna (Greenberg and Tanner 2004). Predicting the restored structure and composition of the dominant vegetation of a disturbed bay is difficult, even using current topographic, soil, and hydroperiod conditions (De Steven and Toner 1997). In a specific restored bay, predicting the species of vertebrates and invertebrates, particularly rare or sensitive species, is even more difficult. Initial estimates by Kirkman et al. (1996), based on 1951 aerial photography, indicated that approximately two thirds of these isolated wetlands and nearly all of the associated uplands had been altered by human

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Figure 3.12. A drainage ditch from a Carolina bay on the Savannah River Site. The bay is visible as the canopy opening in the background (U.S. Forest Service files).

activities such as draining (figure 3.12), farming, harvesting, and restriction of fire. However, beaver dams and other natural processes have closed the drainage ditches in some bays and natural recolonization has occurred without human intervention. Thus, the need for restoration is limited to those sites where the level of disturbance is such that recovery will not occur by natural processes alone. To identify sites effectively altered by drainage activities, SRS scientists recently considered information from geographic information databases, published reports, and field visits (table 3.6), in addition to the 1951 aerial photography (Kirkman et al. 1996). They determined that 195 (57 percent) of the 343 depression wetlands on SRS are not effectively drained. Nineteen bays were destroyed by construction activities in the early decades of Site operations. Of the remaining 129 bays, 4 were restored in the early 1990s, 16 are currently being restored, and another 3 are scheduled for restoration in 2006–2007. Field visits have yet to confirm the status of 92 bays with ditches evident in 1951. Prior to the initiation of restoration, the influence of residual overstory trees, burning, and soil disturbance on vegetation in bays was unknown. In December of 1989, three intact bays (Bays 56, 57, 58) were experi-

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Table 3.6 Level of disturbance to surface hydrology by drainage ditches in isolated depression wetlands at the Savannah River Site in 2002 Status of hydrological disturbance 1951a

No ditch present in Ditch present in 1951, but no drainageb Ditch present in 1951, drainage confirmedc Ditch present in 1951, restoredd Ditch destroyede Ditch present in 1951, drainage status unknownf Total

Number

Percent

124 71 14 23 19 92 343

36.2 20.7 4.1 6.7 5.5 26.8 100

a No

evidence of drainage appeared in 1951 photograph, though some wetlands were probably farmed. b Ditches were filled through natural processes, or slope of drain was inadequate, for drainage. c Not all wetlands are potential restoration candidates due to proximity to site operations. d Includes four restored in the 1990s (Lost Lake, 170, 5119, and 93), sixteen restored in 2002, and three scheduled for 2006. e Destroyed in the early decades of SRS facility development and operations. fNot field checked to confirm condition.

mentally burned and tilled to test certain hypotheses. Soil tillage stimulated vegetation diversity, recruitment from the seed bank, and rare plant occurrence (Kirkman and Sharitz 1994). Active bay restoration (figure 3.8b) started with Lost Lake in the late 1980s and early 1990s (Halverson et al. 1997). Lost Lake is a bay impacted by the M Area waste retention basin overflow. Though farmers had previously drained Lost Lake, contamination from the basin required the bay to be redrained, the contaminated soil removed, and the area revegetated with native species. The hydrologic restoration was successful, but removal of soil probably had a detrimental effect; after restoration, reptiles have declined adjacent to the bay and non-native cattails have invaded (Halverson et al. 1997). Three drained bays (Bays 106, 170, and 5119) were restored in the early 1990s by harvesting the trees and plugging the ditches. However, for a variety of reasons (e.g., potentially limited seed bank, lack of soil disturbance, drought) few if any wetland plants naturally recolonized the areas, and the ditch plug on Bay 106 failed. In 1994, the drainage ditch of Bay 93 was closed, half of the wetland was harvested, and half of each portion (harvest/nonharvest) was burned. After four years, both harvesting

1.4 1.3 3.0 0.4

Species richness

Species richness 2.3 1.3 15.1 15.0

Wetland speciesa NSb NS NS NS

1994

a

0 0 45.1 42.5

Wetland speciesa

Source: J. Singer, Savannah River Ecology Laboratory, unpublished data. Percent obligate and facultative wetland plants. b NS = not sampled.

Control Burn Harvest Harvest and burn

Treatment

1993

1.2 1.0 13.1 10.7

Species richness

1995

0 0 57.7 61.8

Wetland speciesa

3.8 2.1 5.9 4.0

Species richness

1998

NS NS 74.8 61.1

Wetland speciesa

Table 3.7 Effects of burning, harvesting, and harvesting plus burning on the average herbaceous species richness and percent wetland species occurring in Bay 93 on the Savannah River Site before and after closing the drainage ditch in 1994

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and harvesting-plus-burning treatments increased wetland plant species richness (table 3.7; Singer 2002). In the late 1990s, an experimental approach was developed to restore several bays in conjunction with a wetland mitigation banking program. In 1997, SRS established a wetland mitigation bank to compensate for unavoidable wetland losses from future authorized construction and environmental restoration (U.S. Department of Energy 1997). The bank will not only hasten mitigation efforts with respect to regulatory requirements and implementation, but also will provide on-site and fully functional mitigation in advance of impacts. Using information and techniques from previous SRS work (as outlined above), researchers and managers identified nineteen Carolina bays in the nonindustrialized management area of SRS as candidates for restoration (see figure 3.8b). All nineteen bays possessed an active drainage ditch and a vegetation composition characteristic of a disturbed wetland system. Of the nineteen bays, sixteen (totaling approximately 20 ha, or 49 ac) were restored in 2001 by plugging the ditches and altering the vegetation. The remaining three bays serve as nonrestored controls in the interim. Undisturbed bays of similar size were used as reference sites. Several alternatives for restoring bays and adjacent uplands are being compared in a factorial design. On the SRS, two principal upland habitats commonly occur with Carolina bays: fire-managed, open-canopy pine savannas and relatively unmanaged, unburned, closed-canopy mixed pine-hardwood forests. To gain a better understanding of the relationship between buffer zone management and wetland properties, these two upland management alternatives are being examined as longterm goals. Bay-margin treatments were applied to a 100-m (328-ft) radius, from bay rim into the upland (figure 3.13). With each of these two upland alternatives, the bays were organized such that two wetland vegetation types (herbaceous and forested) were established, thus creating four bay-margin community combinations. Approximately 10 percent of the interior of herbaceous bays was planted with obligate wetland grasses (Panicum hemitomon and Leersia hexandra). The remaining area was not planted, but natural succession was encouraged through soil scarification. Forested bays were planted throughout their interior with swamp tupelo and bald cypress. Planting was initially successful, and most of the bays exhibited an increased hydroperiod during the first year of recovery compared to the control and reference systems. By 2002, however, all of the study sites,

a

b

Figure 3.13. Aerial view of restored Carolina bays on the Savannah River Site with (a) a mixed pine-hardwood margin (unthinned) and (b) a pine savanna margin (thinned), 2001 (Westinghouse Savannah River Co.).

including reference wetlands, had dried in response to a severe regional drought. Nevertheless, several species of amphibians, birds, and bats continued to respond positively to the treatments. Monitoring of biotic and abiotic conditions will record progress for five years, 2002–2006, to determine the final net improvement for each wetland.

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Savannas Frost (1997) estimated that fire-maintained savanna communities historically occupied 80 percent of SRS uplands. Grass and herbaceous species originally dominated these communities, which had a pine overstory with scattered fire-tolerant hardwoods (e.g., Q. incana, Q. stellata, Q. marilandica). National programs are conserving and restoring these communities for their tremendous species richness of plants, as many as one hundred species per 0.1 ha (0.25 ac; E. W. Kjellmark, P. D. McMillian, and R. K. Peet, University of North Carolina, unpublished data). In addition, savannas provide habitat for several vertebrate species of concern in South Carolina. These include the gopher tortoise (see tables 4.20 and 4.22 for scientific names not given), gopher frog, pine snake, southern hognose snake, Bachman’s sparrow, northern bobwhite (Colinus virginianus), prairie warbler, and red-cockaded woodpecker. These communities depend on frequent fires to maintain the vegetation complexes. In 1951, many relict savanna plants occurred only along roadsides and in isolated woodlots (W. Batson, University of South Carolina, pers. comm.). Many vertebrate species persisted in clear-cut or heavily thinned stands that simulate the understory vegetation structure of native savannas (Krementz and Christie 1999). In 2001, the Department of Energy approved a plan to restore the gopher tortoise, and approximately one hundred tortoises were reintroduced on SRS (see chapter 4). Through the 1980s, forestry activities indirectly facilitated restoration and recovery of the savanna communities. The area of longleaf pine more than doubled, and over 12,141 ha (30,000 ac) of scrub oak received stem injection to release seeded or natural longleaf. In 1977, the prescribed burning program was greatly expanded to reduce fuel loading. Managers removed undesirable midstory hardwoods with chemical and mechanical treatments to improve red-cockaded woodpecker habitat (see figure 3.8c). The combined effects of harvesting and burning resulted in favorable conditions for savanna flora and fauna (Harrington and Edwards 1999; Johannsen 1998). In 1991, in systematic surveys of the upland pine forests, botanists identified state- and federally listed plant populations (chapter 5). In 1992, managers integrated red-cockaded woodpecker recovery with restoration of the savanna system as a whole. Research has established the composition of the pre-European landscape and general distribution of fire savannas (Frost 1997); the land-use history at SRS (White and Gaines 2000); and the distribution of savanna plant communities with respect to soil, topography, hydrology, and

Figure 3.14. Distribution of remnant and degraded savanna plant communities in relation to land-use and fire exclusion history, mapped for potential savanna restoration on a representative section of the Savannah River Site (C. Frost, The Nature Conservancy, unpublished data).

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Table 3.8 Savanna grasses, composites, and legumes selected for experimental introduction to old-field pine sites at the Savannah River Site to establish founder populations Species Andropogon tenarius Anthaenantia villosa Aristida beyrichiana Aristida purpurascens Aster concolor Aster tortifolius Baptisia lanceolata Baptisia perfoliata Berlandiera pumila Carphephorus bellidifolius Chrysopsis gossypina Coreopsis major Desmodium strictum Eriogonum tomentosum Eupatorium album Eupatorium cuniformis Eupatorium curtsii

Species Galactia macreei Lespedeza hirta Liatris elegans Liatris secunda Liatris tenuifolia Nolina georgiana Petalostemum pinnatum Pityopsis graminifolia Polygonella americana Schizachyrium scoparius Silphium compositum Sorghastrum secunda Sporobolus junceus Stylisma patens Tephrosia florida Vernonia angustifolia

landform (Duncan and Peet 1996). The Nature Conservancy has helped map and classify fragments of the remnant savanna communities with respect to their restoration potential (figure 3.14). Current savanna restoration strategies consist of three components. First, prescribed burning is the key ecological process across the landscape, in conjunction with heavy thinning and midstory control, which stimulates grass and herbaceous species abundance. Second, after removing appropriate mid- and overstory trees, managers burn isolated fragments of intact remnant savanna communities ranging from less than one acre to several acres; this process will increase the abundance and flowering of the understory grass and herbaceous plants already present. Finally, managers and researchers have established local founder populations of rare or uncommon grass and herbaceous species (table 3.8) on old-field pine sites, which have poor seed banks after two hundred years of intensive agricultural use. These populations will ideally recolonize the landscape through dispersal to nearby areas where favorable establishment conditions have been created. Research is evaluating nursery procedures to grow approximately 150,000 individuals of thirty savanna species for

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experimental transplanting to fourteen old-field pine sites (see figure 3.8d). These sites, which represent a range of fertility and moisture regimes, were heavily thinned and will be burned routinely. The research will assess demography and dispersal ability of each species. These studies will produce an operational plan to establish founder populations of rare and threatened species.

4

r

Biotic Communities Plant Communities Donald W. Imm and Kenneth W. McLeod

Aquatic Invertebrates Barbara E. Taylor

Butterflies Nick M. Haddad

Fishes Barton C. Marcy, Jr.

Amphibians and Reptiles Kurt A. Buhlmann, Tracey D. Tuberville, Yale Leiden, Travis J. Ryan, Sean Poppy, Christopher T. Winne, Judith L. Greene, Tony M. Mills, David E. Scott, and J. Whitfield Gibbons

Nongame Birds John C. Kilgo and A. Lawrence Bryan, Jr.

Nongame Mammals Susan C. Loeb, Lynn D. Wike, John J. Mayer, and Brent J. Danielson

103

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The SRS supports a diverse array of plant and animal communities. This chapter describes those communities, exploring how they are arranged on the landscape and how the establishment of the SRS and its subsequent land management practices have affected each group. Most of the sections herein include a matrix of species-habitat relationships. Various workers have used many systems to classify SRS vegetation. In “Plant Communities,” Donald Imm and Kenneth McLeod describe how these ecosystems are distributed according to land-use histories and natural gradients of disturbance, topography, and soil features. They delineate seven major vegetation types: (1) remnant pine savannas and sandhill woodlands; (2) Carolina bays and other isolated wetland depressions; (3) upland pine forests; (4) upland hardwood and pine-hardwood forests; (5) bottomland and floodplain forests; (6) marshes; and (7) upland meadows, old fields, and industrial areas. Within each of these general vegetation types, they describe several subtypes, or communities, defined by ecological setting and dominant species. For example, Carolina bays and isolated wetland depressions may be wet savannas and meadows, dominated by herbaceous plants, or forested wetlands, dominated by various trees. Similarly, upland hardwood forests occur along stream drainages, around old-house sites, or in moist, fertile areas protected from frequent fire. Each setting supports characteristic species. Firemaintained upland pine savannas and sandhill woodlands are influenced by soil characteristics and fire frequency. A wide variety of forested floodplains, bottomlands, and swamps occur along major streams and the Savannah River, depending on hydrologic gradients and soil conditions. Some vegetation types are influenced more by past and current land management. Within certain ecological limits, a wide range of pine forest communities can develop on SRS uplands, depending on forest management practices such as planting, thinning (which affects density and species composition), timber rotation length, and prescribed burning. Vegetation in upland meadows, old fields, and industrial areas is influenced by seeding, planting, and mowing practices. Imm and McLeod provide detailed information on the species composition of the various communities that constitute each vegetation type. Aquatic invertebrates are abundant, productive, and rich in species in the streams, wetlands, impoundments, and other aquatic habitats of the SRS. Invertebrates play central roles in the functioning of those systems, processing both aquatic and terrestrial plant material and converting it to forms usable by many fish and other secondary consumers. They are potentially important in the transfer of contaminants, and their sensitivities to environ-

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mental conditions make them useful in bioassessment protocols. Barbara Taylor describes the invertebrate communities of major aquatic habitats on SRS, including streams, impoundments, Carolina bays and isolated wetlands, and others. She discusses the effects of reactor operations (high water levels and temperatures) and other anthropogenic impacts on aquatic invertebrates. Finally, she outlines conservation concerns related to aquatic invertebrates. Little is known about most groups of terrestrial invertebrates on SRS (but see Van Pelt and Gentry 1985; Scheller 1988; Draney 1997). However, Nick Haddad provides a description of the butterflies known from the site, listing ninety-nine species that have been identified. He discusses their general habitat and relative abundance on SRS. In contrast, most vertebrate groups on SRS have been studied extensively. Barton Marcy lists the eighty-seven species of fish that have been collected on the SRS. In describing the major factors that affect fish distribution on the site, he considers stream order, depth, velocity, and other habitat features (e.g., water chemistry and substrate conditions), as well as such ecological factors as predation and competition. He then describes the composition of fish communities in each of the major SRS streams and water bodies. Kurt Buhlmann et al. list 103 species of reptiles and amphibians that have been documented on the SRS. The distributions of some of these species on SRS are limited because the site is on the edge of their range. Others are difficult to sample because of secretive habits. The distribution and abundance of most, however, are affected by species-specific habitat requirements, wetland hydroperiod, landscape structure, historic land-use patterns, and natural and anthropogenic disturbance. The authors provide examples of species limited by each factor. Finally, they discuss broad historical trends in SRS herptile populations. John Kilgo and Lawrence Bryan note that 259 bird species have been recorded on the SRS. The relative abundance of individual species has been dramatically affected by the establishment of the Site. They describe factors affecting SRS bird distribution, including season (as many birds are migratory), habitat type and successional stage, and landscape structure. They conclude with a discussion of historical trends in bird populations on SRS, observing that the site now supports more forest-associated birds and fewer field-associated birds due to the conversion of agricultural fields to managed forest. Susan Loeb et al. list all fifty-four species of mammals that currently occupy or recently occupied the SRS. This section focuses only on nongame mammals. The authors note that season affects the SRS distribution of only a few bats. Most species are affected by habitat type, various physical factors (e.g., soil type, coarse woody debris), and landscape structure.

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Plant Communities Donald W. Imm and Kenneth W. McLeod The Savannah River Site (SRS) is a predominantly forested tract that lies below the Piedmont and north of the Savannah River. It is in the Sandhill and Upper Coastal Plain physiographic regions. Most of the area occupied by the SRS was once used for agriculture and is now forested with mid- to late-successional plant communities. This section will describe the general vegetation types on the varied landscape of the SRS, identify the factors that regulate or influence the dynamics of each type, and discuss the general impact of current forest management practices and past land-use activities. First, we discuss environmental factors that influence plant distribution (and, hence, community composition); second, we describe previously reported classifications of vegetation cover types on SRS; and finally, we present general descriptions of SRS vegetation types and plant communities. Each broad type of vegetation is typically composed of predictable suites of species, though the range of variation within a type may encompass several distinct subtypes, or “communities.” The appendix lists scientific names and the occurrence of other species in SRS vegetation types. Nomenclature follows Radford, Ahles, and Bell (1968). Tables, the appendix, and interpretations are based on published and unpublished data collected from SRS, review of other SRS studies, and information from the South Carolina Department of Natural Resources (SCDNR) and the Georgia Department of Natural Resources (GADNR) heritage programs.

Factors Influencing Plant Distribution Landscape position, soil type, past land use and disturbance, biological interactions, and chance determine the suite and proportion of species within a given area. Competition between individuals creates growth constraints through resource depletion. Other biological interactions— such as seed movement, predation, herbivory, and nutrient cycling—also affect plant growth and distribution. All of these factors determine the attractiveness and suitability for both existing and potentially existing plants and indirectly set the template for a natural progression of plant communities. Physical attributes also influence plant productivity and the development of plant associations. Such attributes include resource availability, past and present land management, and natural disturbance.

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Resource Conditions Resource conditions, both median and extreme, during any given year or during the lifetime of a plant influence its survival, productivity, and competitiveness. Because much of the SRS has sandy soil surfaces within the rooting zone, capacity for holding resources (moisture, nutrients) and concentrations of ions are low. These conditions result in a magnified influence of soil organic material on soil chemistry. Topographic aspect and steepness influence the diurnal amount and duration of available nutrients during the growing season. Besides competition, tolerance of extreme or catastrophic conditions probably best defines the composition of the forests of SRS. Additional important adaptations for the local flora include the ability to become established through resistance, resilience, recruitment from a seed bank, or invasion via migration.

Land Management Animal migration patterns and historical vegetation influence pollinator activity, seed dispersion, and seed amount across the SRS. These factors are particularly important on the SRS because of the long history of intensive agricultural use (see chapter 1). Most upland areas of the SRS experienced agricultural clearing and planting during the twentieth century. Outside of agricultural weeds and roadside remnants, few species are present in upland forests relative to their presettlement diversity. Some hard and soft mast species (particularly trees) have invaded upland pine stands and in the absence of fire have remained competitive. Another persistent vegetation pattern attributed to human activity is the continued presence of artifial corridors. These corridors include old fence lines, persistent windrows, house places, cemeteries, and wood lots. Many permanent meadow corridors have remnant seed sources of species associated with the longleaf pine savanna. In the absence of fire, many of these species have limited numbers of individuals and seed. Therefore, few have spread into adjacent abandoned old fields and pine plantations. Several remnant populations of species associated with longleaf pine savanna communities have remained persistent in dry upland hardwood forests. Again, having been unburned, few species have spread into adjacent forested areas. Limited air movement due to the density of these forests has also restricted the dispersion of many light-seeded species in forested areas. Forest management plays the role of directing or accelerating the natural progression of plant community development. Subtle differences in

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conditions that affect ecosystem development can lead to different vegetation types. No single soil or landscape condition is solely suited to one particular vegetation type. Similarly, one particular vegetation type is seldom restricted to a single soil or landscape setting. Over much of the SRS, soil conditions are nearly equally suitable for a variety of sustainable pine and hardwood communities. Management activities such as selective removal of trees and saplings, burning, and planting can shift the successional direction toward or away from certain forested communities and vegetation types. The success of these management activities depends on the match of vegetation conditions to the landscape or soil conditions. Well-developed or well-suited biological communities are often either resistant or resilient to changes invoked by forest management. For example, the conversion of established upland hardwood forests on fertile soils to pine savannas requires periodic mechanical and chemical treatments coupled with sustained burning and plant-introduction programs. Similarly, during early years, conversion from a pine forest on a sandy soil to upland hardwood forest requires periodic removal of invasive pine along with fire protection and plant introduction.

Disturbance The most common disturbance types on the SRS are flooding, drought, wind, and fire. Each of these four disturbance mechanisms has different types and magnitudes of influence on plant communities, and each is more likely to occur at particular landscape settings across SRS. Each disturbance benefits different types of species and provides opportunities for ecosystem reorganization.

Flooding Flood conditions that affect vegetation include season, duration, and rate of water movement. Flood frequency, depth, sedimentation rate, and water quality factors (e.g., composition, chemistry) have long-term effects on plant community development. Few species are tolerant of recurring floods during the growing season, but most tolerate flooding and soil saturation during the dormant season. River flooding is greatest February through April but can occur via tropical storms from August to October. Stream flooding can occur throughout the year, particularly during the summer months due to heavy localized precipitation. Flooding affects soil characteristics and understory vegetation. Flowing water transports sediments, organic debris, and living plants. Fine sediments and

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organic material are easily displaced but not easily deposited. Shallowly rooted plants are easily uprooted. Inflexible plants, such as saplings and shrubs, incur greater damage from water flow. Floodwater also causes chemical changes. Upon flooding, soil oxygen dissipates within a few days, resulting in a decline of aerobic processes such as root respiration and bacterial activity. Most species will enter a period of dormancy, but some have specialized adaptations that allow for continued activity. Continued flooding can kill less adapted individuals and species.

Drought The SRS has a warm temperate climate with dry autumn months and occasional summer droughts (see chapter 2). During the afternoon hours of the summer months, plants reach wilting points due to high temperatures and low water availability in sandy soils. To reduce water loss, plants have various structural, morphological, and physiological adaptations. Some species are adapted to avoid water stress through dormancy. Drought conditions in the upland are often coupled with optimal moisture conditions in periodically flooded bottomlands, swamps, and isolated wetlands. Varied rainfall patterns and hydrology influence yearly and seasonal differences in germination success and survival, contributing to the complexity and diversity of these systems. Like flooding, frequent drought causes stress and reduces tolerance to disease and pest attack. It also has a predictable return frequency. Individuals less adapted to drought have reduced vigor, are less able to recover, and are more likely to die. By impacting juveniles and less adapted species, drought reduces the role of certain species in the future succession of a plant community.

Wind Wind disturbance associated with tropical storms may occur from late August to early October. Tornado disturbance may occur from late spring to early autumn. Strong winds can impact forest structure and species establishment. Strong winds blow down canopy trees, snap them at the base, bend them, and partially sheer off limbs. Besides damaging the canopy, however, hurricanes and tornadoes disperse seed regionally and locally. Wind moves new species into adjacent regions and nearby disturbed areas and enhances local genetic diversity. Smaller subcanopy individuals tend to be wind-sheered, bent over, or crushed by falling adjacent trees. Mortality from strong winds frequently occurs at the ridge of steep slopes, along forest-meadow margins, in saturated soils, or where unhealthy or recently overthinned trees occur.

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Within such areas, the most susceptible individuals are shallowly rooted, taller than others in the canopy, or have weakened trunks. Certain species are inherently more susceptible because of wood strength and flexibility, architecture, and rooting patterns. Destructive winds during the dormant season primarily impact evergreen species due to added wind resistance of foliage. Fallen trees directly impact subcanopy and groundstory vegetation, and a disrupted canopy indirectly affects these layers.

Fire Fire historically occurred on SRS through lightning-caused wildfires and burning by Native Americans. Prescribed fire continues to regulate or redirect vegetation structure and plant composition. Many species and vegetation types depend on burning; yet fire disrupts biotic vigor, health, and survival. The influences of burning on plants are selective by species, size, and age. Fire impacts local competitive conditions and removes local insect pests. Burning can change ecosystem processes that regulate future seed pools, resource pools, and resource availability. Burning increases the availability of nutrients for plant uptake but reduces the total pool of nutrients within the ecosystem. The loss of organic material reduces moisture-holding capacities and can result in a xerification of uplands. The loss of surface organic material, which insulates the soil surface, elevates daytime soil temperatures and increases evaporative losses from the soil surface. The seasonality of fire also creates differences in burning effects. Burning has little impact on plants with buried or protected apical buds. Woody perennials in fire-prone habitats typically rely on root sprouting driven by stored carbon reserves and are most vulnerable to burning following spring bud-break during periods of depleted carbon reserves. Therefore, spring burning is a common strategy to reduce midstory hardwoods in pine savanna habitats.

SRS Vegetation Classifications Several vegetation classifications have been conducted on SRS. They have addressed historical conditions (Frost 1997), potential vegetation ( Jones, Van Lear, and Cox 1984; Duncan and Peet 1996; Imm 1996), and present conditions (U.S. Forest Service CISC; Pinder 1998). The U.S. Forest Service employs a standardized classification system called the Continuous Inventory of Stand Conditions (CISC), wherein aerial photography and periodic field checks are used to delineate landscapes into timber stands or

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Table 4.1 Extent of forest cover types on the Savannah River Site CISC code 12 13 14 21 22 25 26 31 32 34 44 46 47 51 53 54 56 57 58 61 62 63 64 67 68 72 95 96 98 99

CISC forest cover type

Acreage

Percent of SRS

Shortleaf pine–oak Loblolly pine–hardwoods Slash pine–hardwoods Longleaf pine Slash pine Mixed yellow pine Longleaf pine–hardwoods Loblolly pine Shortleaf pine Sand pine Southern red oak–yellow pine Bottomland hardwoods–yellow pine White oak–black oak–yellow pine Post oak–black oak White oak–southern red oak–hickory White oak Tulip poplar–white oak–black oak Scrub oak Sweet gum–tulip poplar Swamp chestnut oak–cherrybark oak Sweet gum–willow oak Sugarberry–American elm–green ash Laurel oak–willow oak Bald cypress–water tupelo Sweet bay–swamp tupelo–red maple River birch–sycamore Water Grass Undrained flatwoods Brush species

40 4,888 251 42,028 18,042 271 539 61,942 81 147 424 4,275 601 44 6,188 22 63 449 16,142 218 11,297 920 2,797 6,639 2,574 60 4,131 12,350 596 533

0.02 2.46 0.13 21.17 9.09 0.14 0.27 31.20 0.04 0.07 0.21 2.15 0.30 0.02 3.12 0.01 0.03 0.23 8.13 0.11 5.69 0.46 1.41 3.34 1.30 0.03 2.08 6.22 0.30 0.27

Note: Forest cover types as delineated by the U.S. Forest Service Continuous Inventory of Stand Conditions (CISC) database. 1 ac = 0.405 ha.

areas of relatively homogeneous tree species composition and age. For each stand, forest managers determine the forest type, typically identified by one to three dominant canopy species. The CISC system standardizes forest types across North America and recognizes thirty on SRS (table 4.1). The system suffers from variability associated with multiple classifiers.

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Additionally, some of the standardized types, primarily hardwood associations, do not precisely reflect SRS associations. However, because CISC is based on continually updated, ground-truthed data, it represents the most accurate description of actual current conditions at SRS. Jones, Van Lear, and Cox (1984), Frost (1997), and Imm (1996) used landscape features (e.g., topography, geomorphological classification, soil classification) to project the occurrence of general vegetation types across SRS (figures 4.1, 1.4, and 4.2, respectively). Jones, Van Lear, and Cox (1984) conducted their analyses prior to current red-cockaded woodpecker recovery initiatives and the increased emphasis on management for fire-dependent communities. They delineated existing natural vegetation from successional/management types. Frost’s (1997) classification system addressed plant communities prior to European settlement. Imm (1996) focused on in situ vegetation-type development under current management strategies. Though each made different assumptions, the three systems resulted in roughly 82 percent similarity in classification. All three classifications identified similar amounts of area for longleaf pine–sandhill scrub, cypress–tupelo swamp, Carolina bay, and upland hardwood slope communities. The collective area for bottomland and floodplain forest types was also similar among classifications. Several differences are noteworthy among the classifications. First, they disagreed over the dominant vegetation type associated with moist to mesic, well- to moderately well-drained, sandy loam surface soils. Frost’s (1997) classification assumed more frequent burning and thus favored firetolerant pine savanna associations, while Jones, Van Lear, and Cox (1984) and Imm (1996) favored mixed pine-hardwood associations. Second, they classified forest types associated with well-drained submesic sands of upland areas differently. Jones, Van Lear, and Cox identified upland loblolly pine as a sustainable forest type, Imm identified a mixed pine forest condition, and Frost associated these sites with mesic to submesic longleaf pine savannas. Again, Frost’s classification was based on pre-European settlement conditions in which frequent fire would have favored long-term dominance by longleaf pine. Jones, Van Lear, and Cox based their assumptions on site productivity and the existing conditions (infrequent fire, successional forest composition) prior to 1980. Imm based classification on site productivity and burning regime, wherein longleaf pine would be favored by periodic burning and would eventually become an important forest component, but where the burning frequency would still allow for continued codominance by loblolly pine. Finally, Imm identified a greater number of floodplain forest types than Jones, Van Lear, and Cox or Frost.

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Jones, Van Lear, and Cox conducted fieldwork in the 1970s, while Imm’s fieldwork was some twenty years later. Thus, successional patterns may have led to further differentiations. Frost assumed that periodic burning occurred within the floodplain areas and influenced the forest composition and development. Generally, differences among the classifications focused on which pine would dominate and the relative abundance of hardwood. Pinder (1998) compared patterns of irradiance detected by satellite imagery to existing forest composition at known locations and extrapolated the correlations across SRS. According to Pinder’s analysis, pine forest dominates 42 percent of SRS. Frost (1997) classified 59 percent of SRS as longleaf pine savanna; Imm (1996) and Jones, Van Lear, and Cox (1984) identified 54 percent and 48 percent, respectively, of SRS as upland pine forest. The greatest classification differences between potential forests and Pinder’s (1998) existing habitats are the size and patterns of classified polygons. Nearly all of Pinder’s habitat polygons were less than 25 ha (62 ac), while the classification of potential forest types includes many very large areas of forest with similar composition. The present patchy pattern of habitats at SRS is due in part to human activities, such as logging and previous agricultural use. However, small patches were present in the pre-European landscape: Hardwood inclusions occurred in longleaf pine savannas, and pine inclusions occurred in bottomland hardwoods. Many soil types are well suited for a variety of forest compositions (see chapter 2) and, as evidenced by Pinder’s classification, do occur in mixed mosaics across the landscape. Other classifications of SRS vegetation have focused on specific ecosystems. For example, Gaddy (1994) and De Steven and Toner (1997) classified Carolina bays; Duncan and Peet (1996) and Smith (2000) studied pine and pine-oak communities; and Whipple, Wellman, and Good (1981), Golley, Petrides, and McCormick (1965), Jones, Van Lear, and Cox (1984), and Sharitz, Irwin, and Christy (1974a, b) described bottomland hardwood systems. Because these works were restricted to particular ecosystem types, they were not intended for broad-scale landscape classification.

SRS Vegetation Types Vegetation types are distributed across the landscape in a fairly predictable manner due to differences in history, resource availability, and disturbance patterns. At the tops of ridges, sandhill vegetation types dominate. The first transition along an elevational gradient is generally from the sandhill vegetation type to pine savanna, pine plantation, or

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oak-pine woodland. As moisture and nutrient availability increase along the gradient, sandhill and pine savannas shift to other pine or pinehardwood communities. At depressions, pine and pine-hardwood communities change to Carolina bay and other isolated wetland communities. Near major stream corridors, steep contours support upland hardwoods associated with slopes. Finally, riparian forest types occur on the floodplain. Typically, the transition from pine and pine-hardwood communities to riparian forest communities is gradual. Increasing stream size toward the Savannah River results in expanded riparian area and increased topographic complexity, accompanied by a corresponding complexity in plant community. Smaller streams support unique seep, bog, and pocosin vegetation. In areas with nearly permanent flooding, bottomland and riparian forest types change to stream and river swamp communities. Below, we describe the general vegetation types defined by Imm (1996). The extent of each type on the SRS appears in table 4.2. This system provides greater ecological detail than the CISC system, which relies on only one to three dominant canopy species. Within each type, we also describe several communities. These communities were identified both from the literature and from discriminant analysis of unpublished data, the results of which appear in tables 4.3 through 4.9. Table 4.2 Extent of vegetation types on the Savannah River Site Vegetation type Stream swamp River swamp Bottomland hardwood Blackwater stream bottom Pine–bay hardwood Isolated wetland depressions Southern mixed hardwood Upland hardwood slope Upland pine–hardwood Yellow pine forest Longleaf pine forest Longleaf pine–scrub oak Udorthents Water

Percent of SRS 1.7 4.4 5.7 8.2 0.9 1.0 2.9 4.7 8.3 33.6 19.3 3.8 3.7 1.7

Corresponding CISC forest types 67, 68 67 46, 54, 61, 62, 63, 64, 72 31, 46, 56, 58, 62, 64, 68 31, 46, 68, 98 31, 46, 62, 64, 68, 95, 96, 98, 99 13, 46, 53, 54, 56, 62, 64 12, 32, 51, 53, 56 12, 13, 26, 32, 44, 47, 51 21, 22, 25, 31, 32 21 21, 26, 57 96, 99 95

Note: Vegetation types as delineated by Imm (1996). U.S. Forest Service CISC types included in each are also given.

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Remnant Pine Savannas and Sandhill Woodlands In the early 1950s, limited remnant pine forests and sandhill woodlands harbored seed and isolated populations of species that were once commonly found across the SRS landscape. In most areas, the absence of fire and other land uses had removed pine savanna. Without sustained periods of frequent, low-intensity fires, fire-dependent pine savannas (figure 4.3) succeed to other communities or develop indirect losses in vigor and productivity. Both longleaf pine and wire grass influence fire behavior, are resistant to damage from fire, become competitively superior due to rapid growth response following fire and loss of competitors, and have improved reproductive and recruitment efforts following maintenance fires. Typically, fuel conditions beneath longleaf pine savannas are a continuous layer of accumulated dried grasses interdispersed with pine straw. These fuels dry rapidly and burn rapidly due to their dispersion, the unrestricted air movement, and rapid convective heat transfer via the open canopy. Nearly complete fuel consumption allows for germination from the seed bank and in situ dispersed seed. Though fire-dependent, fireadapted species do suffer some mortality during burn events, individuals that survive enjoy reduced competition and usually flourish. More important, buried seed of suitable species germinates following fire, resulting in a renewed forest floor composition of a wide range of species.

Figure 4.3. Pine savanna (D. Scott).

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Figure 4.4. Sandhill woodland (D. Scott).

Thus, a periodic absence from burning results in a quick decline in new colonization by existing species and new colonials. Prolonged absence of burning results in the gradual loss of annuals from the seed bank and perennials from the typical continuous cover. These changes lead to an absence of exposed mineral soil suitable for colonization, a shift in fuel away from grasses toward pine straw, continued growth of sprouting hardwood shrubs, and ultimately the loss of the savanna structure. Sandhill woodlands are extremely dry and unproductive, and they produce a limited amount of highly flammable leaf litter that is interspersed with bare ground. Fires are therefore infrequent. However, due to litter accumulation over time, burning eventually removes most of the above-ground woody material, which is then replaced by rapidly growing sprouts with extensive root systems. In sandhill woodlands (figure 4.4), many tree species are resilient to fire. Turkey oak and other sandhill species tolerate burning by resprouting from carbon reserves in the root system. The understory composition and aged longleaf pine canopies of a few sites on SRS suggest that some very small areas experienced limited human disturbance. Frost (1997, 1998), Duncan and Peet (1996), and Smith (2000) identified some areas with intact understories and separated various suites of species along moisture and fertility gradients. The lack

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of intact understories in fertile, moist areas likely reflects higher levels and a longer duration of agricultural use. Further, because moist soils tend to be more productive, they experience fewer fires and greater growth rates by invading hardwoods than better soils.

Pine Savanna and Sandhill Woodland Communities Shortleaf pine dominates the canopy on ridgetops and adjacent exposed slopes along major drainages (table 4.3, community 1). Pine ridges periodically burn and have relatively infertile sandy loam surface soils or soils with loamy horizons within 80 cm (31 in). Usually, shortleaf pine canopies incorporate other pines (loblolly, longleaf) or oaks (post, blackjack, scarlet, white, black). Usually shortleaf pine codominates with loblolly pine and longleaf pine on ridges and slopes with sandy loams. Understory shrubs include sparkleberry, blueberries, and mountain laurel. The forest floor has grasses, trailing arbutus, elephant’s foot, woodland coreopsis, asters, licorice goldenrod, blazing stars, and legumes. Infrequent pine-dominated slopes on SRS (table 4.3, community 2) have shallow inclines, submesic surface sands, and west- to southeastfacing aspects. Dominate species include loblolly pine, shortleaf pine, and some hardwoods. Pine slope understories have a sparse herb and shrub cover. Potentially, fire-adapted herbs could become established in these areas if burned. Bigleaf snowbell, fringe tree, and trailing arbutus are scattered along most pine slopes. Mesic pine savannas are composed of longleaf pine and loblolly pine (table 4.3, community 3). Most loblolly pine trees are younger and likely became established during periods of fire protection. Soils are usually loamy sands to a depth of 30 to 60 cm (12–24 in) and are underlain with either loams or clays. Shrubs are usually dense with scattered patches of little bluestem, panic grasses, and herbs. Near wetlands, many wetland herbs and ferns are also present. Dry longleaf pine savannas have a canopy of longleaf pine (table 4.3, community 4) with understory mixtures of blueberry, dwarf huckleberry, sparkleberry, grasses, and bracken fern. Soils are usually deep sands or loamy sands to depths of at least 80 cm (31 in). These soils are excessively drained and usually very limited in organic matter and clay content. Sprouts of many sandhill and drought-adapted woody plants are also present. Loamy pine savannas have sandy loam to loam surface horizons, often underlain with loamy subsoils at depths of less than 50 cm (20 in). In addition to longleaf pine, loblolly pine and shortleaf pine are codom-

Table 4.3 Percent basal area for species associated with sandhill woodland and remnant pine savanna communities on the Savannah River Site Species

1a

Pinus palustrus 1 Pinus taeda 4 Pinus echinata 78 Carya pallida Quercus stellata 3 Carya tomentosa 3 Quercus marilandica 1 Quercus falcata 1 Vaccinium arboreum 3 Quercus nigra 3 Prunus serotina 0 Quercus velutina 0 Cornus florida 2 Quercus alba 0 Nyssa sylvatica 0 Crataegus spp. 1 Diospyros virginiana Liquidambar styraciflua Ilex opaca 0 Carya ovalis 0 Quercus hemisphaerica 0 Quercus incana Quercus margaretta 0 Quercus laevis Rhus copallina 1 Sassafras albinum 0 Vaccinium stamineum 0 Prunus angustifolia Kalmia latifolia 1 Callicarpa americana Symplocos tinctoria Styrax grandiflora Chionanthus virginiana No. of plots 6 Basal area (m2/ha) 33.0

2b

3c

4d

5e

6f

7g

8h

9i

10j

0 50 30 0 1 2 0 2 2 1 0 1 1 1 1 0 0 2 1 1 2

59 31 1 0 1 0 1 0 1 0 1 0 0 0 1 1 0

88 1

32 31 13 1 0 3 0 1 1 0 1

87 1 3 1 2 0 3 0 0 0 1

54 33 9 1

10 13 4 10 1 2

46 0 0 3 0 1 0 0 1

3

0

0

0 0 1

0 1 2

0 1 5 42 0 0 0

11 13 65 0 0 1

0 0 0

0 0 0 1 1 0 0 0 0 0 1

0 0 0 2 2 1 0

0

0

1 0 0

4

0 0 1 0

1 2 5 0 0 0 0

0 2 0 0 0 2 0 0

0 0 1 1 0 0 0 1

1 0 1 0

1 1 0

1 1 0 3

1 0

1 3 1 1 0 1 3 1 0 1 0 0 12 11 15 2 0 0

1 0 1 0 1

0 0 0 1 0 0 0 1 0 0 0 1 0 0 0 0 1 0 15 10 8 5 3 4 18 94 16 29.5 18.1 18.0 25.3 15.1 28.4 17.6 14.8 10.6

Note: Only those species accounting for >1 percent included; 0 indicates present but <1 percent of basal area. a Shortleaf pine ridge. b Shortleaf-loblolly pine slope. c Mesic pine savanna. d Dry longleaf pine savanna. e Loamy pine savanna. f Dry-mesic pine savanna. g Longleaf pine slope. h Dry scrub. i Xeric longleaf pine–oak woodland. j Turkey oak barrens.

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inant species (table 4.3, community 5). Common shrubs include beautyberry, fringe tree, and bigleaf snowbell. The forest floor is usually grassy with a wide range of dominant species. Most of the area on SRS suitable for pine savannas has a dry-mesic soil dominated by longleaf pine (table 4.3, community 6). Besides a scattered canopy of longleaf pine and a nearly continuous cover of grasses and forbs, pine savannas often have scattered clumps of low to mid-sized shrubs and longleaf pine saplings beneath the canopy. Pine savannas have a rich ground cover of small annual and perennial plants. The diversity is interspersed between clump grasses such as wire grass, little bluestem, broom sedges, and Indian grasses. All pine savannas have scattered shrubs that may include Saint-John’s-worts, hollies, plums, and hawthorns. Scattered clusters of small to large hardwood trees include oaks, hickories, and other successional species. Increased plant diversity occurs in areas with increased levels of moisture, fertility, and light, as well as increased frequency of burning. Slopes and ridges associated with small seasonal stream drainages and deep sands have longleaf pine and loblolly pine canopies (table 4.3, community 7) with either wire grass, bracken fern, or sparkleberry understories. Usually very little compositional difference is apparent between the surrounding longleaf pine–dominated plains and longleaf pine–dominated slopes. Roughly 1,416 ha (3,500 ac) of SRS are excessively drained, hilltop Quartzipsamments suitable for supporting sandhill woodland vegetation (table 4.3, communities 8–10). Currently, additional acreage exists due to the prolonged absence of fire from the landscape. Some areas currently growing longleaf pine would be better suited as sandhill woodlands. Typically, several ground cover types exist within sandhills, ranging from bare exposed sand to patches of huckleberry, deerberry, and mixed grasses and forbs. Sandhill woodlands are very unproductive due to limited availability and holding capacity of moisture and nutrients. Sandhill woodlands have three general types. The most common type (table 4.3, community 9) has a broken canopy of longleaf pine and a nearly continuous midstory composed of turkey oak, sand post oak, bluejack oak, and sand hickory. A second type (table 4.3, community 8) occurs on fine-textured deep sands and is dominated by longleaf pine, loblolly pine, sand laurel oak, bluejack oak, sand post oak, and sand hickory. This type also develops in areas that have been protected from fire and is transitional to the more typical longleaf pine–turkey oak type in some areas. Finally, turkey oak barrens (table 4.3, community 10) are

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dominated by turkey oak, bluejack oak, and sand post oak, but little longleaf pine is present. This sandhill woodland type occurs on the most xeric sites and has significant areas with exposed sand. The absence of longleaf pine may reflect past histories of selective logging. Blackjack oak and post oak are also codominant on coarse sands with shallower surface sand profiles. All three canopy types usually include a broken shrub layer of sparkleberry and other shrubs.

Carolina Bays and Other Isolated Wetland Depressions By definition, isolated wetland depressions are disjunct from riparian systems. In the Southeast, types include Carolina bays, bogs, fens, limestone sinks, pocosins, and cypress domes. These depression types differ in geomorphic origin, hydrology, soil chemistry, and vegetation. Roughly 350 isolated depressions on SRS include Carolina bays underlain with impermeable clayey subsoil horizons and other low-lying areas with perched water tables or impermeable drainage. Many isolated depressions seasonally drain to or are fed from the groundwater table (Schalles et al. 1989). Nearly all isolated depressions have seasonally to permanently impermeable subsurface soil horizons. Carolina bays have unique origins related either to cosmic activity (30,000–100,000 BP), eolian sediment deposition, or sublimation of underlying parent material (Schalles et al. 1989). Carolina bays vary in size from less than one acre to hundreds of acres. Nearly all are elliptical with a northwest-to-southeast primary axis and an upland rim best developed on the southeast. Coastward, Carolina bays have accumulations of peat, while those of the Inner Coastal Plain and Sandhill geologic provinces have mineral soil. The presence or absence of peat and organic soil greatly influences soil chemistry, moisture holding capacity, fire behavior, and vegetation. Hydrologic behavior that depends on precipitation varies seasonally and annually. Due to seasonally dependent groundwater input and output, Carolina bay hydrologic patterns do not correlate perfectly with landscape water budgets. Because of variable thickness and limited depth, the subsurface clay layer varies in permeability. With drying, sparse cohesive bonding between clay micelles allows drainage. Continued drought and evapotranspiration improve subsoil permeability. Therefore, summer drought accelerates drying and lessens moisture retention capacity. Oxidation of subsoil horizons also allows for deeper root growth and decomposition of surface organic material. Carolina bays retain

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water after several rainfall events rewet the clay horizon and make the horizon impermeable. Subsurface permeability decreases during winter dormancy when evapotranspiration loss declines. During wet years, impermeable horizons persist, and bays remain hydrated throughout the year. During dry years, water tables fail to reestablish impermeable horizons, and bays remain dry throughout the year. Within any given year, hydrologic patterns affect decomposition and nutrient dynamics (Sharitz and Gresham 1998). With gradual drainage away from the bay margin toward the bay interior, ionic, organically bound, and suspended nutrients migrate and bacteria respond to surface soil oxidation along the moisture gradient. Periodic fires from adjacent uplands mineralize organically bound compounds. Because of ponding and soil saturation, fires are less frequent during spring and summer than in surrounding upland areas. Wet fuels of a bay’s interior burn less intensely than areas along the margin. Without fire, wet fuels continue to build up and eventually lead to highintensity fires. Historically, Carolina bays burned during autumn and early winter and throughout the summer. However, even during dry years, burning may have been infrequent, as occasional hurricaneassociated rains would have recharged Carolina bay interiors and prevented burning during early winter months. Fire alters the vegetation structure and composition of Carolina bays. It benefits species capable of sprouting, rapid invasion, or germination from the seed bank. The reduction of competition and the mineralization of nutrients also benefit canopy species tolerant of low-intensity burning. Following fire, surviving vegetation and charged particles in the soil rapidly sorb mineralized nutrients. Unlike intense logging, intense burning reduces sprout growth and delays the recovery of evapotranspiration. Reduced evapotranspiration may lead to a temporarily elevated water table. Thus, wetter conditions persist for longer durations and encourage obligate wetland species. Following fire, clonal grasses such as Panicum hemitomon and Leersia hexandra grow vigorously, resorb mineralized nutrients, and produce large quantities of seed. However, if flooding shortly follows burning, these grasses die in deeply flooded areas, and species from the seed bank replace them when water levels recede. Autumn and winter burns that follow flooding eliminate rhizomatous species like maidencane and southern cutgrass. During dormancy, dried tissue of these emergent plants transports oxygen to buried root and apical tissue. Burning eliminates dormant foliage, thereby restricting oxygen movement and increasing

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mortality of these species upon flooding (Kirkman 1995). In contrast, burning without postburn flooding stimulates seed production in Panicum hemitomon (Kirkman and Sharitz 1994). When burning eliminates rhizomatous species, a diverse assemblage of annuals and single-stemmed perennials replaces them. The predominant vegetation types of isolated wetland depressions depend on the size and drainage area of the wetland, as well as on groundwater processes. Many Carolina bays on SRS ditched for agriculture during the early twentieth century have since reverted to wetland vegetation (Kirkman et al. 1996) or forest. According to Kirkman et al. and De Steven and Toner (1997), forested bays tend to be small; to have persistent ditches; to be located on coastal plain terraces; and to have thickened A-horizons, fine-textured surface soils, or “flashy” hydrology that limits growing-season flooding. Very small depressions (less than 0.5 ha) do not often differ in canopy composition from the surrounding uplands, and in many cases pine plantations surround them. Shrub and herbaceous layers typically have greater density and biomass, as well as slight to moderate differences in composition. Transitions from upland longleaf pine savannas to wet pine savannas and cypress savannas probably existed in frequently burned areas. Frequently flooded bays burned less frequently, but fuel buildup caused intense fires. Frequently flooded bays probably did not succeed to forest systems. Less frequent burning would facilitate the development of forested bays and pocosin-like appearances. Occasionally, bays returned to herbaceous meadows through catastrophic burning. Some bays probably burned very infrequently due to near permanently wet forest conditions. Then the buildup of litter and limited decomposition due to excessive wetness led to organic material and peat accumulation. Finally, driven by cycles of hydrologic condition and disturbance, nearly all bays probably supported several different vegetation types (Kirkman et al. 1996).

Forested Carolina Bay Communities The majority of isolated wetland depressions on SRS are forested (figure 4.5). The forests include red maple, sweetgum, water oak, sweet bay, red bay, loblolly pine, pond pine, sand laurel oak, gallberry, big gallberry, highbush blueberry, chokeberry, and bamboo vine, as well as clump grasses and perennial herbs in the moist meadow transition. The interior of many ditched Carolina bays also includes pond cypress, southern red oak, longleaf pine, sycamore, American holly, spotted wintergreen, par-

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Figure 4.5. Forested Carolina bay (D. Scott).

tridgeberry, wax myrtle, grapes, poison ivy, trumpet creeper, yellow jessamine, Japanese honeysuckle, greenbriers, and Virginia creeper. Prior to human disturbance, forest transitions of Carolina bays likely were as varied as the bay interiors themselves and included wet pine savannas, mixed pine-hardwoods, and pocosin-like vegetation. Moist oak woodland and wet willow oak forest communities (table 4.4, communities 1 and 2) occur in small Carolina bays, often those with historic ditches. Both communities occur in the interior and flanking transitions of a few Carolina bays on the coastal plain terraces of SRS. These bays have little compositional change from the interior to the periphery. Canopy diversity is moderately low, with a continuous canopy and heavy shading. Shrubs are scattered throughout at low densities, and, except in forest gaps, forest floor vegetation is limited (less than 1 to 10 percent cover). Both communities exist on sand to sandy loam soils and heavy litter cover. Based on flood marks on the bases of trees, moist oak woodland sites have infrequent, shallow flooding, and wet willow oak forest sites have deeper flooding. The wet mixed forest (table 4.4, community 3) occurs in moist transitions to wet forest or meadow interiors. The wet pine forest (table 4.4, community 4) occurs as a transition from upland pine forests to meadow or wet savanna interiors of Carolina bays. This community is well suited

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Table 4.4 Percent basal area for species associated with Carolina bay forests and savanna communities on the Savannah River Site Species Pinus taeda Nyssa biflora Pinus serotina Quercus nigra Acer rubrum Liquidambar styraciflua Magnolia virginiana Persea spp. Quercus hemisphaerica Quercus falcata Carya spp. Nyssa sylvatica Quercus phellos Pinus palustrus Ilex opaca Myrica cerifera Ilex glabra Vaccinium corymbosum Diospyros virginiana Cephalanthus occidentalis Taxodium spp. Ilex myrtifolia Plantanus occidentalis Fraxinus spp. No. of plots Basal area (m2/ha)

1a

2b

3c

4d

5e

6f

7g

8h

9i

7 3 0 43 0 11 0 0 14 9 3 0 2

8 2

20 15 6 11 13 17 6 7 2 0 0 0 0

43 6 20 1 2 6 5 4

0 26 3 1 37 7 5 1 0 0

13 10 11 0 15 8 26 13 0

76 2 1 0 1 2 2 3

5 2

3 2

3 2 78

0 11 7

13 1 1 0 7 3 0 0 61

0 1 0 7

1 1 0 0

0 0 0

0 0 0 1

0

0 1 0

10j

12 61 0 8

3 0 0 1 0

0 0 0 1

0 0 0 8 1 0 0 2 0 1 11 3 17 23 11 9 21.6 26.3 10.7 29.5 22.1 32.4

0 0 2 1 1 0 0 4 0

0 0 7 0 0

4 65

1

1 6 11

1 0 8 8.4

0 2 7.9

3 5.1

3 0.3

Note: Only those species accounting for >1 percent included; 0 indicates present but <1 percent of basal area. a Moist oak woodland. b Wet willow oak forest. c Wet mixed forest. d Wet pine forest. e Red maple–swamp tupelo. f Wet evergreen woodland. g Wet successional pine woodland. h Sweetgum woodland. i Buttonbush shrub woodland. j Pond pine savanna.

for periodic burning and, through litter production and slowed decomposition, encourages the movement of fire from the uplands into isolated wetlands. The red maple–swamp tupelo community (table 4.4, community 5) occurs in wet, ponded interiors and is sparsely stocked with poorly formed trees and scattered shrubs. The wet evergreen woodland (table

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4.4, community 6) occurs in wet forest interiors or as a wet forest transition to more deeply flooded interiors. A wet successional pine woodland (table 4.4, community 7), dominated by young loblolly pine, is transitional from the surrounding forest to wet or moist meadow Carolina bays. It occasionally occurs within the interior of ditched bays. The canopy is composed of high densities of small to medium-sized (3–15-cm, or 1–6-in, diameter at breast height) loblolly pines. Larger pond cypress are scattered throughout with low densities of hardwoods and undergrowth. The forest floor is heavily littered (4–7-cm, or 2–3-in, depth) and has low light availability. Sweetgum woodland (table 4.4, community 8) and buttonbush shrub woodland (table 4.4, community 9) are two similar but less frequent communities. Young sweetgum dominates the sweetgum woodland and brushy mixtures of buttonbush, red maple, and sweetgum dominate the buttonbush shrub woodlands. Pond pine savannas (table 4.4, community 10) are dominated by stunted, sparsely arranged pond pine, sweet bay, swamp tupelo, pond cypress, and myrtle-leaf holly. Gaddy (1994) described a similar “savannalike” community in seven Carolina bays on SRS as a partially forested savanna dominated by pond cypress. Gaddy’s pond cypress savannas have extended periods of ponding into the growing season, but others are more variable in the duration of growing-season flooding regimes and are more likely influenced by fire.

Herbaceous Carolina Bay Communities Vegetation zones of herbaceous Carolina bays (figure 4.6) can change in composition from year to year. Further, similar vegetation zones between bays often differ without obvious relationships to surrounding conditions or land-use history. Typically, a transect from a bay margin to bay interior reveals reduced importance of clump grasses and an increased number of rhizomatous grasses and species with dormant seed tolerant of extended flooding. Bay interiors with prolonged flooding have floating and emergent aquatic species adapted to aquatic settings but are tolerant of periods without flooding. Differences in composition exist between bays because they are isolated and vary in size and chemophysical attributes (De Steven and Toner 1997; A. E. Hodges, Clemson University, unpublished data). Very isolated bays have more individualistic plant compositions than those in clustered distributions due to reduced seed dispersal. Larger bays have a broader range of habitats, greater likelihood of nearly monospecific

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Figure 4.6. Herbaceous Carolina bay (D. Imm).

patches, and localized disturbance regimes within hydrologic zones. Vegetation patterns derive from the relationship between current-year conditions, disturbance, past-year seed production, patterns of perennial plant persistence, and the concentration and composition of the persistent seed bank (Kirkman and Sharitz 1994). Many species in Carolina bay seed banks germinate infrequently but in large numbers, replenishing the seed bank when they do germinate. Very wet interiors of Carolina bays have floating aquatic plants such as water lilies intermixed with emergent sedges, rushes, and cord grasses. Scattered clumps of Leersia hexandra and Panicum hemitomon may also be present. In some cases, tree species such as cypress or swamp tupelo form a sparsely canopied wet savanna. Generally, the absence of trees indicates nearly permanent flooding. However, their absence may be due more to slow invasion or limited establishment than the lack of suitable environmental conditions. Less frequently flooded interior zones of Carolina bays often support rhizomatous grasses such as Leersia hexandra and Panicum hemitomon. Leersia typically occupies meadow areas with extended flood periods. Scattered clumps of buttonbush, pond pine, and myrtle-leaf holly may also occur in wet meadow and ponded meadow vegetation zones. Vines like trumpet creeper, greenbriers, and grapes sometimes dominate formerly disturbed isolated depressional wetlands.

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The moist meadow transition zone includes less frequently flooded areas that are dry during the growing season. This zone has a mixture of rhizomatous grasses such as Leersia hexandra and Panicum hemitomon with clump grasses like big bluestems, plume grasses, and little bluestem. A diverse mixture of perennial and annual forbs and scattered pond pines are often present. Most often, the moist meadow transition zone has the greatest amount of species turnover from year to year and within the growing season. If seasonal changes in life history and repeated drying and flooding expose mineral soil, newly recruited plants from the seed bank quickly occupy it. Scattered floating aquatics are competitively secure only in the absence of herbaceous cover. Because of its dependence on hydrologic condition, this zone differs among Carolina bays, but the most predictable species are clump grasses, sedges, nut rushes, horned rush, meadow beauties, pipeworts, yellow-eyed grasses, and sundews. On SRS, disturbed interiors of bays near streams or river terraces have species associated with ponds, marshes, or streamsides. Elsewhere, disturbed bays often include species associated with upland communities (e.g., panic grasses, bluestem grasses).

Upland Pine Forest Upland pine forests include pines that were planted or naturally regenerated during the last half to three quarters of the twentieth century. Currently, about 53,014 ha (131,000 ac) of SRS (68 percent) are pine forest, and an additional 2,832 ha (7,000 ac) are pine-hardwood mixtures. Plantation pine forests on SRS date back to the early 1900s (White and Gaines 2000), including experimental plantings of longleaf and slash pine, but nearly two thirds of the pine forests on SRS are forty to seventy years old. Following SRS acquisition by the U.S. Atomic Energy Commission, abandoned farmland was returned to forest via planting of yellow pines (longleaf, loblolly, slash, and sand pine) during the late 1950s and early 1960s (see chapter 3). These forests are often referred to as old-field pine. The primary initiative was to reduce sediment loss due to erosion from the overused abandoned farmland. In some cases, poorly suited species grew poorly. Since that time, many of these sites have been converted to more appropriate silvicultural species (e.g., longleaf pine replacing slash pine on excessively drained soils). The agricultural land-use history of SRS has many consequences for the reestablishment of pine forests. Overfarming depletes nutritional resources. Fertilizer additions are generally crop specific and seldom address

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Figure 4.7. Longleaf pine plantation, two to three years old, with well-developed shrub-scrub understory (D. Scott).

the long-term needs of plants. Nitrogen additions accelerate the breakdown of organic material, the loss of which depletes nutrient reserves, as well as moisture and nutrient holding capacities. The loss of organic material is particularly important on sandy soils. Once abandoned, agricultural fields have excessively low or imbalanced nutrient reserves and limited nutrient and moisture holding capacities. Most important, many herbs in pine savannas disappeared from the landscape and have not reappeared in pine plantations. Species loss was caused by herbicide use, sod removal or disruption, altered nutrient budgets, and the elimination of fire from the landscape. Herbicides removed row-crop weeds but also many species of southern pine savannas. Sod removal, disruption due to plowing, and overgrazing removed the rootstock (ramets) of many of the long-lived perennials such as wire grass. Agriculture altered nutrient budgets by increasing uptake, disrupting decomposer activity, limiting returns of organic material, and increasing drainage. The loss of pine savanna species and their buried seed has resulted in limited diversity and reduced specificity to soil and burning regimes. Pine forests on SRS often do not follow typical patterns of plant community development. They are even-aged and are composed of equally spaced, vigorously growing trees (figure 4.7). However, many plantations contain small patches of remnant vegetation. Over time and with ap-

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129

Figure 4.8. Loblolly pine stand on an old-field site (“old-field pine”). Note the lack of an understory due to shading and a depauperate seed bank, caused by the history of intensive agriculture (D. Scott).

propriate management, such patches may replenish local seed banks and allow plantations to succeed to pine savanna or sandhill woodlands. Pine forests that lack remnant patches will require active restoration (see chapter 3) if native savanna structure and composition are to be achieved. Currently on SRS, loblolly and longleaf pine dominate the canopies of pine forests. Understory vegetation is highly varied, ranging from little more than scattered herbs and pine straw (figure 4.8) to grassy, savannalike ground covers to nearly continuous shrub and sapling understories (figures 4.9 and 4.10). Common understory dominants in pine forests include broom sedge, bracken fern, poison oak, deerberry, sparkleberry, wax myrtle, sweetgum, and scrub oaks. The understory and forest floor composition of many young pine stands may have higher plant diversity and more diagnostic composition than many mature pine stands on SRS. Most existing mature pine stands were planted during the late 1950s. In contrast, many young pine stands occupy areas that were forested in 1951 and had been farmed and abandoned much earlier than SRS establishment. These forested areas were harvested from the early 1960s to the late 1980s and were replanted in pine. Thus, young pine stands occupy sites that may not have been as heavily impacted by prior agricultural activity.

Figure 4.9. Mature loblolly pine stand with some understory development (D. Scott).

Figure 4.10. Mature slash pine stand with little understory but a hardwood midstory (D. Scott).

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Figure 4.11. Upland hardwood forest (D. Scott).

In comparing “natural” pine with plantation pine, Smith (2000) found some endemic species in plantations, but most species were restricted to natural pine stands. Besides persistent successional plants, moist pine forests commonly have species that are associated with hardwood systems. These include panic grasses, witchgrasses, ebony spleenwort, spotted wintergreen, and partridgeberry.

Upland Hardwood and Pine-Hardwood Forests Upland hardwood and pine-hardwood forests (figure 4.11) occupy roughly 7 percent of SRS and occur under four general conditions: successional settings; rural vestiges of past home sites, cemeteries, protected woodlots, or fence lines (i.e., ruderal); mesic, loamy uplands; and slopes flanking stream drainages. Most upland hardwood communities are arranged along interconnected corridors of larger stream drainages. A small percentage of the upland hardwood forests, particularly past home sites, are disconnected from stream corridors.

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Ecology and Management of a Forested Landscape

The development rate and composition of upland hardwood forests are strongly influenced by soil resources. Few upland areas with moist fertile soils are present on SRS. Much of the upland is too infertile to allow for rapid enough growth of hardwood canopy species to escape the effects of periodic burning. However, the absence of burning has allowed successional mixtures of pine and hardwoods to become established on lesssuited sites. Without human interference, these sites will continue to support mixtures of pine and hardwood species but will eventually succeed to hardwood mixtures as the pines age and die. Upland hardwood communities are sustainable because a diverse canopy and understory attract wildlife that introduce seed of additional species. Additionally, the forest floor gradually accumulates moisture-rich inflammable fuels and develops an organic-rich surface soil horizon. Roughly 5 percent of SRS has moderately to steeply sloped contours, which provide refuge for species intolerant of burning. Typically, these slopes have a variety of hardwood species and a highly diverse range of shrub and ground cover. Many species on SRS hardwood slopes are more commonly found in Piedmont and Appalachian sections of the Southeast. Forest composition on slopes varies with contour, position, and soil conditions. Along the eastern flank of large streams, west- to north-facing slopes are typically steep, with 10 to 50 m (33–164 ft) of topographic relief. West-flanking slopes along streams are more gradually sloped. Slopes of smaller streams vary from steep to shallow and have less relief. Sloped areas that occur on the Aiken Plateau (in northern and central sections of SRS) usually have greater relief and sandy to sandy loam surface profiles with an underlying loam to clay-loam subsoil at variable depths (20–140 cm, or 8–55 in). Sloped areas that occur on the terrace physiographic sections have less relief, sandy loam to loam surface soil profiles, and are underlain by loam to clay-loam subsoils at less variable depths (20–80 cm, or 8–31 in). Along a transition from ridgetops to slope bottoms, depths to subsoil decrease; therefore, fertility and moisture holding capacity within the rooting zone increase. Steep slopes typically have greater change in depth to subsoil horizons. Steep slopes provide greater protection against burning and have altered angles of solar irradiance. Shallowly rooted trees on steep slopes are more susceptible to wind damage and blowdown. Steep slopes also receive less solar energy than shallow slopes and therefore have less evapotranspirational water loss. To the north, aspect also affects solar irradiance. However, SRS lies too close to the Tropic of Cancer for significant aspect effects to occur during the growing season.

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Soil characteristics along slopes are important because they directly influence growing conditions. Greater nutrient holding and water holding capacities allow more mesophytic species to persist and compete with other vegetation types. Frequently, nutrient content can vary a hundredfold between ridge positions and slope bottoms. Greater resource availability also equates to greater productivity, improved litter quality, and increased decomposer activity. Thus, stable organic material (humus) accumulates more rapidly on soil surfaces of high-quality sites.

Upland Hardwood and Upland Pine-Hardwood Communities Slope ridges and upper slopes are generally submesic to subxeric, infertile, and dependent on occasional fire. Typically, a closed to broken canopy of pines and hardwoods exists, with an underlying shrub layer. The forest floor layer varies with soil and light conditions. Overall, ridgetop communities are transitional to surrounding upland pine-hardwood forests and pine savannas and, thus, share characteristics with slope and upland plain forests (table 4.5). The oak ridge community (table 4.5, community 1) has a canopy of scarlet oak, black oak, southern red oak, post oak, hickories, and some white oak, flowering dogwood, and winged elm. It develops along protected ridges that have dry to dry-mesic soil conditions. Mountain laurel shrub layers are usually present beneath pine or hardwood canopies in areas with shallow (less than 40 cm or 16 in) surface soil horizons. Shallow surface soil conditions also support trailing arbutus. The pine-oak ridge community (table 4.5, community 2) has a canopy of shortleaf pine, post oak, black oak, and loblolly pine, with some southern red oak and hickories. It develops on dry, exposed slopes and ridges that have loamy or clayey horizons within 60 to 80 cm (24–31 in). Occasionally, chestnut oak is also present with dense shrub mixtures of sparkleberry and mountain laurel. Virginia pine and eastern red cedar canopies sometimes develop on ridges with very shallow surface soil conditions above kaolinitic parent material. Such conditions are extremely infrequent on SRS but are more common elsewhere in Aiken County. Dry pine-oak woodland communities (table 4.5, community 3) often occupy dry soils in relatively flat areas with sandy loam to loamy surface or subsurface layers within the rooting zone. Post oak dominates these plant communities; blackjack oak is codominant on drier sites. Longleaf pine, southern red oak, sand hickory, shortleaf pine, and loblolly pine may live on some sites. Commonly occurring shrubs and small trees include rusty blackhaw, fringe tree, winged elm, New Jersey tea, Elliott’s

Table 4.5 Percent basal area for species associated with upland oak–pine woodland and pine–hardwood forest communities on the Savannah River Site Species

1a

2b

3c

Pinus echinata Pinus taeda Quercus margaretta Pinus palustrus Carya pallida Quercus stellata Carya tomentosa Quercus marilandica Quercus falcata Vaccinium arboreum Quercus nigra Prunus serotina Viburnum rufidulum Quercus velutina Cornus florida Quercus alba Nyssa sylvatica Crateagus spp. Diospyros virginiana Liquidambar styraciflua Ilex opaca Quercus coccinea Kalmia latifolia Carya glabra Quercus montana Carya ovalis Quercus hemisphaerica Myrica cerifera Quercus incana Rhus copallina Sassafras albinum Prunus angustifolia Chionanthus virginicus Callicarpa americana Acer rubrum No. of plots Basal area (m2/ha)

1 2 0 0 2 10 7 1 11 1 2 0 0 16 4 5 1

28 16 0 0 2 19 5 0 2 1 1

5 3 5 16 8 22 1 16 4 1 0 1 0 4 3 1 2 0 1 1 0 0

1 1 26 1 3 1

0 8 4 4 1 0 0 4 0

0

0 2 0 1 2 0 0 0 0

2 0 0 1 0 0

0

0

1

4d

0 38 9 5 15 3 11 0 3 5 6

1 1 3 0

5e

6f

7g

8h

9i

3 10 3 21 16 15 5 2 11 1

6 29 0 4 6 7 7 0 14 0 1 0 0 1 3 12 1 0 0 2 0 0

0 10

2 60 0

0 51

3

0

1 0 5 1 3 1 1 0 0 0 0

0 0 0

1

11 38 17 8 36.4 29.9 25.6 15.5

0 6 3

0 2 1

3 2 21 1

8 0 3 1

0 0 0 2

6 2

0 2 1

2 0 46 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 7 30 7 23.5 21.5 24.5

0 0 0 3 0

0 0 0 3 5 0 15 1 0 0 1 0 0 0 1 13 2

0

11 2 0 1 1 1

0 2 1

1 0

1 1 10 65 19.9 26.5

Note: Only those species accounting for >1 percent included; 0 indicates present but <1 percent of basal area. a

Oak ridge. b Pine-oak ridge. c Dry pine–oak woodland. d Dry Carolina bay rim. e Drymesic pine–oak woodland. f Mesic pine–hardwood forest. g Dry-mesic pine–evergreen hardwood forest. h Upland ruderal forest. i Mid-successional mesic pine-hardwood.

Biotic Communities

135

blueberry, and species of Saint-John’s-wort. With frequent burning, many herbaceous species are similar to those in pine savannas and include poverty grass, Coreopsis major, Muehlenbergia capillaris, Galactia spp., trailing arbutus, Agrimonia spp., Paspalum spp., and Desmodium spp. Oak woodlands also serve as refugia for species from longleaf pine savannas. For instance, most clumps of wire grass on SRS lie beneath upland hardwood canopies or sandhill woodlands. Carolina bay rims (table 4.5, community 4) have dry coarse sands that are excessively drained. These habitats are most common along the southeast sections of Carolina bays but usually surround these isolated wetlands and serve as transitional communities from wet forests to the surrounding pine savannas and forests. Woodlands of longleaf pine, sand post oak, blackjack oak, sand hickory, and post oak often surround Carolina bays. The most characteristic shrub is rusty blackhaw. Black cherry, sweetgum, water oak, sand laurel oak, plums, and persimmon may also be present in the canopy. The forest floor has species from other oak woodlands, sandhills, and pine savannas. Grapes and yellow jessamine are characteristic vine species. Mature dry-mesic pine-oak woodland (table 4.5, community 5) dominated by longleaf pine, post oak, sand hickory, loblolly pine, southern red oak, black oak, mockernut hickory, and black gum occur in periodically burned areas with dry sandy or loamy sand surface soils underlain with loamy or clayey subsoils. Usually, this community occurs in small, slightly sloping headwaters of seasonally flowing streams. The understory includes scattered shrubs such as snowbell, fringe tree, Elliott’s blueberry, and beautyberry. Mesic pine-hardwood forests (table 4.5, community 6) are common on SRS. They occur on upland areas that are burned infrequently and may be on slight to moderate slopes and ridges, near small streams, or inclusions in pine-dominated areas. Some mesic pine-hardwood forests are remnant woodlots around old house sites. Others are naturally occurring transitions between upland pine forests and hardwood slopes. Soils typically are moderately fertile, well-drained, sandy loams, with loamy subsoil within the rooting zone. This community is dominated by loblolly pine, shortleaf pine, or longleaf pine, with various hardwoods such as southern red oak, white oak, post oak, and hickories. The understory is usually sparse, with patches of deerberry, sparkleberry, American holly, and other shrubs and saplings that are more common elsewhere. The herbaceous layer is incomplete and often includes woodland aster, panic grasses, bluestems, partridgeberry, bracken fern, ebony spleenwort, and

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Ecology and Management of a Forested Landscape

spotted wintergreen. Grasses and forbs associated with other upland communities also occur. Dry-mesic pine-evergreen hardwood forests (table 4.5, community 7) occur across SRS on dry to mesic fine sands, loamy sands, and sandy loams. This community is particularly common in infrequently burned or unburned areas with dry-mesic soils on the Sunderland and Brandywine physiographic terraces. Sand laurel oak, water oak, sand hickory, longleaf pine, and loblolly pine dominate the canopy. The few shrubs present include blueberries and sparkleberry. The forest floor consists of patchy mixtures of grasses and perennial forbs common in other upland communities. Rural vestiges of upland ruderal forest (table 4.5, community 8) associated with abandoned home sites, cemeteries, farm woodlots, and fence lines are scattered throughout SRS. Common tree species at abandoned home sites include loblolly pine, sand laurel oak, water oak, post oak, white oak, southern red oak, and hickories. Some home sites also have southern magnolia, live oak, and eastern red cedar, as well as large fruitand nut-bearing trees such as pecan. To some degree, the number, type, and variety of trees surrounding home sites is related to the size of the home, site quality, and income level of its past occupant. Larger homes had greater diversity and more exotic shade trees, shrubs, and gardens. Beneath the canopy, various shrubs and ornamental plants (e.g., Ligustrum spp.) have flourished and now dominate some abandoned home sites. Several commonly planted perennials are also usually present. Mid-successional mesic pine-hardwoods (table 4.5, community 9) are common on SRS and have a near even-aged canopy of trees roughly fifty to seventy years old. The past land use ranges from clear-cut harvesting to selective harvesting and pasture. These communities occur on a variety of soils with similar compositions. Loblolly pine, sweetgum, water oak, southern red oak, and mockernut hickory dominate the canopy; and in some areas, sand laurel oak, American holly, black oak, sand hickory, and white oak are also present. Vines include greenbrier, muscadine, poison ivy, honeysuckle, Virginia creeper, and yellow jessamine. Common herbs include elephant’s foot, ebony spleenwort, partridgeberry, spotted wintergreen, witchgrasses, panic grasses, violets, and tick trefoil.

Upland Hardwood Slope Communities Less than 121 ha (300 ac) of SRS have slopes that exceed 40 percent; most of these bluffs are north to northwest facing and have canopies exceeding one hundred years old with little evidence of past land use. Relative

Biotic Communities

137

to other slope conditions, steep bluffs typically have shallow depths to loam subsoils, low rates of litter accumulation due to surface movement, low to moderate humus content, moderate cation concentrations, low levels of total nitrogen, varied levels of available nitrogen and phosphorus, and moderate moisture availability. Beech bluffs (table 4.6, community 1) have canopies dominated by beech and limited amounts of white oak and pignut hickory. Florida maple often codominates the subcanopy on fertile sites, and hornbeam codominates in drier areas. Usually, the understory is open, with scattered shrubs such as sweetleaf, serviceberries, and winterberries. Usually, a sparse forest floor is present, with scattered American alumroot, hairy hawkweed, Solomon’s seal, squawroot, and panic grasses. Rich streamhead slopes (table 4.6, community 2) have loamy moist soils that are well drained and have canopies of tulip poplar, white oak, and sweetgum. The understories are mixtures of bottomland and upland species including sweetleaf, red bay, and azaleas. The forest floor has partridgeberry, wild ginger, carrion flower, bloodroot, violets, and panic grasses. Bottomland species such as jack-in-the-pulpit, Indian cucumber root, ladies’ tresses, fringed orchids, and gentians are also present. Terrace slopes (table 4.6, community 3) have moist fertile alluvium with canopies of white oak, pignut hickory, shagbark hickory, white ash, southern red oak, sweetgum, and flowering dogwood. Beech, swamp chestnut oak, and Shumard oak may also be present. The understory has sparsely scattered shrubs and nearly continuous ground cover of grasses and mixed herbs such as wild ginger, Solomon’s seal, panic grasses, and bloodroot. Calcic slopes and bottoms occur in areas with neutral soil inclusions that have moist loamy horizons (table 4.6, community 4). These slopes usually occur on the Aiken Plateau in shallow slopes with east to southwest aspects or along small stream slopes. Soils typically have pH values near 7.0, with calcium, phosphorus, and magnesium concentrations ten times greater than those of surrounding slope areas. The canopy is dominated by black walnut with scattered white oak, mockernut hickory, sweetgum, and pines. A scattered subcanopy includes red mulberry, flowering dogwood, hornbeam, winged elm, redbud, maple-leaved viburnum, and smooth blackhaw. A nearly continuous understory of oat grass includes scattered herbs such as southern lady fern, wild ginger, jack-inthe-pulpit, Solomon’s seal, bloodroot, and Huger’s carrion flower. Moist slope bottoms (table 4.6, community 5) are dominated by a mixed deciduous hardwood community on moist alluvium loam deposits

Table 4.6 Percent basal area for species associated with upland slope and hardwood communities on the Savannah River Site Species Quercus alba Fagus grandiflora Carya tomentosa Liquidambar styraciflua Carya glabra Quercus rubra Quercus stellata Pinus taeda Cornus florida Quercus velutina Quercus falcata Pinus echinata Juglans nigra Quercus coccinea Liriodendron tulipifera Ilex opaca Carya ovata Quercus laurifolia Quercus nigra Fraxinus americana Carya pallida Nyssa sylvatica Carya ovalis Morus rubra Carya cordiformis Carpinus caroliniana Callicarpa americana Quercus shumardii Tilia americana Vaccinium arboreum Acer floridanum Symplocos tinctoria Celtis tenuifolia Persea spp. Cercis canadensis Sassafras albinum Quercus hemisphaerica Viburnum rufidulum

1a

76 2 3 2

2

2b

3c

4d

5e

6f

7g

8h

9i

10j

25

20 3 4 5 11 0 0 0 3 3 10

16

4 34 7 4 4

8 0 8 18 2 0 1 13 5 2 10 3

36 1 5 4 8 18 6 3 5 5 2 1

0

33

17 11 0 12 10 0 0 6 0 1 0 0 2 0 0 0 4

16 0 15 4 1 0 20 0 6 7 14 0 0

0

31 0 32 1 13 0 0 0 8 7 0 0 0 0

1 0 0 0 0 4 1 1 0

1 0 1 0 0 1 1 1 0

1 0 0 0 0 7 3 1 0

6 11 3 5 0 0 2 5

6 6 0 3 0 6 4 3 0

6 3

2

2 1

1 1 1

28 2 0 1 1 0 0 1 0 2 3 0 0 0

5 2 2

1 17 0 1 10 0 1 0 1 0 1 0 1 0

0 1 1 0 1 1 1 3 0 3 2 2 0 0

0 0 0

1 0 1 1 0

1 1 2 1

0

1

0

2 3 15 9 1 1 0 2 1 1 0 0 0 1 1 0 2

3 0 0 0 6 0 5 3 1

0 0 0

0 3 0 8 10 0 1 1 1 0 0 0 0 0 0 0 0 0 0 0 1 1 0

0 0

0

0

0 1

0

0 0 0 0 0

0 0 0 0 0

0 0 0 0 0

0 (continued)

Biotic Communities

139

Table 4.6 (continued) Species Ulmus alata Oxydendrum arboreum Kalmia latifolia Quercus michauxii Rhododendron spp. Ostrya virginiana Halesia spp. Magnolia grandiflora No. of plots Basal area (m2/ha)

1a

2b

3c

0

0

4d

5e

6f

7g

8h

9i

10j

0 0 1 1 0 0 1 1 0 0 0 0 1 0 0 0 1 0 1 0 1 0 0 0 1 0 1 0 2 13 17 14 14 6 234 29 72 62 22.7 36.3 22.8 34.7 41.2 37.9 26.2 31.0 26.5 24.0

Note: Only those species accounting for >1 percent included; 0 indicates present but <1 percent of basal area. a Beech bluff. b Rich streamhead slope. c Terrace slope. d Calcic slope. e Moist slope bottom. f Cove hardwoods. g Moist mixed forest. h North-facing slope. i Mesic slope. j Dry-mesic exposed slope.

that transition to swamps and bottomlands near the Savannah River. The canopy is often a near even mixture of beech, laurel oak, and American holly, with lesser amounts of mockernut hickory, white oak, sweetgum, and loblolly pine. Shrubs tend to be scattered to sparsely clustered and include red buckeye, American strawberry bush, Carolina holly, and spicebush. Commonly occurring vines include poison ivy, rattan vine, cross vine, ladies’ eardrops, frost grape, and summer grape. A fairly diverse and continuous forest floor includes gentians, Indian pink, river oats, butterweed, mayapple, and little sweet Betsy, as well as other species associated with mesic hardwood forests. Cove hardwoods (table 4.6, community 6) have fertile soils and usually occur on or just below moderately steep slopes with northeast to northwest aspects. Soils are typically deep sandy loams with nearly 5 percent humus. Soils are slightly less rich than those associated with the walnutdominated canopy type but are much greater than those associated with mesic slopes. Light availability at the forest floor is less than that on the more typical mesic slopes and walnut-dominated fertile slopes. The canopy is nearly equally composed of white oak, sweetgum, beech, pignut hickory, and lesser amounts of loblolly pine, Shumard oak, basswood, shagbark hickory, and bitternut hickory. The subcanopy and shrub layer consist of scattered clusters of common silverbell, redbud, and other

140

Ecology and Management of a Forested Landscape

shrubs associated with upland hardwood forests. The forest floor has large patches of mixed herbs. In addition to herbs of mesic forests, other common species include bloodroot, false Solomon’s seal, toothwort, blue star, Solomon’s seal, mottled trillium, and squirrel corn. Moist mixed forests (table 4.6, community 7) that occur on lower slopes and slope bottoms with acidic soils have mixtures of loblolly pine, sweetgum, southern red oak, and water oak. Some areas also have white oak, laurel oak, mockernut hickory, and American holly. Large patches of shrubs are generally present, with the most common species being mountain laurel, azaleas, sweetleaf, hollies, aromatic sumac, Indian olive, and deerberry. The forest floor is dominated by scattered patches or individuals of species such as southern grape fern, southern maidenhair fern, partridgeberry, crane-fly orchid, and turpentine root. White oak, northern red oak, and pignut hickory codominate on north-facing or protected steep slopes (table 4.6, community 8). Black oak, post oak, sweetgum, mockernut hickory, flowering dogwood, and hornbeam are also present on less protected bluffs with an understory of sourwood, azaleas, and mountain laurel. Common herbs include hairy hawkweed, American alumroot, Solomon’s seal, bellworts, resurrection fern, crane-fly orchid, southern twayblade, carrion flower, and squawroot. Mesic slopes (table 4.6, community 9) with moderate grades typically occur along small stream drainages or on slopes with west to northeast aspects. Generally, loamy or clayey subsoils are within 40 cm (16 in) of the surface, and fertility levels are intermediate between infertile pine uplands and stream bottoms. Most of the contoured area on SRS is in the mesic and submesic slope groups. Their distribution on the landscape is related to the magnitude of exposure, as well as soil textural differences at varying depths. Mesic slopes have canopies dominated by white oak, black oak, southern red oak, mockernut hickory, pignut hickory, and beech (table 4.6). Sweetgum and loblolly pine are usually scattered throughout. Upper-slope positions have a scattered understory of Georgia hackberry, rusty blackhaw, beautyberry, and flowering dogwood, while lower-slope positions have a continuous understory of American holly. In addition to the herbs of steep bluffs, the forest floor consists of sparsely scattered to dense patches of rattlesnake plantain, woodland coreopsis, squawroot, smooth foxglove, violet wood sorrel, bluets, wild yams, wild geranium, carrion flower, and gerardia. Dry-mesic exposed upper slopes (table 4.6, community 10) are similar in composition to pine-oak and oak ridges. Canopies are composed of post oak, white oak, southern red oak, black oak, mockernut hickory,

Biotic Communities

141

sand hickory, flowering dogwood, and pines. Mixed herbaceous and shrub communities lie beneath submesic canopies and include common witch hazel, sourwood, Georgia hackberry, sweetshrub, hawthorns, and eastern chinquapin. Scattered to patchy ground covers include blueberries, carrion flower, and turpentine root. Common herbs include hairy hawkweed, elephant’s foot, woodland coreopsis, green-and-gold, downy false foxglove, spiderworts, little ladies’ tresses, and grasses.

Bottomlands and Floodplains Swamps and riparian bottomlands occupy roughly 22 percent of SRS. Shallow swamps are flooded for part of the growing season; deepwater swamps are flooded for most or all of the growing season (Penfound 1952; Conner and Buford 1996). Other riparian wetland areas that have saturated soils or standing water during the dormant season are considered riparian bottomlands. These bottomlands can be further divided into those associated with the Savannah River and those associated with stream drainages (e.g., Upper Three Runs). Shallow and deepwater swamps are similar, but stream and river bottoms are treated separately due to biogeochemical differences.

Swamps Swamps associated with the Savannah River include nonriverine sloughs, fringe swamps, backwater swamps, oxbow swamps, and blackwater swamps of large streams (figure 4.12). Bald cypress and water tupelo are dominant or codominant components of each type. Though similar in canopy composition, each type has different hydrologic and chemical features, as well as understory components. The most important factors that influence swamp plant community composition are soil texture, seasonal hydrology, and transfer rates of sediment, chemicals, and seed. Each affects biological functions such as decomposition, soil acidity, soil chemical exchange, nutrient availability, soil oxygenation, plant germination, and plant growth. Flood control and navigable water measures have significantly altered the hydrology of swamps. For the most part, the effects of flood control are reduced dormant-season flood frequency, depth, and duration and, in turn, reduced sediment and chemical input. In contrast, navigable water measures produce near permanent flooding in areas that normally have extended periods without flooding or soil saturation. As a result, inappropriate species persist in areas where they normally would not; as

142

Ecology and Management of a Forested Landscape

Figure 4.12. Flooded swamp (D. Scott).

well, seasonally limited processes occur for prolonged periods, thus changing the biogeochemical pathways of the river swamp vegetation type. Deeply flooded river swamps occur in low-lying backwater areas and fringe areas along the Savannah River (table 4.7, community 1). These swamps are characterized by flooding during most of the growing season and have clayey to loamy surface soils that are nearly neutral in acidity. Deeply flooded swamps have canopies dominated by bald cypress and water tupelo with some ashes. Beneath the canopy are few shrubs and varied ground covers that depend on soil features and hydrology. Ground covers of permanent open-water channels are nearly continuous stands of coontail and parrot feather. Ground covers in periodically dry areas have a mudflat appearance dominated by golden club, sedges, and butterweed. During inundation, floating aquatic plants like floating hearts, cow lily, fragrant water lily, duck potato, pondweeds, and duckweed are also present, particularly in well-lit areas. Deeply flooded river swamps with shorter-duration flooding often have a near continuous forest floor cover of mixed grasses, sedges, herbs, and numerous seedlings with some scattered shrubs and understory trees. Sparsely scattered understory trees include water elm, water locust, Carolina ash, black willow, buttonbush, and southern swamp dogwood. Other common forest floor species beneath cypress-tupelo canopies include water willow, false nettle, skull-

Biotic Communities

143

caps, swamp milkweed, bur reed, pickerelweed, arrow arum, arrowhead, Ludwigia spp., marsh Saint-John’s-wort, water pennywort, rice grass, numerous sedges, and other marsh species. Deeply flooded sloughs (table 4.7, community 2), like river swamps, have fine-textured, poorly drained soil composed predominantly of clays. However, sloughs are less frequently inundated and thus have less accumulation of alluvium and suspended material. The presence of finely textured soils results in high cation exchange capacities and equally high levels of total nutrient content. However, nutrient availability is limited. Limited bacterial activity associated with nitrogen fixation, nitrification, and decomposition, as well as elevated rates of denitrification and ammonia volatilization, reduces nitrogen availability. Sloughs are dominated by water tupelo and bald cypress, as well as some swamp tupelo, ashes, red maple, and laurel oak. Shrubs are scattered throughout, unlike deep river swamps. The presence of shrubs may reflect differences in hydrologic period as well as water flow patterns during flood periods. As in deeply flooded river swamps, ground cover is highly variable and ranges from dominance by lizard’s tail or perennial graminoids to floating aquatics like bladderworts and duckweed. Shallowly flooded swamps (table 4.7, community 3) are transitional from deeply flooded river swamps and sloughs to bottomlands. Shallow swamps are inundated less frequently, for shorter durations, and at shallower depths. Bald cypress and water tupelo dominate the canopy of shallow swamps, but bottomland species have greater importance. Those species include green ash, laurel oak, sycamore, swamp cottonwood, American elm, overcup oak, water hickory, and sugarberry. Beneath the canopy, greater numbers of small trees and shrubs include water elm, water locust, Carolina ash, swamp forestiera, hawthorns, hollies, and various vines. Along larger blackwater creeks, swamps are dominated by bald cypress, water tupelo, swamp tupelo, red maple, laurel oak, sugarberry, and willow oak (table 4.7, community 4). Scattered understory species include water elm, Carolina ash, titi, Virginia willow, and buttonbush. Forest floor vegetation depends on draw-down patterns within the swamp and seasonal recruitment from seed banks. Unlike river swamps, most deposited alluvium tends to be sand along the stream and organic material away from the stream channel. Flood water is rich in organic acids, with limited amounts of mineral cations and suspended materials. Relative to large stream and river swamps, small stream swamps (table 4.7, communities 5 and 6) are less frequently and less deeply flooded

Table 4.7 Percent basal area for species associated with swamp communities on the Savannah River Site Species

1a

2b

3c

4d

Taxodium distichum Nyssa aquatica Nyssa biflora Liquidambar styraciflua Acer rubrum Fraxinus pennsylvanica Liriodendron tulipifera Quercus nigra Quercus phellos Quercus laurifolia Fraxinus caroliniana Pinus taeda Ilex opaca Carpinus caroliniana Persea spp. Magnolia virginiana Nyssa sylvatica Ulmus americana Plantanus occidentalis Quercus lyrata Carya aquatica Quercus michauxii Gleditsia aquatica Planera aquatica Salix nigra Cornus stricta Betula nigra Acer negundo Acer saccharinum Populus heterophylla Celtis laevigata Alnus serrulata Cephalanthus occidentalis Itea virginiana Cyrilla racemiflora No. of plots Basal area (m2/ha)

73 18 0 0 0 5

24 61 8

37 21 0 0 0 11

38 3 10 9 7 0

1

3 3

1 3 1

8 1

0

0 0

0 0 0 0 0 0 0 0

0 1

2 4 6 5

1 0

0 0

1 2 10 2 3 1 2 2

1

3 1

2

5e

42 13 29 1 1 0

2 1 0 0 0 2 0

6f

22 8 23 1 2 6 13 8 1 3 1 2 2 3 0

7g

77 6 7 0 4

8h

9i

0 0 0 1 5

4 7 0 0 0

0 0 11

1 5

0 0

3 1 1

0

1 1

0 0 0

1

0

0 1 3 1 1 2

0 12 4 2 0 0

3 1

1 1

0 0 15 8 4 6 73.1 46.2 54.1 49.3

29 1 4 26 3 5 7.8 13.1

66 2 11 14 2 35.8 34.1 22.9

Note: Only those species accounting for >1 percent included; 0 indicates present but <1 percent of basal area. a

Deeply flooded river swamp. b Deeply flooded river slough. c Shallowly flooded swamp. d Large stream swamp. e Streamside swale. f Small stream swamp. g Forested stream pond. h Buttonbush swamp. i Streambank swamp.

Biotic Communities

145

during the growing season. Red maple and swamp tupelo dominate streamside swales and upstream swamps; bald cypress and water tupelo dominate swamps downstream. Willow oak, laurel oak, water oak, sweetgum, ironwood, and sweet bay are also abundant in stream swamps. The forest floor has scattered cover of sedges, horned rushes, chain fern, royal fern, lizard’s tail, arrow arum, Sagittaria spp., golden club, and scattered shrubs such as Virginia willow, sweet pepperbush, red bay, and titi. Many river swamp vines also occur in stream swamps, in addition to leather flower, climbing hydrangea, poison ivy, and cross vine. Forested stream ponds (table 4.7, community 7) and depressions with sluggish water movement occur sporadically along small streams. Ponds behind beaver dams also occur along streams. Swamp tupelo usually dominates the canopy of these ponds, with various bottomland species along the margins. Depending on light availability, the understory ranges from a few scattered wetland shrubs and sedges to nearly complete cover by species associated with marsh habitats. Buttonbush swamps (table 4.7, community 8) are shrub dominated and shift successionally to other river and stream swamp communities. This type of community occurs on catastrophic disturbed sites with frequently flooded soils. Other common shrubs are swamp dogwood, wax myrtle, and Virginia willow. Other flood-tolerant, light-seeded tree species, such as Carolina ash, red maple, box elder, black willow, swamp cottonwood, water elm, and river birch, are also usually present. Stream bank swamps (table 4.7, community 9) are also shrub dominated, successional communities that occur along sections of streams that have weakly defined channels and either unconsolidated sediments or recently deposited alluvium. Common dominant shrubs include titi, willows, Virginia willow, swamp dogwood, tag alder, and sweet pepperbush. Saplings of red maple, sweetgum, ironwood, river birch, and sycamore are also scattered throughout the shrub layer. Stream bank and buttonbush swamps have scattered ground covers beneath the shrub canopy; usually, the ground cover community is composed of cosmopolitan wetland herbs and graminoids. Both communities may have high densities of marsh vines.

River Bottoms Many processes that influence river swamps also affect bottomlands. However, terrestrial processes are more important in bottomlands because they are less flooded than swamps. Features that govern the floristic composition of bottomlands include isolation from viable seed

Table 4.8 Percent basal area for species associated with river and large stream bottom habitats on the Savannah River Site Species Quercus pagoda Quercus michauxi Quercus phellos Quercus laurifolia Liquidambar styraciflua Liriodendron tulipifera Pinus taeda Fraxinus spp. Quercus austrina Ulmus americana Carya aquatica Plantanus occidentalis Quercus nigra Carya glabra Populus heterophylla Carpinus caroliniana Ulmus alata Celtis laevigata Betula nigra Quercus shumardii Quercus falcata Fraxinus caroliniana Acer negundo Acer saccharinum Fagus grandifolia Carya ovata Ilex decidua Acer rubrum Crataegus spp. Ilex opaca Aesculus pavia Quercus lyrata Nyssa aquatica Taxodium distichum Morus rubra Acer floridanum Planera aquatica Gleditsia aquatica

1a

1 0 3

2b

3c

8 2 1 17 7 0

15 16 5 6 27 2 4 5

9

9

4 1 27 3

4 11 13 1 8 3

5

1 10

11 22

2

3 1

4d

5 10 17 12 11 2 0 4

23

0 5 1

0 0 0 2 2 0 0

0

3

2

2 1 1 1 0 0 0 0

6f

21 20 1 2 11 0 4 5 4 3 5 0 4 0

10 13 3 14 1 3 2 0 0 0

2 3 0

0 1 2

2 1

5 2

3 4

4

2 3

0

0 0

1 1

0 1 0

1 0 0 1 0 0

4 3

5e

1 1

8h

9i

10j

1 2 6 23 0

0 39 5 2

3 2 37 5

0 6 2

22

1

0 13

29

17

5 13 3

6 1

3 0 0 0 0 1 1 0 0

11 8 0 0 0 1 1

0

0 2

1 0 0 0

7g

8 3 9 1

0 13 1

0 0

2

0

1 0

5

1

0 0 1 0

1

4 3 0

1

3

7

0 0

1 1 12 3 4

2 3 0

10 19 9

0 1

1 0

1

(continued)

Biotic Communities

147

Table 4.8 (continued) Species

1a

2b

3c

4d

5e

6f

7g

8h

9i

10j

Magnolia grandifolia 0 Nyssa biflora 0 0 0 1 Carya cordiformis 0 0 2 Quercus alba 0 0 4 4 14 0 Lindera benzoin 0 0 1 Forestiera acuminata 0 0 1 0 Cephalanthus occidentalis 1 0 0 No. of plots 3 9 6 23 23 4 3 4 3 2 Basal area (m2/ha) 42.3 76.8 32.2 23.9 29.1 48.6 33.0 22.2 37.2 45.3 Note: Only those species accounting for >1 percent included; 0 indicates present but <1 percent of basal area. a River bank. b River levee. c Loamy floodplain. d Sand floodplain. e High terrace. f Loamy terrace. g Moist clay terrace. h Willow oak flat. i Wet loamy flat. j Flooded low flat.

sources, soil texture, landscape and topographic position, soil chemistry, decomposition, and depth of water table. Water table depth and flood regime, as well as soil texture, affect seed germination and seedling growth. Hydrologic patterns create habitat conditions that influence animal movement and, hence, seed dispersion. Bottomlands are often composed of species with varied tolerance to flooding and saturated soils. Many upland and wetland species are intermixed in bottomland areas. Upland species are more frequent on moist ridges; in wet areas, they tend to have shallow roots above the water table and are susceptible to windthrow. Over time, periodic wind damage will effectively eliminate shallowly rooted species from the forest composition. Root damage and root stress caused by water logging will inhibit growth and also reduce competitive vigor. At the edge of the Savannah River, the riverbank community (table 4.8, community 1) has sycamore, silver maple, river birch, box elder, green ash, and lesser amounts of American elm, swamp cottonwood, sweetgum, and sugarberry. The banks of the Savannah River are unconsolidated clays, silts, and loamy alluviums. These sediments are often steeply sloped and highly eroded during periods of increased water flow and water level. Therefore, riverbank plant communities are variable in composition and successional setting. Vine- and shrub-dominated thickets common along the riverbank include possum haw, river cane, sugarberry, water elm, trumpet creeper, grapes, peppervine, Dutchman’s pipe,

148

Ecology and Management of a Forested Landscape

Virginia creeper, poison ivy, cross vine, and rattan vine. Kudzu, an exotic weed, also dominates some areas along the Savannah River. Above the riverbank, natural levees have developed from flood deposition of sediments. River levees act as barriers to direct flooding and scouring of bottomlands and swales and maintain the integrity of river channels. Levees are composed of rich sandy loam alluvium that supports a productive forest of cherrybark oak, laurel oak, water hickory, pignut hickory, sycamore, green ash, sweetgum, and subcanopy species such as sugarberry, possum haw, box elder, and red buckeye (table 4.8, community 2). River oats commonly dominate the understory of levees, along with various sedges, river cane, and wild rye. Away from the riverbank and levees, river bottom communities generally separate along an elevational gradient, with poorly drained flats (table 4.8, communities 8–10) in low-lying areas and well-drained terraces (table 4.8, communities 5–7) slightly higher; differences of a few inches in elevation can determine community composition. Floodplains (table 4.8, communities 3 and 4) are areas that lack the topographic variation that separates terraces and flats. Communities can be differentiated further on the basis of soil texture, which influences fertility and drainage. Loamy floodplains (table 4.8, community 3) have canopies of swamp chestnut oak, cherrybark oak, sweetgum, laurel oak, willow oak, loblolly pine, green ash, white oak, southern red oak, water oak, and hickories. Understory trees include winged elm, ironwood, possum haw, red buckeye, swamp palmetto, and hawthorns (figure 4.13). Postagriculture loamy floodplains usually have sweetgum canopies. Floodplains with sandy to loamy sand surface sediments and periodic dormant season flooding have canopies of laurel oak, water oak, sweetgum, loblolly pine, swamp chestnut oak, willow oak, and American elm (table 4.8, community 4). Earlier successional settings are dominated by water oak, sweetgum, and loblolly pine. As in subcanopies on loamy floodplains, scattered ironwood, winged elm, and hawthorns are present. The understory is usually river cane and scattered patches of swamp palm and mixtures of other bottomland grasses and herbs. High terraces (table 4.8, community 5) seldom flood, have moist loamy to sandy loam soil, and are well drained. Available and total nutrient concentrations are usually high with rapid rates of decomposition. Canopy dominants include cherrybark oak, swamp chestnut oak, white oak, Shumard oak, bluff oak, sweetgum, water oak, American elm, ashes, loblolly pine, and hickories. Common understory species include flowering dogwood, deciduous hollies, southern highbush blueberry, red

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149

Figure 4.13. Bottomland hardwood forest with herbaceous understory (D. Scott).

buckeye, possum haw, winged elm, swamp palmetto, and river cane (figure 4.14). Loamy terraces (table 4.8, community 6), or “first terraces,” are immediately adjacent to river swamps. Soils are similar to those of high terraces, but many bottomland species are absent, presumably due to limited seed dispersion in areas away from adjacent uplands. Dominant canopy species include white oak, beech, shagbark and other hickories, cherrybark oak, swamp chestnut oak, sweetgum, and southern red oak. Loamy terraces have scattered understories of Florida maple, sugarberry, red buckeye, American holly, and hawthorns. Moist clay terraces and willow oak flats (table 4.8, communities 7 and 8) occur on the heavy clay bottoms or clay depressions with restricted water percolation. These conditions can occur in river or stream bottomlands. In addition to willow oak, slightly wetter sites have sweetgum, green ash, American elm, laurel oak, overcup oak, sycamore, water hickory, water tupelo, and bald cypress. Wet loamy flats (table 4.8, community 9) are frequently flooded but more readily drained. Loamy flats have a canopy dominated by green ash, laurel oak, sycamore, American elm, and lesser amounts of willow oak, water oak, swamp cottonwood, and sweetgum. A nearly continuous subcanopy of sugarberry is also present. Other species include sycamore, bald cypress, water elm, and water locust.

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Figure 4.14. Bottomland hardwood forest with switchcane understory (D. Scott).

Flooded low flats are more frequently flooded and usually have lower diversity of canopy species. They are transitional to swamps and sloughs. Soil characteristics are also transitional, with loamy surface soils shallowly underlain with clays. Periodic flooding, particularly during the growing season, results in mixed compositions of swamp and bottomland species such as water tupelo, green ash, bald cypress, overcup oak, water hickory, and laurel oak.

Stream Bottoms Blackwater streams and their associated wetlands account for a significant portion of the SRS, as well as the Sandhills and Upper Coastal Plain provinces of the Carolinas and Georgia. Differences in stream bottom communities can be attributed to stream size, local hydrology and chemistry, and soil texture and genesis. The most typical condition is a moderately to slightly acidic sandy to sandy loam bottom that is moist to seasonally wet but seldom flooded for long periods. These conditions contrast with those of river bottoms, which typically are neutral to slightly acidic loam to clay loam and moist to permanently wet with periodic flooding. Larger blackwater streams allow for enhanced community development due to broadened riparian areas and more complex topographic and hydrologic environments. Small streams afford the development of

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locally unique habitats due to isolation and site-to-site differences. These include various types of seeps, streamheads, bayheads, baygalls, and pocosin-like habitats, as well as narrowed riparian corridors that allow for unique mixtures of upland and lowland species. Small stream watersheds are also more susceptible to timbering and other activities that affect the hydrology of adjacent uplands. Mesic pine communities (table 4.9, community 1) occur on higher portions of bottoms and usually have histories of agriculture. Pine bottoms have sandy to loamy sediments and are infrequently flooded but have imperfect drainage. Eight understory types commonly occur: mixed shrub and herbaceous, red bay, blackhaw, gallberry-blueberry, fetter bush, wax myrtle, switchcane, and swamp palmetto. The mixed type usually includes shrub components of the other seven types, as well as sedges, horned rush, panic grass, yellow root, black bayberry, pink lady’s slipper, fringed orchids, partridgeberry, and spotted wintergreen. The seven shrub-dominated understories have nearly continuous layers of shrubs and midstory composed of single or multiple species, such as switchcane, gallberry, big gallberry, red bay, smooth blackhaw, fetter bush, highbush blueberry, wax myrtle, and swamp palmetto. The latter species grows on soils with elevated soil pH levels (more than 6.0), and the former species are associated with more frequent burning regimes. Moist stream bottoms typically have nearly equal mixtures of bottomland and upland species (table 4.9, community 2). Soils are usually loamy sands to clay loams that are moist to wet throughout much of the year but are seldom flooded, though standing water may occur during the dormant season. Common dominants include red maple, water oak, sweetgum, tulip poplar, swamp chestnut oak, loblolly pine, beech, white oak, southern red oak, mockernut hickory, pignut hickory, and flowering dogwood. The understory is typically composed of scattered Elliott’s blueberry, Carolina holly, azaleas, Carolina arrowwood, little pawpaw, and beautyberry. Common herbs include wild ginger, jack-in-the-pulpit, partridgeberry, lady fern, Easter lily, sedges, and other mesic herbs and grasses. Occasionally, a lawnlike forest floor dominated by Panicum and Carex species can develop on fertile, moist soils that are infrequently flooded. These “lawns” occupy lower positions than cane-dominated areas but are above small sloughs dominated by lizard’s tail and Sagittaria spp. They also support various herbs and ferns such as fringed orchids, lady fern, jack-in-the-pulpit, and marsh Saint-John’s-wort. Mixed pinehardwood bottoms (table 4.9, community 3) have similar understories and environmental settings but are dominated by loblolly pine.

Table 4.9 Percent basal area for species associated with stream bottom communities on the Savannah River Site Species

1a

2b

3c

4d

5e

6f

7g

8h

9i

Liquidambar styraciflua Pinus taeda Quercus nigra Liriodendron tulipifera Acer rubrum Nyssa biflora Magnolia virginiana Persea spp. Pinus serotina Gordonia lasianthus Ilex opaca Quercus laurifolia Pinus palustrus Pinus echinata Ulmus americana Cornus florida Quercus pagoda Quercus michauxii Quercus alba Quercus phellos Carpinus caroliniana Carya glabra Plantanus occidentalis Carya tomentosa Fraxinus spp. Nyssa sylvatica Quercus falcata Fagus grandifolia Betula nigra Myrica cerifera Ulmus alata Carya ovalis Symplocos tinctoria Lindera benzoin Viburnum nudum Lyonia lucida No. of plots Basal area (m2/ha)

11 60 10 0 1 1 1 3 0

14 38 7 13 4 0 0 1 1 0 4 1

19 19 17 1 6 1 1 1 0

18 1 12 37 4 3 2 2 0 9 3

6 8 6 11 13 16 19 5 1 0 4 2

2 8 1 1 0 0 17 6 35 17 1 0 2

0 1

0 0 1

7 31 5 5 2 2 5 3 2 1 3 4 4 11

15 6 1 16 9 19 11 2

5 2

16 6 6 11 4 36 1 3 0 0 6 3

2

2

1

1

1

0 1

0

0

1

1

0 1

2

0

3 1 1

0 0

0

0

0

0

0

0

1

2 2 0 0 0 1 1 0 1

0 0 1

3 1 0

0 2 0 4 0 1 3 1 0 1 1

0 0 0 1

2 3 0 0 3 0 0 1 1 1 2 1 3 0 2 1 2 1 0 0

2 0 0 1 1 1 0 0 1 0 0 0 0 0 0 0 1

10 16 46 24 39.8 37.5 28.7 32.1

0 2 0 2

0 1 0

0 0 1 0 1

7 3

1

1 2 0 33 21 5 33.8 34.5 34.0

2 1 2

0 0 1 10 15 49.2 37.2

Note: Only those species accounting for >1 percent included; 0 indicates present but <1 percent of basal area. a Mesic pine bottom. b Moist stream bottom. c Mixed pine-hardwood bottom. d Small stream bottom. e Wet mixed forest. f Bayhead. g Stream pocosin. h Pine seep. i Wet streamhead.

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Small stream bottoms (table 4.9, community 4) have canopies dominated by mixtures of tulip poplar, sweetgum, water oak, and American holly. Sweet bay, loblolly pine, white oak, southern red oak, and hickories are also commonly present. Because these stream bottoms are usually narrow, many upland species occur in the canopy and understory. The understory has varied composition dependent on soil and moisture conditions. Mucky soils have sphagnum mats with many of the same species as seeps, while moist sands and loams have species similar to those found in larger blackwater stream floodplains. The most prevalent understory species are switchcane, blueberries, red bay, blackhaw, doghobble, and hollies. Many orchids and other mesophytic herbs are associated with moist but rarely flooded soil conditions found along small blackwater streams. Wet mixed forests (table 4.9, community 5) along blackwater stream floodplains are frequently flooded during the dormant season and periodically flooded during the growing season. The topography consists of pit-mound contours intermixed with meandering tributary streams and raised terraces. The complex topography results in sharp texture, moisture, and nutrient gradients beneath the wet forest canopy. Wet mixed forests have canopies dominated by swamp tupelo, sweetgum, and tulip poplar, with lesser amounts of loblolly pine, water oak, and American holly. Sphagnum pockets dominate small, inactive sloughs that are surrounded by a nearly continuous shrub layer on slightly higher areas. Small, active sloughs have lizard’s tail, arrow arum, golden club, pickerelweed, Sagittaria spp., and Rhynchospora spp. Blackhaw and dog-hobble dominate along small stream tributaries, particularly those with acidic sediments. Fetter bush and gallberry dominate slightly larger riparian areas with organic sandy soils. Switchcane is more cosmopolitan and dominates in less frequently flooded areas with varied soil conditions. Open understories with poorly drained organic mucks often develop into fern glades with chain fern, cinnamon fern, sensitive fern, and royal fern, as well as scattered shrubs and herbaceous species. Bayhead communities are spring-fed systems within small stream bottoms. They occur along small streams in unflooded areas but with saturated soils that are drained by surface runoff. Bayheads grade slowly into more typical mixed pine-hardwood bottomland communities. The bayhead community dominants are sweet bay, loblolly bay, red bay, tulip poplar, sweetgum, water oak, loblolly pine, red maple, and American holly (table 4.9, community 6). The understories vary from nearly complete dominance by dog-hobble or fetter bush to open conditions with exposed muck sediments.

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Stream pocosins have pond pine, sweet bay, and loblolly bay (table 4.9, community 7), with either an evergreen or dense switchcane thicket beneath. Typically, evergreen thickets develop in less frequently burned areas or on more acidic soils that remain saturated for longer periods. Unlike bayheads, stream pocosins develop with occasional to periodic intense fires that often extend to the stream margin. Generally, slopes are more gradual with less topographic relief that allows fire to move from the upland to the wetland. Stream pocosins occur on organic soils or hummock soils underlain by spodic horizons. In either case, periodic burning reduces surface litter. Following fire, a diverse assemblage of herbs follow, which include ferns, sundews, pitcher plants, gentians, common marsh pink, fringed orchids, other orchids, sedges, and various grasses. Seeps commonly occur at the transition from upland to stream bottoms. Pine seeps or seepage bogs have shallow contours with nearly continuous leakage of surface water. Dominant canopy species are loblolly pine, shortleaf pine, and periodically longleaf pine and pond pine (table 4.9, community 8). Scattered hardwood trees and shrubs are also present. Usually, switchcane dominates the understory with a limited variety of other herbs. Pine seeps that are periodically burned have extremely rich herbaceous floras dominated by a variety of grasses, composites, legumes, and other herbs. Like other seeps, the soil remains moist and is usually acidic due to decomposition of pine litter; however, the spring water may contain varied amounts of minerals that strongly influence soil chemistry. Wet streamhead dominants are swamp tupelo, sweetgum, tulip poplar, sweet bay, and red maple (table 4.9, community 9). These areas usually have mucky to wet sandy sediments with slow water movement into permanent streams. The understory consists of a dense thicket of hollies, gallberry, and ericaceous shrubs (e.g., dog-hobble, blueberries). Evergreen-dominated seeps have heavy litter layers, acidic soil profiles, and low levels of available nutrients.

Streamsides and Marshes Marshes and swamps differ in hydrology, chemistry, and vegetation structure. Marshes are permanently flooded areas that limit or restrict the natural establishment of tree seedlings (Kushlan 1990). Marshes are critical because they store and sequester carbon reserves, as well as filtering colloids and dissolved elements from moving water. Less frequently flooded marshes require other disturbances to reduce or eliminate the recruitment of tree seedlings. Coastward, frequent burning reduces the en-

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croachment of woody species into marshes; brackish water and soil salinity also reduce the number of species suitable for invasion. Further inland, once common fires in stream bottoms resulted in the development of “canebrakes.” Switchcane dominates canebrakes, along with a few scattered trees such as pond pine. Canebrakes once covered extensive areas of the Southeast and continue to persist on military installations that have intense, frequent fires. Very little marsh habitat existed on SRS before its establishment by the Atomic Energy Commission. Most marsh habitat was confined to low areas along the Savannah River, wet cutover areas, pond margins, and clearings along utility rights-of-way, roadways, and railroads. Today, those same habitat settings continue to offer conditions suitable for marsh development. In addition to those areas, extensive marsh habitat exists in delta areas of thermally impacted streams and adjacent portions of the Savannah River swamp. Most former farm ponds are now marshes or young swamp forests. Reservoir margins are also important marsh habitats. Marsh vegetation depends on sediment type, flooding depth, and rate of water movement, as well as flooding frequency, season, and duration. Fire, marsh size, and soil and water chemistry also influence marsh vegetation. In the absence of disturbance, maintenance, and water level control, most marsh habitats on SRS gradually become forested. Large extensive deltas and thermally impacted areas are slower to become reforested due to limited recruitment of seed from adjacent sources. As well, unconsolidated mucks are unstable soils highly sensitive to displacement and, therefore, offer unstable habitat conditions for seedling establishment. Over time, increased channelization of streams will occur in thermally disturbed deltas, and streamside zones will stabilize and likely become vegetated by early successional woody plants such as willows, wax myrtle, water loosestrife, buttonbush, tag alder, swamp dogwood, and Virginia willow. A few scattered saplings may exist of wind-dispersed or buoyantfruit species, such as bald cypress, red maple, ashes, ironwood, sweetgum, box elder, river birch, eastern cottonwood, sycamore, and water elm. In addition, marshy areas associated with timber harvesting have a significant component of sprouts of those species removed or damaged; therefore, species with less mobile seed such as oaks, hollies, hickories, and sugarberry are also present. Loblolly pine and tulip poplar are very common saplings in marshy, cutover areas near streams. During high water periods, woody stems at the stream margin will slow water velocities, particularly out of the stream channel, and will increase deposition at the bank. With continued channelization and stream

156

Ecology and Management of a Forested Landscape

bank deposition, a stream levee will provide suitable habitat for streamside forests. During early stream development, many stream braids replace others and slowly accumulate sediment. However, woody corridors that develop during channelization often persist and provide attractive nesting and perching habitat for birds that carry in seed. Succession in large barrens, such as thermally disturbed deltas on SRS, also includes encroachment of seedlings from adjacent mature seed sources. In drier sandy alluvium, immigrants include loblolly pine seedlings; low mucky areas support bald cypress seedlings. Bulrushes dominates marshy areas with wet sands, and Rubus spp. dominate slightly higher areas. Cattails often dominate loamy organic rich soils with fairly stable water levels and limited water movement.

Streamside and Marsh Communities Large marshy areas with unconsolidated mucks have diverse mixtures of emergent plants such as water primrose, marsh Saint-John’s-wort, cord grasses, sedges, nut rushes, fimbry, horned rushes, and a variety of floating aquatics. Marsh fleabane commonly occurs around the fringe of unconsolidated sediments and slowly replaces early invading graminoids. Water willow and lizard’s tail are common emergent plants in streamside marshes, as well as beneath open- or closed-canopy streamside swamp forests. Along the margins of slow-moving streams, emergent grasses such as manna grasses and rice grass are usually present. Marshes with less frequent or dormant-season flooding have bluestems, little bluestem, panic grasses, witchgrasses, love grasses, switchcane, giant reed, plume grass, Sacciolepis striata, and Paspalum spp. Several successional weeds such as dog fennel, horseweed, cudweed, morning glories, and Verbena brasiliensis commonly occur in marshy areas, particularly those created by forest harvesting. Common forbs in marshes include gerardia, Bidens spp., common marsh pink, meadow beauties, cardinal flower, lobelias, hydrolea, and ironweeds. Marshes along roadsides, railroads, and utility corridors also have several bottomland species such as ladies’ tresses, fringed orchids, butterweed, pitcher plants, Easter lily, whorled loosestrife, skullcaps, and gentians. Ferns such as netted chain fern, chain fern, cinnamon fern, and royal fern are also commonly present, particularly in marshy areas that are mowed or managed without significant soil disturbance. Marshes with extensive soil disturbance, such as thermally impacted deltas, have various vines and emergent species. Common vines include

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smartweeds, jewelweeds, poison ivy, greenbriers, climbing hempweed, pepper vine, climbing dogbane, climbing hydrangea, bedstraws, and grapes. Water pennywort, buttercups, spike rush, and bur-head are found in mucky unconsolidated sediments that are saturated to shallow-flooded during the growing season. Water pennywort occurs along infrequently flooded streamsides. Well-lit areas along slowly moving streams or beaver ponds usually have submerged plants such as bladderworts and emergent plants such as wapato, alligator weed, coralbeads, and Carolina water hyssop. Submergent plants and unattached floating aquatic plants dominate deeply flooded areas. Rooted floating aquatic plants dominate slightly shallower ponds. Ponds and quiet stream waters often support floating aquatic plants such as frogs-bit, cow lily, water shield, white water lily, floating-hearts, Spirodela polyrrhiza, and Wolffiella floridana. Partially shaded, quiet ponds also have unattached floating plants such as duckweeds. Eel grass is the most common submergent plant in fast-moving streams. Other submergent species such as pondweeds, coontail, and water milfoil more frequently occur in slow-moving or standing water impoundments (e.g., reservoirs, ponds). Usually, fast-moving streams have very few floating aquatic plants and several emergent plant species. Unconsolidated sediments along fastmoving streams often have pickerelweed, bulrushes, horned rushes, spike rushes, arrow arum, duck potato, and arrowheads.

Upland Meadows, Old Fields, and Industrial Areas The SRS maintains meadows as permanent grasslands adjacent to facilities, burial grounds, utility corridors, and roadsides to reduce surface erosion (figure 4.15). Maintenance includes periodic seeding, mowing, fertilizing, and selective use of herbicides to reduce encroachment by woody species. In the past, seed mixtures included centipede grass, ryegrass, barnyard grass, orchard grass, Kentucky bluegrass, fescue, sericea lespedeza, and Korean clover. The current mixture of seed during the growing season includes browntop millet, hulled Bermuda grass, and Bahia grass. Panicum spp. and little bluestem are also used in nonindustrial areas. Winter seed mixtures include ryegrass, unhulled Bermuda grass, and Bahia grass. Crimson clover and hairy vetch are also added for shady areas. Generally, Bermuda grass dominates seeded areas for the first three years and then Bahia grass dominates. In addition, many native

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Ecology and Management of a Forested Landscape

Figure 4.15. Old-field conditions typical of rights-of-way and other open areas (D. Scott).

and non-native species germinate following soil disturbance and often persist or increase following site preparation. Weeping love grass helps stabilize soil and gives the appearance of wire grass. Though weeping love grass readily burns, thus benefiting other herb cohorts in pine savannas, it often produces hot fires that cause uncontrolled, adjacent spot fires. Sericea lespedeza was once planted to control erosion and stabilize roadside ditches, as well as in wildlife food plots. It has persisted in many areas and has spread to other areas. The most common setting is along abandoned logging roads or well-shaded secondary roads. Small to intermediate-sized food plots are maintained on the Crackerneck Wildlife Management Area and Ecological Reserve (CWMA) and once existed elsewhere on SRS. Seed mixtures for food plots include chufa, sericea lespedeza, Korean clover, Japanese clover, Lespedeza thunbergii, Lespedeza bicolor, ryegrass, browntop millet, winter wheat, partridge pea, oats, sorghum, southern six-weeks fescue, squirreltail fescue, and sesban. The South Carolina Department of Natural Resources mows and fertilizes CWMA food plots and occasionally reseeds them to establish additional desirable species. Several old fields, abandoned at the time of SRS establishment, persist for scientific investigation (e.g., set-aside areas 1 and 28, fields 3-412 and

Biotic Communities

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3-409; Davis and Janecek 1997). SRS planted the remaining abandoned old fields with pine. Secondary old-field succession (Odum 1960; Collins and Pinder 1990) on SRS followed the general pattern of transition from weedy annuals and short-lived perennials (foxtail grasses, fireweed, horseweed, dog fennel, pokeweed) to increased dominance of perennial bunch grasses (little bluestem, broom sedge). During this period, patchy clusters of woody plants (blackberries, plums, sassafras, grapes) became established and are expected to lead to canopy closure through continued growth and establishment of woody plants (pine, sweetgum, persimmon). The rate of succession and species turnover depends on site productivity, past land-use activity, proximity to seed of successors, and size of the succeeding area.

Meadow, Old-Field, and Industrial Communities Annual and short-lived forbs and graminoids dominate disturbed areas. In most cases, the community drastically changes in composition through the growing season. Most grasses grow slowly during the spring months, thus allowing a procession of sheep sorrel, blue toadflax, oxeye daisy, Phlox spp., thistles, creeping dewberry, and field garlic. Later in the spring, bent grasses, Paspalum spp., Rosa spp., woolly ragwort, dwarf dandelions, sow thistle, sorrels, violets, clovers, lyre-leaved sage, seedbox, rabbit tobacco, and blue-eyed grasses are also dominant. Dominant early summer plants include wild indigos, cornflower, bitterweed, black-eyed Susans, Coreopsis spp., cudweed, daisy fleabane, and evening primroses. By midsummer, grasses, horseweed, dog fennel, beggar-ticks, and Lespedeza spp. dominate most old fields, meadows, and disturbed areas. Other flowering species such as milkweeds, sneezeweeds, silk grass, common ragwort, throughworts, Asiatic dayflower, sensitive brier, coffee weed, Venus looking-glass, spiderworts, blue curls, and peppergrass are also present. Autumn plants include poverty grass, crabgrass, foxtail grasses, redtop, witchgrasses, smut grass, panic grasses, fall witchgrass, and muhly grass. Forbs such as goldenrods, camphor weeds, golden asters, Diodia spp., and Richardia spp. also dominate during the late summer and autumn months. Poison oak and large grasses such as broom sedge, little bluestem, Bermuda grass, and Bahia grass are dominant throughout most of the growing season. Reindeer moss (Cladina spp.) and eastern prickly pear also dominate in dry sandy or extremely infertile areas. Throughout the growing season, disturbed areas also support weedy species such as pokeweed, fireweed, common ragweed, lamb’s-quarters, wild lettuce, maypop,

160

Ecology and Management of a Forested Landscape

Queen Anne’s lace, chicory, and black medic. Heavily disturbed areas also support pigweed, Mexican tea, common chickweed, bedstraws, Johnson grass, yarrow, plantains, mullein, henbit, nightshades, heal-all, rattlebox, and Sida rhombifolia. Moist or clay-rich sites are frequently dominated by woody plants and vines such as blackberries, trumpet creeper, Virginia creeper, muscadine grape, greenbriers, pepper vine, honeysuckles, morning glories, and smartweeds. Besides those in disturbed sites, other common herbs on clayey or moist sites include Indian strawberry, cranesbill, horse nettle, cinquefoil, polypremum, and yankee weed. Several grasses and forbs from pine savannas are also common in less frequently manipulated permanent meadow settings. Natural meadows are important seed sources of species that are absent or infrequent in pine forests. Species include dropseeds, Indian grasses, sand grasses, poverty grass, wire grass, and other Aristida spp. Other graminoids such as path rush, nut rushes, and sedges are more common in native meadow settings. Ferns such as bracken fern and ebony spleenwort are also more common in these areas. Other more frequently occurring plants in native meadow habitats include green eyes, Saint-John’s-wort, compass plant, pineweed, golden asters, Silene spp., Gerardia spp., Liatris spp., Verbena spp., false foxgloves, southern beardtongue, Florida wire plant, butterfly weed, and Carolina puccoon. Legumes are also prevalent in areas of native plants and include partridge pea, wild indigos, dollarleaf, goatsrue, lupines, spurred butterfly pea, butterfly pea, and a great diversity of native beggar-ticks and Lespedeza spp. Thickets of exotic species are common in maintained meadow areas and near facilities. Patches of kudzu, privets, oriental Wisteria spp., Japanese honeysuckle, and bamboo dominate portions of roadsides, utility rights-of-way, and pine regeneration areas. Native woody species are also common in patches or as individuals in permanent meadows. In regeneration areas, sprouts from hardwood stumps commonly occur and, without control, can impact the regeneration success of planted seedlings. Regeneration areas also have seedlings from buried seed or adjacent seed sources. The most common conifers in maintained meadows and regenerated old-field habitats are loblolly pine, slash pine, longleaf pine, and eastern red cedar. Common hardwoods include sweetgum, sassafras, persimmon, black cherry, sand laurel oak, water oak, and mockernut hickory. Dry sites also have seedlings and sprouts of sand hickory, turkey oak, and sand post oak. Fertile and moist sites have red maple, tulip poplar, switchcane, gallberry, American holly, flowering dog-

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wood, willows, and bald cypress. Most succeeding areas have common shrubs such as wax myrtle, Chickasaw plum, flatwoods plum, winged sumac, blueberries, sparkleberry, blackberries, and hollies.

Aquatic Invertebrates Barbara E. Taylor Multicellular aquatic invertebrates span a taxonomic range from sponges to insects. They are abundant in all of the streams, floodplains, impoundments, and wetland ponds of the Savannah River Site (SRS). They also inhabit springs, ditches, puddles, tree holes, and even groundwater. Although often inconspicuous to the human observer, they play central roles in the functioning of those systems. Many are benthic, living in or on sediments, or littoral, living in shallow water at the margins of ponds or in wetlands; others are planktonic, swimming or drifting in open water. Their trophic roles include primary consumers, detritivores, and predators. Aquatic invertebrates in turn constitute the main food resources for many fishes and some amphibians; they are also consumed by reptiles, birds, and mammals such as raccoons (Procyon lotor) and bats.

Major Groups of Invertebrates Members of the phylum Arthropoda, animals with chitinous exoskeletons, are the most diverse and successful of the aquatic invertebrates. Among them, insects generally predominate in littoral and benthic habitats, while crustaceans predominate in planktonic habitats. Annelids, molluscs, rotifers, and a half dozen other phyla are also important. Many groups of aquatic invertebrates on the SRS are poorly known taxonomically and ecologically. Detailed analyses will undoubtedly reveal additional species new to science.

Insects Most of the aquatic insects (table 4.10) have life cycles that are effectively amphibious, with an aquatic juvenile stage and a terrestrial adult stage, although adults of many beetles and bugs also use aquatic habitat. Stoneflies, mayflies, dragonflies, damselflies, and true bugs have a juvenile stage or nymph that resembles the adult in general form. The other

Table 4.10 Habitats of aquatic insects on the Savannah River Site Flood- Wetland ImpoundClassification

Streams plains

ponds

ments

Order Plecoptera stoneflies

√

Order Ephemeroptera mayflies

√

√

√

√

Order Odonata dragonflies & damselflies

√

√

√

√

Order Hemiptera true bugs

√

√

√

√

Order Megaloptera dobsonflies & alderflies

√

Order Neuroptera spongillaflies

√

Order Coleoptera beetles

√

√

√

√

Order Trichoptera caddisflies

√

√

√

√

√

Local species Upper Three Runs: 28 spp., 8 fam. (Morse et al. 1980)a Upper Three Runs: 32 spp., 12 fam. (Morse et al. 1980)a 2 SRS bays: 2 spp., 2 fam. (McClure 1994) SRS: 69 spp., 7 fam. of dragonflies (Kondratieff and Pyott 1987) Upper Three Runs: 24 spp., 8 fam. (Morse et al. 1980)a 2 SRS bays: 18 spp., 4 fam. (McClure 1994) Upper Three Runs: 27 spp. (Morse et al. 1980)a 2 SRS bays: 18 spp., 8 fam. (McClure 1994) Upper Three Runs: 6 spp., 2 fam. (Morse et al. 1980)a 2 SRS bays: 1 sp., 1 fam. (McClure 1994) Upper Three Runs: 2 spp., 1 fam. (Morse et al. 1980)a Upper Three Runs: 85 spp., 14 fam. (Morse et al. 1980)a 2 SRS bays: 52 spp., 8 fam. (McClure 1994) Upper Three Runs: 123 spp., 14 fam. (Floyd et al. 1993) 2 SRS bays: 2 spp., 1 fam. (McClure 1994) (continued)

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Table 4.10 (continued) Flood- Wetland ImpoundClassification Order Lepidoptera moths Order Diptera true flies: midges, mosquitoes, crane flies, black flies, horse flies, deer flies, and others

Streams plains

ponds

ments

√

√

√

√

√

√

√

√

Local species SRS: 15 spp., 1 fam. (Herlong 1978) Upper Three Runs: 230 spp., 13 fam. (Morse et al. 1983)a Rainbow Bay: 9 fam., 59 spp. in fam. Chironomidae (Leeper and Taylor 1998b) 2 SRS bays: 3 fam., 8 spp. in fam. except Chironomidae (McClure 1994)

Note: Check indicates occurrence in habitat; blank indicates usual absence. Sources consulted include studies cited here and in text, as well as other SRS studies summarized in Halverson et al. (1997). a May include species from floodplain and other habitats.

orders have larvae that are typically grublike or wormlike. The larvae enter a quiescent pupal stage to undergo metamorphosis to adult form. Most insects live in benthic or littoral habitat, and many are associated with aquatic vegetation. Odonate nymphs, hellgrammite larvae, most bug nymphs and adults, some stonefly nymphs, some beetle larvae and adults, and some dipteran larvae, among others, are predators. Depending on size and opportunity, insect predators capture other invertebrates or even small fishes and amphibians. Larvae of spongillaflies live and feed only on freshwater sponges. Many other aquatic insects, including the bulk of the chironomid midge larvae, mayfly nymphs, and caddisfly larvae, feed on fine particles of algae and detritus, collecting it with filtering appendages or nets or scraping it from surfaces. Some beetles, stoneflies, and crane flies, among others, process coarse plant debris, including leaves and wood. Other beetles and the larvae of pyralid moths feed directly on living aquatic plants. Many biting flies, including mosquitoes, horse flies, deer flies, and black flies, have aquatic or semi-aquatic larvae. These flies can become serious nuisances and vectors of disease to humans, livestock, and wildlife.

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Life cycles of insects range from a few weeks for midges to a year or more for large odonates and stoneflies. Productivity of species with short life cycles is potentially enormous. The biomass of midge larvae can increase by as much as 20 percent per day (Stites and Benke 1989; Hauer and Benke 1991).

Crustaceans With the exception of crayfishes, the crustaceans (table 4.11) are strictly aquatic, although many can survive desiccation in resting stages. Some copepods and cladocerans are planktonic; other crustaceans use benthic or littoral habitats. Microcrustaceans (less than 5 mm, more typically less than 2–3 mm) include cladocerans, copepods, and ostracods. Most microcrustaceans, clam and fairy shrimps, and decapod shrimps feed on algae and small particles of detritus. Amphipods, isopods, and crayfishes feed on periphyton, detritus, or scavenged material. A few crustaceans, including Argulus in subclass Branchiura and some highly specialized copepods, parasitize fish and amphibians. Life cycles range from less than a week for cladocerans to more than a year for crayfishes. Microcrustaceans are capable of explosive growth rates under favorable conditions: cladocerans can increase at rates of 30 to 40 percent or more per day (Taylor and Mahoney 1990; Leeper and Taylor 1995).

Other Invertebrate Phyla Most other invertebrates (table 4.12) are strictly aquatic. Among them, mollusks are the only well-studied group. Adult bivalves filter fine particles; larvae of species in the family Unionidae must encyst on the gills or fins of fish. Snails live on vegetation or other structure in littoral habitats or in soft sediments; they feed on algae, other microorganisms, and organic material. Snails serve as intermediate hosts for a variety of parasites. Annelid worms, including oligochaete worms and leeches, live mainly in benthic and littoral habitats; many feed on detrital material, algae, and bacteria; others are predators or ectoparasites. Rotifers, although usually very small (≤0.1 mm), are often an important component of the plankton; most feed on fine particles. Turbellarian worms are common and sometimes abundant, as are hydras and nematodes. Among phyla omitted from table 4.12, freshwater sponges (Porifera) and moss animals (Bryozoa or Ectoprocta) live in colonies on submerged wood or vegetation. The

Table 4.11 Habitats of aquatic arthropods (arachnids and crustaceans) on the Savannah River Site

Classification

Flood- Wetland ImpoundStreams plains ponds ments

Class Arachnida, Order Acarina mites

√

√

Class Crustacea Subclass Branchiopoda Order Anostraca fairy shrimps

Subclass Ostracoda seed shrimps Subclass Copepoda Order Calanoida

√

√

Par Pond: 9 gen., 7 fam. (Kondratieff et al. 1986)

√

√

√

√

SRS: 2 spp., 2 fam. (DeBiase and Taylor 2003) SRS: 2 spp., 2 fam. (DeBiase and Taylor 2003) Par Pond: 40 spp., 7 fam. in Par Pond (Berner 1982 ) Wetland ponds and impoundments: 72 spp., 9 fam. (DeBiase and Taylor 2005)

√

√

√

√

No information

√

√

√

Wetland ponds and impoundments: 15 spp., 3 fam. (DeBiase and Taylor 2005) Wetland ponds and impoundments: 25 spp., 1 fam. (DeBiase and Taylor 2005) No information

√

Order Conchostraca clam shrimps Order Cladocera water fleas

√

Local species

Order Cyclopoida

√

√

√

√

Order Harpacticoida Subclass Malacostraca Order Isopoda aquatic sow bug

√

√

√

√

√

√

√

√

Order Amphipoda scuds

√

√

√

√

Order Decapoda shrimps, crayfishes

√

√

√

√

Note: Symbols and sources as for table 4.10.

Caecidotea commonly reported (Halverson et al. 1997) Hyalella commonly reported (Halverson et al. 1997) SRS: 18 spp., 2 fam. of crayfish, 1 sp. (Hobbs et al. 1978)

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Table 4.12 Habitats of other aquatic invertebrates on the Savannah River Site Flood- Wetland ImpoundClassification

Streams plains

ponds

ments

Local species Hydra sp. commonly reported (Halverson et al. 1997); 2 additional spp. reported from Par Pond (Kondratieff et al. 1986) Dugesia tigrina commonly reported (Halverson et al. 1997) Par Pond and Pond B: 64 spp., 11 fam. in plankton (Chimney et al. 1986) No information

√

√

√

√

Phylum Platyhelminthes √ turbellarians, flatworms

√

√

√

Phylum Rotifera rotifers

√

√

√

√

Phylum Nematoda nematodes Phylum Mollusca Class Pelecypoda clams & mussels

√

√

√

√

√

√

Class Gastropoda snails & limpets Phylum Annelida Oligochaeta earthworms & kin

√

√

√

√

√

√

√

√

Hirudinea leeches

√

√

√

√

Phylum Cnidaria hydras & jellyfishes

√

SRS: 31 spp., 3 fam. (Britton and Fuller 1979; Davis and Mulvey 1993) SRS: 17 species, 9 fam. (Wood 1982) Lumbriculidae, Tubificidae, Naididae commonly reported (Halverson et al. 1997) No information

Note: Symbols and sources as for table 4.10.

sponges have siliceous spicules that can be preserved as microfossils in sediments. Additional phyla are represented by small, soft-bodied creatures such as nemertean worms (Nemertea), gastrotrichs (Gastrotricha), and water bears (Tardigrada). Biomass of oligochaete worms can increase by 10 percent per day (Leeper and Taylor 1998a). Planktonic rotifers, which have life cycles of a week, can achieve growth rates of more than 100 percent per day in numbers and biomass (Leeper and Taylor 1995).

Biotic Communities

167

Habitats and Assemblages Although aquatic invertebrates are nearly ubiquitous, their assemblages differ widely among habitats. The most important environmental factor is flow of the water. Lotic habitats, such as rivers and streams, require different adaptations for maintaining position and gathering food than lentic habitats such as lakes, ponds, and wetlands. Substrates, food resources, and water chemistry also greatly influence the assemblages, as does permanence of the habitat. Ponds, wetlands, and streams that dry up require adaptations to desiccation. Some species persist through the dry season in resting stages or as terrestrial forms; many others, mainly insects with winged adult stages, recolonize seasonally or opportunistically.

Streams and floodplains The dark, tannin-stained, mildly acidic to circumneutral water of SRS streams is typical of coastal plain streams. In these habitats, the stream bottom is typically sand or silt, and structure is supplied mainly by snags and other woody debris. Beds of macrophytes can develop where gaps in the tree canopy allow sunlight to reach the stream. Extensive floodplain wetlands, largely forested, lie adjacent to the Savannah River and its tributaries. Highest water levels typically occur in late winter and early spring, but year-to-year variation is great. The various substrates support different assemblages of invertebrates. In Cedar Creek, a second-order stream in the Upper Coastal Plain of South Carolina (Smock, Gilinsky, and Stoneburner 1985), chironomids dominated the biomass of invertebrates in sandy sediments; mayflies and chironomids in silty sediments; caddisflies on snags; and caddisflies and chironomids in a bed of the bur reed Sparganium americanum. Although numbers, biomass, and production per unit area were greatest on the snags, the greatest part of the invertebrate production in the stream, about 40 percent, occurred on the sand or silt substrates. In a stretch of the Satilla River in the Lower Coastal Plain of Georgia, Benke, Van Arsdall, and Gillespie (1984) similarly found that productivity and diversity of the invertebrates were highest on snags. However, 70 to 80 percent of the total production occurred on sand or mud substrates. In coastal plain streams generally, production of the invertebrates probably depends heavily on allochthonous detrital material, such as leaves and woody debris, from the adjacent floodplains (Smock and Gilinsky 1992). Much of this material is converted to fine particles before

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it enters the stream. Fine particulate organic material supported about half of the macroinvertebrate production at three sites in Cedar Creek, South Carolina (Smock and Roeding 1986); algae and animal prey also provided significant contributions. In the floodplains of the Coosawhatchie River in the Lower Coastal Plain, Braccia and Batzer (2001) suggested that terrestrial and aquatic consumers might be important in processing coarse woody debris. In experimental studies with leaf packs in Upper Three Runs, shredding insects were uncommon, and microbial processes seemed to dominate degradation (McArthur et al. 1994; Rader, McArthur, and Aho 1994). The SRS streams support large numbers of insect species. Species richness in Upper Three Runs, the only stream system that did not receive heated effluents from nuclear reactors, is unusually high (Morse et al. 1980, 1983; Floyd, Morse, and McArthur 1993). Among more than 650 species reported, the largest numbers were dipterans, trichopterans, and coleopterans. These studies yielded dozens of species reported as new to science. Some, such as Cheumatopsyche richardsoni, a small net-spinning caddisfly, may prove to be endemic to Upper Three Runs (Plague and McArthur 1998). Voelz and McArthur (2000) speculated that the great number of species is due to the relatively undisturbed watershed or to heterogeneity of the habitat, including beds of aquatic macrophytes in the stream and broad floodplains adjacent to it. The largest invertebrates of the SRS are decapod crustaceans. Crayfishes (Hobbs, Thorp, and Anderson 1978) inhabit the floodplains and stream banks as well as the stream channels; many use burrows. Shrimp occur in impoundments and slow-moving water of streams. Decapods do not figure prominently in estimates of biomass or production for southeastern streams and floodplains, but their importance is probably underestimated because they are difficult to sample quantitatively. The streams support a notable diversity of freshwater mussels. Davis and Mulvey (1993) reported on a complex of freshwater mussels of the genus Elliptio that may include undescribed species. Diversity and abundance tend to be greater in the Savannah River than in the tributary streams.

Impoundments Impoundments created by humans and by beavers provide the main lakelike habitats on the SRS. In addition, two oxbow lakes occur on the Savannah River floodplain in the Crackerneck Wildlife Management Area and Ecological Reserve. The impoundments, and probably the oxbows,

Biotic Communities

169

are relatively recent and transient additions to the landscape. The larger impoundments represent a type of habitat without prehistoric analog in the region. In the open water of impoundments, small (less than 2 mm) crustaceans, mainly copepods and cladocerans, and rotifers dominate planktonic assemblages (e.g., Taylor, DeBiase, and Mahoney 1993). These animals feed on planktonic algae and detritus or prey upon smaller invertebrates. The only insect important in the plankton is the larva of the phantom midge Chaoborus, a predator. The shallow waters of impoundments of the SRS typically develop dense beds of aquatic macrophytes, which can extend into water of 2 to 3 m (7–10 ft) in depth. The littoral zone is a region of intense biological activity. At Pond B, dipteran larvae, mainly chironomids and Chaoborus, snails, and odonates dominated the biomass of macroinvertebrates (collected on 0.5-mm, or 0.04-in, mesh sieves; Whicker 1988—original estimates of snail biomass corrected to exclude shell). At Dick’s Pond, a small impoundment, Benke (1976) found that mainly chironomid and ephemeropteran prey sustained production of odonate nymphs. Construction of large impoundments apparently permitted two planktonic copepods to expand their ranges onto the SRS (DeBiase and Taylor 1993). Eurytemora affinis invaded from coastal brackish waters. The source of Epischura fluviatilis is unknown, although it was described originally from Alabama. First collected on the SRS in the 1980s, both species are now common.

Carolina Bays and Other Isolated Wetland Ponds Carolina bays and other wetland ponds provide shallow aquatic habitats with fluctuating water levels (Schalles et al. 1989; Taylor et al. 1999). The hydroperiod, the duration of the inundated period, ranges from ephemeral to semipermanent, and water levels are typically highest in late winter and spring. Although some Carolina bays are geologically quite old (probably more than 100,000 years; see Brooks et al. 2001), the modern hydrologic regimes of wetland ponds on the SRS developed about three to four thousand years ago (Brooks, Taylor, and Grant 1996; Gaiser, Taylor, and Brooks 2001). The water is usually acidic and often very dark in color. Vegetation ranges from forested wetlands to wet meadows to aquatic macrophytes. Hydroperiod is the primary factor influencing composition and dynamics of the communities, although vegetation is also important.

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At Rainbow Bay, oligochaete worms, chironomid larvae, cladocerans, and isopods dominated the biomass of invertebrates (Leeper and Taylor 1998a). These consumers feed on detritus and fine particulate organic material, including algae. Aquatic invertebrates, such as shredders, that use coarser organic material were virtually absent. The contribution of plant material of terrestrial origin is unknown but probably large. It is possible that substantial processing of this organic material occurs during the dry phase of the hydroperiod. Odonates were sparse at Rainbow Bay. In contrast, predators, mainly odonate nymphs, dominated the measured biomass at Thunder Bay (Schalles and Shure 1989). The samplers used in this study did not collect microinvertebrates (less than 0.5 mm, or 0.04 in, in length) quantitatively. Assemblages of microcrustaceans are unusually rich compared with other temporary ponds worldwide (Mahoney, Mort, and Taylor 1990; Dietz 2001). A single bay may support as many as a hundred species of aquatic insects and more than thirty species of crustaceans (Taylor et al. 1999). Ponds inundated more than 80 percent of the year on average support two to three times as many species of microcrustaceans as ponds inundated less than 40 percent of the year (DeBiase and Taylor 2005). The increase in species with hydroperiod is generally additive. However, a few taxa, including clam shrimps, are specialized to shorter hydroperiods. The bays support distinctive copepods and branchiopods that are absent from other lentic habitats of the SRS. Copepods of the genera Aglaodiaptomus and Onychodiaptomus are bright red and blue in color. One of the most common is Aglaodiaptomus atomicus, a species described from Flamingo Bay on the SRS (DeBiase and Taylor 1997). Fairy shrimps, clam shrimps, and the cladoceran Daphnia laevis are also common in wetland ponds but absent from impoundments. Occasional drying combined with absence of surface inlets or outlets eliminates fish from many bays (Snodgrass et al. 1996). Vulnerability to predation by fish probably prevents these species from becoming established in impoundments. Some also require a period of desiccation to complete their life cycles.

Other Aquatic Habitats Other aquatic habitats include groundwater, springs, ditches, and more ephemeral pools. Little is known about the invertebrates of these habitats. Reid et al. (1999) described a new species of cyclopoid copepod, Rheocyclops carolinianus, and Wägele, Voelz, and McArthur (1995) de-

Biotic Communities

171

scribed a new species of isopod, Microcerberus carolinensis, both from wells near Meyers Branch. Taxonomic affinities of the isopod suggest that the group has been present in the region since the Cretaceous, before the continents of Europe and North America separated.

Responses to Change on SRS Construction and operation of the cooling water systems for the five nuclear production reactors caused the most profound changes to aquatic habitats on the SRS. Initially, all of the reactors were operated with oncethrough cooling systems using water pumped from the Savannah River. The SRS released this water into streams that flowed through floodplain swamp before returning to the Savannah River. Construction of cooling reservoirs on two streams partially mitigated the effects of high flow and elevated temperature on the streams and floodplains. Thermal effluents greatly reduced abundances and richness of invertebrates in the streams and probably increased export of organic material (Poff and Matthews 1986). Substantial repopulation by the invertebrates occurred within weeks of reactor shutdown (e.g., Fourmile Branch: studies summarized in Halverson et al. 1997). Complete recovery has been a slower process, depending in part on reestablishment of the floodplain forest. However, it is unlikely that the forest in the Savannah River floodplain will return to its pre-SRS condition, in part because construction of large impoundments on the Savannah River upstream of the SRS has profoundly altered patterns of seasonal flooding. At Pen Branch, a comprehensive study of postthermal recovery and restoration techniques included aquatic macroinvertebrates (Barton et al. 2000). Functional composition of the invertebrate assemblages of Pen Branch appears to be tracking structure of the habitat. Eleven years after thermal discharge ceased, canopy adjacent to the stream had not yet closed, and species associated with macrophyte beds in the streams dominated the invertebrate assemblages, rather than species associated with woody debris, as in the closed-canopy reference site (Lakly and McArthur 2000). During reactor operation, water temperatures in Pond C, the upper portion of the middle branch of Par Pond, sometimes exceeded 55°C (131°F; Leeper and Taylor 1995). The normal summer maximum for this region is ~30°C (86°F). Few zooplankton species tolerated temperatures above 35°C (95°F), and all disappeared at 45°C (113°F). However, unique, thermally tolerant assemblages of invertebrates developed: two species

Status

State: special concern; world: secure

State: special concern; world: secure

Pyganodon cataracta Eastern floater

Strophitus undulatus Squawfoot Toxolasma pullus Savannah lilliput

State: special concern; world: imperiled

State: special concern; world: vulnerable/apparently secure State: special concern; world: vulnerable

Lampsilis cariosa Yellow lampmussel Lampsilis splendida Rayed pink fatmucket

Phylum Mollusca, Class Bivalvia, Family Unionidae Anodonta couperiana State: special concern; world: apparently secure Barrel floater Anodonta triangulata World: imperiled, questionable taxonomic status Southern elktoe Elliptio congaraea State: special concern; world: apparently secure Carolina slabshell Elliptio fraterna World: critically imperiled/imperiled, questionable Brother spike taxonomic status Elliptio hepatica World: imperiled/vulnerable Brown elliptio Elliptio folliculata World: imperiled/vulnerable, questionable Pod lance taxonomic status Elliptio lanceolata State: special concern; world: imperiled/vulnerable Yellow lance

Species

Table 4.13 Conservation status of aquatic invertebrates of the Savannah River Site

Savannah River (Carunculina pulla, Britton and Fuller 1979)

Larger creeks and river habitats near SRS (Lampsilis radiata splendida, Britton and Fuller 1979) Lower Three Runs; Savannah River (Anodonta cataracta, Britton and Fuller 1979) Savannah River (Britton and Fuller 1979)

Reedy Branch, Lower Three Runs (Davis and Mulvey 1993) Tributaries of Upper Three Runs; Pen Branch; Lower Three Runs; Savannah River (Britton and Fuller 1979) Savannah River (Britton and Fuller 1979)

Mill Creek, Tinker Creek (Davis and Mulvey 1993)

Savannah River (Britton and Fuller 1979)

Savannah River (Britton and Fuller 1979)

Savannah River (Britton and Fuller 1979)

Savannah River (Britton and Fuller 1979)

Occurrences on SRS

Upper Three Runs (Morse et al. 1980) Upper Three Runs (Morse et al. 1980)

Blackwater streams (Kondratieff and Pyott 1987) Blackwater streams (Kondratieff and Pyott 1987)

Blackwater streams (Kondratieff and Pyott 1987)

Wetland ponds (DeBiase and Taylor 1993)

Par Pond; Pond B (Anodonta imbecillus, Britton and Fuller 1979) Tributaries of Upper Three Runs; Savannah River (Britton and Fuller 1979) Tributaries of Upper Three Runs; Savannah River (Britton and Fuller 1979)

Note: Status in South Carolina is based on the South Carolina Rare, Threatened, and Endangered Species Inventory published by the South Carolina Department of Natural Resources (www.dnr.state.sc.us). Global status is based on lists prepared by the Association for Biodiversity Information (1999, freshwater mussels, crayfishes, dragonflies, and damselflies; 2001, large branchiopods, mayflies, stoneflies) or the International Union for the Conservation of Nature and Natural Resources (Hilton-Taylor 2000, other taxa). None of these species appears on the current list of Threatened and Endangered Animal Species published by the U.S. Fish and Wildlife Service (endangered.fws.gov). SRS species lists checked were those of molluscs (Britton and Fuller 1979; Davis and Mulvey 1993); decapod crustaceans (Hobbs et al. 1978); branchiopods (Mahoney et al. 1990); calanoid copepods (DeBiase and Taylor 1993); mayflies (Morse et al. 1980); dragonflies and damselflies (Kondratieff and Pyott 1987; Morse et al. 1980); stoneflies (Morse et al. 1980). Species are shown here if they appear on the state list or have a status of vulnerable (G3) or worse on global lists.

Phylum Arthropoda, Class Insecta, Order Odonata Gomphus diminutus World: vulnerable Twin-striped clubtail Ophiogomphus incurvatus World: vulnerable Appalachian snaketail Phylum Arthropoda, Class Insecta, Order Plecoptera Leuctra moha World: vulnerable Perlesta frisoni World: vulnerable

Utterbackia imbecillus State: special concern; world: secure Paper pondshell Villosa delumbis State: special concern; world: apparently secure Eastern creekshell Villosa vibex State: special concern; world: apparently secure, Southern rainbow questionable taxonomy Phylum Arthropoda, Class Crustacea, Subclass Copepoda, Order Calanoida Hesperodiaptomus augustaensis World: vulnerable Phylum Arthropoda, Class Insecta, Order Ephemeroptera Ephemerella inconstans World: vulnerable

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of the cladoceran Moina and the rotifer Filinia longiseta were abundant at temperatures up to 43°C (109°F). After shutdown of the reactors, the impoundments rapidly developed planktonic assemblages typical for the region (Taylor, DeBiase, and Mahoney 1993; DeBiase and Taylor, unpublished data). Establishment of littoral invertebrates tracks establishment of the littoral vegetation, which occurs more slowly. At Pond B, littoral vegetation continued to expand more than twenty years after shutdown of the reactor (Rea et al. 1998). In wetland ponds, as in other systems, the structure and trophic resources that plants provide exert a strong influence on the community. Batzer, Jackson, and Mosner (2000) found that logging on the coastal plain of Georgia initiated changes in small depressional wetlands that persisted fifteen years post-harvest. Most of the wetland ponds on the SRS had been cleared, ditched, drained, cultivated, or otherwise altered before the federal government acquired the land in 1951. Since then, marked successional changes in vegetation have occurred in many of these wetlands (Kirkman et al. 1996), and the aquatic invertebrates undoubtedly responded to those changes. Experimental restorations currently underway in wetland ponds of the SRS (see chapter 3) include studies of aquatic invertebrates (Dietz et al. 2001).

Conservation More than twenty species of SRS invertebrates appear on state or global conservation lists (table 4.13). Neither the state of South Carolina nor the U.S. Fish and Wildlife Service presently lists any as threatened or endangered. Most of these species occur in blackwater streams, principally Upper Three Runs. The copepod occurs in a few wetland ponds. Freshwater mussels may be exceptionally vulnerable due to their dependence on particular species of fish to host the parasitic larval stage. Davis and Mulvey (1993) note an “alarming reduction in species collected and species abundance” in the Savannah River. The SRS is in danger of receiving, as well as losing, invertebrate species. Invaders may displace indigenous species, as well as creating other problems. Fuller and Powell (1973) detected the Asiatic clam Corbicula fluminea in the Savannah River in 1973. Probably carried onto the SRS during the 1970s with Savannah River water used to cool the reactors, it has subsequently moved into some of the streams (Voelz, McArthur, and Rader 1998). Abundances in the cooling reservoir system appear to have declined since the shutdown of the reactors. Although shells are still

Biotic Communities

175

abundant along the margins of Pond 4, Taylor and DeBiase (unpublished data) encountered no living specimens in extensive benthic sampling in 1998–1999. Among other nonindigenous aquatic species now present in South Carolina (Benson, Fuller, and Jacono 2001), two are likely to appear on the SRS. The crayfish Cambarus longirostris has moved into the Savannah River drainage from its native range in adjacent drainages to the west. Hobbs, Thorp, and Anderson (1978) did not collect it in the vicinity of the SRS. The African cladoceran Daphnia lumholtzi, a planktonic species, has appeared in large impoundments elsewhere in South Carolina but has not been detected on the SRS.

Butterflies Nick M. Haddad Butterflies, including skippers, are probably the best-studied terrestrial insect taxa at the Savannah River Site (SRS). Historically, butterflies have been a critical group in the study of ecology and evolution, and baseline information on butterflies will aid future studies of their populations, including potential efforts to monitor biodiversity. I collected data on butterfly occurrences and abundances in a number of ways. In 1993, I systematically surveyed different habitats across the SRS. In 1994–1997, I recorded butterfly occurrences on infrequent visits to high-abundance areas, usually openings or roadsides with high flower abundances or riparian zones near streams. The insect collection at the University of Georgia stores specimens of all butterfly species listed at SRS. The SRS hosts at least 99 species of butterflies (tables 4.14 and 4.15). For reference, 160 species have been identified in all of North Carolina (LeGrand and Howard 2000). Nearly half of the species are Hesperiidae. For ten species, the SRS represents an extension of the previously recorded range (Scott 1986; Opler and Malikul 1998; LeGrand and Howard 2000). Table 4.14 presents the known phenology of all butterfly species at SRS. Most butterflies are active between mid-March and early October. Species diversity peaks in mid-April and mid-August. Table 4.14 provides information on the relative abundance of each butterfly species according to the following scale: Rare = 1–10 observations per year; Uncommon = 1–10 observations per week; Common = 1–10 observations per day; Abundant = tens to hundreds of observations

Colias philodice Colias eurytheme

clouded sulphur orange sulphur

Family: Papilionidae Battus philenor pipevine swallowtail Eurytides marcellus zebra swallowtail Papilio polyxenes black swallowtail Papilio cresphontes giant swallowtail Papilio glaucus eastern tiger swallowtail Papilio troilus spicebush swallowtail Papilio palamedes Palamedes swallowtail Family: Pieridae Eurema daira barred yellow Eurema lisa little yellow Eurema nicippe sleepy orange Phoebis sennae cloudless sulphur Pieris rapae cabbage white Pontia protodice checkered white Anthocharis midea falcate orangetip

Species

Common name

x x x x x x x x

Common

Possible Common Common Common Rare Rare Locally common Possible Uncommon

x x x x x x x x

Common

x x

x x x x

x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x

x x

x x x x x x x x

x x x

A S O N D

x

J

Rare Rare Possible Common

F M A M J

x x x x

J

Common

Abundance

Month

Habitat

x x

x x x x x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

Opening/ early Hardwood Carolina succession Savanna forest Riparian bay

Table 4.14 Butterfly species of the Savannah River Site, organized by family, with month and habitat of occurrence

King’s hairstreak striped hairstreak southern hairstreak brown elfin

frosted elfin Henry’s elfin eastern pine elfin juniper hairstreak Hessel’s hairstreak white m hairstreak gray hairstreak red-banded hairstreak Hemiargus ceraunus Ceraunus blue Everes comyntas eastern tailed-blue Celestrina ladon spring azure violacea

Satyrium kingi Satyrium liparops Satyrium favonius Callophrys augustinus Callophrys irus Callophrys henrici Callophrys niphon Callophrys gryneus Callophrys hesseli Parrhasius m-album Strymon melinus Calycopis cecrops

harvester American copper great purple hairstreak coral hairstreak

southern dogface

Uncommon

x

x x x x x x x x x x x x

x x

Rare Abundant Uncommon

x

x

x x

x x

x

x x x x x x x x x x x x x x x x x x

x x

x x

x x

x x x x x x

Rare Rare Rare Rare Possible Rare Common Common

Possible Rare Possible Possible

Rare Rare Locally common Satyrium titus Locally common Satyrium edwardsii Edwards’ hairstreak Possible Satyrium calanus banded hairstreak Uncommon

Colias cesonia Family: Lycaenidae Feniseca tarquinius Lycaena phlaeas Atlides halesus

x x x

x x

x

x

x

x

x x x

x

x x

x

x

x

x

x

x x

x

x

x

x

(continued)

x

Celestrina ladon summer azure neglecta Family: Riodinidae Calephelis little metalmark virginiensis Family: Nymphalidae Libytheana American snout carinenta Agraulis vanillae Gulf fritillary Euptoieta claudia variegated fritillary Chlosyne gorgone Gorgone checkerspot Chlosyne nycteis silvery checkerspot Phyciodes texana Texan crescent Phyciodes tharos pearl crescent Polygonia question mark interrogationis Polygonia comma eastern comma Nymphalis antiopa mourning cloak Vanessa virginiensis American lady Vanessa cardui painted lady Vanessa atalanta red admiral Junonia coenia common buckeye Limenitis arthemis red-spotted purple

Species

Common name

Table 4.14 (continued)

Uncommon Uncommon Common Rare Uncommon Abundant Common

Common Common Locally common Possible stray Possible stray Common Common

Uncommon

Possible stray

Uncommon

Abundance

J

A S O N D

x x x x x x x x x x x x

x x x x x

x

x x x x x x x x x x x x x x x x x x x x x x x x x x

x x x

x

x

x

x

x

x

x

Opening/ early Hardwood Carolina succession Savanna forest Riparian bay

x x x x x x x x x x x x x

x x x x x x x x x

x x x x x x

F M A M J

x x x x x x x x x x x x x x x x x x x x

J

Month

Habitat

x x x x x x x x x x x x x

x x x

Common Rare

Common Common

x x x x x x x x

x x x x

x x x x x x x x

Common

Uncommon Uncommon

Viola’s wood-satyr common wood-nymph monarch queen x x

Possible

Georgia satyr

x x x x x x x x x x x x x x x

x x x x x x x x x x x x x x x

x x x x x x x x x x x x x x x x

Uncommon Possible stray

Common Abundant

Uncommon Rare Common Uncommon Uncommon Common Uncommon

viceroy goatweed leafwing hackberry emperor tawny emperor southern pearly-eye Creole pearly-eye Appalachian brown gemmed satyr Carolina satyr

Danaus plexippus Danaus gilippus Family: Hesperiidae Epargyreus clarus silver-spotted skipper Urbanus proteus long-tailed skipper Autochton cellus golden-banded skipper Achalarus lyciades hoary edge Thorybes bathyllus southern cloudywing

Limenitis archippus Anaea andria Asterocampa celtis Asterocampa clyton Enodia portlandia Enodia creola Satyrodes appalachia Cyllopsis gemma Hermeuptychia sosybius Neonympha areolata Megisto viola Cercyonis pegala

x x

x

x

x

x

x

x

x

x

x x

x

x

x x

x x x

x

(continued)

x

Abundance

northern Uncommon cloudywing Thorybes confusis confused Rare cloudywing Staphylus hayhurstii Hayhurst’s Rare scallopwing Erynnis brizo sleepy duskywing Common Erynnis juvenalis Juvenal’s duskywing Abundant Erynnis horatius Horace’s duskywing Abundant Erynnis martialis mottled duskywing Rare Erynnis zarucco Zarucco duskywing Common Erynnis baptisiae wild indigo Rare duskywing Pyrgus communis common Rare checkered skipper Pholisora catullus common Rare sootywing Nastra lherminier swarthy skipper Common Lerema accius clouded skipper Common Ancycloxypha least skipper Common numitor Copaeodes minimus southern Rare skipperling

Thorybes pylades

Species

Common name

Table 4.14 (continued)

J

J

A S O N D

x

x

x

x

x

x x

x

x x x x x

x x x

x x

x x x x x x

x x x x x x x x x x x x x x x x x

x

x x x x

x

x

x

x

x

x x x x x x

x

x

x

Opening/ early Hardwood Carolina succession Savanna forest Riparian bay

x x

x x x x x x

F M A M J

Month

Habitat

fiery skipper dotted skipper Meske’s skipper tawny-edged skipper crossline skipper whirlabout southern broken-dash northern broken-dash little glassywing sachem

Delaware skipper Byssus skipper Zabulon skipper Yehl skipper broad-winged skipper Euphyes dion Dion skipper Euphyes vestris dun skipper Atrytonopsis hianna dusted skipper Amblyscirtes hegon pepper and salt skipper Amblyscirtes lace-winged aesculapius roadside skipper Amblyscirtes Carolina roadside carolina skipper

Wallengrenia egeremet Pompeius verna Atalopedes campestris Atrytone logan Problema byssus Poanes zabulon Poanes yehl Poanes viator

Polites origenes Polites vibex Wallengrenia otho

Hylephila phyleus Hesperia attalus Hesperia meskei Polites themistocles

x

x

Rare Possible

x

x

Possible

Rare

Possible Uncommon Possible Rare

Rare Rare Uncommon Uncommon Rare

x

x

x

x

x x x x x x x x

x

x x x

x x x x x

x x x x x x x

Uncommon

Uncommon Abundant Common

Common Possible Rare Possible

x

x

x

x

x x x

x

x

x x

x

x

x

x

x

x x x

x

x

(continued)

Cofaqui giant skipper

reversed roadside skipper common roadside skipper Bell’s roadside skipper dusky roadside skipper Eufala skipper twin-spot skipper Brazilian skipper Ocola skipper yucca giant skipper

Rare

Rare Rare Possible stray Common Uncommon

Rare

Rare

Rare

Possible

Abundance

J

x x

x

x

x

J

x

x

x x x x x

x

x x

A S O N D

x x x

F M A M J

Month

x

x

x

x

x

x

x

x

x

x

x

Opening/ early Hardwood Carolina succession Savanna forest Riparian bay

Habitat

Note: Where month is not recorded, the information was taken from a collection at SRS where dates were not listed on labels. Where habitat information is not recorded, the butterfly was collected on a roadside with a variety of habitats nearby. Key to abundance: rare = 1–10 observation/year; uncommon = 1–10 observation/week; common = 1–10 observations/day; abundant = tens to hundreds of observations daily; locally common = in general rare, but common in isolated populations.

Amblyscirtes alternata Lerodea eufala Oligoria maculata Calpodes ethlius Panoquina ocola Megathymus yuccae Megathymus cofaqui

Amblyscirtes belli

Amblyscirtes reversa Amblyscirtes vialis

Species

Common name

Table 4.14 (continued)

Biotic Communities

183

Table 4.15 Number of butterfly species on the Savannah River Site (SRS), by family. Possible species have ranges that include SRS, or are infrequent migrants that may be found there. Family

No. species

No. possible species

No. range extensions

Papilionidae Pieridae Lycaenidae Riodinidae Nymphalidae Hesperiidae Total

6 8 17 0 25 43 99

1 2 5 1 4 7 20

0 0 2 0 3 5 10

daily; Locally Common = in general rare but common in isolated populations. Additional information on listed butterflies, including their distributions, host plants, habitat preferences, and other natural history information, appears in Harris (1972), Scott (1986), Opler and Malikul (1998), and Legrand and Howard (2000; available online at www. ncsparks.net/butterfly/nbnc.html). Butterflies are affected most by the distribution of their resources, which include host plants used by caterpillars and flowering plants used by adults. Many species use flowering plants in openings or on roadsides. Because butterflies are often generalists with respect to flowering plants, it is often difficult to infer habitat use by the presence of adults. The most important resources of concern in managing butterflies are suitable host plants. Some host plants are naturally rare, even in pristine habitats. Land-use change has reduced the abundance of other plants. Butterflies at the SRS are often associated with host plants in open habitats, hardwood forest, pine savanna, scrub oak forest, riparian habitats, marshes and bays. Typically, not many butterfly species or individuals occur in planted pine forest. Only one species at SRS uses pine as a host plant (Callophrys niphon), and planted pine shades the understory for butterflies and their food plants. A number of the species at SRS are rare. These are typically associated with riparian habitats or with longleaf pine (Pinus palustris) savanna. It is instructive to look at the rare species that occur on site, as well as those that are not known to occur at SRS but could occur given their historical distributions. Species that are typically associated with longleaf pine habitat and occur on site include Callophrys irus, Hesperia meskei, Problema byssus, and Amblyscirtes alternata. In addition, three species that

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occur in the collection at the Savannah River Ecology Laboratory, Lycaena phlaeas, Autochton cellus, and Atrytone logan, were taken in 1968–1969 and have not been encountered since. It is also interesting to note those species that have not yet appeared in surveys but could. Of greatest concern for natural resource management, fifteen species’ known distributions include the Savannah River Site, and five species have strayed into this region (table 4.14). Of the fifteen species whose distributions include the SRS but are not currently known to occur on site, half are associated with longleaf pine savanna or scrub oak forest. With greater sampling intensity, we may find that these species already occur in these habitats on site. Alternatively, recovery of these rare species (which, at best may be locally common wherever they occur) may indicate successful restoration of longleaf pine and scrub oak understory communities that support these butterflies. Besides the species inventories, there have been detailed ecological and behavioral studies of butterflies at SRS (Haddad 1999a, b, 2000; Haddad and Baum 1999; Haddad and Hicks 2000). Experimental studies have assessed the value of habitat corridors, or long, thin strips of habitat, in reducing the effects of habitat loss and fragmentation on species loss and endangerment. These studies focused on five butterfly species that are fairly common in open areas at SRS, including Euptoieta claudia, Eurema nicippe, Junonia coenia, Papilio troilus, and Phoebis sennae. They have provided evidence that open corridors increase dispersal and perhaps population sizes of some butterfly species within open habitat patches. Importantly, habitat-restricted species that are limited by food resources or behaviors to openings also move more frequently between and reach higher population sizes within connected patches. Initial results for butterflies have proven consistent with other studies on diverse plant and animal species (Haddad et al. 2003)

Fishes Barton C. Marcy, Jr. The Savannah River Site (SRS) supports a diverse fish fauna in a variety of aquatic habitats. Since the early 1950s, scientists have collected eightyseven fish species in twenty-three families from SRS streams, ponds, and lakes and along the Savannah River adjacent to the site (table 4.16; see figure 2.4 for stream, lake, and pond locations). The SRS is located in the

Table 4.16 Fish species confirmed at the Savannah River Site Common name

Scientific name

Family

Shortnose sturgeon Atlantic sturgeon Longnose gar Florida gar Bowfin Tarpon American eel Blueback herring Hickory shad American shad Gizzard shad Threadfin shad Goldfish Bannerfin shiner Whitefin shiner Common carp Eastern silvery minnow Rosyface chub Bluehead chub Golden shiner Ironcolor shiner Dusky shiner Spottail shiner Yellowfin shiner Taillight shiner Coastal shiner Pugnose minnow Lowland shiner Creek chub Quillback Creek chubsucker Lake chubsucker Northern hogsucker Spotted sucker Notchlip redhorse Robust redhorse Snail bullhead White catfish Yellow bullhead Brown bullhead Flat bullhead Channel catfish Tadpole madtom Margined madtom Speckled madtom Redfin pickerel Chain pickerel Eastern mudminnow

Acipenser brevirostrum Acipenser oxyrhynchus Lepisosteus osseus Lepisosteus platyrhincus Amia calva Megalops atlanticus Anguilla rostrata Alosa aestivalis Alosa mediocris Alosa sapidissima Dorosoma cepedianum Dorosoma petenense Carassius auratus Cyprinella leedsi Cyprinella nivea Cyprinus carpio Hybognathus regius Hybopsis rubrifrons Nocomis leptocephalus Notemigonus crysoleucas Notropis chalybaeus Notropis cummingsae Notropis hudsonius Notropis lutipinnis Notropis maculatus Notropis petersoni Opsopoeodus emiliae Pteronotropis stonei Semotilus atromaculatus Carpoides cyprinus Erimyzon oblongus Erimyzon sucetta Hypentelium nigricans Minytrema melanops Moxostoma collapsum Moxostoma robustum Ameiurus brunneus Ameiurus catus Ameiurus natalis Ameiurus nebulosus Ameiurus platycephalus Ictalurus punctatus Noturus gyrinus Noturus insignis Noturus leptacanthus Esox americanus Esox niger Umbra pygmaea

Acipenseridae Lepisosteidae Amiidae Megalopidae Anguillidae Clupeidae

Cyprinidae

Catostomidae

Ictaluridae

Esocidae Umbridae (continued)

Table 4.16 (continued) Common name

Scientific name

Family

Pirate perch Swampfish Atlantic needlefish Golden topminnow Lined topminnow Eastern mosquitofish Brook silverside White bass White perch Striped bass Banded pygmy sunfish Mud sunfish Flier Blackbanded sunfish Bluespotted sunfish Banded sunfish Redbreast sunfish Green sunfish Pumpkinseed Warmouth Bluegill Dollar sunfish Redear sunfish Spotted sunfish Redeye bass Largemouth bass White crappie Black crappie Savannah darter Swamp darter Christmas dartera Turquoise darter Tessellated darter Sawcheek darter Yellow perch Blackbanded darter Mountain mullet Striped mullet Hogchoker

Aphredoderus sayanus Chologaster cornuta Strongylura marina Fundulus chrysotus Fundulus lineolatus Gambusia holbrooki Labidesthes sicculus Morone chrysops Morone americana Morone saxatilis Elassoma zonatum Acantharchus pomotis Centrarchus macropterus Enneacanthus chaetodon Enneacanthus gloriosus Enneacanthus obesus Lepomis auritus Lepomis cyanellus Lepomis gibbosus Lepomis gulosus Lepomis macrochirus Lepomis marginatus Lepomis microlophus Lepomis punctatus Micropterus coosae Micropterus salmoides Pomoxis annularis Pomoxis nigromaculatus Etheostoma fricksium Etheostoma fusiforme Etheostoma hopkinsi Etheostoma inscriptum Etheostoma olmstedi Etheostoma serrifer Perca flavescens Percina nigrofasciata Agonostomus monticola Mugil cephalus Trinectes maculatus

Aphredoderidae Amblyopsidae Belonidae Fundulidae Poeciliidae Atherinidae Moronidae

Elassomatidae Centrarchidae

Percidae

Mugilidae Soleidae

Source: D. E. Fletcher, Savannah River Ecology Laboratory, supplemented from Marcy et al. (2005). Note: Additional species of possible occurrence: sea lamprey (Petromyzon marinus), grass carp (Ctenopharyngodon idella), highfin carpsucker (Carpiodes velifer), brassy jumprock (Scartomyzon sp. cf. lachnrei ), Everglades pygmy sunfish (Elassoma evergladei), bluebarred pygmy sunfish (Elassoma okatie), southern flounder (Paralichthys lethostigma). a Occurrence reported but not confirmed.

Biotic Communities

187

middle Savannah River basin, where ninety-eight species and twentyfour families of fish have been identified from 759 collection records made from 1879 to 2002. More than 450 papers and reports on laboratory and field studies of fishes at SRS have appeared since 1951 (Marcy et al. 2005). Fish assemblages in SRS streams unimpacted by Site operations are generally typical of similar-sized streams from other areas of the Southeast (Dahlberg and Scott 1971; Bennett and McFarlane 1983). However, stretches of Fourmile Branch, Steel Creek, and Pen Branch downstream of C, L, and K Reactors were largely devoid of fish during reactor operations due to the high cooling water discharge flows and temperatures. These areas have been recolonized since the reactors ceased operating, the last in 1989. The Steel Creek fish assemblage below the L Lake reservoir, constructed in 1984, was not significantly influenced by L Reactor restart and operations except for the reach directly below L Lake, where increased discharges and emigration of L Lake fish altered community structure (Aho et al. 1986). Most SRS streams are low gradient and consist of pools and runs with predominantly sand bottoms and numerous sunken logs, branches, and leaves. Many of the undisturbed streams traverse bottomland hardwood forests and have tea-colored, acidic water as a result of organic compounds leached from leaves and other plant debris. Smaller undisturbed streams are often heavily shaded by canopy trees. Perhaps most unique about SRS streams, some have been relatively free of human influence for at least fifty years. There are few other places on the south Atlantic upper coastal plain where such resources still exist. The diversity of habitats encompassed in these undisturbed streams, together with the SRS streams in various states of recovery from previous impacts, constitutes a unique resource for fish research.

Factors Affecting Fish Communities Each species of fish has evolved to specific habitat conditions. Habitat characteristics to which body forms and mouth structures have adapted include substrate, depth, and flow. Stream flow controls depth, width, current velocity, and substrate composition. Floods and drought, therefore, can be major causes of unpredictable perturbation on fish populations.

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Ecology and Management of a Forested Landscape

Stream Order Species composition and abundance, as well as the size of individuals, vary with stream size, which is strongly correlated with stream order (the relative rank of a stream channel segment within a drainage). Species richness typically increases with stream order, although it may plateau as stream order increases above four to six. Larger streams support more large piscivorous fish (e.g., largemouth bass, chain pickerel; see table 4.16 for scientific names) and large benthic insectivorous fish (e.g., spotted sucker) than smaller streams, which support surface water insectivores and general insectivores (e.g., most minnows, shiners, and small sunfishes). However, the number of species found in headwater streams and the number of species replacements (as opposed to species additions without replacement) as one moves from lower- to higher-order streams may be somewhat greater in the South Carolina coastal plain than in other parts of the country (Paller 1994b). South Carolina coastal plain headwater streams support relatively large numbers of species, possibly due to the relatively mild climate and lack of steep elevation gradients. Deeper water farther downstream apparently permits the establishment of larger species that may eliminate some headwater species through predation or competition. Paller (1994b) sampled fish assemblages in upper-terrace streams on SRS. Although many factors affect the highly variable species composition and abundance among sites, the most important is stream size. Small, shallow headwater streams (first and second order; figure 4.16) primarily support minnows (Cyprinidae), bullheads and madtoms (Ictaluridae), sunfishes (Centrarchidae), and darters (Percidae). Among the most common species in such streams are yellowfin shiner, bluehead chub, and pirate perch. Other common species include creek chub, dollar sunfish, spotted sunfish, redbreast sunfish, dusky shiner, tessellated darter, yellow bullhead, speckled madtom, margined madtom, creek chubsucker, and redfin pickerel. A typical 100- to 200-m (330–660-ft) stream segment on SRS supports from five species in very shallow, narrow, undisturbed first-order streams to fifteen to twenty species in larger second-order streams (Paller 1995). Examples of undisturbed first- and second-order streams on the SRS include Reedy Branch, Mill Creek, and the upper reaches of Pen Branch and Meyers Branch. Larger streams on the SRS upper terrace support somewhat different species assemblages. The greater depth and habitat space provided by third- (figure 4.17) through fifth-order streams permit occupation by

Biotic Communities

189

Figure 4.16. First-order (headwater) stream (D. Scott).

larger fish, including largemouth bass, spotted sucker, redbreast sunfish, chain pickerel, and large American eel. Other common species in larger streams include pirate perch, spotted sunfish, blackbanded darter, flat bullhead, and various shiners, particularly the dusky shiner. Larger upperterrace streams generally support more species than smaller streams. Typical 100- to 200-m (330–660-ft) reaches in larger streams often support twenty to thirty species (Paller 1995). Deeper pools in upper-terrace streams sometimes hold surprisingly large fish, including longnose gar

190

Ecology and Management of a Forested Landscape

Figure 4.17. Third-order stream (D. Scott).

exceeding 1 m (3.3 ft) and striped bass exceeding 5 to 10 kg (11–22 lbs). The latter species occurs during the summer in the lower reaches of Upper Three Runs, where relatively cool temperatures are produced by groundwater inputs. Striped bass return to the Savannah River when river temperatures cool later in the year. Examples of undisturbed third- through fifth-order streams on the SRS include Tinker Creek and Upper Three Runs. Disturbed third-order streams include the mid and lower reaches of Pen Branch, Fourmile Branch, Steel Creek, and Lower Three Runs.

Stream Depth and Velocity At a smaller scale, Meffe and Sheldon (1988) focused on first- through third-order streams on SRS to assess the importance of fifteen habitat variables to fish communities. They concluded that stream depth and velocity, and to a lesser extent substrate type, were the most important determinants of fish assemblage composition in these smaller streams. Most species prefer deeper, slower sites to shallower, faster sites. Several sunfish species, chubsuckers, American eels, and yellow bullheads dominate slow, deep, muddy habitats, whereas Savannah, tessellated, and blackbanded darters, northern hogsuckers, and margined madtoms dominate where current velocities are faster. Creek chubs, a headwater species, occur in smaller slower habitats.

Biotic Communities

191

Habitat Features Other habitat considerations include physical characteristics of the water, such as temperature, turbidity, and the concentration of dissolved oxygen and various chemicals, as well as the availability of food and spawning and resting areas. The type of habitat sought for spawning is often different than that sought for feeding and growth stages. The presence of woody debris is an important habitat feature for many species. In addition to providing added surface area for food and cover, it can alter habitat structure by decreasing water velocity and increasing depth, thereby capturing sediment that may be important for spawning. Riparian vegetation provides foraging areas and shade that reduces water temperature. Other features of stream habitat include floating leaf packs and roots (Meffe and Sheldon 1988). Habitat diversity is an important influence on the structure of stream fish assemblages. For example, species composition and relative abundance remain fairly constant in deep pool areas with diverse habitats but can change dramatically in shallow, less diverse habitats. Deeper pools provide cooler water, feeding areas, and refuge from predators and high flow. Thus, fish communities are more diverse where depth varies within channel stretches. On SRS, upper-terrace streams typically lack the riffles found in streams that traverse steeper gradients but do possess welldefined pools and runs. Pools provide deeper and slower water and often have a silty bottom littered with submerged logs, branches, leaves, and other woody debris. Runs provide shallower, swifter water and a sand or, less commonly, gravel bottom frequently strewn with sunken logs and branches. Pools and runs often support different fish assemblages, with pools having mostly sunfishes, bullheads, eels, suckers, and in larger streams, largemouth bass, and runs having mostly shiners, chubs, and darters (M. Paller, Westinghouse Savannah River Co., pers. comm.).

Ecological Processes Fish community structure in small streams can be affected by ecological factors such as competition, predation, and the ability of a species to adapt and recolonize. These influences can vary considerably among habitat gradients. Spatial changes in community structure reflect species’ responses to varying environmental conditions in different stream segments, as each stream exerts specific constraints on its inhabitants. The fish assemblages in a variety of habitats follow for each of the major water bodies on SRS.

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Ecology and Management of a Forested Landscape

Aquatic Habitat and Fish Communities Primary aquatic habitats for fish at SRS include streams, impoundments, isolated wetlands, and the Savannah River.

Streams Fishes have been sampled in all major streams on SRS. These include Upper Three Runs, Beaver Dam Creek, Fourmile Branch, Pen Branch, Steel Creek, and Lower Three Runs.

Upper Three Runs Sampling of adult and juvenile fish indicates that the assemblages in Upper Three Runs are typical of those in third- and fourth-order streams on SRS (Paller 1992). Shiners, sunfish, and darters dominate numerically (table 4.17). Larger predatory and benthic insectivorous species are present, as is typically the case in larger streams. Striped bass often seek the cooler waters of Upper Three Runs during the summer, away from the warmer Savannah River. Shiners, followed by pirate perch, madtoms, and darters dominate the smaller tributaries. This pattern, too, is typical of unimpacted streams on the SRS (Paller 1992). However, studies of ichthyoplankton (fish eggs and larvae) in Upper Three Runs indicate that the dominant species is spotted sucker (Paller 1985; Paller, Saul, and Hughes 1986). Larvae of this species are not found in such numbers in any of the other SRS creeks, suggesting that Upper Three Runs is an important spawning site for spotted sucker. Other relatively abundant ichthyoplankton taxa are darters, crappie, minnows, blueback herring, and American shad. The occurrence of American shad in Upper Three Runs reflects the relatively large size and substantial flow of this creek that make it a suitable spawning area for this anadromous species (which migrates from salt to freshwater to spawn).

Beaver Dam Creek A variety of sampling methods collect a representative sample of fish relative to size, species-type, and habitat type. Specht et al. (1990) collected forty-five species by electrofishing and hoopnetting during a period when the D Area power plant discharged heated cooling water. The most abundant species (by number) collected by electrofishing were spotted sucker, coastal shiner, redbreast sunfish, largemouth bass, and spotted sunfish. Sunfish were the most abundant family, comprising nearly 40 percent of the fish collected. Minnows and shiners (26 percent) and suckers (17 percent) were also abundant. Several taxa, including the bannerfin

Table 4.17 Relative density of fish (number/100 m2) in streams recovering from thermal impacts (Pen Branch and Fourmile Branch) and in undisturbed streams (Meyers Branch and Upper Three Runs) on the Savannah River Site Recovering streams Species

Main channel Side channel

American eel Whitefin shiner Eastern silvery minnow Rosyface chub Bluehead chub Golden shiner Ironcolor shiner Dusky shiner Yellowfin shiner Coastal shiner Sailfin shiner Creek chub Creek chubsucker Lake chubsucker Northern hogsucker Spotted sucker Yellow bullhead Flat bullhead Tadpole madtom Margined madtom Speckled madtom Redfin pickerel Chain pickerel Eastern mudminnow Pirate perch Lined topminnow Eastern mosquitofish Brook silverside Bluespotted sunfish Redbreast sunfish Warmouth Dollar sunfish Spotted sunfish Largemouth bass Savannah darter Tessellated darter Sawcheek darter Blackbanded darter Source: Marcy et al. 2005.

0.3 0.4 0.5 0.2 0.0 0.2 0.0 35.7 7.8 2.7 0.0 0.0 1.6 0.5 0.0 2.7 0.3 0.2 0.1 0.0 1.1 0.1 0.0 0.0 1.9 0.0 2.7 0.1 0.1 1.6 0.1 0.1 5.7 0.8 0.0 0.3 0.0 1.2

1.2 0.6 0.0 0.0 0.3 0.6 1.9 77.4 21.7 6.8 0.0 0.0 6.8 1.6 0.0 1.6 0.7 0.0 0.7 0.0 6.1 1.0 0.0 0.1 4.4 0.1 6.0 0.1 0.4 7.1 0.4 2.4 10.4 1.9 0.0 3.0 0.1 7.7

Undisturbed streams Main channel Side channel 1.3 0.0 0.0 0.0 0.1 0.0 0.2 2.2 7.7 0.7 0.4 0.0 0.2 0.0 0.2 0.0 0.0 0.0 0.0 0.1 1.2 0.1 0.1 0.0 1.4 0.0 0.1 0.0 0.0 0.1 0.0 0.0 0.3 0.5 0.4 1.3 0.0 1.0

0.8 0.0 0.0 0.0 0.1 0.0 0.0 4.9 6.0 5.0 2.5 0.2 0.3 0.0 0.0 0.0 0.5 0.0 0.4 0.2 3.2 1.8 0.0 0.0 9.7 0.0 0.7 0.0 0.7 0.3 1.1 2.2 0.9 0.0 0.1 5.0 0.0 0.1

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shiner, blackbanded darter, and channel catfish, exhibited a distinct longitudinal zonation, being more abundant either toward the headwaters or toward the stream mouth. Most of the more common species, however, were abundant throughout the stream. Hoopnetting collected seventeen species. The greatest number of fish and greatest number of species occurred at the mouth. Sunfishes and black bass dominated (38 percent of the collections), followed by minnows (23 percent), suckers (15 percent), and catfishes (11 percent). The relative abundance of minnows and sunfishes was within the range of the other southeastern streams, but the relative abundance of suckers and catfishes was greater. The fish assemblage in Beaver Dam Creek compared favorably with the fish assemblages in other southeastern streams. Taxa richness, relative abundance of major taxa, densities, and catch rate were within the ranges measured in the other streams. Dominant species collected by electrofishing during the winter were redbreast sunfish (26 percent), spotted sunfish (21 percent), spotted sucker (16 percent), largemouth bass (9 percent), bowfin (7 percent), gizzard shad (7 percent), striped mullet (3 percent), and bluegill (2 percent). In Beaver Dam Creek, ichthyoplankton studies collected larval fish and fish eggs, representing at least nine taxa (Specht 1987). Most occurred at the lower end of the stream. The spawning season encompassed the collection period, with the peak being in April. Sunfishes in general, particularly bluegill and pygmy sunfish, were the most abundant group, constituting approximately 53 percent of the total number of larvae and eggs. Other relatively abundant taxa were percids (19 percent) and suckers (12 percent). Greater densities and species richness occurred in the lower reaches, reflecting the relative importance of this portion of the stream as a spawning area for some species.

Fourmile Branch Aho et al. (1986) studied the fish assemblage structure within the Savannah River swamp system. They collected fifty-one species by electrofishing, the vast majority year-round residents. Two species (hickory shad and striped mullet) were migratory. Sunfishes and minnow families represented more than 40 percent of the taxa and individuals.

Pen Branch The fish assemblage structure varies throughout the Pen Branch system, both as a result of the former influence of K Reactor’s thermal discharge and from natural changes in habitat from a small headwater stream to

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the Savannah River swamp. When K Reactor operated, water temperature exerted a controlling influence on community structure. Fish essentially disappeared from Indian Grave Branch and the midreaches of Pen Branch, with the exception of a few species in relatively cool areas off the main channel. After K Reactor was shut down, fish began to recolonize formerly thermal areas, and considerable recovery has occurred. In the absence of elevated temperatures, habitat is the primary determinant of community structure. Mealing and Heuer (1989a, b, c, d) collected forty-two species from 1988 to 1989 after shutdown of K Reactor and found that small stream species such as yellowfin shiner and bluehead chub inhabited the upper reaches. Sunfishes, chubsuckers, and largemouth bass predominated in the midreaches. A typical southeastern swamp community, including longnose gar, brook silverside, largemouth bass, coastal shiner, and chain pickerel, inhabited the deep swamp reaches. In sampling both Pen Branch and Fourmile Branch, Paller et al. (2000) found that species richness, disease incidence, and taxonomic composition at the family level did not differ between disturbed and undisturbed streams; however, the disturbed streams were characterized by higher densities of a number of species (table 4.17).

Steel Creek Aho et al. (1986) sampled adult and juvenile fishes by electrofishing in Steel Creek and two other streams to assess the persistence and stability of the fish assemblages in those streams. Steel Creek had slightly higher species richness and diversity than the other streams. Species richness was highest in the lower reaches. The numbers of species and fish density were highest in the Steel Creek marsh, where habitat diversity, structural complexity, and primary productivity were high as a result of abundant macrophyte growth. Small-bodied species such as minnows and brook silversides dominated sites in the Steel Creek marsh, while larger species were more common in closed canopy areas with less macrophyte growth. While the fish assemblages in the Steel Creek marsh and swamp varied temporally and annually, assemblage stability and persistence of species were generally high, with most species found repeatedly over census periods and the rank order of species abundance relatively constant over time. The ecological importance of the lower reaches of Steel Creek led to the decision to build a cooling reservoir (L Lake) to reduce the temperature of L Reactor cooling water to environmentally acceptable levels before it entered the lower reaches of Steel Creek. L Reactor operated from

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Ecology and Management of a Forested Landscape

1986 to mid-1988, discharging large volumes of water to Steel Creek, but it has not operated since July 1988. The shutdown of L Reactor, coupled with some decreases in natural runoff due to low rainfall, greatly diminished reservoir releases to Steel Creek. Resulting instream changes included lower depths, current velocities, and habitat volumes. After the restart of L Reactor in 1986, studies in Steel Creek assessed possible impacts of L Lake on stream fish. The recovered fish population resembles assemblages present prior to creation of L Lake. These studies have revealed the presence of adult and juvenile fish and ichthyoplankton throughout Steel Creek. Ichthyoplankton composition in Steel Creek near its confluence with the Savannah River has varied over the years. Larval minnows, larval yellow perch, larval sunfish and bass, and blueback herring were the most abundant taxa in 1983. Species composition was fairly similar in 1984, except that darters replaced yellow perch. However, species composition changed in 1985, when American shad, blueback herring, and darters were the dominant species and minnows and sunfishes were comparatively rare (Paller et al. 1984; Paller, O’Hara, and Osteen 1985; Paller, Saul, and Hughes 1986). Despite this variability, Steel Creek was consistently one of the most productive Savannah River tributaries in its contribution to the river ichthyoplankton assemblage. Paller et al. (1984, 1985) and Paller, Saul, and Hughes (1986) assessed this contribution by determining the number of ichthyoplankton transported from creek to river. In 1983, Steel Creek ranked ninth among the thirty-three major tributaries between river kilometers 47.6 and 301 (river miles 29.6 and 187.1), essentially from Savannah to Augusta, Georgia. The only creeks with greater ichthyoplankton contributions were in lower reaches of the river. Spawning generally begins in March, peaks in April and May, then declines through June and July (Paller 1985; Paller, Saul, and Hughes 1986). Species composition differs among habitats, with American shad, blueback herring, and darters predominating in the creek mouth and channel and minnows and darters predominating farther upstream. These data indicated the importance of the creek mouth and creek channel habitats as spawning areas for anadromous fish.

Lower Three Runs Most of the 1,483 ichthyoplankters collected in a Lower Three Runs study came from a tailwater pool just downstream from the Par Pond dam, and their numbers generally decreased downstream (Paller, Saul, and Hughes 1986). Densities averaged 625/1,000 m3 (17.7/1,000 ft3) in

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the tailwaters, compared with 14/1,000 m3 (0.4/1,000 ft3) at Road A and 24/1,000 m3 (0.7/1,000 ft3) in the creek mouth. Most of the larvae collected in the Par Pond tailwaters were sunfish and bass, crappie, and yellow perch that probably were spawned in Par Pond and entered Lower Three Runs in Par Pond overflow. Sampling in Par Pond indicated that all three taxa were abundant there (Paller, Saul, and Hughes 1986). Minnows and darters numerically dominated the tailwater samples early in the spawning season. However, as the season progressed, crappie, sunfish and bass, and brook silversides became increasingly common. Ichthyoplankton densities rapidly declined to comparatively low levels within 400 to 500 m (1,312–1,640 ft) of the Par Pond dam, suggesting that ichthyoplankton conveyed from Par Pond to Lower Three Runs were not transported far downstream. Ichthyoplankton collected from the four sample stations downstream of the Par Pond tailwaters consisted primarily of darters, sunfish, and suckers, species typical of most streams on SRS (Paller, Saul, and Hughes 1986). Paller (1992) collected electrofishing samples from two small, sandbottom first- to second-order tributaries of Lower Three Runs. They were heavily shaded, and the predominant instream structure consisted of snags and woody debris. The fish assemblages in these streams were numerically dominated by small species, including pirate perch, shiners, small sunfishes, darters, madtoms, bullheads, and redfin pickerel.

Lakes and Ponds Fish communities in the lakes and ponds of SRS have been the subject of extensive study. Major impoundments include L Lake, Par Pond, Pond B, and Pond C.

L Lake Extensive sampling of the L Lake fish community from January 1986 to December 1989 began approximately two months after the lake was filled in November 1985. Somewhat less extensive sampling continued from January 1990 to December 1992 and November to December 1995 (Halverson et al. 1997). L Lake was stocked with approximately forty thousand juvenile (20–30 mm, or 0.75–1 in) bluegill in fall 1985 and approximately four thousand juvenile largemouth bass in spring 1986. Largemouth bass, bluegill, redbreast sunfish, and threadfin shad dominated the L Lake fish community between 1987 and sometime after 1992. The most important trends in the fish community in recent years

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involve changes in the abundance of these species and interactions between the dominant fish species and lower trophic (feeding preference) levels, particularly zooplankton. Several of the dominant fish taxa in L Lake have declined in abundance from previous levels. After reaching peak population densities in 1988, threadfin shad densities declined to low levels, and they did not appear in 1995 samples. Decreases in bluegill and redbreast sunfish numbers coincide with changes in condition and size distribution (Sayers and Mealing 1992). Brook silversides and coastal shiner, which were rare in the reservoir after summer 1986, were again common in 1995. Yellow perch and chain pickerel, which had never before been common, were numerically important members of the fish assemblage in 1995 (Paller 1996). After the damming of Steel Creek, the fish community in the lower half of L Lake developed as expected during the lake’s early years, though the warmer temperatures near the reactor discharge point precluded normal community development in the upper half. Since L Reactor has ceased operating and nutrient loading as a result of Savannah River input has decreased, the L Lake fish community has continued to change. Currently, it includes at least nineteen species, the most abundant being brook silversides, yellow perch, bluegill, redbreast sunfish, coastal shiner, largemouth bass, chain pickerel, and spotted sunfish. These species are generally common in southeastern reservoirs with abundant aquatic vegetation. Most or all of these species appear to have successfully reproducing and self-sustaining populations in L Lake (Paller 1996). Mercury contamination is common in fish taken from SRS water bodies that receive or received input from the Savannah River. The mercury concentrations in fish analyzed from SRS waters ranged from a high of 2.9 µg/g in a largemouth bass from Par Pond to a low of 0.11 in a bream in Pond B. Mercury concentrations in off-site fish ranged from a high of 1.27 µg/g in a largemouth bass from the mouth of Steel Creek at the Savannah River to values of 0.01 in mullet upstream of the Highway 17 bridge over the Savannah River (Arnett and Mamatey 1999).

Par Pond, Pond B, and Pond C Par Pond received continuous infusions of nutrients from the Savannah River for over thirty years, resulting in a highly productive aquatic system. The fish community of Par Pond, Pond B, and Pond C developed from Lower Three Runs populations before the dams were built and from

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Table 4.18 Percent composition (by weight) of fishes from Par Pond on the Savannah River Site, 1969–1980 Species Bowfin Blueback herring Golden shiner Lake chubsucker Spotted sucker Bullheads Chain pickerel Bluegill Other sunfishes Largemouth bass Black crappie Yellow perch Miscellaneous fish

1969 2.5 0.1 0.4 15.4 2.2 0.8 4.5 25.3 13.1 22.8 2.6 5.8 4.6

1972

1977

1980

1.8

2.7

5.2 42.3

5.0 33.8

0.4 0.1 7.3 19.7

2.3 12.9 13.7 13.7 5.6 1.7 0.9

2.4 7.5 25.1 10.8 8.0 1.1 3.4 0.2

0.5 5.4 30.5 15.0 17.4 2.5 1.2 0.4

Source: Data were obtained from various cove rotenone studies, as presented by Marcy et al. (2005): 1969 and 1972 (Clugston 1973), 1977 (Hogan 1977), 1980 (Martin 1980).

movement of water from the Savannah River as part of the once-through cooling system. Par Pond was never stocked. Apart from the congregation of some species in thermal areas and lower than average condition (measure of relative robustness) among adult largemouth bass, the Par Pond fish community has been typical of southeastern reservoirs (table 4.18). In 1996, flow from the Savannah River ended, and the reduction in nutrient inputs will probably result in the development of aquatic communities (i.e., plankton and fish) that more closely resemble those of typical southeastern reservoirs with low nutrient inputs. About sixty papers and reports have appeared on the fishes of Par Pond. Most have emphasized the effects of elevated temperatures on fish behavior, physiology, and ecology. General surveys of abundance and distribution by Clugston (1973), Siler (1975), Hogan (1977), Martin (1980), and Bennett and McFarlane (1983) identified thirty fish species from Par Pond. Of those species, seventeen were also reported from Pond C and fourteen from Pond B. Lower Three Runs has these same thirty species. The Par Pond fish community was comparable to other U.S. reservoirs in species number, diversity, and standing crop of all species summed together (Paller and Saul 1985). However, largemouth bass,

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Ecology and Management of a Forested Landscape

bluegill, and lake chubsucker were more abundant in Par Pond than in most other reservoirs in the Southeast. Estimates of largemouth bass populations have ranged from 29,000 to about 100,000 (about 99 per ha, or 40 per ac; Gibbons and Bennett 1971; Martin 1980; Gilbert and Hightower 1981). In contrast, Pond C had a largemouth bass population estimated at approximately 800 fish, or about 12 per ha (5 per ac; Siler and Clugston 1975). High densities of largemouth bass in Par Pond are due in part to a virtual absence of fishing pressure. Many largemouth bass in Par Pond suffer from red-sore disease (Esch et al. 1976). Outbreaks of redsore disease, caused by a bacteria (Aeromonas spp.) occur in several reservoirs in the Southeast. Of eleven taxa of fish larvae and eggs collected from Par Pond, black crappie was the most abundant taxon (36 percent), followed by sunfish (33 percent), and darters (15 percent; Halverson et al. 1997). When Par Pond was drawn down from 1991 to 1995 to repair the dam, the reservoir’s surface area diminished by 50 percent and its volume by 65 percent (U.S. Department of Energy 1994), resulting in the loss of virtually all littoral zone emergent and submerged vegetation. Electrofishing data from before, during, and after the drawdown were used to compare the fish community during those times (Marcy et al. 1994). The drawdown severely disturbed the fish community, reducing the number of species and abundance, particularly of those species dependent on littoral zone vegetation. The size structure of individual species also was affected. Many species that declined during the drawdown (e.g., brook silverside, lake chubsucker, yellow perch, and dollar sunfish) prefer littoral zone habitats. Small largemouth bass, lake chubsuckers, and bluegills decreased during the drawdown and increased following refill. However, the fish community structure in Par Pond rapidly recovered during approximately nine months following refill, due to spawning success and restoration of habitat. The fish community recovered in number of species and overall fish abundance, and nearly recovered in species composition, indicating its resilience to disturbances from changes in water level (Paller 1997). Dominant adult and juvenile fish species in Pond B were gizzard shad (16 percent), largemouth bass (18 percent), brook silversides (34 percent), yellow bullhead (7 percent), bluegill (5 percent), and flat bullhead (3 percent). Among fish larvae and eggs in Pond B, at least six taxa were collected. As in Par Pond, the most abundant taxa were sunfish (57 percent), black crappie (19 percent), and darters (11 percent; Halverson et al. 1997).

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201

Isolated Wetlands Fourteen species have been identified from SRS isolated wetlands (Snodgrass et al. 1996, 1998; table 4.19). However, of the approximately 350 Carolina bays and isolated depression wetlands on SRS, fewer than 10 percent have permanent fish populations (Schalles et al. 1989). Most of these wetlands dry seasonally, but overwash from neighboring swamps or streams may occasionally reestablish the ichthyofauna. In 1994, Snodgrass et al. (1996) found that only twenty-nine of sixty-three randomly selected isolated wetlands held water during their sampling season. Thirteen (21 percent) of those contained fish. Dollar sunfish and lake chubsucker dominated fish communities in wetlands along the upper portions of drainage basins, and mud sunfish and eastern mosquito fish dominated along the downstream portions of drainage systems (Snodgrass et al. 1996).

Savannah River The Academy of Natural Sciences of Philadelphia began sampling Savannah River fish in 1951 to determine the effects, if any, of discharges from the SRS on the fish community. Between 1980 and 1995, fifty-nine Table 4.19 Number of fish (and percent composition) captured in two studies of Carolina bays and isolated depression wetlands on the Savannah River Site Species Lake chubsucker Dollar sunfish Eastern mosquitofish Mud sunfish Flier Warmouth Golden shiner Eastern mudminnow Redfin pickerel Yellow bullhead Brown bullhead Bluespotted sunfish Swamp darter Lined topminnow

Snodgrass et al. (1996)a

Snodgrass et al. (1998)b

474 (38%) 418 (34%) 165 (13%) 59 (5%) 36 (3%) 25 (2%) 24 (2%) 19 (2%) 8 (1%) 6 (<1%) 6 (<1%) 1 (<1%)

1,792 (26%) 753 (11%) 1,049 (15%) 1,285 (19%) 662 (10%) 103 (1%) 127 (2%) 492 (7%) 342 (5%) 83 (1%) 100 (1%) 66 (1%) 34 (<1%)

Source: Snodgrass et al. 1996, 1998. a Thirteen wetlands sampled in one year with baited hoop nets and minnow traps. b Twenty-five wetlands sampled over three years by passive trapping.

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Ecology and Management of a Forested Landscape

species were collected in the annual program with a median of thirtythree species per year. The 1980–1995 surveys show little evidence of long-term increases or decreases in species abundance, but many species exhibited temporary increases in abundance. Such increases may represent strong year classes that persist for one to several subsequent years. However, there is no evidence of detrimental effects on the fishery of the Savannah River in the vicinity of SRS (Academy of Natural Sciences of Philadelphia 1996). Halverson et al. (1997) and Boltin (1999) reported that the dominant fish species in the river near the site included redbreast sunfish, spotted sunfish, bluegill, yellow perch, spotted sucker, largemouth bass, American shad, striped mullet, channel catfish, white catfish, and bullhead. While early studies emphasized the importance of striped bass spawning areas in the lower river, Paller et al. (1984) later demonstrated that striped bass spawn throughout the midreaches of the Savannah River, as far north as Augusta, Georgia. Subsequent studies assessed the importance of spawning sites in the midreaches of the Savannah River (Van Den Avyle et al. 1990; Wallin et al. 1991). Marcy and O’Brien-White (1995) reported 87 freshwater and 125 saltwater fish species in the Edisto River basin east of SRS. In 1991, Georgia Wildlife Resource Division biologists discovered the robust redhorse at Sinclair Dam on the Oconee River. The State of Georgia currently classifies this fish as an endangered species under the Endangered Wildlife Act (Nichols 1999). The robust redhorse is a large, heavy-bodied sucker with a life span of twenty-five to thirty years. In May 1999, twenty-three adults in spawning condition were collected from the Savannah River in the Augusta shoals area and some between Highway 301 and North Augusta. The size of the Savannah River population is uncertain at this time and is under investigation (Nichols 1999). Intake entrainment is the passage of eggs and larvae through intake screens with intake water. At SRS, spawning in the intake canals, water withdrawal rate, ichthyoplankton density, and spatial distribution of river ichthyoplankton in relation to the intake canals all influenced entrainment. Several taxa, especially gizzard shad in 1982 and 1983, crappie in 1983 and 1984, and spotted sucker in 1985, occurred in unusually high densities in the intake canals, suggesting that they were spawned there (Paller et al. 1984, 1985; Paller and Saul 1986). Species that spawned in the intake canals tended to suffer increased entrainment. Similarly, when drifting eggs and larvae were more abundant, more were entrained, although percentage losses did not necessarily increase. The spatial dis-

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203

tribution of the fish eggs also influenced entrainment losses. Entrainment losses averaged 10.0 × 106 eggs and 18.8 × 106 larvae annually. Entrainment losses were primarily American shad and other herring species. Impingement occurs when juvenile and adult fish are captured on the mesh of the intake screens. Paller et al. (1984, 1985) and Paller and Saul (1986) conducted impingement and entrainment studies from 1983 to 1985. During that period, river water pump intake screens impinged an average of 7,603 fish each year. Species most affected by impingement were bluespotted sunfish and threadfin shad. Paller (1994a) evaluated entrainment losses in light of low Savannah River water levels and recent changes in the SRS mission. Entrainment was greatest when periods of high river water usage coincided with low river discharge during the spawning season. The two species of greatest concern, American shad and striped bass, spawn primarily during April and May in the midreaches of the Savannah River. Savannah River discharges during April and May 1973–1989 indicated the potential for entrainment of 4 to 18 percent of the American shad and striped bass eggs that drifted past the SRS (assuming that percentage entrainment was equal to percentage water withdrawal). Average April and May entrainment rates would have consistently exceeded 12 percent during the lowwater years of 1985–1989. This analysis assumed the concurrent operation of L, K, and P Reactors. Those reactors are now shut down and are not to be operated in the future, thus virtually eliminating most of the entrainment and impingement impacts on fish populations of the Savannah River.

Amphibians and Reptiles Kurt A. Buhlmann, Tracey D. Tuberville, Yale Leiden, Travis J. Ryan, Sean Poppy, Christopher T. Winne, Judith L. Greene, Tony M. Mills, David E. Scott, and J. Whitfield Gibbons Since the establishment of the Savannah River Site (SRS), 103 species of amphibians and reptiles have been documented there (Gibbons and Semlitsch 1991; Frazer 1995; Gibbons et al. 1997). Extensive long-term research has been conducted on the herpetofauna of the SRS, largely by the Savannah River Ecology Laboratory. Since the early 1990s, the U.S. Forest Service–Savannah River, the Westinghouse Savannah River

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Company, and their cooperators have conducted considerable herpetological research. The location of the SRS on the Upper Coastal Plain physiographic province and its large variety of habitats allows a high diversity of herpetofauna. In addition, over the past fifty years, the SRS landscape has recovered from intensive agricultural use and is now reforested. Although not pristine, in need of restoration for certain habitats, and managed for timber products, the SRS has been spared from the residential, commercial, and agricultural development that has fragmented the surrounding landscape. Amphibians and reptiles occur in all habitats on the SRS. Many common species occur over a range of habitat types and successional stages (Grant et al. 1994). Often species that are rare or in decline are restricted to specific habitats. Furthermore, although some snake and lizard species live only in terrestrial habitats, many amphibians and reptiles require both aquatic and terrestrial habitats to complete their life cycles (Bennett, Gibbons, and Franson 1970; Gibbons 1970; Gibbons and Bennett 1974; Semlitsch 1981; Gibbons, Greene, and Congdon 1983; Burke and Gibbons 1995; Pechmann 1995). Each of the 103 species of amphibians and reptiles on the SRS has its own habitat requirements, some of which we do not adequately understand. The design of management strategies that will benefit amphibians and reptiles has been recognized as an essential conservation priority by Partners in Amphibian and Reptile Conservation (PARC; Gibbons and Stangel 1999). The SRS National Environmental Research Park is in a unique position to lead in this effort. Few other locations in the southeastern United States provide the opportunity found on the SRS for long-term conservation, research, and management of a coastal plain amphibian and reptile assemblage. This section will assess amphibian and reptile distributions on the SRS and report how both historical land use and current SRS management affects them. We provide information that will help manage, preserve, and enhance herpetofaunal diversity. For species that are rare or habitat specific, we provide distribution maps and specific information about their ecology and management needs. We present an evaluation of the commonness or rarity of each species occurring on SRS (table 4.20), following a model (table 4.21) proposed by Rabinowitz (1981).

Pelobatidae

Salamandridae Plethodontidae

Ambystomatidae

Amphiumidae Sirenidae

Amphibians Proteidae

Family

Eurycea guttolineata Eurycea quadridigitata Plethodon chlorobryonis Pseudotriton montanus Pseudotriton ruber Scaphiopus holbrookii

Necturus punctatus Amphiuma means Siren intermedia Siren lacertina Ambystoma maculatum Ambystoma opacum Ambystoma talpoideum Ambystoma tigrinum Notophthalmus viridescens Desmognathus fuscus Desmognathus auriculatus Eurycea cirrigera Eurycea chamberlaini

Scientific name

dwarf waterdog two-toed amphiuma lesser siren greater siren spotted salamander marbled salamander mole salamander tiger salamander red-spotted newt northern dusky salamander southern dusky salamander two-lined salamander Chamberlain’s dwarf salamander three-lined salamander dwarf salamander slimy salamander mud salamander red salamander eastern spadefoot toad

Common name

2 7 5 8 1 3 6

3 6 6 5 1 7 7 5 5 ? 3 5

Rarity

A

O

B

C

O O

O O S

M O O O

S

S

D

Table 4.20 Habitat characterizations and rarity rankings of amphibians and reptiles of the Savannah River Site

O

S

O O O

E1

O

O

S

O O O O S

E2

Habitat

O

O

S

O O O O O

E3

S

F

H

(continued)

S

S S S

O

G

Microhylidae Ranidae

Hylidae

Bufonidae

Family

Table 4.20 (continued)

Bufo quercicus Bufo terrestris Bufo fowleri Acris crepitans Acris gryllus Hyla avivoca Hyla chrysoscelis Hyla cinerea Hyla femoralis Hyla gratiosa Hyla squirella Pseudacris brimleyi Pseudacris crucifer Pseudacris nigrita Pseudacris triseriata Pseudacris ocularis Pseudacris ornata Gastrophryne carolinensis Rana capito Rana catesbeiana Rana clamitans Rana grylio Rana palustris

Scientific name 3 8 ? 8 8 1 8 8 7 7 6 ? 8 6 ? 1 7 8 5 6 6 3 2

Rarity

oak toad southern toad Woodhouse’s toad northern cricket frog southern cricket frog bird-voiced treefrog Cope’s gray treefrog green treefrog pine woods treefrog barking treefrog squirrel treefrog Brimley’s chorus frog spring peeper southern chorus frog striped chorus frog little grass frog ornate chorus frog eastern narrow-mouthed toad Carolina gopher frog bullfrog bronze (green) frog pig frog pickerel frog

Common name

A

S

B

C

M S

O O

D

O O O O

M

O

S

O

O

O O

E1

S

M

O S O O O O O S O O O

O O O M M

E2

Habitat

O O O O O O O O O O O O

O O O O O

E3

O

O O

M

M

F

M M

G

M

H

Teiidae Scincidae

Trionychidae Testudinidae Iguanidae

Emydidae

Reptiles Alligatoridae Chelydridae Kinosternidae

Alligator mississippiensis Chelydra serpentina Kinosternon bauri Kinosternon subrubrum Sternotherus odoratus Chrysemys picta Clemmys guttata Deirochelys reticularia Pseudemys concinna Pseudemys floridana Terrapene carolina Trachemys scripta Apalone spinifera Gopherus polyphemus Anolis carolinensis Sceloporus undulatus Cnemidophorus sexlineatus Eumeces fasciatus Eumeces inexpectatus Eumeces laticeps Scincella lateralis

Rana utricularia Rana virgatipes American alligator common snapping turtle striped mud turtle eastern mud turtle stinkpot painted turtle spotted turtle chicken turtle river cooter Florida cooter eastern box turtle slider turtle spiny softshell turtle gopher tortoise green anole eastern fence lizard six-lined racerunner five-lined skink southeastern five-lined skink broadheaded skink ground skink

southern leopard frog carpenter frog 4 6 2 7 8 2 1 5 3 6 6 8 2 1 8 6 5 5 5 6 8

8 1

O O

O

O O S O

O S

O

S

O

S

O O O

O

O

S

S

O

O

S S O S O

M O

O O

M

S O

O

M

O

O

S O

O

O

O

O O

O O

S

S O

O

S S

O S

(continued)

M O

S

S

S S

Colubridae

Anguidae

Family

Table 4.20 (continued)

Ophisaurus attenuatus Ophisaurus ventralis Carphophis amoenus Cemophora coccinea Coluber constrictor Diadophis punctatus Elaphe guttata Elaphe obsoleta Farancia abacura Farancia erytrogramma Heterodon platirhinos Heterodon simus Lampropeltis getula Lampropeltis triangulum Masticophis flagellum Nerodia floridana Nerodia erythrogaster Nerodia sipedon Nerodia fasciata Nerodia taxispilota Opheodrys aestivus Pituophis melanoleucus Regina rigida

Scientific name slender glass lizard eastern glass lizard worm snake scarlet snake black racer ringneck snake corn snake rat snake mud snake rainbow snake eastern hognose snake southern hognose snake eastern kingsnake scarlet kingsnake coachwhip Florida green water snake red-bellied water snake northern water snake banded water snake brown water snake rough green snake pine snake glossy crayfish snake

Common name 5 6 1 5 8 6 5 6 5 2 6 5 6 5 5 2 6 ? 8 3 6 5 2

Rarity

O

O

S O S

S

A

O

O S O O

S S O O O O O O

B

S S

O

S S M

S

O

O O

C

O

O S O

O

S

O O O

S

D

S

O

O S

O S

E1

S

E2

Habitat

O

O

S

E3

S

S M

F

M

M O S O

G

O

M

H

queen snake pine woods snake black swamp snake brown snake red-bellied snake southeastern crowned snake eastern ribbon snake common garter snake rough earth snake smooth earth snake eastern coral snake copperhead cottonmouth canebrake rattlesnake pygmy rattlesnake

1 1 3 6 6 5 2 6 6 6 1 6 8 6 2 O

O

O O

O O O O O

O O S

O

S

O

O S

O

S

O

O

S

O

S

S

O

Note: See text for explanation of habitat codes. Rarity rankings follow table 4.21. A rarity rank of “?” indicates that the species has been reported from the SRS at least once but without subsequent verification. Most species of amphibians and reptiles also have a temporal component to their detectable presence and abundance that the ranking scheme does not address. “O” designates optimal habitat; “S,” suitable; “M,” marginal.

Colubridae (continued) Regina septemvittata Rhadinaea flavilata Seminatrix pygaea Storeria dekayi Storeria occipitomaculata Tantilla coronata Thamnophis sauritus Thamnophis sirtalis Virginia striatula Virginia valeriae Elapidae Micrurus fulvius Crotalidae Agkistrodon contortrix Agkistrodon piscivorus Crotalus horridus Sistrurus miliarius

S

Constantly sparse over a large range and in several habitats 6

LOCAL POPULATION SIZE Small, nondominant

Constantly sparse in a specific habitat but over a large range 5

Locally abundant over a large range in a specific habitat 7

Specific

SRS-wide

Locally abundant in several habitats but restricted geographically 4 Constantly sparse and geographically restricted in several habitats 2

General

SRS-restricted

Locally abundant in a specific habitat but restricted geographically 3 Constantly sparse and geographically restricted in a specific habitat 1

Specific

SRS-restricted

Source: Modified from Rabinowitz 1981. Note: Instead of ranking each species from its global distributional perspective, we have evaluated its distributional perspective on the SRS.

Locally abundant over a large range in several habitats 8

General

HABITAT SPECIFICITY

LOCAL POPULATION SIZE Large, dominant somewhere

SRS-wide

GEOGRAPHIC RANGE

Table 4.21 A typology of species rankings for amphibians and reptiles on the Savannah River Site based on geographic range, habitat specificity, and local population size

Figure 1.4. Pre-European vegetation types of the Savannah River Site, as classified by Frost (1997).

Figure 1.6. Land use on the Savannah River Site in 1951, derived from a U.S. Forest Service orthorectified mosaic of 1951 aerial photos.

Figure 1.7. Satellite image of the Savannah River Site and surrounding region, March 1999. Darker shades represent forest cover and lighter shades represent open conditions (e.g., agriculture, development, bare ground). The body of water in the northwest corner is the Strom Thurmond Reservoir on the Savannah River (Image provided by D. Karapatakis, Savannah River Ecology Laboratory).

Figure 1.8. Land-use areas of the Savannah River Site: the primary red-cockaded woodpecker habitat management area (primary RCW HMA) and supplemental RCW HMA; area with heaviest existing and potential infrastructure development (other use area); major swamps and bottomlands (Savannah River swamp, Lower Three Runs corridor); the Crackerneck Wildlife Management Area and Ecological Reserve (Crackerneck WMA); and the research set-aside areas.

Figure 2.3. General soil map of the Savannah River Site (Rogers 1990).

Figure 4.1. Forest land-use associations of the Savannah River Site, as classified by Jones et al. (1984).

Figure 4.2. Potential vegetation types of the Savannah River Site, as classified by Imm (1996).

Figure 4.22. Locations of terrestrial refugia for wetland turtles in uplands surrounding Dry Bay, a Carolina bay on the Savannah River Site, during autumn-winter, 1994–1997. Colored circles indicate refugia for chicken turtles (yellow), eastern mud turtles (blue), musk turtles (green), snapping turtles (black), and striped mud turtles (red). The inner blue line represents the delineated wetland boundary, and the three black lines represent 50-, 100-, and 150-m (164-, 328-, and 492-ft) distances from the delineated wetland boundary. A two-lane state highway borders Dry Bay on the west (left) and a powerline right-of-way is located to the northeast (right). Reprinted by permission from Buhlmann and Gibbons 2001.

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Landscape Features Many amphibians and reptiles with complex life cycles use both terrestrial and aquatic habitats (Buhlmann, Mitchell, and Pague 1993; Buhlmann 1995; Semlitsch and Bodie 1998). Landscape linkages between diverse habitats are critical for maintaining populations (Morreale, Gibbons, and Congdon 1984; Burke, Greene, and Gibbons 1995). Each species on the SRS uses one or more of the habitats listed below (see table 4.20): A. upland, sandhill and longleaf pine communities—xeric conditions B. upland, mixed pine and hardwood forests—mesic conditions C. old fields, grasslands, sparse canopy forests D. stream and riverine floodplain forests E. isolated wetlands, including Carolina bays 1. relatively permanent 2. seasonal 3. in combination with surrounding upland habitat, usually forested F. reservoirs, lakes, farm ponds G. streams H. river Although E3 habitats include habitat similar to A and B, many amphibians that use A and B habitats also require adjacent aquatic habitats. Recent research has demonstrated the importance of this habitat juxtaposition to adult amphibians and reptiles (Bennett 1972; Semlitsch and McMillian 1980; Semlitsch, Pechmann, and Gibbons 1988; Burke and Gibbons 1995; Buhlmann 1998; Semlitsch 1998; Semlitsch and Bodie 1998). However, these habitats must be within the home range or dispersal distances of the animals using the aquatic sites. Consideration of this important landscape linkage is critical in interpreting such influences as timber harvest and potential positive effects of coarse woody debris. Species that occur in upland forest habitats but do not need isolated wetlands are assigned to habitat type A or B, whereas those requiring wetlands are assigned to E3.

Factors Affecting Species Distribution Many amphibians and reptiles common on the SRS occur in a wide variety of habitats. Such habitat generalists, which often coexist with many anthropogenic impacts and need the least conservation management, are

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Figure 4.18. Terrestrial snakes associated with xeric upland habitats (southern hognose snake, northern pine snake, pigmy rattlesnake, coral snake, and pine woods snake) and mesic floodplain habitats (worm snake) on the Savannah River Site.

classified as Rarity Type 8 (table 4.21). Other species require specific habitats or are limited in their geographic occurrence on SRS (see Rarity Types 1–7 in table 4.21). Some species on the SRS are secretive or possess other traits that make assessment of their distributions difficult. For example, the eastern worm snake (see table 4.20 for scientific names) is a clandestine species found primarily in mixed hardwood-pine areas beneath leaf litter or several centimeters below ground. Russell and Hanlin (1999) found worm snakes abundant in the ecotone between seasonal wetlands and uplands in east-

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Figure 4.19. Aquatic snakes associated with stream systems (queen snake) and Carolina bays (black swamp snake, glossy crayfish snake, and green water snake) on the Savannah River Site.

ern South Carolina, and they are common in some Piedmont habitats north of Aiken. Yet despite extensive coverboard and drift fence surveys in wetland ecotone habitat, only one population is known at SRS, between Hogbarn Road and Pen Branch (figure 4.18). A primary factor limiting the local distribution of some less abundant species is that the SRS may be near the periphery of their geographic ranges. Queen snakes live in mountain and piedmont streams in South Carolina. However, they occur in the Upper Three Runs drainage on the SRS, which is the southeastern extent of their range (figure 4.19). The

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Figure 4.20. Salamanders (tiger salamander and spotted salamander) and frogs (pickerel frog, gopher frog, pig frog, and carpenter frog) associated with Carolina bays on the Savannah River Site.

bird-voiced tree frog is known only from the southern portion of the SRS within the Savannah River floodplain forests; the SRS is the easternmost range of this primarily Gulf Coastal Plain species. Pickerel frogs generally live west, north, and east of the SRS but are absent from much of central South Carolina (Conant and Collins 1991). Individuals have been found at Ellenton Bay, Risher Pond, and in the Steel Creek delta. However, only a single breeding population is known from a wet meadow in a power line right-of-way near Ellenton Bay (figure 4.20; Gibbons and Semlitsch 1991). The species is apparently uncommon on SRS.

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Factors that affect local distribution include the availability of suitable habitat, wetland hydroperiod, habitat juxtaposition within the landscape, historical land-use patterns, and natural and anthropogenic disturbances. More than one factor is likely to affect each species.

Specific Habitat Requirements The specific habitat requirements of some species limit their distributions on SRS because those habitats are spatially restricted. Many aquatic amphibians and reptiles on the SRS are associated with natural wetlands, specifically Carolina bays and swamp forests (Gibbons 1969; Caldwell 1987; Lovich 1990; Dorcas, Gibbons, and Dowling 1998; figures 4.19–4.21, table 4.20). Fewer species use artificial reservoirs and ponds (table 4.20). Some species are associated with a particular set of upland conditions. For example, the few records for coral snakes suggest a preference for well-drained soils with a loamy subsoil, conditions that occur in the northern portion of the SRS (figure 4.18). Similarly, upland xeric sandhill communities provide habitat for rare herpetofauna such as the southern hognose snake and pine snake (figure 4.18). Several species require bottomland hardwood or swamp habitat. For example, both spotted turtles and striped mud turtles are restricted to the floodplain forested wetlands of the Savannah River terrace (figure 4.21; Lamb 1983; Lovich 1990). Glossy crayfish snakes have been captured within only 5 km (3 mi) of the southwestern boundary of the SRS, mostly in the historical floodplain of the Savannah River (figure 4.19). The greatest numbers come from the Steel Creek delta. Glossy crayfish snakes require wetland habitats with crayfish populations. Spotted salamander adults, egg masses, and larvae have been recorded only in bottomland hardwood wetlands along the Savannah River floodplain (figure 4.20; Gibbons and Semlitsch 1991). Adults are restricted to the forests surrounding these breeding sites. The few known spotted salamander populations on the SRS occur along Steel Creek, Risher Pond, and the floodplain forest edge. These sites are separated by 10 to 15 km (6–9 mi). No systematic studies have quantified the abundance of spotted salamanders on the SRS. Carolina bays and isolated wetlands are important amphibian habitats. As in Florida (Ligas 1960; Wood et al. 1998), pig frogs occur on the SRS in large, relatively permanent bays but not in seasonal wetlands that dry completely. Pig frogs are known from two widely separated Carolina bays on the SRS, Steel Creek Bay and Craig’s Pond (figure 4.20), and they

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Figure 4.21. Turtles (chicken turtle, spotted turtle, and striped mud turtle) associated with Carolina bay wetlands on the Savannah River Site.

have been found at two locations in the Steel Creek delta and in the upper reaches of Par Pond. Carpenter frogs also occur in Steel Creek Bay and several nearby wetlands. Carpenter frogs generally require permanent acidic bogs and wetlands throughout their range (figure 4.20; Mitchell and Pague 1991). Gopher frogs are terrestrial as adults, but they breed at SRS only in firm-bottomed and grass-dominated bays, with hydroperiods of several months (figure 4.20; Semlitsch, Gibbons, and Tuberville 1995). A species of special concern in South Carolina, most of the populations in the state occur on the SRS (S. Bennett, South Carolina

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Department of Natural Resources, pers. comm.) but are small at each breeding site (unpublished data). Adults have been found in mature pine habitat on SRS (M. Komoroski, Savannah River Ecology Lab, unpublished data). Gopher frogs move several hundred meters away from wetlands into the surrounding forest, where they seek refuge in burrows and stump holes ( J. Neufeldt, pers. comm.; S. Richter, pers. comm.). Eastern tiger salamanders breed in Carolina bays (Semlitsch 1983b) similar to gopher frog breeding sites. In fact, the two species often occur sympatrically, although the tiger salamander is more widespread (figure 4.20). Tiger salamander adults inhabit the forested upland habitats around isolated wetlands up to 300 m (984 ft) from the wetland boundary (Semlitsch 1983c). Metamorphic juveniles may disperse even greater distances (M. Komoroski, unpublished data). Because of the wide range of habitat requirements among species and the diversity of habitats on SRS, the diversity of amphibians and reptiles is higher than in the surrounding landscape. An oak-hickory habitat on the SRS had higher amphibian diversity than an adjacent managed pine stand (Bennett, Gibbons, and Glanville 1980). The SRS includes many wetland types with a reduced level of human impact (e.g., ditching and draining), and the broad array of natural, floristically diverse upland habitats yields greater structural and biotic diversity, both within and between habitats.

Wetland Hydroperiod The length and timing of wetland hydroperiod required for amphibian reproduction vary among species (Pechmann et al. 1989, 1991; Mohr and Dorcas 1999; Semlitsch 2000). Bullfrogs need permanent water habitats because their tadpoles require more than one year to complete metamorphosis. Red-spotted newts in artificial, permanent-water farm ponds can coexist with predatory fish since these salamanders are highly toxic to predators. Tiger salamanders and gopher frogs use isolated wetlands that have hard-pan bottoms with grasses, open canopies, and a hydroperiod of at least four consecutive months. Spadefoot toads reproduce most successfully in wetlands with very short hydroperiods (less than two months), as the larvae may progress from egg to toadlet in less than thirty days (Semlitsch and Caldwell 1982). Large, completely aquatic salamanders such as greater sirens and amphiuma are most common in isolated permanent wetlands (Snodgrass et al. 1999); otherwise, wetlands that dry periodically must have deep muck substrates where these

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salamanders can survive in mucous cocoons. Semipermanent wetlands contain populations of yellow-bellied sliders and Florida cooters (Gibbons and Coker 1977), species that feed on abundant vegetation. Conversely, seasonal wetlands support chicken turtles and eastern mud turtles, which feed on aquatic insects and crayfish (Demuth and Buhlmann 1997). Maintaining diverse hydrologic conditions among SRS wetlands is necessary to support the diversity of amphibians and reptiles.

Landscape Structure The position of habitats within the landscape is an important management consideration for amphibians and reptiles. For long-term population persistence, individuals must be able to move to other suitable habitats during periods of adverse environmental conditions, such as wetland drying. Less mobile than other vertebrates, amphibians and reptiles may not be able to escape adverse conditions or recolonize sites as effectively. The ability of amphibians to recolonize breeding ponds is related to pond isolation; the greater a pond’s distance from a source population, the less colonization (Skelly, Werner, and Cortwright 1999). The exchange of individuals between populations enhances genetic viability and prevents possible inbreeding effects (Scribner, Smith, and Gibbons 1984). Populations of chicken turtles are generally most abundant near clusters of isolated wetlands and bays with varying hydroperiods (figure 4.21). Yellow-bellied sliders and Florida cooters regularly move between Dry Bay and Ellenton Bay, a distance of more than 3 km (2 mi); chicken turtles do this rarely and mud turtles never (Buhlmann 1998). Slider turtles originally marked in Ellenton Bay have been captured 5 km (3 mi) distant (Burke, Greene, and Gibbons 1995). Habitat corridors between wetlands may help freshwater turtles move diurnally during the warm seasons (Buhlmann 1998). Large clear-cuts may be dispersal barriers because of heat and dryness. Roads adjacent to wetland habitats are partial barriers to dispersal because they lower survivorship. Turtles must be able to disperse across the landscape for recolonization (Tuberville, Gibbons, and Greene 1996).

Historical Land Use Current distributions of some herpetofauna, both on and off the SRS, may result from historical land-use patterns such as agricultural cultivation and wetland drainage. Several species have unexplained spotty dis-

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tributions. For example, pygmy rattlesnakes, coral snakes, and pine woods snakes occur only at a few mixed pine-hardwood sites. Although farming heavily impacted the SRS until the 1950s, perhaps these species were persisting in small pockets of habitat at that time. Franklin et al. (2000) used the term biological legacy to describe the process by which some organisms survive large-scale disturbances and thus provide on-site remnants to rebuild populations. For example, the pine woods snake’s occurrence on the SRS is disjunct from the continuous species range by more than one hundred miles (Young and Davis 1988; Conant and Collins 1991; Whiteman et al. 1995). Perhaps SRS establishment prevented its extirpation here, while it disappeared from the surrounding landscape. The gopher tortoise historically occurred in Aiken County (Holbrook 1836–1838). For the most part, tortoises were extirpated from the region by the early 1900s, likely due to the cumulative effects of consumptive harvest for human food and extensive conversion of land to agriculture. However, a few small relict populations exist in the landscape surrounding the SRS (Clark, Tsaliagos, and Pittman 2001). Isolation of the SRS from other known tortoise colonies has probably limited its ability to reestablish naturally, although individual tortoises have been discovered on SRS in recent years. The return of forest cover and the use of prescribed fire that promotes open herbaceous understories has created habitat on SRS that appears capable of supporting viable tortoise colonies. In 2001, researchers from the Savannah River Ecology Laboratory and the U.S. Forest Service–Savannah River moved a population of more than one hundred gopher tortoises to the SRS from an industrial park construction site in nearby Georgia. This experimental reintroduction seeks to establish the gopher tortoise as a functioning ecosystem component on SRS and will also identify appropriate relocation methodologies for gopher tortoises, with eventual application to other areas and species. Widespread ditching and draining of wetlands may have limited at least two species’ distributions. Eastern green water snakes inhabit a few relatively permanent Carolina bay wetlands on the SRS (figure 4.19). They are poor overland dispersers and may have difficulty reestablishing populations once extirpated by drought or wetland drainage (Seigel, Gibbons, and Lynch 1995). The SRS is one of only two areas in South Carolina where eastern green water snakes occur (Buhlmann and Gibbons 1997), and it has the largest concentration of populations. SRS sites include Ellenton Bay, Craig’s Pond, Pond B, and Par Pond. The severe drought during the 1980s extirpated the population at Ellenton Bay and led to a

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several-year hiatus during which no specimens appeared. Four green water snakes were captured at Ellenton Bay during the 1990s, but there is no evidence that a reproducing population is once again established. Similarly at SRS, the black swamp snake has a disjunct distribution, occurring only in relatively permanent isolated wetlands (Dorcas, Gibbons, and Dowling 1998; figure 4.19). It is a species of special concern in South Carolina (Buhlmann and Gibbons 1997). Dodd (1993) suggested that this species might be able to recolonize nearby ponds when they are connected by high water. However, compared to other water snakes (i.e., Nerodia spp.; Winne et al. 2001), black swamp snakes lose body water rapidly, a condition that may limit their ability to move between wetlands (e.g., Seigel, Gibbons, and Lynch 1995). Therefore, disruptions of wetlands could have long-term detrimental effects on all species similar to green water snakes and black swamp snakes.

Continuing Anthropogenic Alterations Some amphibians and reptiles, primarily widespread, mobile, habitatgeneralist species, use early successional habitats created by timber operations. Black racers and coachwhips, large fast-moving snakes, hunt six-lined racerunners and fence lizards in open habitats (e.g., Plummer and Congdon 1994). Other lizards, primarily skinks (Eumeces spp.), prefer large old trees typical of mature forests (Cooper et al. 1983; Cooper 1993). Mechanical site preparation affects fossorial amphibians and reptiles. Blymer and McGinnes (1977) found fewer salamanders in clear-cuts relative to uncut forests and suggested that high temperatures and low soil moisture were limiting. Herbeck and Larsen (1999) suggested that appropriate forest microhabitats must remain available post-harvest for nonmigratory, territorial plethodontid salamanders. The source for reestablishing a population following harvest will come from the biological legacy that remains (Frankin et al. 2000). The worldwide decline of amphibians has been linked to toxic pollution, disease, ozone depletion, global warming, ultraviolet radiation, and habitat loss. Although none of these factors account for all observed declines, impacts are likely cumulative and synergistic. On the SRS, coal ash may cause mouth deformities and swimming ability defects in bullfrog tadpoles (Rowe et al. 1996; Rowe, Kinney, and Congdon 1998; Raimondo, Rowe, and Congdon 1998). Elevated levels of certain hormones have been found in southern toads and trace metals in banded water snakes living near coal combustion waste (Hopkins, Mendonca, and Con-

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gdon 1997; Hopkins, Rowe, and Congdon 1999). Long-term population effects are unknown. Prescribed burning of pine forest habitats promotes a diversity of understory herbaceous vegetation that likely benefits herpetofaunal species. However, the effects of burning season on amphibians and reptiles are unknown. In the southeastern United States, naturally occurring fires were historically more frequent in summer. Winter burns are more typical in modern forest management for logistical reasons, but they do not promote grass and forb establishment (Brockway and Lewis 1997) and might impact winter-breeding amphibians. For example, ambystomatid salamanders are fossorial most of the year, but during winter months they migrate on the surface to breeding wetlands (Semlitsch 1983a). Summer burns maintain the open canopies and depths of Carolina bay wetlands by burning out peat and muck layers when the pond basins are dry (Russell, Van Lear, and Guynn 1999), and protective firebreaks around wetlands may damage wetland ecology (Hipes and Jackson 1996). Many species of amphibians and reptiles on the SRS benefit from protection of both wetlands and their surrounding upland habitat. For example, chicken turtles and mud turtles inhabit Carolina bays and other seasonal wetlands. When those wetlands are dry, they seek refuge underground in adjacent forests (Burke and Gibbons 1995; Buhlmann 1998; figure 4.22). Turtles return annually to the same terrestrial refugia sites, and they prefer forested habitat over open, clear-cut habitats, as indicated by their movement and behavior (Buhlmann 1998). Thus, a boundary of upland forest left as a “buffer” to protect the wetland actually serves as critical core habitat for such species. Management impacts that extend to the wetland edge, such as clear-cuts, affect this necessary habitat component (Buhlmann and Gibbons 2001). For chicken turtles (and other species that use such E3 habitat), a buffer would surround the critical core habitat. Finally, life history strategies of many amphibians and reptiles limit their ability to cope with certain land management activities. Relative to birds and mammals, many species of amphibians and reptiles are long lived and exhibit delayed sexual maturity (Gibbons 1987; Congdon and Gibbons 1990; Congdon, Dunham, and van Loben Sels 1993). Slider turtles may require six or seven years to reach sexual maturity and can live for twenty-five years or more (Gibbons and Semlitsch 1982). Red-spotted newts may take seven or more years to reach maturity (Gill 1978). Juveniles exist as terrestrial salamanders in forested habitats near the wetlands in which they will eventually breed. In contrast, white-tailed deer (Odocoileus

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virginianus) may begin reproducing between 0.5 and 1.5 years of age and have a life span of less than ten years; a typical deer herd might go through two or more generations from the time a female newt or slider turtle is born until she lays her first eggs. Many species of amphibians and reptiles require relatively stable long-term habitat conditions and high adult survivorship. Large-scale, human-made disturbances fragment landscapes, impede movements, and may lower survivorship.

Natural Disturbance Natural disturbances (fire, windstorms, flooding, and drought) may perturb the structure and suitability of habitats and thus alter the abundance and composition of amphibian and reptile species. Hurricanes and fires maintain forest diversity essential to the variety of flora and fauna (Sharitz et al. 1992). Hurricanes and other windstorms can create local high densities of downed woody debris that provide cover and structure for amphibians and reptiles. Fire maintains certain open-canopy, grass- and herb-dominated habitats for amphibians and reptiles (Palis 1997). Russell, Van Lear, and Guynn (1999) emphasized the role of fire in maintaining open-canopy conditions in wetlands, reducing the accumulation of organic debris, and preventing bogs and shrub thickets from succeeding to hardwood forest. Kirkman and Sharitz (1994) noted that episodic disturbance to wetlands, such as fire and tilling, which often occur in prolonged droughts, may favor endemic, fugitive, and rare species of plants. Natural and anthropogenic disturbances tend to affect local herpetofauna in different ways. Human-imposed disturbances typically remove more vegetation more uniformly and more frequently than natural disturbances (Franklin et al. 2000). Timber harvest that retains structure and species composition more closely mimics natural disturbance regimes. To benefit amphibians and reptiles, land managers should not expect recolonization but rather should ensure that biotic elements survive disturbance.

Historical Trends and the Future Amphibians and reptiles benefited greatly from the establishment of the SRS in 1951. A large area of coastal plain habitat was reforested after being under intensive agriculture. Floodplain hardwood forests were largely protected. Thus, the 310 square miles that constitute the SRS are primarily forested, whereas the surrounding South Carolina landscape

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is primarily agricultural and becoming more developed. In addition, wetland destruction on SRS was slowed greatly relative to the surrounding landscape. Most of the intact Carolina bays in South Carolina are on the SRS (S. Bennett, pers. comm.). The creation of the Par Pond reservoir unintentionally created a refuge for American alligators at a time when the species was in danger of extinction throughout its range (Brandt 1991a, b; Brisbin et al. 1997). Some species that have apparently disappeared from the surrounding landscape have managed to persist on the SRS, including the green water snake and pine woods snake. Although unquantified, large snake species such as pine snakes and canebrake rattlesnakes appear to be encountered more frequently on the SRS than in the surrounding landscape, perhaps as a result of fewer roads and the lack of human residents who kill them. Southern hognose snakes are disappearing from throughout their range in the southeastern United States. For example, no southern hognose snakes have been seen in Alabama in over twenty years despite extensive survey efforts (Tuberville et al. 1999). Habitat destruction and degradation, road mortality, and the introduction and spread of red imported fire ants (Solenopsis invicta) are possible factors leading to the species’ perceived decline in much of its range. The southern hognose snake appears to be more common on the SRS than in the surrounding landscape. Timber rotation lengths on portions of the SRS (see chapter 3) do not allow for establishment of mature native habitat and therefore may not be in the best interest of all herpetofaunal species. However, considerable habitat restoration is occurring, and opportunities for applied research, restoration, and conservation of natural habitats (e.g., isolated wetlands and longleaf pine forests), as well as reintroductions of historically occurring species, are excellent on the SRS. The herpetofaunal diversity on the SRS is unrivaled anywhere else in the state of South Carolina. Nowhere else are the prospects and opportunities greater for long-term conservation of Southeastern Coastal Plain biodiversity than on the SRS.

Nongame Birds John C. Kilgo and A. Lawrence Bryan, Jr. The Savannah River Site (SRS) provides habitat for an impressive array of avian species. During its fifty-year existence, 259 bird species have been recorded there (Mayer et al. 1997 and unpublished data). This figure

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represents more than two thirds of the 379 species on the South Carolina state list (McNair and Post 1993). Explanations for SRS’s diverse avifauna include its location along the Savannah River migratory flyway, its predominantly forested landscape (in stark contrast to the surrounding counties; see figure 1.7), and the great diversity of habitat types on the site. SRS habitats span a continuum from xeric longleaf pine–turkey oak (see appendix for scientific names of plants) sandhills to hydric cypresstupelo forests and from early successional pine regeneration stands to mature bottomland hardwood forests. The urban or developed habitats of the facilities areas and the lacustrine habitats of the cooling reservoirs add to the habitat diversity and support many species. Since its inception, the SRS has been the subject of intensive avian study. In 1951, Dr. Eugene Odum and a team of scientists from the University of Georgia initiated avian surveys to establish baseline ecological information for the Department of Energy and to identify patterns of oldfield succession. As this early research program grew into the Savannah River Ecology Laboratory, its avian research focus shifted toward radioecology, waterfowl, and endangered species studies. Meyers and Odum (2000) have described early ornithological work on the SRS. In recent years, the U.S. Forest Service has initiated considerable avian research and monitoring efforts. In 1996, the Forest Service symposium on long-term avian research on the SRS produced the publication Avian Research at the Savannah River Site: A Model for Integrating Basic Research and Long-Term Management (Dunning and Kilgo 2000). This valuable resource includes contributions from most ornithologists who worked on SRS in the 1980s and 1990s. This section focuses on nongame forest and wading birds. Sections of chapters 5 and 6 cover endangered species and game birds.

Factors Controlling Bird Distribution Many factors, both temporal and spatial, control the distribution and occurrence of birds on SRS. These factors include season, habitat type, and landscape structure.

Season A species’ seasonal occurrence depends on its migratory habits. Most species on SRS fall into one of three categories: resident, Neotropical migrant, or Nearctic migrant. Resident species (e.g., northern cardinal, Car-

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olina wren) occur on SRS year-round (see table 4.22, which appears at the end of this section, for scientific names of birds not given in text). Neotropical migrants (e.g., hooded warbler, wood thrush) breed on SRS but winter south of the Tropic of Cancer, primarily in the Caribbean and Central America. Finally, Nearctic migrants (e.g., hermit thrush, whitethroated sparrow) breed in North America and migrate southward to winter in southern North America. Nearctic migrants include species that do not breed at SRS but do winter here, as well as species (e.g., white-eyed vireo, common yellowthroat) that do breed here but migrate short distances (relative to Neotropical migrants) to winter along the South Atlantic Coast or in Florida. Each group is highly varied, and some species are difficult to categorize even according to these broad definitions. Even within a species, not all individuals necessarily follow the same pattern. For example, whiteeyed vireos are abundant breeders at SRS but are much less common during the winter. Whether the individuals at SRS during the winter are breeders that have remained or are birds that bred to the north is unknown, but it is possible that some SRS breeding white-eyed vireos are resident even if most are short-distance Nearctic or even Neotropical migrants. Other species, like brown thrashers, are resident at SRS, but during the winter an influx of migratory individuals from more northerly breeding populations augments SRS populations. Thus, some brown thrashers at SRS could be considered Nearctic migrants. Despite such difficulties, these designations help characterize major migratory patterns. The general migratory habits of a species provide insight as to when it most likely occurs at SRS.

Habitat The relationship between bird communities and vegetation structure has long been recognized, and most species are associated with specific habitats or habitat features. For many species, habitat associations may be quite predictable, so that habitat types can often categorize bird communities. Table 4.22 predicts habitat-specific suitability for nongame and nonendangered species that breed or winter at SRS. The degree to which the avian communities of various habitats are distinct depends on the habitat preferences of each species in a community. Many species that are habitat specialists are closely tied to the narrow range of habitat conditions met in one or a few particular habitat types. Habitat generalists, which prefer a broader range of features that may be present in many

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different habitats, are not as closely associated with a particular type. Thus, a community that includes many specialists will be more distinct from other communities than one that includes many generalists. Generally, species-habitat associations are most pronounced during the breeding season; most species have specific nesting requirements, and birds tend to use habitats that meet those requirements. During breeding, birds are most vocal and detectable. In fall and winter, when birds sing much less, it is more difficult to determine their habitats, particularly those of small cryptically colored, secretive birds that use dense vegetation. Finally, given the importance of nesting in the life history of birds, research has emphasized nesting habitat requirements. Therefore, our understanding is greatest of species-habitat associations during the breeding period. Many parameters describe a habitat. Two primary factors for birds are vegetation cover type and successional (seral) stage. Thus, our discussion of community and species distribution refers to these habitat attributes.

Cover Type Managed pine forests occupy a large proportion of the SRS land area. The avian communities of these forests range from depauperate to speciesrich, depending on the structure of individual stands. Just as birds select particular habitat types, they also may prefer certain structural configurations within a habitat. Habitat structure refers to the relative density and composition of ground cover (grasses and forbs), understory (shrubs and seedlings), midstory (saplings and small trees), and canopy layers (dominant and codominant trees). Each habitat layer can be subdivided any number of times, depending on the complexity of the forest. With few exceptions, the species of pine per se does not seem important to birds at SRS, except to the extent that tree species dictates management alternatives and, hence, the structure of the stand. Because loblolly pine has been planted across the SRS on a variety of site types, and because managers often tailor silvicultural practices in established stands as much to site-specific conditions as to a particular species, later successional loblolly and longleaf pine forests on SRS often are quite similar in vegetation structure. Thus, bird communities are similar in longleaf and loblolly pine. Presettlement avian communities may have differed substantially between longleaf and loblolly forests, because in the absence of management intervention, these species occupied and shaped different site types.

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Contrary to the general theory that bird species diversity is a function of foliage height diversity, the habitat structure that tends to support the most diverse bird community in mid- to late-successional southern pine forests includes a well-developed grass-forb understory, a sparse midstory, and a canopy of large pines, i.e., the structure found in mature, firemaintained pine forests and savannas (Wilson, Masters, and Bukenhofer 1995; White et al. 1999; Krementz and Christie 1999). The bird community typical of such sites at SRS consists of a diverse array of species that nest on the ground, in the understory (i.e., shrub-scrub birds), and in the canopy, as well as a few midstory-nesting species. This community of breeding birds is among the most diverse of any habitat at SRS (table 4.23, 60-year pine forest). Generally, when understory development is enhanced in SRS pine forests, bird diversity and abundance increase. Thinning, for example, stimulates the development of the understory by opening the forest canopy and allowing more sunlight to reach the ground (although understory development may be limited by prior land-use effects on the seed bank). Conversely, when the understory is diminished, bird diversity and abundance decline. Both canopy closure in young stands and hardwood midstory encroachment in older stands shade out the understory. Unthinned old-field pine stands on many SRS sites frequently have little to no midstory or understory, and the only ground cover may be pine straw. Such species-poor stands lack birds that nest in the understory. They are occupied almost exclusively by canopy-nesting species such as the great crested flycatcher, blue jay, pine warbler, and woodpeckers (see table 4.23, 25-year pine stand). Similarly, pine stands with well-developed hardwood midstories often lack understory and groundnesting birds because the lower layers have been shaded out. Such stands may support a few additional species, such as wood thrush and red-eyed vireo, that use the midstory, but still lack the suite of species associated with the ground and understories of the mature pine forest (i.e., the shrub-scrub community). Manipulating the frequency and timing of prescribed fire can control midstory encroachment (see chapter 3). Frequent burning, particularly during the growing season, suppresses the growth of hardwood trees and thus limits midstory development and enhances ground and understory development. Stands that escape burning for more than five years, especially if recently thinned, often develop a hardwood midstory and support a bird community with few ground nesters. In some stands at SRS,

Mourning dove Common ground dove Eastern kingbird Great crested flycatcher Carolina chickadee Tufted titmouse Carolina wren Eastern bluebird Gray catbird Northern mockingbird Brown thrasher White-eyed vireo Prairie warbler Common yellowthroat Yellow-breasted chat Northern cardinal Blue grosbeak Indigo bunting Eastern towhee Bachman’s sparrow Field sparrow

Pine forest (60-yr) Yellow-billed cuckoo Red-headed woodpecker Red-bellied woodpecker Red-cockaded woodpecker Northern flicker Pileated woodpecker Eastern wood-pewee Great crested flycatcher Carolina chickadee Tufted titmouse Brown-headed nuthatch Carolina wren Eastern bluebird Pine warbler Prairie warbler Summer tanager Northern cardinal Blue grosbeak Indigo bunting Eastern towhee Bachman’s sparrow Chipping sparrow

Upland hardwood Yellow-billed cuckoo Red-bellied woodpecker Downy woodpecker Northern flicker Pileated woodpecker Great crested flycatcher Blue jay American crow Carolina chickadee Tufted titmouse Carolina wren Blue-gray gnatcatcher Wood thrush Red-eyed vireo Northern parula Summer tanager Northern cardinal

Yellow-billed cuckoo Red-bellied woodpecker Downy woodpecker Pileated woodpecker Acadian flycatcher Great crested flycatcher American crow Carolina chickadee Tufted titmouse Carolina wren Blue-gray gnatcatcher Wood thrush White-eyed vireo Yellow-throated vireo Red-eyed vireo Northern parula American redstart Prothonotary warbler Swainson’s warbler Louisiana waterthrush Kentucky warbler Hooded warbler Summer tanager Northern cardinal

Bottomland hardwood

Cypress-tupelo Yellow-billed cuckoo Red-bellied woodpecker Pileated woodpecker Acadian flycatcher Great crested flycatcher Carolina chickadee Tufted titmouse White-breasted nuthatch Carolina wren Blue-gray gnatcatcher Yellow-throated vireo Red-eyed vireo Northern parula Yellow-throated warbler American redstart Prothonotary warble Summer tanager Northern cardinal

Sources: Pine plantation, Irby et al. (1995, 1996), Krementz and Christie (1999), J. Dunning, unpublished data; pine forest (25-yr), Kilgo, unpublished data, Droge et al. (1993); pine forest (60-yr), Krementz and Christie (1999), Droge et al. (1993); upland hardwood, Kilgo et al. (1997), Plissner et al. (1993c); bottomland hardwood, Kilgo et al. (1998), Plissner et al. (1993a); cypress-tupelo, Plissner et al. (1993b).

Pine forest (25-yr)

Yellow-billed cuckoo Red-bellied woodpecker Eastern wood-pewee Great crested flycatcher Blue jay Carolina chickadee Tufted titmouse Brown-headed nuthatch Carolina wren Blue-gray gnatcatcher Pine warbler Summer tanager

Pine plantation (4-yr)

Table 4.23 Typical avian communities associated with six common habitats on the Savannah River Site (nesting species only)

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mechanical and chemical means are required to control hardwood encroachment (see chapter 5). Whether by fire, mechanical, or chemical means, midstory control and the enhanced understory development benefit birds that nest and forage in the understory, such as prairie warbler, blue grosbeak, indigo bunting, and Bachman’s sparrow, yielding a more diverse avian community (Burger, Hardy, and Bein 1998). Other aspects of forest structure that affect the avian community of SRS pine stands include the size of overstory trees and the presence and size of coarse woody debris (i.e., large dead wood), both standing snags and downed logs (Lohr, Gauthreaux, and Kilgo 2002). The size of trees and snags primarily affects cavity-nesting species. Many primary and secondary cavity-nesting species, including great crested flycatcher, brownheaded nuthatch, and eastern bluebird use dead branches and malformations in the crotches of large living trees. Similarly, population levels of many cavity-nesting birds are related to the number of snags present in a stand; stands with snags experimentally removed supported fewer cavity-nesting birds (figure 4.23; Lohr, Gauthreaux, and Kilgo 2002). Rotation length limits the size that trees and snags are able to attain. The shortest for pines on SRS is 50 years, and many stands are on 100- or 120-year rotations. Assuming snags are not removed, nearly all pine stands on SRS can potentially produce enough trees and snags of sufficient size to support all cavity-nesting species. Large cavity nesters such as red-headed, red-bellied, and pileated woodpeckers are common in mature pine forests of SRS (Droge et al. 1993; Lohr 1999). In contrast to pines, most hardwood forests at SRS receive little direct forest management (but see chapter 3); many are reserved from management in set-aside areas (Davis and Janecek 1997; chapter 1). However, as site type has a greater effect on the composition of the overstory (as well as the under and midstories) than in pine forests, there is considerable variation in the avian communities of these forests. The primary site factor affecting the bird communities of hardwood forests is slope position: upland or bottomland. As in pine stands with poorly developed understories, canopy-nesting species generally dominate the avian communities of upland hardwood forests (table 4.23). These forests lack the dense understory preferred by most shrub-nesting birds; northern cardinal is the only true shrub-nesting species common in these forests. There seems to be little difference between the avian communities of mesic and xeric upland sites; however, two species characteristic of mesic deciduous forests throughout their range, the ovenbird and the black-and-white warbler, seem to occur more frequently in xeric scrub oak forests of SRS

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Figure 4.23. Abundance of strong- and weak-excavating cavity-nesting birds and total bird species richness on 9.3-ha (23-ac) experimental plots with all coarse woody debris removed (snags and logs) and with none removed (controls) on the Savannah River Site, 1997–1999 (Lohr et al. 2002). Strong excavators included woodpeckers, and weak excavators included great crested flycatcher, eastern bluebird, brown-headed nuthatch, tufted titmouse, and Carolina chickadee.

(pers. obs.). The reason is unclear, though it is likely related to differences in the forest floor between site types, as both species are ground nesters. On bottomland sites, the most important factor affecting bird occurrence is flooding regime. Infrequent and shallow flooding, characteristic of most stream and some Savannah River bottomland sites on SRS, results in forests dominated either by oaks and sweetgum or by red maple, swamp gum, and yellow poplar. Both types support a similar suite of species (see table 4.23, bottomland hardwood). The avian community of most SRS bottomland hardwoods is more diverse in ground, understory, midstory, and canopy-nesting species than any other habitat on SRS, as each of these layers generally is well developed. Kilgo et al. (1998) recorded fifty-six species in twenty bottomland forests in or near SRS. The understory of these forests is denser than that of upland hardwoods and is often dominated by switchcane, an important nesting substrate for species such as hooded, Kentucky, and Swainson’s warblers and northern cardinals. Some species such as Acadian flycatcher, yellow-throated vireo, and American redstart, all midstory or canopy nesters, seem to prefer these moister forests over dryer upland sites, whereas others, such as prothonotary warbler and Louisiana waterthrush nest exclusively near water. Bald cypress and water tupelo generally dominate bottomland sites that experience deeper and more prolonged flooding, which occurs

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throughout much of the Savannah River swamp. Deep flooding reduces the understory, so species that nest on drier bottomland sites do not occur as frequently in cypress-tupelo swamps. Instead, as in other habitats lacking a dense understory, canopy-nesting species dominate the avian community. The white-breasted nuthatch and yellow-throated warbler, two canopy nesters that are uncommon at SRS, reach their greatest abundance in cypress-tupelo swamps. In addition, several species of wading birds may use cypress-tupelo swamps for nesting or foraging. These include anhinga, cattle egret, green heron, great blue heron, great egret, little blue heron, white ibis, and wood stork (Mycteria americana). Foraging, the greater use of SRS swamps by these species, occurs after breeding. However, three wading-bird breeding colonies exist in the Savannah River swamp at Beaver Dam Creek (1990–present), at the Pen Branch delta (1989–present), and west of the Steel Creek delta (1989–present). These three colonies, typically thirty to sixty nests each, are mixed heronries of great blue herons, great egrets, and anhingas. Great blue herons (twenty-five to fifty nests) also nested in the Fourmile Branch delta from 1983 to 1989. Nesting there may have ceased in response to the hydrologic and vegetative changes following the shutdown of C Reactor in the mid-1980s; water no longer surrounded nest trees because of reduced stream flows. Generally, there appears to be a gradual increase in numbers of nesting wading birds on the SRS, although this possible trend is clouded by inconsistent monitoring efforts. The high variability of such habitats complicates discussion of avian use of nonriparian wetland habitat at SRS. The vegetation of Carolina bays, for example, may be forested, herbaceous, shrubby, or any combination thereof, and the hydroperiod ranges from a few days to permanently. Thus, the opportunities that Carolina bay habitat affords to birds depends on the specific bay. Generally, regularly flooded forested bays (cypress-tupelo), if large enough, may support an avian community similar to that of cypress-tupelo riparian wetlands, whereas herbaceous bays may support an avian community similar to that of early-successional swamp forests (e.g., the Pen Branch delta; see below). Wading birds may use reservoirs, Carolina bays, and depression wetlands for foraging and occasionally for breeding. Breeding colonies of great blue herons and/or anhingas, containing two to ten nests, have been observed in Peat Bay, Eagle Bay, Dunbarton Bay, and a beaver pond near Upper Three Runs. Green herons, approximately twenty pairs, currently nest in ponds associated with the D Area ash basins and have nested historically on the

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periphery of Par Pond and an island in Pond B. Great blue herons and great egrets frequently forage on the periphery of the major reservoirs. The lawns, shrubbery, parking lots, and buildings of SRS facilities provide nesting, roosting, or foraging habitat for many species, several of which occur nowhere elsewhere at SRS. Urban birds such as rock dove, house finch, and house sparrow are locally abundant in these areas. Many other species with limited habitat availability elsewhere on SRS, such as black vultures, barn owls, and purple martins, use these areas as well. Mayer and Wike (1997) list urban birds at SRS.

Successional Patterns Most early-successional habitat at SRS is in regenerating pine stands. In pine forests, avian diversity and abundance are greatest in young plantations (before canopy closure) and mature forests and lowest in midrotation plantations (Dickson and Segelquist 1979; Meyers and Johnson 1978; Johnson and Landers 1982). The first peak in bird diversity and abundance occurs in young plantations around age three to six. Shrubscrub species dominate the avifauna of such sites at SRS (table 4.23, 4-year pine plantation) until canopy closure (Krementz and Christie 1999). Many forest-nesting species also heavily use young plantations for foraging and cover, bringing in recently fledged broods from the adjacent stands where they nested (Krementz and Christie 1999). Including these forest species, the avian communities of young plantations are among the most diverse of any habitat on SRS, second only to bottomland hardwood forests. J. Dunning et al. (Purdue University, unpublished data) recorded fifty-four species during the breeding season in two- to sevenyear-old pine regeneration stands at SRS. In contrast, from the time the understory begins to diminish from canopy shading (usually around six or seven years in loblolly stands and eight or ten years in longleaf stands) until the canopy thins and the understory begins to redevelop (age twenty-five to forty or later, depending on site conditions and management actions), bird abundance and species richness of SRS pine plantations are extremely low. A few forest species invade, but most shrub-scrub species abandon closed-canopy plantations and do not return until much later in the rotation (see above discussion of mid- and late-rotation pine forests). As in older stands, structural features of early-successional pine habitat that attract birds include understory development and residual snags and coarse woody debris. Site-preparation technique and manipulation of tree density affect these habitat components. Several workers (O’Connell

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1993; Sparling 1996; Branch 1998, reviewed by Kilgo, Miller, and Moore 2000) have investigated the effects of site-preparation methods on birds in pine plantations at SRS. Although the overall composition of avian communities is similar, bird abundance and diversity are greater on chemically treated sites than mechanically treated sites (O’Connell 1993). Where snags and other coarse woody debris are piled into windrows on mechanically prepared sites, cavity-nesting species such as eastern bluebird are less abundant. However, species that use these slash piles and windrows for nesting or cover, such as Carolina wren and yellow-breasted chat, are more abundant on mechanically prepared sites (O’Connell 1993). Bird use apparently does not differ among sites prepared with either of three common herbicides—imazapyr, hexazinone, or a picloram + triclopyr mixture (Sparling 1996; Branch 1998). Tree density in young plantations affects understory structure through its effects on timing of canopy closure; the fewer the trees, the longer it takes for the canopy to close and the longer the period of high habitat quality will persist. When longleaf stands were experimentally thinned at age eight to ten and competing hardwoods were controlled with herbicide and fire, some shrub-scrub species (e.g., prairie warbler, blue grosbeak, Bachman’s sparrow) persisted as late as eleven to fourteen years after planting ( Johannsen 1998). Loggerhead shrikes occurred in eightto ten-year-old stands similarly treated, whereas they normally are restricted to one- to three-year-old stands ( J. Dunning, unpublished data). Presumably, the same pattern occurs in stands planted at lower densities or where the trees suffer high mortality. Less is known of successional patterns in avian communities of bottomland forests on SRS. Apparently, few old fields existed on bottomland sites at the time of acquisition, and little forest management has occurred on them since, so there has been less opportunity to observe earlysuccessional bottomland communities. Buffington et al. (1997) studied the avifauna of SRS sites recovering from deforestation caused by the increased temperature and flow associated with reactor discharge (figure 4.24). Total bird abundance was greater in the early-successional bird community of the Pen Branch floodplain (two to three years recovery time) than in that of the mid-successional Steel Creek (twenty-seven to twenty-eight years recovery time) and late-successional Tinker Creek (more than sixty years since last timber harvest). However, species richness and diversity were greatest in Tinker Creek and lowest in Pen Branch, which was dominated by a few common species (red-winged blackbird, common yellowthroat, white-eyed vireo, and indigo bunting

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Figure 4.24. Abundance, species richness, and diversity (Shannon-Weaver index) of birds on 50-m (164-ft) radius plots in three successional stages of bottomland hardwood forest on the Savannah River Site, 1995–1996 (Buffington et al. 1997).

equaled 70 percent of the birds detected). In small patches (0.1–0.5 ha, or 0.3–1.25 ac) of early-successional bottomland habitat created by group selection timber harvest, according to Moorman and Guynn (2001), the same species, with the exception of red-winged blackbird, dominated two to four years post-harvest. However, they also noted use of these habitats by foraging family groups of forest-edge species such as northern parula and hooded warbler during mid to late summer. Other early-successional habitats at SRS include road, railroad, and utility rights-of-way and old fields. Old fields, which dominated the SRS landscape during the 1950s and 1960s, were the focus of intensive study on old-field succession by Odum (1960) and other Savannah River Ecology Lab (SREL) researchers. Savannah sparrows, common during winter, were studied intensively (Norris and Hight 1957; Odum and Hight 1957; Norris 1960). However, by 1990 only 640 ha (1,581 ac) of old-field habitat remained at SRS (Workman and McLeod 1990). Rights-of-way are extensive at SRS, amounting to approximately 2,671 ha (6,600 ac), and may provide habitat similar to old fields, depending on vegetation control schedules. Although area-sensitive grassland species, such as Savannah and vesper sparrows, do not winter at SRS in the numbers seen during the 1950s and 1960s, these species do winter in rights-of-way and roadside corridors at SRS. During winter, the Henslow’s sparrow, a sensitive species on SRS (see chapter 5), prefers utility rights-of-way, and Bach-

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man’s and grasshopper sparrows also use those habitats frequently (P. Champlin, U.S. Forest Service, and J. Kilgo, unpublished data). The breeding bird communities of old fields and rights-of-way are similar to those found during the first one to two years following planting in pine regeneration stands, when grasses and forbs still primarily dominate.

Seasonal Habitat Shifts Although patterns of breeding-season habitat use generally persist throughout the year, many species relax their habitat preferences outside of the breeding season and use a greater diversity of habitats. For some species, such habitat shifts may be dramatic. During late summer and fall migration, many migrant species that use only mature bottomland hardwood forest during the breeding season move into the dense understory of early-successional bottomland habitat created by selection timber harvest (Kilgo, Miller, and Smith 1999). Lohr (1999) reported that redheaded woodpeckers were absent during the winter from pine forests in which they regularly bred, but Christmas Bird Count data indicate that they are common during the winter in bottomland hardwood forests on SRS. During the winter, foraging flocks of forest birds may use habitats that individual species in the flock (e.g., chickadees, titmice, woodpeckers) would not use during the breeding season. We need much more information on habitat-use patterns of birds outside of the breeding season.

Landscape Structure Landscape structure and composition can have dramatic influences on bird communities. Although much of the landscape of the upper coastal plain surrounding the SRS is highly fragmented, the SRS landscape is nearly continuous forest (see chapter 1). Clear-cut timber harvests constitute a potential fragmenting effect, but those disturbances are temporary, and intensive research on SRS has documented few of the negative effects of forest fragmentation (e.g., increased nest depredation and brood parasitism). Brown-headed cowbirds do occur commonly throughout the SRS during the breeding season, and Moorman, Guynn, and Kilgo (2002) determined that parasitism of hooded warbler nests by brown-headed cowbirds did increase the closer a nest was to a habitat edge. However, the rate of brood parasitism was so low that it did not affect overall nesting success. Other studies have documented similarly low rates of brood parasitism on SRS (Sargent et al. 1998; Moorman 1999;

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Figure 4.25. Probabilities of occurrence of four area-sensitive birds in bottomland hardwood forests of various widths on the Savannah River Site, 1993–1995 (Kilgo et al. 1998).

Stober and Krementz 2000, reviewed by Kilgo and Moorman 2003), and these rates are far below those reported for other regions of the country. Presumably, this trend results from the lower abundance of brownheaded cowbirds on SRS than in the surrounding landscape (Kilgo, Franzreb et al. 2000), which itself apparently is due to the general unsuitability of the forested SRS landscape as foraging habitat for cowbirds. The landscape structure of SRS has resulted in a greater diversity of forest birds that breed on SRS than in the adjacent fragmented landscape of the upper coastal plain of Georgia and South Carolina but a lower diversity of field or open-habitat birds (Kilgo, Franzreb et al. 2000). Seventeen species were more abundant on SRS than off. Of these, nearly all were forest-interior species that prefer mature pine or bottomland hardwood forest. Thirty-two species were less abundant on SRS than off. These primarily included urban-suburban species and those characteristic of open fields. The number of species in a given stand is positively related to size of the stand. In bottomland hardwood forests on SRS, the number of species increases as the width of the riparian zone (a correlate of stand size) increases (Kilgo et al. 1998). Area-sensitive species—those that occur only in large stands—include Swainson’s warbler, prothonotary warbler, northern parula, barred owl, and Mississippi kite (figure 4.25; Kilgo et

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Figure 4.26. Number of shrub-successional bird species (closed circles) and total number of bird species (open circles) in clear-cuts of various sizes on the Savannah River Site, 1995–1996 (Krementz and Christie 2000).

al. 1998). Similarly, species richness is positively associated with stand size in SRS upland hardwood forests (Kilgo et al. 1999) and two- to sevenyear-old longleaf and loblolly stands ( J. Dunning, unpublished data). However, Krementz and Christie (2000) reported the opposite effect in two- to six-year-old longleaf pine stands (figure 4.26). The habitat adjacent may affect the occurrence of some species in a given stand. For example, wood thrushes, red-eyed vireos, and ovenbirds do not occur in small upland hardwood stands surrounded by open habitat but do occur in stands of similar size and habitat surrounded by closedcanopy pine forest (Kilgo et al. 1997). The presence of forested habitat surrounding a woodlot, even if of a different type and age, may increase the functional size of the woodlot and allow certain area-sensitive species to persist there. Isolation of a stand from other stands of similar habitat can affect the ability of some species to occupy a site. Kilgo et al. (1997) reported that the more isolated a stand of upland hardwoods, the lower the abundance of red-eyed vireos. Similarly, Dunning et al. (1995) reported that Bachman’s sparrows were less likely to colonize isolated patches of suitable habitat (pine plantations one to five years old) than to colonize connected patches of habitat. Among unconnected patches, the greater the distance between a patch and a source population, the less likely the sparrows were to colonize the patch (figure 4.27). Therefore, Bachman’s sparrows are absent from some areas of seemingly suitable, but isolated,

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Figure 4.27. Densities of Bachman’s sparrows in clear-cuts isolated by various distances from areas with source populations on the Savannah River Site in 1992 (reprinted by permission from Dunning et al. 1995, © 1995 Blackwell Publishing Ltd.).

habitat (Dunning and Watts 1990). Liu, Dunning, and Pulliam (1995) provided a model of the long-term impact of timber management on Bachman’s sparrow populations by tracking their ability to use the temporally ephemeral and spatially scattered clear-cut habitat over a fiftyyear time frame.

Historical Trends and the Effect of SRS Establishment Bird censusing techniques have changed markedly over the fifty-year history of the SRS, making assessment of historical trends in bird abundance highly problematic. Fortunately, however, the SRS is one of the few sites with at least some form of long-term bird population data. The early surveys by Odum and Norris provide a rough baseline to compare species occurrence, if not abundance, over time. Three species that neither Odum (1952–1953) nor Norris (1957, 1963) reported as breeding on SRS, American redstart, black-and-white warbler, and ovenbird, now occur on site regularly during the breeding season, and breeding has been documented for the latter two. All three are forest-interior Neotropical migrants that have expanded their breeding ranges southward in recent years. Odum, Allen, and Pulliam (1993) noted similar southward range expansions in the vicinity of Athens, Georgia, approximately 161 km (100 mi) northwest of SRS. Whether these range expansions represent recolonization of once occupied habitat or new expansions is unclear. Nev-

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ertheless, habitat conditions during the 1950s likely were not as suitable because of the highly fragmented nature of the landscape at the time, whereas present habitat conditions seem favorable. American redstart and ovenbird still do not breed or are extremely rare breeders in the landscape surrounding the SRS (Kilgo, Franzreb et al. 2000). Conversely, once common species of open fields, particularly wintering birds such as Savannah and Henslow’s sparrows, are rare or uncommon; Norris (1963) considered Savannah sparrows to be the most common species inhabiting old fields, a habitat nearly gone from SRS. Although the counties surrounding the SRS underwent considerable reforestation during the latter half of the twentieth century, the landscape still has a significant agricultural component (Tansey and Hutchins 1988). This landscape may approximate habitat conditions available for birds on the SRS in 1950 better than its current reforested landscape. Thus, the abundance of forest birds and the rarity of open-field and suburban birds on the SRS relative to the surrounding counties (Kilgo, Franzreb et al. 2000) are likely representative of the changes in the SRS avifauna over the past fifty years. McCallum, Leatherman, and Mayer (2000) identified raptors, aerial foragers, and nocturnal birds as groups that have “fallen between the cracks” in research and monitoring, and we know little of their ecology on the SRS. The habitat associations of these species, some of which are common, appear in table 4.22, at the end of this section. However, some species in these groups are either uncommon or are the subject of regional concern (e.g., American kestrel: Beheler and Dunning 1998; chapter 5), so monitoring of these groups on site is warranted. Christmas Bird Count data (available at www.audubon.org/bird/cbc/ index.html) indicate that king, Virginia, and sora rails occur regularly in the Pen Branch delta during winter. King rails reportedly nested in Craig’s Pond and possibly other Carolina bays in 1956 (Norris 1963), but no recent breeding records exist, perhaps due to a lack of survey effort. Norris (1963) reported only a few records of Mississippi kites during the 1950s. The species currently is common during the breeding season along the Savannah River and in late summer across the SRS. Swallow-tailed kites, listed as endangered by the state of South Carolina, apparently did not occur on SRS during the 1950s (Norris 1963). They are now observed regularly during the breeding season, and one nest has been documented on SRS. More work is needed to determine the status of many species on SRS (McCallum, Leatherman, and Mayer 2000).

This matrix presents predictions of the suitability of four successional stages of seven vegetation types as habitat for birds that use the SRS during the breeding season and the winter. The matrix, condensed and adapted from Hamel (1992), includes just those habitats that occur at SRS. However, this matrix differs somewhat from Hamel’s. Predictions for some species, as footnoted, reflect our perceptions of SRS-specific habitat-use patterns. Where known, we include information on the validity of the predictions (see below). Finally, we have added information on the migratory status of each species. After species, the first column of the matrix, labeled “Migrant,” contains a code for the migratory status of each species. “R” represents resident, “T” represents Neotropical migrant, and “A” represents Nearctic migrant. See the text for definitions of these classifications. The matrix does not include species that migrate through the SRS annually during the spring and fall, as no adequate information is available on the habitatuse patterns of migrating birds. Mayer et al. (1997) present information on the status of these species on SRS. The column labeled “Season” indicates whether the species is present at SRS during the breeding season (“B”), defined as May–August; during the winter (“W”), defined as November–March; or both (indicated when information is given in both rows). Generally, species with predictions during the breeding season nest at SRS but not always. For example, only three species of wading birds nest on SRS, but several more use the site during the breeding season for foraging and so have habitat predictions for the breeding season. The remaining columns represent habitats and particular successional stages. The vegetation types considered here, as defined by Hamel (1992), are longleaf pine–slash pine (LLSL), loblolly pine–shortleaf pine (LBSH), mixed pine-hardwood (MPHW), oak-hickory (OKHK), southern scrub oak (SOSO), oak-gum-cypress (OGCY), and bay swamp–pocosin (BSPO). LLSL includes longleaf and slash pine forests and is equivalent to USFS types 21 (longleaf pine) and 22 (slash pine). LBSH includes loblolly pine forest (shortleaf pine is rarely dominant at SRS) and is equivalent to USFS type 31 (loblolly pine). MPHW includes forests in which hardwoods (usually oaks) and pines (usually loblolly) each constitute at least 25 percent of the stocking. MPHW is equivalent to USFS types 13 (loblolly pine–hardwood), 44 (southern red oak–yellow pine), and 46 (bottomland hardwood–yellow pine). OKHK includes forests in which “a plurality of the stocking comprises upland oaks and hickories, singly or in combination, and where pines make up less than 25% of the stocking” (Hamel 1992). It is equivalent to USFS type 53 (white oak–red oak–hickory). SOSO includes forests of sandy, upland topography in which various species of scrub oaks make up at least 75 percent of the stocking. It is equivalent to USFS type 57 (scrub oak). OGCY includes bottomland forests in which water tupelo, black gum, sweetgum, oaks, or cypress dominate the canopy. It is

Table 4.22 Bird habitat matrix for the Savannah River Site

Double-crested cormorant Phalacrocorax auratus Anhingaa Anhinga anhinga Great blue heron Ardea herodias

Species

are footnoted.

R

R

A

W B W B W

B

Migrant Season

1 2 3 4

LLSL 1 2 3 4

LBSH 1 2 3 4

MPHW

1 2 3 4

OKHK

1 2 3 4

SOSO

O M M M M

M M M O

M O

1 2 3 4

OGCY

Habitat suitability by vegetation type and successional stage

(continued)

M M S

1 2 3 4

BSPO

equivalent to USFS types 61 (swamp chestnut oak–cherrybark oak), 62 (sweetgum–Nuttall oak–willow), 64 (laurel oak–willow oak), and 67 (bald cypress–water tupelo). BSPO includes forests of boggy, poorly drained soils in which various species of broadleaf “bay” trees dominate the canopy. Primary species are swamp tupelo, red maple, red bay, and sweet bay. BSPO is equivalent to USFS type 68 (sweet bay–swamp tupelo–red maple). Under each vegetation type are listed four successional stages: 1 (grass/forb), 2 (shrub/seedling), 3 (sapling/poletimber), and 4 (sawtimber). The suitability ratings given in the body of the matrix are marginal (“M”), suitable (“S”), and optimal (“O”). Blank cells indicate unsuitable habitats. According to Hamel (1992, 12), “Optimal habitats are those in which the species occurs in highest frequency, greatest numbers, or both. Similarly, suitable and marginal habitats are those in which the species occurs in successively lower numbers and frequency.” These designations imply nothing about relative productivity in various habitats. Kilgo et al. (2002) tested the ability of Hamel’s matrix to predict presence or absence by considering predictions of “S” or “O” as habitats in which a species should be present and predictions of “M” or absent (i.e., blank cells) as habitats in which a species should be absent. Those species for which presence or absence was predicted well, when compared to actual field data,

Ardea albus Snowy egreta Egretta thula Little blue herona Egretta caerulea Tricolored herona Egretta tricolor Cattle egret Bubulcus ibis Green heron Butorides striatus Black-crowned night herona Nycticorax nycticorax Yellow-crowned night herona Nycticorax violacea White ibisa Eudocimus albus

Great egreta

Species

Table 4.22 (continued)

S S O O

1 2 3 4

A

R

A

A

A

A

W B W

M S O S

M O O S

S S O S

S S S S

S S O S

S S O S

M O O

1 2 3 4

OGCY

W B

1 2 3 4

SOSO

A

1 2 3 4

OKHK

S S S S

1 2 3 4

MPHW

A

1 2 3 4

LBSH

B W B W B W B W B W B W B

A

Migrant Season

LLSL

Habitat suitability by vegetation type and successional stage

M S S

M S S

M S M

S S M

M S M

M S M

M S M

M S M

M S S

1 2 3 4

BSPO

Ictinia mississippiensis Northern harrier Circus cyaneus Sharp-shinned hawka Accipiter striatus Cooper’s hawk Accipiter cooperii Red-shouldered hawk Buteo lineatus Broad-winged hawka Buteo platypterus Red-tailed hawk Buteo jamaicensis American kestrel Falco sparverius King rail Rallus elegans

Black vulture Coragyps atratus Turkey vulture Cathartes aura Osprey Pandion haliaetus Swallow-tailed kite Elanoides forficatus Mississippi kiteb

R

R

R

T

R

A

A

A

T

T

A

R

R

B W B W B W B W B W B W B W B W B W

B W B W B W B W M

M M S S M

M M

M M S S

M M M M M M M M M

M M M M M M M M

M

M M M M M M

M

S M S M M

S S M M S S

S M S M M

M S M M S S O M

M

M M M M M M

M

M

O S O S

O O M O O O

O S O S

O S M S O S O M

S

M M M M M M

S M O M

O

M M M O M M

S M O M

O S M S O S O M

S

M M M M M M

S M S

O O O O

M M M M S M

M

S M S S M S

M M M M

O O O O M M

M M

M

M M M M M M S

S

M M M M

M M M O O

O

O O O O O O O

O O S S M M

S M S O O M

M

O O S S S S M

(continued)

M M

M M M M M

S M S M S M S

M

S M S M M M

Virginia rail Rallus limicola Sora Porzana carolina Common moorhen Gallinula chloropus Killdeer Charadrius vociferus Rock dove Columba livia Common ground-dove Columba passerina Yellow-billed cuckoob,c Coccyzus americanus Eastern screech-owl Otus asio Great horned owl Bubo virginianus Barred owl Strix varia Common nighthawk Chordeiles minor

Species

Table 4.22 (continued)

T

R

R

R

T

R

R

R

R

A

A

B W B W B W B W B W B W B W B W B W B W B W

Migrant Season

M S M S S M S

M M M M

M M

1 2 3 4

LLSL

M M M M O M S M

M O M O O M O

1 2 3 4

LBSH

M M M

M M

M O M O O M O

M S

1 2 3 4

MPHW

M M

M

M O M O S M S M M

S S

1 2 3 4

OKHK

S O S

M M

O S O O S M

M M

1 2 3 4

SOSO

M S M S M M M S O S O

O O

M M M M M M M M M M M

M

1 2 3 4

OGCY

Habitat suitability by vegetation type and successional stage

M S M S M M M S S

O O

1 2 3 4

BSPO

Chuck-will’s-widowb Caprimulgus carolinensis Whip-poor-will Caprimulgus vociferus Chimney swift Chaetura pelagica Ruby-throated hummingbirda Archilochus colubris Belted kingfisher Ceryle alcyon Red-headed woodpeckerb Melanerpes erythrocephalus Red-bellied woodpeckerb Melanerpes carolinus Yellow-bellied sapsucker Sphyrapicus varius Downy woodpeckerb,c Picoides pubescens Hairy woodpeckerb Picoides villosus Northern flickerb Colaptes auratus Pileated woodpeckerb,c Dryocopus pileatus

R

R

R

R

A

R

R

R

T

T

T

T

B

B W B W B W B W B W B W

W B W B W

W B W B W B

S

M

M M M M M M M M M

M M M M M S S S M

M S M S

M O M S

M M

M M S S M M M M M M S M S

S S S M M S S S S

M S M S S

M S M M

S S

S O

S S S S M M M S M M S M S

O O O S S O S S S

S O M S S

M S M M

M M M

S O S S S O

O O O O O S S O S O

S S S S M S S M S S S

S O S S O

M M M M M M

M S S

M

S S

M S

S S S S S S S S S S

M M S

M M

S S

M S M S O M S O M O M O S S M S S M O M O

M O M O

S O

M S M S

M S S

M

M S S S S M S S S (continued)

M

M M M M M M S

M O M O

M S

S S S

M M

M S

B W B W B W B W B W B W B W B W B W B W

T

R

R

R

T

T

A

T

T

R

B W

T

Migrant Season

Empidonax virescens Eastern phoebe Sayornis phoebe Great crested flycatchera,b Myiarchus crinitus Eastern kingbirdb Tyrannus tyrannus Horned larka Eremophila alpestris Purple martin Progne subis Barn swallow Hirundo rustica Blue jay Cyanocitta cristata American crow Corvus brachyrhynchos Fish crow Corvus ossifragus

Eastern wood-peweec Contopus virens Acadian flycatcherb,c

Species

Table 4.22 (continued)

M M M M S M M M M M M

M

M

S

S S M M M M

M

M M M M M O

M O

1 2 3 4

LLSL

M M M M S M M M S M M

M

M M

S

S S O O O S

S S S M M M S

M M O

1 2 3 4

LBSH

M M S S S M S M S M M

M

M M

M

O O O O S S

S S S M M S O

M M

M O

1 2 3 4

MPHW

M M S M S M M

M

M M

M

O O S M

M M S O S M M M S

M M

M O

1 2 3 4

OKHK

S M S M S M M M S M M S

M

M

M M M M

M

M

1 2 3 4

SOSO

M M M M S M M M S M M

M

M M

S S M M M M

M M S O S S M S S

O O

M M M

1 2 3 4

OGCY

Habitat suitability by vegetation type and successional stage

M M M M S M M M S S M S

M

M

M M M M S S

S S S M M S

M S

M O

1 2 3 4

BSPO

Carolina chickadeeb Poecile carolinensis Tufted titmouseb,c Baeolophus bicolor Red-breasted nuthatch Sitta canadensis White-breasted nuthatch Sitta carolinensis Brown-headed nuthatchc Sitta pusilla Brown creeper Certhia americana Carolina wrenb,c Thryothorus ludovicianus House wren Troglodytes aedon Winter wren Troglodytes troglodytes Golden-crowned kinglet Regulus satrapa Ruby-crowned kinglet Regulus calendula Blue-gray gnatcatcherc Polioptila caerulea Eastern bluebirdc Sialia sialis

R

A

A

A

A

A

R

A

R

R

A

R

R

B W B W B W B W B W B W B W B W B W B W B W B W B W M M O O

S

S S S M

S M S S S S S S

S S S M M

M S S

M S S S

S S M S S M S S

M S M M S M S

M M S M M S M M M O M M O O

M S

M S S M M M S M S S

S O O

M O O

M M

S O M S S M S S

M O M M S M S

S S S S S O M S M S S O M M M M

S S

S O M M O M M M M M

O S O M M

M O O

M M

S O S O O S O O

M S M M M M

S S O S S O S O M S O

M M

S S

M M M M M M M

S S S M S

M M

S S S O O S O O

M O M O

M M S M S S S S O M S O

M S M M S S M S S M S

M O S

M S O S O

S S S S M S

S S O O

M S

O O

M S O M O M M M M

M M

S S M O O M O O

M S M S

M M S M M S S M S

S S S S

M M

O O

(continued)

S S S M O M O O

M S

M M S O O S O O

M M M M

M M S M M S M M M

Hylocichla mustelina American robin Turdus migratorius Gray catbirdb Dumatella carolinensis Northern mockingbirdb Mimus polyglottos Brown thrasherb Toxostoma rufum Cedar waxwing Bombycilla cedrorum Loggerhead shrike Lanius ludovicianus European starling Sturnus vulgaris White-eyed vireob,c Vireo griseus Blue-headed vireob Vireo solitarius

Hermit thrush Catharus guttatus Wood thrushb,c

Species

Table 4.22 (continued)

B W B W B W B W B W B W B W B W B W B W

T

A

A

R

R

A

R

R

R

R

B W

A

Migrant Season

S

M S

M S S M S S M M S M M

M M

1 2 3 4

LLSL

M M

M M S O

M M M S

S S M S M S S M M S M M

M M M

M M

S S

1 2 3 4

LBSH

S S S S

M M M M M M

M M S O

M M M M M M M M S

M M M

M M S S M M M M O O

M S

O O

1 2 3 4

MPHW

M

M M

M M M M M M M M S

S S M S

M M M M

O S M M S

M M M S M M M M O S O

S O

S S

1 2 3 4

OKHK

S S

S

S M O S

M M

O S S O S

M M

M M

S

M

1 2 3 4

SOSO

M M

M S S S S O S M M

M M M

S S S S

M M S O M M S S M

M O

S S

1 2 3 4

OGCY

Habitat suitability by vegetation type and successional stage

S O

M S S O S O O S M

M O O

S M M M M M

S O O M M O O S

M S

O O

1 2 3 4

BSPO

Yellow-throated vireob,c Vireo flavifrons Red-eyed vireoc Vireo olivaceous Orange-crowned warbler Vermivora celata Northern parulaa,b,c Parula americana Yellow-rumped warbler Dendroica coronata Yellow-throated warblera,c Dendroica dominica Pine warblerb,c Dendroica pinus Prairie warblera,b Dendroica discolor Palm warbler Dendroica palmarum Black-and-white warbler Mniotilta varia American redstarta,b,c Setophaga ruticilla Prothonotary warblerc Protonotaria citrea Swainson’s warblerc Limnothlypis swainsonii Ovenbirdb Seiurus aurocapillus

T

T

T

T

T

A

T

R

T

A

T

A

T

T

B

W B W B W B W B W B W B W B W B W B W B W B W B W B W

M M M

S S O S S S O O S

M M M M M

M M

S O M

M M S O M S S O O S

M S S M S

M

M M

S O

M S M M S M S

M M S S M S S S S

S O O M S

M M M M M S

M S

S

S O

M M M S O M M

M

M M M M M

S

S O

O

S O M S M

M M M M

S S

M S M S

M S

S O

S O

S S S O O S

S O O M O

M S S S S O M M

M O

O

(continued)

M S

S O

M S

M S M M M S O O S

O O O M S

M O S M S

M S

M

B W B W B W B W B W B W B W B W B W B W B W

T

R

R

T

T

T

R

T

T

T

A

B W

T

Migrant Season

Oporornis formosus Common yellowthroatb,c Geothlypis trichas Hooded warblerb,c Wilsonia citrina Yellow-breasted chata,b,c Icteria virens Summer tanagerb Piranga rubra Northern cardinalb,c Cardinalis cardinalis Blue grosbeakb Guiraca caerulea Indigo buntinga,b,c Passerina cyanea Painted buntingb Passerina ciris Eastern towheeb,c Pipilo erythrophthalmus Bachman’s sparrowb,c Aimophila aestivalis

Louisiana Seiurus motacilla Kentucky warblerb,c

waterthrushb,c

Species

Table 4.22 (continued)

M S

O O O S O S

O O M M

S S O O

S M S

S S S M S S S S

S

M S M M M M

1 2 3 4

LLSL

S S S O S M

S

M O

S S M M

S S S S

M

S S S S S S S M S

M S

M O M

S M M M

1 2 3 4

LBSH

S O

M S

O O S O O S M S M M

M S M M

S S O S O O O M S

M S

S S M M

M

M

1 2 3 4

MPHW

S O

O S S O M M

M S M M

O O S S S S S M M

M S

S S M M

1 2 3 4

OKHK

S

O O O O

M M

S S S S M

M M S

1 2 3 4

SOSO

M S

S M M S M M

S

M S M S

M S S S M S S S M M

S

S O M S M M S O

S O

M O

1 2 3 4

OGCY

Habitat suitability by vegetation type and successional stage

M M

S O

S S M S S M

S M M

M S S S M S S S M

M O S O

S S

M O

1 2 3 4

BSPO

Chipping sparrowb,c Spizella passerina Field sparrowc Spizella pusilla Vesper sparrow Pooecetes gramineus Savannah sparrow Passerculus sandwichensis Grasshopper sparrow Ammodramus savannarum Henslow’s sparrow Ammodramus henslowii Fox sparrow Passerella iliaca Song sparrow Melospiza melodia Swamp sparrowb Melospiza georgiana White-throated sparrow Zonotrichia albicollis Dark-eyed junco Junco hyemalis Red-winged blackbird Agelaius phoeniceus Eastern meadowlarkb Sturnella magna

R

R

A

A

A

A

A

A

A

A

A

R

R

M M S S M M S M M M

M M M M

M

M M M M

M M

M

S M

M

M S

M M M M S S S

B

W B W B W B W B W B W B W B W B W B W B W B W B W M S O

M S S O S M O M O M

M M M M

S M

M

M

M M S M M S O S

S M

S

S

M S S O

M M S M M M O S

M S S O S M O M O M

M M S S

M

M S O M S M

M M

S

S

M M S O

M M

M M M

M M S S M M M M M M S M O M O M

S M

M

S

S

O O S

M

M M M M

M M M

M

M

M

S M

S M M

O O O O S M M M

M M S O

S O

M M

M M M M

M

S

M S O

(continued)

M M M M O O M O O S M

M S S O

S O

S M

O

M

M

B W B W B W B W B W B W B W B W B W B W B W M M

M M M M

M M M

M M

M O M S M M M M M S M

M M

1 2 3 4

LLSL

M M

S O

M S S O M M O S S S

M

S M S M M

M S

S M M O M M M M S M

M

1 2 3 4

LBSH

M M

M O

M S S O M M O S S S

M M

b Hamel’s

S M M M

S O

S M M M M M M M

M

M M

1 2 3 4

MPHW

M M

M M

M M M M S S S S S

M S M M

M S

M M M M M M M M M M M M

M

M M

1 2 3 4

OKHK

M M

M M M

M M M M M M M M

1 2 3 4

SOSO

M M S S

S S S

M S

S M M S S M M M O M M M M

M M S O

1 2 3 4

OGCY

Habitat suitability by vegetation type and successional stage

(1992) matrix modified to reflect SRS-specific seasonal occurrence. (1992) matrix modified to reflect SRS-specific habitat associations. c Hamel’s (1992) matrix adequately predicted presence/absence (Kilgo et al. 2002).

a Hamel’s

R

A

R

A

R

A

T

R

R

A

A

Migrant Season

Rusty blackbird Euphagus carolinus Brewer’s blackbird Euphalus cyanocephalus Common grackle Quisculus quiscula Brown-headed cowbirdb Molothrus ater Orchard orioleb Icterus spurius Purple finch Carpodacus purpureus House finch Carpodacus mexicanus Pine siskin Carduelis pinus American goldfinchb Carduelis tristis Evening grosbeak Hesperiphona vespertina House sparrow Passer domesticus

Species

Table 4.22 (continued)

M M

M M M M

M M M

M S

M S S M M M O M M S S

M M S O

1 2 3 4

BSPO

Biotic Communities

253

Nongame Mammals Susan C. Loeb, Lynn D. Wike, John J. Mayer, and Brent J. Danielson Fifty-four species of mammals inhabit (or have recently inhabited) the Savannah River Site (SRS; Cothran et al. 1991; table 4.24). Although far fewer in number than other taxa (see the previous five sections of this chapter), the mammals of SRS represent a wide diversity of body sizes, life histories, habitat affinities, and food habits. They range in body size from approximately 5 g (0.2 oz; the least shrew; see table 4.24 for scientific names) to 200 kg (441 lbs; black bear). They feed on herbaceous material, acorns, mushrooms, insects, other invertebrates, and vertebrates. Various mammals on SRS use underground tunnels, semi-aquatic environments, terrestrial habitats, and trees. They also employ a wide variety of locomotory modes, including burrowing, swimming, running, gliding, and flying. Other than the eastern cougar, which has been extirpated regionally, no mammals on the SRS are on the federal list of threatened and endangered species. However, the South Carolina Department of Natural Resources has designated Rafinesque’s big-eared bat as endangered, the southeastern bat as threatened, and the star-nosed mole, hoary bat, northern yellow bat, little brown bat, swamp rabbit, fox squirrel, eastern woodrat, spotted skunk, and black bear as species of special concern (table 4.24). The SRS has been a center of mammal research since its establishment in the early 1950s (Cothran et al. 1991). Extensive studies conducted by Drs. Eugene P. Odum, Frank B. Golley, and Michael H. Smith of the University of Georgia and the Savannah River Ecology Laboratory (SREL), along with their students, have contributed greatly to our knowledge of SRS mammals, as well as to the field of mammalogy generally. Cothran et al. present a cross-indexed bibliography of the 304 references published between the mid-1950s and 1991 on mammals of the SRS, which is an invaluable reference for anyone working on mammals of the southern coastal plain. Because the SRS was primarily in old fields and cleared areas in the 1950s (White and Gaines 2000), much of the initial research focused on early-successional species such as the old-field mouse, cotton rat, and southern short-tailed shrew, as well as their mammalian predators (Cothran et al. 1991). To aid management, extensive work has been conducted on the population dynamics, biology, and genetics of white-tailed deer and wild hog populations. Much of the mammal

Table 4.24 Taxonomic listing and conservation status of the mammals of the Savannah River Site Order

Family

Scientific name

Statusa

Common name

Marsupialia Didelphidae Insectivora Soricidae

Didelphis virginiana Virginia opossum Blarina carolinensis Southern shorttailed shrew Cryptotis parva Least shrew Sorex longirostris Southeastern shrew Talpidae Scalopus aquaticus Eastern mole Condylura cristata Star-nosed mole Chiroptera Vespertilionidae Corynorhinus Rafinesque’s bigrafinesquii eared bat Eptesicus fuscus Big brown bat Lasionycteris Silver-haired bat noctivagans Lasiurus borealis Red bat Lasiurus cinereus Hoary bat Lasiurus intermedius Northern yellow bat Lasiurus seminolus Seminole bat Myotis Southeastern bat austroriparius Myotis lucifugus Little brown bat Nycticeius humeralis Evening bat Pipistrellus subflavus Eastern pipistrelle Tadarida brasiliensis Brazilian freetailed bat Xenarthra Dasypodidae Dasypus Nine-banded novemcinctus armadillo Lagomorpha Leporidae Sylvilagus floridanus Eastern cottontail Sylvilagus aquaticus Swamp rabbit Sylvilagus palustris Marsh rabbit Rodentia Sciuridae Sciurus carolinensis Gray squirrel Sciurus niger Fox squirrel Glaucomys volans Southern flying squirrel Castoridae Castor canadensis Beaver Cricetidae Oryzomys palustris Marsh rice rat Reithrodontomys Eastern harvest humulis mouse Peromyscus Old field mouse polionotus

SC SE

SC SC ST SC

SC

(continued)

Table 4.24 (continued) Order Rodentia

Family Cricetidae

Muridae

Carnivora

Canidae

Felidae

Mustelidae

Procyonidae Ursidae Artiodactyla Cervidae Suidae

Scientific name

Common name

Peromyscus leucopus White-footed mouse Peromyscus Cotton mouse gossypinus Ochrotomys nutalli Golden mouse Sigmodon hispidus Hispid cotton rat Neotoma floridana Eastern wood rat Microtus pinetorum Pine vole Ondatra zibethicus Muskrat Rattus norvegicus Norway or brown rat Rattus rattus Roof or black rat Mus musculus House mouse Canis latrans Coyote Canis familiaris Feral dog Urocyon Gray fox cinereoargenteus Vulpes vulpes Red fox Felis catus Feral cat Felis concolor Cougar Lynx rufus Bobcat Lontra canadensis River otter Mephitis mephitis Striped skunk Spilogale putorius Eastern spotted skunk Mustela vison Mink Mustela frenata Long-tailed weasel Procyon lotor Raccoon Ursus americanus Black bear Odocoileus virginianus White-tailed deer Sus scrofa Wild hog

Statusa

SC

FE

SC

Note: Species in bold type are discussed in this chapter. Others are discussed in other chapters in this volume. Common and scientific names follow Wilson and Reeder (1993). a SC = state species of concern; ST = state threatened; SE = state endangered; FE = federally endangered.

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research on site prior to the late 1980s was conducted by scientists and cooperators of the Savannah River Ecology Laboratory and the University of Georgia. However, since then, there has been greater involvement by researchers from other institutions, such as the U.S. Forest Service Southern Research Station, Westinghouse Savannah River Company, and Clemson University. In addition, as the site has become increasingly forested, recent studies include more forest-dependent species such as southern flying squirrels (e.g., Heiterer 1994; Risch 1999; Brady, Risch, and Dobson 2000) and bats (Carter 1998; Menzel 1998, 2003; Menzel, Menzel, Kilgo, et al. 2003). This section will discuss the distribution and abundance of nongame mammals on the SRS. Sections in chapter 6 cover small game species, furbearers, wild hogs, and white-tailed deer.

Factors Controlling Mammal Distribution and Abundance Many factors affect the distribution of mammals on the landscape and thereby determine community composition. These include season, habitat condition, physical features of habitats, and landscape structure.

Season All of the mammals of the SRS are year-round residents except for some of the bats. Little is known about bats’ seasonal use of the SRS; however, the silver-haired bat and the hoary bat likely use the site in winter or in transit on their migratory routes in spring and fall. In contrast, red bats are very common on SRS during summer (Menzel 1998), but some may migrate south during the winter (Whitaker and Hamilton 1998). Other species that may occupy the site only seasonally include the southeastern bat, the little brown bat, and the evening bat. Season may also influence the distribution of animals among habitats on the SRS. For example, during winter, southern flying squirrels are more abundant in pine stands with a dense midstory, whereas in summer they make greater use of upland pine stands with no hardwoods (Heiterer 1994). Other species such as the eastern harvest mouse, cotton rat, and old-field mouse seasonally select habitats by the amount of cover provided (Briese and Smith 1974; Lidicker et al. 1992).

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Habitat Successional stage and vegetation type are the most important habitat attributes affecting the distribution and abundance of mammals on the SRS. Small-mammal communities in the piedmont and on the coastal plain of the Southeast exhibit a relatively consistent pattern of abundance and composition dependent on successional stage. In general, small mammals are very abundant in the early stages of succession and then decline as the canopy closes and ground vegetation decreases (Kirkland 1977; Atkeson and Johnson 1979; Mengak, Guynn, and Van Lear 1989). However, the number and diversity of small mammals increase again as the forest matures, self-thinning occurs (Harris et al. 1974), and more sunlight reaches the forest floor. The subsequent growth of grasses, herbs, and woody shrubs changes the composition of the small-mammal community in a rather predictable fashion (figure 4.28). Granivores, such as old-field mice and harvest mice, and grazers, such as cotton rats, flourish in the early stages of succession when grasses, forbs, and shrubs dominate the habitat (Atkeson and Johnson 1979; Mengak, Guynn, and Van Lear 1989; Danielson and Anderson 1999). Golden mice, which prefer thick midstories and dense vines, become far more abundant in the middle stages of forest succession (Loeb 1997). As the forest reaches maturity, cotton mice reach their highest density, and arboreal species such as flying squirrels also become very abundant (Loeb 1997; Loeb, Chapman, and Ridley 1999). Thus, although they make up less than 20 percent of the area on SRS, open habitats are important for a number of species that are primarily found there (table 4.25).

Figure 4.28. Number of small mammals captured in longleaf pine stands of various ages on the Savannah River Site, 1990–1992 (Loeb 1997).

Short-tailed shrew Least shrew Southeastern shrew Eastern mole Star-nosed mole Big brown bat Silver-haired bat Red bat Hoary bat Northern yellow bat Seminole bat Southeastern bat Little brown bat Evening bat Eastern pipistrelle Big-eared bat Nine-banded armadillo Southern flying squirrel Marsh rice rat Eastern harvest mouse Old field mouse Cotton mouse Golden mouse Hispid cotton rat Eastern wood rat Pine vole Black rat Norway rat House mouse

Common name

X X

X

X X X X

X X

X X

X X

X X

X

X X

X X

X X

X

X X

X

X X

X X

X X X X X

X

X

X

X X

X

X X

X

X

hardwoods

Bottomland

X

X X

X X X

Upland hardwoods

X

hardwood

Mesic pine-

X

X

X X X X

Upland pine

X X X

X X X X

clear-cuts

Old fields/

Table 4.25 Primary habitats of nongame mammals of the Savannah River Site Aquatic/

X

X

semi-aquatic

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Three types of open habitats occur on the SRS: old fields, clear-cuts, and rights-of-way. Old fields are dominated by perennial grasses and patches of short, semi-woody shrubbery such as blackberry (Rubus spp.). Clear-cuts contain mixtures of annual, biennial, and perennial plants. Utility rights-of-way are frequently mowed, burned, or sprayed for woody vegetation control and contain mixtures of perennial plants and blackberry. Species found primarily in these habitats include the least shrew, southern short-tailed shrew, southeastern shrew, old-field mouse, harvest mouse, cotton rat, eastern mole, and pine vole (table 4.25). However, because the three open habitats differ in amount of woody vegetation; amount of downed, woody debris; and specific vegetation, they may also differ in the relative abundance of small mammal species (e.g., Golley, Gentry et al. 1965). For example, the least shrew and the southern shorttailed shrew are common in old fields, but the southern short-tailed shrew is rarely captured in clear-cuts or rights-of-way (Danielson, pers. obs.). Clear-cuts, the most common open habitat on the SRS, are similar to power line rights-of-way; cotton rats and old-field mice strongly dominate small-mammal communities in both habitats (Anderson 1995; Danielson and Anderson 1999). Blackberry thickets and shrubs provided dense cover ideal for cotton rats (Bowne, Peles, and Barrett 1999; Lidicker et al. 1992). Cotton mice may also be found in early-successional habitats but are most common in older successional stages (Golley, Gentry et al. 1965; Loeb 1997). Open habitats are also important as foraging sites for some species of bats. Big brown bats, evening bats, eastern red bats, and Seminole bats commonly feed over open habitats at SRS (Menzel, Menzel, Kilgo et al. 2003). Menzel et al. detected bat activity at 75 percent of “grass/brush” survey points on SRS, a level exceeded only at wetland survey points (table 4.26). Similarly, Menzel (1998) found higher levels of foraging and feeding activity by bats in open areas within bottomland forest, such as skidder trails and small forest gaps created by a group selection harvest, than in the mature, intact bottomland hardwood forest. Forested habitats make up more than 80 percent of the SRS. Both physiography and land-use history strongly influence their distribution (White and Gaines 2000). Imm and McLeod (see the first section, “Vegetation Types,” in this chapter) use many forest-type classifications to describe the forests of SRS. For this section, we chose to classify forests as upland pine (including longleaf, loblolly, and slash pines; see appendix for scientific names of plants), mesic pine-hardwood, upland hardwood, and bottomland hardwood-swamp forests. In 1997, 70 percent of the forested

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Table 4.26 Levels of foraging bat activity (percent of sampling points with bat activity, all species combined) over nine habitats on the Savannah River Site Habitat Lakes and ponds Carolina bays Grass/brush Forest gaps Bottomland hardwoods Upland hardwoods Longleaf pine Pine/hardwood Slash/loblolly pine

Activity level (%) 88 80 75 71 67 64 59 57 49

Source: Menzel, Menzel, Kilgo et al. 2003.

area was in upland pines, 3.5 percent in mesic pine-hardwood, 3.4 percent in upland hardwood, and 23.2 percent in bottomland hardwood– cypress tupelo forests (White and Gaines 2000). Few nongame mammals are restricted to one forest type. Rice rats occur predominantly in bottomland hardwoods associated with wetlands and swamps (Wolfe 1982), but they also occupy pine stands with a dense understory (Mitchell et al. 1995) or clear-cuts near marshes or swampy areas (Sparling 1996). Star-nosed moles are semi-aquatic and usually live in close proximity to swamps, lakes, and Carolina bays (Petersen and Yates 1980). Occasional captures in upland pine forests on the SRS probably represent dispersal movement (McCay, Komoroski, and Ford 1999). Seminole bats apparently prefer to roost in pine foliage, whereas red bats prefer to roost in the foliage of hardwoods (Menzel et al. 1998). Pipistrelles may also rely on hardwood foliage for roost sites (Carter et al. 1999). Most of the other species associated with forests occupy a wide cross-section of forest types. For example, southern short-tailed shrews, southern flying squirrels, and cotton mice commonly occur in all of the forest types on the SRS (table 4.25) but probably prefer forests containing abundant hardwood mast, particularly during fall and winter (e.g., Heiterer 1994). The eastern woodrat is also a habitat generalist (Wiley 1980; Whitaker and Hamilton 1998), found in both upland and bottomland hardwood forests, open sites, near abandoned structures (Cothran et al. 1991), and in mature longleaf pine stands (Loeb 1999).

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261

Physical Factors Factors other than vegetation type and age may also affect the distribution of mammals. For example, soil type is an important factor governing the distribution of fossorial mammals. Thus, species that require well-drained soils, such as the eastern mole and the pine vole, are absent from areas such as bottomland hardwoods, with their heavy soils (Yates and Schmidly 1978; Smolen 1981). The presence and amount of coarse woody debris within a habitat may affect the abundance of some mammalian species. Snags and stumps are important roost and nest sites for a number of mammals (Loeb 1996b). For example, cotton mice use stumps as their primary day refuge in upland pine forests on the SRS (McCay 2000), southern flying squirrels commonly use cavities in snags (Muul 1974), and eastern woodrats occasionally use large stumps and snags for nesting (Fitch and Rainey 1956). Cavities and the loose bark of snags are also important roosting sites for evening bats (Menzel 1998; Menzel, Carter et al. 2001) and silver-haired bats (Whitaker and Hamilton 1998). Although cotton mice do not require coarse woody debris, they are more abundant (figure 4.29) and have higher reproductive and survival rates in longleaf pine stands with abundant coarse woody debris than in areas with almost no coarse woody debris (Loeb 1999). The characteristics of coarse woody debris may also be important. Cotton mice in upland loblolly pine stands on the SRS preferentially select longer logs over shorter logs for travel (McCay 2000).

Figure 4.29. Number of cotton mice captured during winter (W) and spring (S) 1991–1994 on plots where tornado damage created a pulse of dead wood in 1989 on the Savannah River Site (adapted from Loeb 1999). Salvaged plots had dead wood removed within the first year; unsalvaged plots did not.

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Landscape Factors Although vegetation type, successional stage, and certain structural characteristics are important in determining the suitability of a habitat patch for a particular species, the landscape context of that patch must also be considered (Lidicker 1995). A landscape is a spatially heterogeneous area with many habitats and is considered at spatial scales from hectares to many square kilometers (Turner 1989). Each habitat or patch within a landscape may be characterized by its size, shape, isolation, and juxtaposition to other patch types. All of these factors may have a large effect on the plants and animals that inhabit a patch. In particular, as patches get smaller and more isolated, they will likely support fewer species, and the populations of organisms within those patches will be more vulnerable to local extinction (Harris 1984). The field of landscape ecology is relatively new, but extensive studies on the SRS have tested the effects of habitat fragmentation on abundance and distribution of small mammals. For example, Yates, Loeb, and Guynn (1997) found that clear-cut size had a significant effect on small mammal species richness and diversity (figure 4.30). The greatest impact was on cotton rats. The relative density of cotton rats increased with clear-cut size, and no cotton rats were captured in clear-cuts of less than 6 ha (15 ac). Although this suggests that clear-cuts must be of a minimum size to support cotton rat populations, Menzel et al. (in press) found cotton rats

Figure 4.30. Diversity (Shannon-Weaver index) and species richness of small mammals in three sizes of clear-cuts on the Savannah River Site, 1991–1992 (Yates et al. 1997).

Biotic Communities

263

occupying canopy gaps of less than 0.6 ha (1.5 ac), and Anderson (1995) did not find a significant effect of patch size on cotton rat habitat use on the SRS. Clear-cuts are temporally dynamic habitats that are created after the previous stand has been harvested and then quickly regenerate into forest. Thus, animals that prefer these early-successional habitats, such as old-field mice and cotton rats, must disperse to and colonize the sites quickly. Because travel corridors increase connectivity among patches within a habitat mosaic, they may be important for colonization of newly created sites such as clear-cuts (Harris 1984). Menzel et al. (in press) found that species richness and diversity of small mammals that colonized gaps or small clear-cuts in bottomland hardwood forest were inversely related to distance to other open areas. Skidder trails created during harvesting operations probably acted as important travel corridors. In contrast, Anderson (1995) did not find a correlation between colonization of clear-cuts and distance to the nearest open site, and there was little correlation between the numbers of animals captured in clearcuts and adjacent power line rights-of-way on SRS (Anderson 1995; Danielson and Anderson 1999). Further, in an experimental landscape designed specifically to test the effects of corridors on animal movement patterns, corridors had no effect on dispersal of old-field mice (Danielson and Hubbard 2000) and little effect on the dispersal patterns of cotton rats (Bowne, Peles, and Barrett 1999). Thus, corridors may not be particularly important for early-successional small mammal species on SRS, perhaps due to its extensive road system. In areas where there are fewer roads, however, such as in bottomland hardwood forests, the creation of corridors such as skid trails may facilitate the colonization of newly created open areas. Forested corridors may be important for species such as flying squirrels, which require a forest canopy for movement. Lack of forested corridors may restrict their movements and prevent dispersal among forested patches. The juxtaposition of habitats may also determine the suitability of a habitat for a species. For example, cotton rats living near Carolina bays prefer blackberry thickets bounded by tall grassland over blackberry thickets bounded by water (Lidicker et al. 1992). These observations highlight the need for more information on the effects of landscape structure and dynamics on the long-term viability of mammal populations.

5

r

Threatened and Endangered Species Smooth Purple Coneflower Donald W. Imm

Sensitive Plants Donald W. Imm

Shortnose Sturgeon Barton C. Marcy, Jr.

American Alligator I. Lehr Brisbin, Jr.

Wood Stork A. Lawrence Bryan, Jr.

Bald Eagle A. Lawrence Bryan, Jr., and William L. Jarvis

Red-Cockaded Woodpecker Peter A. Johnston

Sensitive Animals William L. Jarvis

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265

Seven species of federally threatened or endangered plants and animals exist on the SRS. This chapter includes sections on each species except pondberry (which was discovered after work on this book was well underway), as well as sections on other sensitive plants and animals. Donald Imm describes the three populations of the endangered smooth purple coneflower that occur on SRS, two of which are increasing and one of which has declined gradually since 1985. All are associated with right-of-way boundaries and extend into sparse pine and oak-pine woodlands. Although the coneflower thrives in open areas with frequent disturbance, it has persisted for extended periods in some areas on SRS in less optimal (shady) conditions. Management efforts that follow the U.S. Fish and Wildlife Service (USFWS) coneflower recovery plan will hopefully improve habitat conditions on SRS and favor successful seedling establishment, as well as vigorous growth and flowering of the existing plants. In addition to the coneflower, the SRS supports populations of forty-four plant species designated by the Site as “sensitive.” These are species that are not federally protected but are of local concern, according to various sources. Imm briefly discusses the habitat associations of each. Most occur in longleaf pine savannas, bottomland hardwood forests, or Carolina bay wetlands. He describes SRS management for sensitive plants and provides estimates of population trends for each species. The shortnose sturgeon is an endangered anadromous fish that occurs in the Savannah River adjacent to the SRS. Barton Marcy describes its habitat requirements, noting that the species was not known from the middle reaches of the Savannah River until 1982. It spawns upstream and downstream from the SRS, and potential spawning habitat exists in a portion of the river adjacent to the site. Lehr Brisbin describes the history of the American alligator on SRS, which is listed as “threatened due to similarity of appearance.” A few individuals were likely present on the SRS in the 1950s, but alligators benefited greatly from the construction of cooling reservoirs, particularly Par Pond, where current population estimates range from 300 to 350. L Lake also supports a large population, and individuals regularly use SRS streams and smaller water bodies. Lawrence Bryan discusses use of the SRS by the endangered wood stork. Although the species does not breed on the site, birds from nearby nesting colonies in Georgia use SRS wetlands for foraging. Peaks of stork use occurred when reactor operations influenced water levels and foraging habitat in the Savannah River swamp. Since reactor operations have ceased and vegetative structure has changed, the swamp is no longer a consistent foraging habitat for storks, but some storks continue to forage in Carolina bays and other ephemeral wetlands on the site. Bald eagles, currently listed as threatened, have used SRS reservoirs year-round since the

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1950s. The first known nesting on SRS was in 1986, and a second nest was located in 1990. Lawrence Bryan and William Jarvis describe SRS management for bald eagles. Although nesting attempts at the two sites were generally successful through much of the 1990s, both nests have failed since 1999. Avian vacuolar myelinopathy is suspected in the failures, and the future of bald eagle nesting at SRS is uncertain. Management for the endangered red-cockaded woodpecker is the single greatest driver of land management activity on SRS. The species requires large pine trees and an open understory, maintained primarily through frequent prescribed burning. Many aspects of forest management, including rotation length, thinning, and frequency and timing of prescribed burning, are geared toward providing nesting and foraging habitat for red-cockaded woodpeckers. Peter Johnston describes the history of the SRS population and the management activities aimed at recovery of the species. The population declined to a low of four birds scattered among three groups in 1985 but has since recovered dramatically through intensive population and habitat management. In 2000, the population totaled 165 birds in 34 groups; it had exhibited an unprecedented annual rate of growth of 22 percent over the preceding ten years. The population is expected to reach 250 breeding groups, the target for “secondary core populations,” as defined by the USFWS recovery plan, by 2037. The SRS has designated thirty-two species of animals as sensitive—one insect, eight mollusks, one fish, seven reptiles and amphibians, eight birds, and seven mammals. In the final section, William Jarvis discusses the population status, distribution, and habitat associations of each.

Smooth Purple Coneflower Donald W. Imm The U.S. Fish and Wildlife Service designated the smooth purple coneflower (Echinacea laevigata) an endangered species in 1992 (U.S. Fish and Wildlife Service 1992) and developed a draft recovery plan in 1995 (U.S. Fish and Wildlife Service 1995). The primary objectives of this recovery plan are (1) to implement protective management for extant populations, (2) to survey suitable habitat for additional populations and reintroduction, (3) to protect viable populations, (4) to monitor existing populations, (5) to conduct research on the biology of the species, and (6) to maintain cultivated seed sources.

Threatened and Endangered Species

267

The smooth purple coneflower (hereafter coneflower) ranges from Virginia to South Carolina and Georgia and occurs in dry oak woodlands, sparsely wooded prairies, and roadsides in the Piedmont and at low elevations of the Blue Ridge province (Kral 1983b; Rayner et al. 1984; Gaddy 1991). Because of habitat differences and geographic locale, coastal plain populations were considered to be disjunct from those within the native range (Kral 1983b). The origin of the coastal plain populations is debatable; however, no evidence seems to exist that these populations were originally planted (Gaddy 1991). The coneflower occurs on poorly drained, shallow clay soils that are seasonally dry to excessively dry during the growing season. These soils are derived from parent rock material such as limestone, gabbro, diabase, and marble. Divalent and trivalent cations such as magnesium, calcium, and manganese dominate soil chemistry. Extremely high cation exchange capacities with high levels of base saturation and low acidity buffer these soils. Nitrogen availability may become limited during the summer months, through either cation competition with clay binding sites or drought-reduced nitrogen fixation and slowed decomposition rates. Like most members of the Asteraceae, the coneflower is not likely to be growth-limited by low nitrogen availability and may benefit from reduced nitrogen levels through lessened competition. Similarly, growingseason drought may enhance the competitiveness of the species. The coneflower is a light-demanding species. Shade reduces vigor and flowering (Kral 1983b). Because of its limited competitive abilities, the coneflower is best adapted to well-lit areas with either frequent disturbance or limiting resources that discourage competition. Disturbance (e.g., scarification, tilling, mowing, fire) prevents dominance by more competitive species and provides suitable mineral soil germination sites. The coneflower is a short-lived rhizomatous perennial that can flower the first season following germination if optimum growth conditions exist. Seeds germinate during the early spring and grow rapidly to maturity. Growth and survival of seedlings are primarily dependent on soil moisture conditions and root competition. With continued survival and growth, new shoots arise along a common perennial rhizome through hormonal stimulation at lateral bud points. Though not known for the smooth purple coneflower, rhizomatous shoots of other species can be stimulated by direct light, mechanical damage, increased nitrogen levels, and high temperature conditions. Flowering begins in early to mid June, and seeds are mature by early to late October (Radford, Ahles, and Bell 1968). A number of granivorous

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birds and small mammals associated with temperate meadows and woodlands eat the seeds. A small percentage of the seed may be dispersed through caching or mishandling by fauna. Most seed not eaten is gravitationally dispersed away from the slender parent flower stalk. Therefore, in-place seeding may be more common than dispersal to new locations. Seeds dispersed away from a population are less likely to successfully become established because of the low probability of reaching an area with suitable germination conditions (i.e., exposed mineral soil, nearly full sunlight, little competition). Anecdotal information suggests ten to thirty years persistence in the seed bank. Smooth purple coneflower plants have persistent rhizomes that can endure long periods of heavily shaded conditions (Kral 1983b). These rhizomes are revitalized following forest thinning and litter removal. Therefore, recovery of declining populations may be possible through management activities that recreate suitable habitat conditions.

SRS Population History The three coneflower populations that exist on the Savannah River Site (SRS; figure 5.1) are associated with right-of-way boundaries and extend into sparse pine and oak-pine woodlands. At each location, soils are dry and characterized by exposed plinthite at the soil surface. The soils have slightly higher cation content and slightly lower acidity than similar soils from other sites (pH of 5.6 compared to 5.2 on similar sites). The Burma Road population is on Troup soil series, while the Tennessee Road and Road 9 populations lie above a complex of Blanton, Wagram, and Vaucluse soil series. The Road 9 and Tennessee Road populations are adjacent to a stand with drought-tolerant perennial forbs and grasses beneath a scattered canopy of oaks (post, southern red, and blackjack), hickories (mockernut and sand), and pines (longleaf and loblolly). The Burma Road population lies adjacent to a longleaf pine plantation with seedlings of the same species listed above. All three sites have sparkleberry, deerberry, and tree saplings and seedlings that dominate a patchy moderate to sparsely developed understory and ground cover. Within the right-ofway population areas, annual and perennial herbaceous grasses and forbs are prevalent, as well as saplings of early-successional woody species. Long histories of right-of-way maintenance activities such as fertilizing, mowing, and selective use of herbicides have influenced these seral communities. The Tennessee Road and Road 9 populations have increased significantly since discovery, whereas the Burma Road population

Threatened and Endangered Species

269

Figure 5.1. Locations of smooth purple coneflower populations on the Savannah River Site.

has declined (table 5.1). Variation in numbers may be related to changes in reproductive success, local habitat change, or disturbance patterns.

Burma Road Population Since 1988, the Burma Road population has been monitored annually (Knox and Sharitz 1990). This site initially had 323 stems. It has fluctuated annually since then, reaching a low of 169 stems in 2000, and although it had grown to 212 by 2003, it has remained below the 1988 level.

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Table 5.1 Number of ramets (stems) for three smooth purple coneflower populations on the Savannah River Site, 1988–2003 Population Year

Burma Road

1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003

323 304 285 244 265 188 221 254 202 219 244 214 169 199 254 212

Road 9

Tennessee Road

600 589 511 1,492 1,906 1,698 1,534 1,505 1,634

219 517 443 407 435

Source: B. Collins, Savannah River Ecology Laboratory, unpublished data.

In 1992 and 1993, the declining population, its limited flowering, and its absence of recruitment led to a cooperative effort to rehabilitate the population through burning, thinning, and reducing the impact of the road right-of-way. Burning and thinning treatments used an experimental block design whereby portions were either thinned, burned, thinned and burned, or used as a control (no treatment). Burning resulted in a slight increase in the numbers of individuals (figure 5.2) and a slight increase in the number of flowering individuals (figure 5.3). However, two years after the experiment was initiated, the population returned to a pattern of decline. The limited success of these efforts may have resulted from a continual deposition of road dust on the plants, as well as a conservative approach to thinning. Between 1992 and 1996 the road rightof-way was paved to prevent the accumulation of road dust on the plants. The following recommendations arose from this effort: exclude the forest border from thinning; increase thinning efforts away from the border to increase the amount of light at the ground surface; and develop a prescribed burning program on a three- to four-year summer burn rotation

Figure 5.2. The response of individual smooth purple coneflower plants to burning and cutting treatments at the Burma Road population area, Savannah River Site (B. Collins, Savannah River Ecology Lab, unpublished data).

Figure 5.3. Flowering patterns of smooth purple coneflower following burning and cutting treatments at the Burma Road population area, Savannah River Site (B. Collins, Savannah River Ecology Lab, unpublished data).

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(P. Dixon, Savannah River Ecology Lab, unpublished data). The first action would allow woody perennials to “filter” airborne particulates moving into the population area. To date, thinning of small shrubs and trees in the midstory has occurred, but drought conditions during optimal periods have prevented burning. Though the coneflower has increased vigor and flowering effort with thinning and soil disturbance, the net increase in competing vegetation (Rubus, woody sprouts, weeds) encouraged by disturbance may counteract the positive effects on the coneflower.

Road 9 Population The Road 9 population was located in June 1994. This population was substantially larger than the Burma Road population and appeared to be vigorous, with 600 stems and over 200 flowering individuals. Despite several disturbances in the general vicinity of the population, the total number of stems has increased since discovery, peaking in 1999 at 1,906 stems (table 5.1). Herbicides were inadvertently used in the area during power line maintenance activities in July 1995. Following that incident, individuals were recounted and marked in October 1995. Individuals along the right-of-way were again tallied in October 1996. An escaped fire burned a portion of the population in January 1997. The population was then inadvertently mowed in September 1997 after seed set. The population also may have been fertilized inadvertently during the same period in 1997. Individuals were again marked and tallied in October 1997. Recent management has included the removal of small trees and shrubs from the population area in the bordering woodland during the winter of 2000, a prescribed burn in the wooded and right-of-way portions of the population during the autumn of 2001, and diversion of the road that runs through the right-of-way to eliminate dust on the plants during summer 2002. In 2003, the population numbered 1,635 stems.

Tennessee Road Population The Tennessee Road population (219 individuals) was discovered in August 1999. During winter 1999–2000, managers removed understory shrubs and small trees and closed a secondary road that bisected the population. The population peaked in 2000 at 517 individuals, with more than half flowering. Prescribed burning was conducted during the autumn of 2001. In 2003 the population included 435 stems.

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Population Management and Protection The current management strategy focuses on removing the populated areas from the land base used for conventional resource management practices. Coneflower areas are excluded from burning and other ground disturbing activities, including roadside and right-of-way maintenance activities such as mowing and herbicide use. Ample permanent signs and roped enclosures indicate the presence of a federally protected plant. The SRS populations have presumably been present along these roadsides and utility corridors, as well as in the adjacent woods, since the establishment of the SRS. They likely received the same maintenance treatments as other roadsides, utility corridors, and adjacent wood lots. The exclusion of these maintenance treatments may actually be responsible for the decline in population numbers over the past few years. Current activities exclude the use of fertilizers from the population areas. Nitrogen additions are likely to encourage the growth of competitors and result in competitive losses through increased shading. Most oldfield species are unresponsive to the addition of phosphates and cations (e.g., potash, lime, gypsum), so managers will address use of these fertilizers on a case-by-case basis. Research should be conducted to address the impact of all fertilizers on growth performance of the coneflower and its competitors. The federal recovery plan (U.S. Fish and Wildlife Service 1995) suggests burning as the most appropriate management tool to perpetuate the coneflower. Burning removes litter and debris that shades the soil surface and inhibits seed germination. Fire also mineralizes organically bound nutrients and reduces shade competition via mortality of fireintolerant species. The timing of fire is critical for maintaining plant communities and habitat conditions specific to species. Burning during periods of seed maturation effectively eliminates a seed crop for one year and favors the establishment of other species. Those other species include competitors from persistent seed, current-year seed, annuals with later maturity and high dispersal rates, and grasses with rapid-growth capabilities and short seed maturation cycles. Winter burning (after coneflower seed drop) prepares a satisfactory seedbed and results in increased nutrient availability but does not allow for seed germination because of the onset of dormancy. Winter burning reduces shading by woody competitors and reduces ground litter that may inhibit the thermal stratification, seed germination, and stimulation of shoot growth.

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Late winter and early spring burning delays coneflower vernal release and growth but stimulates overall productivity and additional shoot development. Successful germination of persistent coneflower seed could occur with the reduction of litter and the release of mineralized nutrients. Late spring and early summer burning delays flowering of coneflower but stimulates additional shoot growth and flowering effort. Early summer burning also reduces survival of woody competitors. Reduced competition and nutrient release stimulate coneflower growth. Late spring and early summer burning also effectively eliminates seed production by spring-flowering competitors and persistent woody invaders, but early summer burning enhances the growth of late-blooming competitors (heavy seeded annuals, biennials, perennials). Because many herbicides reduce the survival of woody plants and broadleaf weeds (Asteraceae), herbicides can reduce or eliminate coneflower populations if chemical contact is made. Most herbicides induce rapid growth to the point that water and resource demand exceeds the capability to provide those resources from the root system. The affected plants basically outgrow the capabilities of their habitat and die. Infrequent seasonally appropriate mowing can maintain populations that are inappropriate to burn or in highly productive areas with staunch competition. Mowing is common in nursery or garden environments, where it encourages vigorous growth prior to flowering or dormancy. Infrequent mowing allows foliage and flower development and seed maturation. Seasonally appropriate periods of mowing are important to avoid destruction of flowers and seed. Generally, the most appropriate period for mowing is prior to the development of the flowering stalk or after seed maturity (October to May). During years without burning, population areas are mowed in October to facilitate seed dispersal and reduce competition from late-season annuals and perennials. Thinning of the surrounding forest increases light attenuation at the forest floor. Hand tools and chain saws are used to thin shrubs, saplings, and small trees within the coneflower population areas. Individual trees are felled away from heavily populated areas during the winter months. Collectively, these practices should benefit coneflower populations on SRS.

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Sensitive Plants Donald W. Imm Worldwide, one in ten plants are considered rare species (Wilson 1988). The term rare plants refers to threatened, endangered, and sensitive plant species that need special consideration, as well as those species that are perceived to have declined or are thought to be limited at the local, regional, or global level. Rarity is a natural phenomenon, particularly on local landscapes (Collins, White, and Imm 2001). If common species exist through persistence, high levels of establishment, or competitive success, then other species would be subordinate. A portion of the remaining subordinate species would be expected to have unsustainably low densities and be at risk of local extinction. Rarity exists for a variety of reasons that may or may not be related to human activities (Rabinowitz 1981). Many species have highly specific habitats that are extremely limited in occurrence or are associated with habitats that have been significantly altered. Other species are restricted to small geographic areas or are extremely sparse in distribution. Still others are dependent on rare pollinators or rare disturbance events. Species threatened or in danger of extinction usually have combinations of these reasons. The Savannah River Site (SRS) sensitive plant list currently includes forty-four species (table 5.2). This list is based on the list generated by U.S. Forest Service Southern Region. Other considerations include periodic updates in the Federal Register, status updates at the state level produced by the South Carolina Department of Natural Resources, and global and state ranking values of rarity derived by The Nature Conservancy. Species with global rank values of G1, G2, and G3 or state rank values of S1, S2, and S3 (table 5.3) are included in the SRS list. State and federal agencies and other contractors review this list every two years. In addition, local experts and their publications (e.g., Knox and Sharitz 1990; Kral 1983a, b; Radford, Ahles, and Bell 1968; Rayner et al. 1984) help determine the status of plant species on SRS.

Sensitive Plant Species and Their Habitats Several plants associated with the once common pine savannas are sensitive species. In addition, SRS lies within the range of and has suitable habitat for several other pine savanna species, including some that are federally protected (Walker 1993). Hairy milkpea (see table 5.2 for scientific

Striped garlic (Allium cuthbertii) Gerardia (Agalinus decemloba) Incised groovebur (Agrimonia incisa) Dutchman’s-pipe (Aristolochia macrophylla) Great Indian plantain (Arnoglossum muehlenbergii) Hairy milkpea (Astragalus villosus) Sandhills milkpea (Astragalus michauxii) Lanceleaf wild indigo (Baptisia lanceolata) Chapman’s sedge (Carex chapmanii) Collins sedge (Carex collinsii) Cypress-knee sedge (Carex decomposita) Long sedge (Carex folliculata) Eastern few-fruit sedge (Carex oligocarpa) Nutmeg hickory (Carya myristiciformis) Rose coreopsis (Coreopsis rosea) Elliott’s croton (Croton elliottii) Carolina larkspur (Delphinium carolinianum) Smooth purple coneflower (Echinacea laevigata)b Little bur-head (Echinodorus tenellum var. parvulus) Southern swamp privet (Forestiera acuminata) Green-fringe orchid (Platanthera lacera) Two-wing silverbell (Halesia diptera) Little silverbell (Halesia parviflora) Pondberry (Lindera melissaefolium)b

Species G3G4 G3 G3 G5 G4 G4 G3 G4 G3 G4 G3 G3 G4 G4 G3 G2G3 G3 G2 G3 G4 G5 G5 G3 G2

G rank S3 S1 S1 S3 S1 S1 S1 S3 S1 S1 S3 S2 S2 S1 S2 S2 S1 S1 S2 S1 S1 S1 S2 S1

S rank

3

0 1 2 8 0 1 8

1

0 2 2 4

1990a

0 1 2 17 3 0 2 1 1 1 2 17 1 2 11 0 7 1 1

7 0 0

1995 17 1 3 2 2 1 2 52 7 1 2 1 1 1 1 21 2 3 6 5 5 2 1 1

2000 9 0 0 0 1 0 0 14 0 0 0 0 0 0 0 11 1 3 0 0 0 0 0 0

No. of large populations S S S 0 S – S 0 S S U U U S U S S S – S U S S –

Trend

Table 5.2 Sensitive plants occurring on the Savannah River Site, with their global (G) and state (S) ranking and number of populations for each species in 1990, 1995, and 2000

G2 G2G3 G2G4 G2G3 G4 G4 G3G5 G3 G5 G3 G3 G3 G3G4 G3G4 G3 G3G4 G4 G3T2 G3G5 G4

S2 S2 S2 S3 S1 S2 S3 S3 S1 S2 S1 S2 S1 S2 S1 S1 S1S2 S1 S1 S1 27 20 0 2 5 0 31 2 9 1 0 0 0 8 3

5 3 2

0 11 3

7 2 6 0

5

15 2 17 6

6 2 5

20 1 18 11 1 43 33 0 3 5 1 51 3 12 3 1 1 1 8 3

0 0 2 4 0 12 17 0 0 2 0 4 0 0 0 0 0 1 0 0

S U S U S 0 0 – S U U S U S S S S S U U

Note: Blank cells indicate that species were unlisted during that time period. Also listed are the number populations with more than fifty individuals for each species and the general trend of individuals within the populations during the past ten years (+ = increasing, – = decreasing, S = stable, U = unstable). a Values taken from Knox and Sharitz (1990). b Federally endangered species.

Bog spicebush (Lindera subcoriacea) Boykin’s lobelia (Lobelia boykinii) Spatulate seedbox (Ludwigia spathulata) Carolina birds-in-nest (Macbridea caroliniana) Canada moonseed (Menispermum canadense) Indian olive (Nestronia umbellula) Sandhill lily (Nolina georgiana) American nailwort (Paronychia americana) Durand oak (Quercus durandii) Three-awned meadow-beauty (Rhexia aristosa) West Indies meadow-beauty (Rhexia cubensis) Oconee azalea (Rhododendron flammeum) Drowned horned rush (Rhynchospora inundata) Slender arrowhead (Sagittaria isoetiformis) Sweet pitcher plant (Sarracenia rubra) Canby’s bulrush (Scirpus etuberculatus) Baldwin’s nut rush (Scleria baldwinii) Least trillium (Trillium pusillum) Florida bladderwort (Utricularia floridana) Dwarf bladderwort (Utricularia olivacea)

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Table 5.3 The Nature Conservancy and South Carolina Department of Natural Resources rarity and vulnerability rankings used on the Savannah River Site Rankinga G1 G2 G3 G4 G5 S1

S2 S3 S4 S5 S? Q

Definition Critically imperiled globally due to worldwide extreme rarity Imperiled globally due to worldwide rarity Either very rare throughout its range or found locally in a restricted range, or having factors that make it vulnerable Apparently secure globally, though it may be rare in parts of its range Demonstrably secure globally, though it may be rare in parts of its range Critically imperiled statewide because of extreme rarity or because of some factors that make it especially vulnerable to extirpation; or fewer than 6 occurrences in the state Imperiled statewide because of rarity or factors making it vulnerable; or 7–20 occurrences in the state Rare or uncommon in the state; or 21–100 occurrences in the state Apparently secure in the state; or >100 occurrences in the state Demonstrably secure in the state South Carolina Heritage Trust has not assigned species an S ranking such as S1 to S5 Questionable taxonomy that may reduce conservation priority

a Combined

rankings such as S2S3 and G3G4 denote borderline species; for example, a species ranked S2S3 could be considered S2 or S3.

names) and lanceleaf wild indigo are pine savanna species that occur principally in the southeastern sections of SRS. Sandhill lily occurs in pine savannas and forests, oak woodlands, and turkey oak barrens. Carolina larkspur occurs in moist to submesic oak woodland margins and pine savannas. Sandhills milkpea is restricted to xeric pine and pine-oak barrens. American nailwort is associated with recently disturbed areas such as those that develop following thinning operations or fire. Striped garlic, incised groovebur, and Indian olive are associated with pine to hardwood shallow-slope transitions and oak woodlands. Chapman’s sedge and Oconee azalea are associated with steep hardwood bluffs and slopes. Oconee azalea also occurs on lower acidic slopes near transitions to stream bottoms and seeps. Several other potentially rare species also occur in these habitats (Imm et al. 2001). The least trillium and great Indian plantain are associated with broad, moist, blackwater stream floodplains underlain with partially impermeable clay horizons and springs. Both silverbells occur along fertile lower slopes or margins of small streams.

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279

Seasonally flooded small stream margins that have loamy, welldrained soil support populations of green-fringe orchid. Bog spicebush populations occur in similar areas but with soils that are usually sandy and slightly more acidic. Sweet pitcher plant occurs along boggy small streams with acidic soils and streamside pocosins. Carolina birds-in-nest occurs along large blackwater streams in infrequently flooded areas. Durand oak occurs on ancient floodplain terraces that are infrequently flooded with loamy to loamy clay soils. Nutmeg hickory occurs on similar soils of floodplain terraces but is usually associated with calcic soil chemistries. Dutchman’s-pipe and southern swamp privet are both associated with river bottomlands and natural levee forests. Cypress-knee sedge is associated with cypress swamps and deeply flooded river marshes. Of the nearly 350 isolated depressions on SRS, 37 support sensitive species associated with open meadow and wet savanna Carolina bay habitats. Spatulate seedbox and little bur-head occupy interiors of small temporary ponds. Little bur-head is associated with recently disturbed bay interiors. Rose coreopsis occurs in forest–wet meadow transitions of intermediate-sized Carolina bays. Three-awned meadow-beauty and Boykin’s lobelia occupy seasonally flooded transitions of large to intermediate-sized Carolina bays. Slender arrowhead occurs in seasonally flooded meadows and the drawdown margins of ponded interiors. Elliott’s croton is associated with drawdown zones of recently ponded areas. Three of the Elliott’s croton populations are in wet roadside ditches. Florida bladderwort and dwarf bladderwort are floating aquatic plants that occur in the ponded interior of some Carolina bays, as well as some of the reservoirs on SRS. Several wetland emergent sensitive plants such as drowned horned rush, Canby’s bulrush, and Baldwin’s nut rush occur along large stream margins with permanently wet, unconsolidated mucks. Pondberry is a federally endangered species that was recently discovered in a deeply flooded Carolina bay dominated by a sparse canopy of swamp tupelo. Twenty-three stems were counted, and all appear to be male.

Status and Locations of Sensitive Species on SRS Certain locations are critical areas for sensitive plant protection and management. Most of the sensitive plants of longleaf pine savannas are in mature hardwood or pine forests that existed prior to 1951. The southeastern sections of SRS support many of the upland sensitive plant populations. Most of the sensitive plants on hardwood slopes and bottomlands occur along major stream drainages in sections that had

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little or no agricultural activity. Though nearly all Carolina bays have some history of human use, those with sensitive species do not appear to have had histories of crop production. Many were ditched and were likely used for grazing. Most of the species in marshes and ponds are scattered throughout the wetland areas of SRS. Collectively, the best sensitiveplant habitats on SRS had little or no human use during the twentieth century and, with the exception of pine savannas and meadows, have had minimal management activity in the recent past. The number of sensitive species and populations has increased during the past ten years. The increase in the number of known populations has resulted from increased survey efforts, while the increase in the number of sensitive species on SRS has resulted from finding additional species and the inclusion of additional species on the sensitive plant list. During the past ten years, many additional populations of sandhill lily and lanceleaf wild indigo have been located. Populations of those two species have also expanded in size and number during the same period. Both of those species are associated with fire-maintained pine savannas, and their increases may be in response to increased burning. Many additional populations of Oconee azalea, slender arrowhead, bog spicebush, Indian olive, and Elliott’s croton also have been located through increased survey efforts. Most sensitive species have moderately stable population sizes. Populations of perennial woody and nonwoody species have changed little in size during the past ten years. Populations of West Indies meadow-beauty and green-fringe orchid appear stable but have suffered volatile increases and decreases in numbers during the past ten years. Most species sensitive to changes in hydrology are expected to exhibit such fluctuations from year to year. In the past ten years, some species have declined in number. These include little bur-head, which is associated with mudflat zones of Carolina bays, and American nailwort, which is associated with disturbed understories of sandy soils beneath longleaf pine savannas. Both species are associated with recent disturbance within their habitat.

Management of Rare Species In most cases, sensitive plants are affected in some way by natural resource management activities because of loss of individuals, as well as direct and indirect changes that occur on the landscape. Several species are adapted to and dependent on periodic disturbance. Disturbance results

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281

in the reordering of biological relationships and provides opportunities for new establishment and changes in abundance. It also tends to result in temporary increases in the availability of light, water, and nutrients. Following disturbance, most remaining species respond to increased resources with increased growth and reproductive effort. However, the temporary increase in resource availability is usually followed by an extended period of reduced availability. Prolonged periods of reduced availability result in the loss of many less competitive and less frequent species. The loss of species during such periods can result in local extinction if a species has limited occurrence elsewhere on the landscape. To avoid loss of rare plant species, areas targeted for forest management are surveyed prior to any activity. Habitats are inventoried and populations are then monitored to determine existing densities and population stability. If activities are conducted, monitoring of pre- and post-conditions can be used to evaluate population change. Monitoring information is also collectively used to assess and project species response to other planned activities. Activities that result in irreparable damage to sensitive populations are avoided in the future. In some cases, populations are protected by other land-use initiatives (e.g., the Set-Aside Program) or become protected from specific detrimental land management activities, such as herbicide use. Management of sensitive plant species also includes proactive measures such as local reintroduction into areas devoid of a species or suite of species. Reintroduction efforts at large scales can be costly and labor intensive. In many cases, habitats are managed to improve conditions if positive responses are well documented. For example, many sensitive species are adapted to and benefit from fire, so periodic burning is used to improve habitat conditions. Though long-term benefits result for fireadapted sensitive species following burning, fires do eliminate individuals within a population and could result in local extinction of small populations. Management for sensitive species also considers the potential for interaction between isolated populations, expansion of existing populations, and establishment of new populations. The potential for interaction relies on the movement of pollen and seed by physical means or animal vectors. Patterns of spore movement for mycorrhizal fungi are also considered. An analysis of expansion of sensitive populations into adjacent areas requires a close inspection and inventory of the surrounding habitat, as well as monitoring of individual growth, longevity, genetic makeup,

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arrangement, and reproductive effort. Habitat conditions that are suitable for maintaining populations are unlikely to be the same as those that lead to rapid expansion. Plant populations are innately capable of explosive increases in numbers when conditions are suitable but are also well adapted to lying in wait for such conditions to develop. Therefore, land management decisions should be made to maximize the opportunity for sensitive plant population expansion in suitable areas to allow for genetic flow between populations. Without genetic flow between populations, population viability is reduced due to increased rates of self-crossing between related individuals (Godt and Hamrick 2001). Management for sensitive plants also should consider providing suitable habitat for pollinators and those animals involved in seed dispersal.

Shortnose Sturgeon Barton C. Marcy, Jr. The shortnose sturgeon (Acipenser brevirostrum) is the only federally endangered species of fish that occurs on or near the Savannah River Site (SRS). An anadromous fish, it migrates from salt to freshwater to spawn in large Atlantic coastal rivers from New Brunswick, Canada, to northern Florida (Scott and Crossman 1973). The impoundment of rivers, water pollution, and overfishing all contributed to the decline of the species. Recruitment rates appear too low to replenish depleted populations (Heidt and Gilbert 1978). Two species of sturgeon, the Atlantic and the shortnose, occur in the Savannah River (Paller, Saul, and Hughes 1986). The shortnose sturgeon, first documented in the Savannah River near SRS in 1982 (Muska and Matthews 1983), is rare, and the National Marine Fisheries Service (NMFS) lists it as an endangered species in the United States (50 Code of Federal Regulations 17.11 and 17.12). Muska and Matthews (1983), Specht (1987), and Marcy et al. (2005) have reviewed the biology of the shortnose sturgeon. Breeding populations normally use estuary-river complexes that have a strong flow of freshwater. Brundage and Meadows (1982) showed it to be more abundant in some drainage systems than was previously known. Access to the sea is apparently not a requirement for reproductive success. Landlocked populations occur in the Holyoke Pool section of the Connecticut River

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283

(Taubert 1980a, b) and in the Lake Marion–Moultrie system in South Carolina (Marchette and Smiley 1982). Shortnose sturgeon grow slowly, reach sexual maturity relatively late in life, and live as long as thirty years (Scott and Crossman 1973). Fish from southern populations can grow faster and mature earlier than those from northern populations (Heidt and Gilbert 1978). Adults apparently return to natal streams to spawn at two- to five-year intervals (Rulifson, Huish, and Thoesen 1982). Spawning occurs from February to May, depending on the latitude. Ripe and spent females have been collected from January to April in the Savannah River (Marchette and Smiley 1982). Temperature appears to be the major factor governing spawning, although other factors include the occurrence of freshets and substrate character (Dadswell 1979). Shortnose sturgeon spawning occurs between 9° and 12°C (48–54°F). After fertilization, eggs sink quickly and adhere to sticks, stones, gravel, and rubble on the stream bottom (Crance 1986). Water temperature, current velocity, and substrate type apparently determine suitability of spawning habitat and affect hatching success. Little is known of larval and juvenile distribution and movement because so few have been collected (Rulifson, Huish, and Thoesen 1982).

Status on SRS Halverson et al. (1997) and U.S. Department of Energy (1997) discussed the status of shortnose sturgeon on SRS. The section of the Savannah River adjacent to SRS contains potential spawning habitat (figure 5.4). As in northern rivers (Taubert 1980a, b), the spawning grounds for Savannah River sturgeon are in regions of fast flow (40–60 cm/sec, or 1.3–2 ft/sec) with gravel or rubble bottoms (Hall, Smith, and Lamprecht 1991). Collins, Kennedy, and Smith (1992) identified three areas of potential spawning habitat in the Savannah River at river kilometers 179–190, 220–230, and 275–278 (river miles 111–118, 137–143, and 171–173). These areas have moderate to strong current (50–100 cm/sec, or 1.6–3.2 ft/sec) and a substrate of gravel or submerged logs. The spawning location from river kilometer 220–230 (river mile 137–143) is adjacent to SRS. Before 1982, shortnose sturgeon were not known to occur in the middle reaches of the Savannah River. When workers collected twelve shortnose sturgeon larvae near SRS in 1982 and 1983 (U.S. Department of Energy 1987), the Department of Energy notified the NMFS as required under Section 7 of the Endangered Species Act of 1973 (Muska and Mathews 1983).

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Figure 5.4. Potential shortnose sturgeon spawning habitat in the Savannah River adjacent to the Savannah River Site.

A subsequent biological assessment evaluated the potential impact of SRS operations on shortnose sturgeon. The assessment concluded that existing and proposed operations of the SRS (specifically, of L Reactor) would not affect the continued existence of the sturgeon in the Savannah River (Muska and Mathews 1983). That conclusion was based on the facts that (1) shortnose sturgeon spawned upriver and downriver of the SRS; (2) thermal effluents did not block passage up and downstream; (3) shortnose sturgeon did not spawn or forage in the SRS streams and swamps that received thermal discharges; (4) entrainment was unlikely

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because shortnose sturgeon eggs are demersal, adhesive, and negatively buoyant; and (5) impingement of healthy juvenile and adult shortnose sturgeon on cooling water system screening devices was highly unlikely given their strong swimming ability. The NMFS concurred with the DOE determination that SRS operations did not threaten the Savannah River population of shortnose sturgeon. Little more is known of the status of shortnose sturgeon in the Savannah River adjacent to SRS.

American Alligator I. Lehr Brisbin, Jr. Like other crocodilians, the American alligator (Alligator mississippiensis) is one of the last living remnants of the ancient Archosaurian reptiles that ruled the earth during the age of the dinosaurs. It is one of the most prominent members of the southeastern herpetofauna and has been studied extensively at the Savannah River Site (SRS). Normally tropical or subtropical, alligators occupy the coastal plain of the southeastern United States, and a few scattered individuals occasionally appear north and inland from the fall line. Although alligators occur as far north as the North Carolina coast, the SRS represents the northernmost inland extension of the species’ range in South Carolina. SRS alligators, therefore, must occasionally face colder temperatures than any other naturally occurring crocodilians in the world. When their aquatic habitat freezes, SRS alligators either become semidormant in subterranean dens or move into shallow water, where they maintain small breathing holes in the ice. Alligators reach a length in excess of 3.7 m (12 ft) and a weight of 150 kg (325 lb). At 3.92 m (12 ft 9 in), an alligator from Par Pond on SRS was one of the largest ever recorded in South Carolina. Although abundant in 1900, by the 1950s, rangewide alligator numbers had dwindled to fewer than 100,000, primarily as a result of intense hunting and habitat destruction. The alligator benefited from federal protection under the Lacey Act and the Endangered Species Act during the 1960s and 1970s. As a result of the recovery brought about by that legislation, the U.S. Fish and Wildlife Service reclassified the alligator from “endangered/threatened” to “threatened due to similarity of appearance.” While the alligator is no longer endangered or threatened, legally obtained skins and leather products manufactured from alligator hides can be difficult to distinguish from those of other highly endangered

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crocodilians. This categorization helps to prevent harvest of those other species by controlling illegal international trade in crocodilian leather products. Nevertheless, the public can now harvest alligators in South Carolina during special limited hunting seasons—but not on SRS. Alligator skins taken during these hunts occasionally enter the international leather trade, and the meat may be sold for human consumption. Although alligators appear in larger wetlands throughout the Southeast, their greatest population densities occur in open coastal and freshwater marshes and in larger lakes or reservoir impoundments with stabilized water levels and heavy stands of emergent shoreline macrophytes. Lower numbers live in the larger rivers and riverine swamp systems. A few individuals inhabit isolated Carolina bays, farm ponds, golf course impoundments, and municipal water treatment facilities.

Population History on SRS Halverson et al. (1997) reviewed alligator studies at the SRS; most of the work was conducted in Par Pond during the period when it received heated reactor effluents. Par Pond was constructed in 1958 by damming Lower Three Runs. A few alligators probably were present in that creek at the time, and in 1963, Jenkins and Provost (1964) estimated the sitewide population at about two dozen animals. In 1974, Murphy (1977) estimated the Par Pond population at 110 adults and juveniles (table 5.4). By 1988, the population had grown to an estimated 197 adults and juveniles (Brandt 1989). The estimated average annual exponential rate of increase for the population was 0.06 (figure 5.5; Brandt 1989).

Table 5.4 Estimated population size and rex ratios of American alligators in Par Pond on the Savannah River Site 1972–1974 and 1986–1988

Year

Age class

Population size

95% confidence interval

Sex ratio

1972–1974

Adults Juveniles Total Adults Juveniles

70 10 110 108 83

29–143 19–72 48–215 97–120 45–121

3.7:1 1.8:1 3.2:1 2.5:1 3.1:1

Total

197

1986–1988

Source: Adapted from Brandt 1989.

2.6:1

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287

Figure 5.5. Population growth of American alligators in Par Pond on the Savannah River Site, 1972–1988 (Brandt 1989).

Murphy (1981) reported that larger alligators moved into the warmer parts of the lake during colder winter months. In the early 1970s, reproductive output of the Par Pond alligators was unusually low. Murphy attributed this to an asynchrony of male and female breeding cycles. Larger breeding males that remained active all winter in the warmer reactor outflows tended to come into breeding condition earlier than the females, which tended to winter in cooler parts of the lake in a semidormant state. In addition, big crocodilians can exert severe inhibition on the recruitment of juveniles in some populations (Messel and Vorlicek 1987; Webb et al. 2000). If that occurred in Par Pond, it may have compounded the poor reproductive output. The population age structure had an unusually high proportion of older (larger) adults relative to hatchlings, juveniles, and subadults less than or equal to 1.5 m (5 ft) in length (Murphy 1981). After reactor operations ceased and Par Pond water temperatures returned to normal, the reproductive output of the population increased (Brandt 1989), presumably because the timing of male and female reproductive cycles became more synchronized. In the summer of 1991, the Par Pond water level was lowered approximately 6 m (18 ft) for repairs to the dam. Soon after drawdown, several adult alligators left the reservoir, but most resident alligators remained during the four years of low water level (Brisbin et al. 1992). Both clutch sizes and hatchling weights of Par Pond alligators were significantly lower

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in 1994 than in previous years when the lake was at full pool (Brisbin et al. 1997). However, hatch rates were higher, and nest predation was lower, which may have offset the smaller clutch sizes and hatchling weights.

Current Status and Distribution on SRS Former reactor cooling reservoirs at SRS continue to support the largest numbers of alligators on the site. After the refill of Par Pond in 1994– 1995, a healthy reproducing alligator population was reestablished there (Brisbin et al. 1997). Using an annual exponential population growth rate of 0.06, Brandt (1989) estimated that more than 320 individuals would occupy Par Pond by 2000. No recent attempts have been made to directly count alligators. However, nest searching efforts for genetic studies in the late 1990s suggest that 50 to 100 or more breeding-size adults and a total population of 300 to 350 may be a reasonable current estimate for Par Pond. No comparable data is available for L Lake, but anecdotal observations confirm that a large population of likely reproducing breeding-size adults is present. In 1986, twelve alligators occupied the Pond B reservoir (Brisbin 1989), but nothing is known of their current population trend. Alligators regularly reproduced in the more northerly reaches of Pond C in the mid-1970s, when water temperatures in most of that impoundment were well above lethal limits for alligators (Murphy 1981). Now that water temperatures have returned to ambient throughout Pond C, both reproductive efforts and hatchling survival have probably increased, but their current status is unknown. Smaller numbers of alligators occasionally breed at several locations in the Savannah River swamp and other SRS wetlands. Beaver Dam Creek historically has had frequent sightings of juvenile and subadult alligators, suggesting successful reproduction there. Steel Creek below L Lake supports a small breeding population of alligators, with most animals occurring in the swamp delta. Since reactor operations ceased, alligators have frequently appeared in Fourmile Branch, primarily in the swamp delta and lower stream channel. Population numbers there are low, however, and no reproduction has been documented. Other areas of the SRS where alligators occur have not been systematically surveyed. Lower Three Runs supports an apparently self-sustaining population directly below the dam. Upper Three Runs also provides some suitable habitat, and evidence of nesting has been observed; but few alligators have been seen. Steeds Pond supported a moderate population until it was drained in 1984. Scattered lone individuals occasionally occur

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in abandoned farm ponds and Carolina bays on the SRS, but evidence of self-sustaining populations in these wetlands is lacking. Long-term surveys of alligator population numbers and distribution in Par Pond should use historic survey techniques (e.g., Murphy 1981; Brandt 1989) to build on the thirty-year data base for this unique population. DNA profiles from blood and tissue are helping to evaluate the possibility of genetic damage in alligators that live and breed in contaminated reservoirs of the SRS. In addition, molecular genetic studies now show the surprising occurrence of multiple paternity in some SRS alligator nests. This kind of basic information will aid the effective future management of SRS alligator populations.

Contaminant Impacts and Public Health Concerns Recent studies have assessed the fate and effects of mercury and cesium137 in alligator tissues (Brisbin et al. 1998). Mercury in Par Pond is believed to have come from industrial releases to the Savannah River. Past reactor operations released cesium-137 into this reservoir system. The concentrations of cesium-137 did not change in alligator tissues before versus after Par Pond refill. Alligator meat is now widely marketed for human consumption. Although SRS does not permit direct harvest, alligators probably leave the site. On off-site public lands, state-licensed trappers can harvest nuisance alligators, and their meat can be sold for human consumption. A detailed risk assessment (Brisbin et al. 1998) has shown that mercury rather than radioactive contamination is the larger health risk from meat of SRS alligators. According to health standards set by the U.S. Environmental Protection Agency, a person can safely consume no more than 45 g (0.1 lb) of SRS alligator meat per week (Brisbin et al. 1998). Mercury levels in SRS alligators, however, are lower than those in alligators from many other portions of the Southeast, particularly southern Florida.

Wood Stork A. Lawrence Bryan, Jr. The American wood stork (Mycteria americana) was classified as a federally endangered species in 1984 due to population declines thought to result from loss of wetland foraging habitats (U.S. Fish and Wildlife Service

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1986, 1996). It is a frequent summer and fall visitor to wetlands of the Savannah River Site (SRS), particularly the swamp system along the Savannah River (SRSS), Carolina bays, and other ephemeral wetlands. Storks typically use these wetlands as foraging sites, preying primarily on fish. Storks generally occur in small flocks (of fewer than fifteen) on the SRS, although large aggregations (of more than one hundred) appear when foraging conditions are ideal. Three wood stork breeding colonies exist within 50 km (31 mi) of the SRS, but storks do not breed on SRS. Two colonies, Birdsville and Chew Mill Pond, in Jenkins County, Georgia, typically have a combined total of 300 to 350 stork nests. The Jacobson’s Landing colony in Screven County, Georgia, is less consistent than the other colonies. It averages only thirty to forty nests in good hydrologic years when sufficient rain maintains water underneath the nest trees to limit predation by raccoons.

Habitat Requirements and Occurrence on SRS Storks typically breed from March to June, and most sightings on the SRS occur from late June through September (figure 5.6). Most storks on the SRS are probably birds dispersing from nearby colonies at the end of the breeding season. Storks nesting in the Birdsville Colony foraged in

Figure 5.6. Seasonal use of the Savannah River swamp system by wood storks, 1983–2002. Use is defined as the total number of storks observed during a month divided by the total number of surveys. The latter is shown in parentheses.

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the SRS river swamp at Beaver Dam Creek and Steel Creek delta in 1983 and 1984, respectively (Meyers 1984; Coulter 1986). Wood storks typically forage in shallow wetlands. Approximately 20 percent of the Carolina bays on the SRS maintain fish populations (Snodgrass et al. 1996). Ephemeral wetlands on the SRS, such as Carolina bays, lose water to evapotranspiration during the spring and summer months, concentrating fish and other aquatic prey in diminishing volumes of water. Wood storks feed by tactilocation, often pushing their bills through the water, bumping into prey and grabbing it with a quick bill snap. Concentrated fish in drying bays on SRS are particularly attractive to storks. The bays that storks most frequently used as foraging sites are Craig’s Pond, Steel Creek Bay, and Peat Bay. Peat Bay also serves as a roosting site. Reactor operations used to impact water levels in the swamp along the Savannah River. Since reactor operations ceased, rainfall and upstream reservoir management practices determine water levels.

Anthropogenic Effects The importance of water depth to storks, combined with the impacts of SRS operations on the hydrology of both natural and artificial wetlands, has resulted in fluctuating habitat conditions across the site over time. Site operations have particularly impacted habitat quality in the SRSS and in Par Pond.

Reactor Operations and the SRSS Although storks have used the SRSS on a regular basis historically, various Site operations have affected their distribution within the SRS. The high temperature and fluctuating flow of cooling water discharged into some SRS streams altered many downstream aquatic habitats, creating deltas where these streams entered the SRSS (chapter 2). Peaks of stork use occurred in the SRSS from 1983 to 1985, 1992 to 1993, and in 1997 (table 5.5, figure 5.7); the two early peaks were probably associated with reactor operations (Bryan, Coulter, and Brisbin 2000). Specifically, testing of the L Reactor in 1983–1984 resulted in fluctuating water levels in the Steel Creek delta, presumably concentrating fish in the delta areas and attracting storks in high numbers. Also, when C Reactor ceased operations in 1985, lower water levels in the Fourmile Branch delta and the interdelta area to the east presumably concentrated fish and attracted high numbers of storks. In 1992, when K Reactor was tested for several

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Table 5.5 Wood stork use of the Savannah River swamp system, 1983–2000 Steel Creek

Inter-

Pen Branch

Inter-

Fourmile Branch

Beaver Dam

Year

Na

delta

delta areab

delta

delta areac

delta

Creek

1983 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 Mean

35 89 120 115 123 143 99 12 34 41 40 29 26 16 17 31 27 20 0 15

2.5 1.1 0.1 0.7 1.1 0.0d 0.1 0.1 0.0d 0.2 0.6 0.7 0.2 0.3 0.6 0.0d 0.0 0.0

0.0 0.0 0.0 0.0 0.0 0.0d 0.0d 0.0 0.5 1.9 0.0d 0.1 0.3 0.0 1.1 0.0d 0.0 0.0

0.2 0.2 0.1 0.0 0.0 0.0 0.0d 0.0 0.0d 1.8 0.4 0.0d 0.0 0.0 2.1 0.0 0.0 0.0

0.0 1.1 2.0 0.0 0.0 0.0 0.1 0.0 0.5 0.2 1.7 0.0 0.0d 0.0 0.5 0.2 0.0 0.0

0.0 0.5 2.9 0.8 0.1 0.0 0.1 1.0 1.1 0.0 1.4 0.2 0.0 0.1 0.1 0.7 0.0 0.0

4.9 1.2 0.0 0.1 0.0 0.0 0.0d 0.0 0.2 0.1 0.2 0.0d 0.0 0.0 0.1 0.3 0.0 0.0

0.0 0.4

0.0 0.2

0.0 0.3

0.0 0.3

0.0 0.5

0.0 0.4

Note: Numbers represent the average number of storks observed per survey for each area. a N = number of aerial surveys. b Area between Steel Creek delta and Pen Branch delta. c Area between Pen Branch delta and Fourmile Branch delta. d Low numbers (1–5) of storks were sighted in these areas.

weeks, water-level fluctuations in the Pen Branch delta briefly attracted storks. In 1997, when severe drought conditions reduced the number of Carolina bays with water (and fish), storks shifted to SRSS wetlands. Since 1998, however, no storks have been observed during surveys of the SRSS.

Par Pond Drawdown The Par Pond reservoir is a 1,012-ha (2,500-ac) impoundment on the SRS. Its water level was constant from 1960 until July of 1991, when structural anomalies in the dam required lowering the level by 6 m, reducing its

01

293

20

98 19

95 19

92 19

89 19

86 19

19

83

Threatened and Endangered Species

Figure 5.7. Average numbers of wood storks observed per aerial survey of the Savannah River swamp system, 1983–2002. No surveys were conducted in 2001.

volume and surface area by 50 percent and 65 percent, respectively. Wood storks do not typically forage in lacustrine habitats; however, the drawdown forced small fish from the safety of large beds of aquatic macrophytes along the reservoir shore, exposing them to predation in the shallows. From one to eighty-three storks foraged daily in Par Pond for approximately 3.5 months (Bryan et al. 2000). In the fall of 2000, after a thirty-month drought, the water level in Par Pond dropped by 1 to 2 m (3–7 ft), and most of the Carolina bays used by storks were completely dry. Several coves and other portions of Par Pond were shallow enough for stork foraging, and one to ten birds foraged there daily from September to November. As the water level has risen since 2000, stork use has declined, though occasional use by a few individuals continues during periods of extended drought.

Historical Trends Wood storks have occurred in the central Savannah River drainage (including SRS) since the early 1900s. Murphey (1937) reported that storks did not breed in this area but large, late-summer flocks of young-of-the-year

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birds were frequent. Norris (1963) observed storks on the SRS in the mid1950s and early 1960s. In 1980–1981, prior to the restart of L Reactor, stork use of the Steel Creek delta varied relative to the size and productivity of the nearby Birdsville Colony (Smith, Sharitz, and Gladden 1982). Consultation between the U.S. Fish and Wildlife Service and the Department of Energy concerning the L Reactor restart (mandated by Section 7 of the Endangered Species Act) led to approximately eight hundred aerial surveys of the SRSS from 1983 to 1992. Stork use during that period depended on reactor operation impacts on water levels and stage of the breeding season. The Section 7 consultation also required replacement of the foraging habitat impacted by reactor operations (Bryan et al. 2000). The Kathwood foraging ponds built on the National Audubon Society’s Silverbluff Sanctuary near Jackson, South Carolina, have operated from 1986 through the present. These impoundments, which were stocked with fish and partially drained in late summer, successfully attracted a maximum of one hundred to more than three hundred storks per day. In some years, these impoundments probably reduced the number of storks using SRS wetlands. However, in other years, they also may have attracted storks into the general region, increasing sightings on the SRS after the impoundments were refilled for the fall. Aerial surveys for wood stork use have declined in recent years (table 5.5) but now include many Carolina bays and baylike ephemeral wetlands. Storks foraged in those wetlands, but they were not systematically surveyed prior to the 1990s. Storks use them regularly in the late-summer and fall months and depend on fish populations affected by rainfall. With the cessation of SRS reactor operations, stork use of the SRSS has declined. Vegetative succession is reducing the amount of open water and number of prey available for foraging (Coulter 1989). Current water fluctuations in the SRSS are less intense than those during reactor operations, being driven by rainfall amounts and, to a lesser extent, water releases into the river from Thurmond Reservoir. Therefore, long-term stork use of the SRSS as foraging habitat likely will be minimal, although local conditions may make the swamp attractive for short periods.

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Bald Eagle A. Lawrence Bryan, Jr., and William L. Jarvis The bald eagle (Haliaeetus leucocephalus) has a varied history in the United States. Regionally abundant since the colonial period, the species became somewhat rare in the contiguous United States in the mid-1900s due to human persecution (hunting, poisoning) and reduced reproduction due to pesticides, primarily DDT (Buehler 2000). Bald eagles were listed for protection under the Bald Eagle Protection Act in 1940, the Endangered Species Preservation Act of 1966 (southern subspecies), and the Endangered Species Act (ESA) of 1973 (population within the contiguous United States). As environmental DDT levels and human persecution have decreased, portions of the population have made significant increases and may have reached pre-DDT levels. In 1995, the U.S. Fish and Wildlife Service down-listed the status of the bald eagle from endangered to threatened under ESA, and in 1999 the agency proposed delisting the species. No ruling has yet been offered on that proposal, and bald eagles remain in the threatened category. Bald eagles have used reservoir habitats on the Savannah River Site (SRS) since 1959 (Norris 1963), and one to two pairs breed annually on the site (figure 5.8). Eagles appear throughout the year, indicating that migratory transients and prebreeding eagles use the SRS during the nonbreeding season as well.

Habitat Requirements and Occurrence on SRS Bald eagles typically nest in close proximity (less than 2 km, or 1.3 mi) to extensive aquatic foraging habitat (McEwan and Hirth 1979; Wood, Edwards, and Collopy 1989). On the SRS, the Eagle Bay nest is located in a cypress wetland 0.9 km (0.6 mi) south of the 1,012-ha (2,500-ac) Par Pond reservoir, and the Pen Branch nest is on the creek drainage 1.4 km (0.9 mi) west of the 418-ha (1,033-ac) L Lake reservoir (figure 5.8). Breeding eagles generally occupy these nest territories during the fall and winter months (October–March). This timing allows the adult eagles to forage on seasonally abundant waterfowl, primarily migratory American coots, and then shift to abundant fish in the reservoirs (Bryan 1999). Eagles using SRS habitats during other portions of the year feed primarily on fish or possibly carrion.

Figure 5.8. Locations of bald eagle nest sites and management areas on the Savannah River Site.

Threatened and Endangered Species

297

Eagles most commonly appear on L Lake, Par Pond, and Ponds B and C, and less so in the Savannah River swamp system (Mayer, Hoppe, and Kennamer 1986). Five to six eagles are typically observed on the SRS during the winter-spring months; two to three are more typical of the summer and early fall months.

Anthropogenic Effects Reservoir construction is probably the single most important anthropogenic factor affecting eagles on the SRS. The construction of Par Pond, L Lake, and Ponds B and C provided relatively isolated foraging and breeding habitat for bald eagles when South Carolina’s eagle population was expanding inland from historical coastal territories. Wintering and migratory waterfowl, common prey for eagles, use SRS reservoirs extensively during the fall-winter period (Mayer, Kennamer, and Hoppe 1986). Fish are abundant in these reservoirs; their only losses result from environmental monitoring collections and natural predators, such as eagles. Eagles nesting on Pen Branch consume primarily largemouth bass (Bryan 1999). Inland reservoirs were important in the expansion of South Carolina’s eagle population (Mayer, Hoppe, and Kennamer 1985; Bryan et al. 1996). The SRS built both Par Pond and L Lake as cooling reservoirs for nuclear reactors on the site. Radiocesium (137Cs) is present in the sediments and fish of both sites, with Par Pond fish having almost an order of magnitude more cesium than L Lake fish (Halverson et al. 1997). Effects of long-term cesium exposure on avian species are largely unknown, but an assessment of cesium risks to SRS eagles suggested that concentrations in fish pose relatively minor threats to the eagles (Hart et al. 1996; Bryan et al. 2002). Also, water pumped from the Savannah River currently maintains both reservoirs. Mercury in river water from off-site sources has contaminated both. Par Pond has a well-established bass population and maintains a cohort of larger, older fish with relatively high mercury concentrations. The more recently constructed L Lake reservoir (1985) has elevated mercury concentrations common to new reservoirs and flooded soils (Bodaly et al. 1997). Mercury levels in bass from Par Pond and L Lake surpass that recommended for a “sensitive avian species” (Eisler 1987) and may pose a threat to bald eagles. Mercury concentrations in eagle nestlings from Pen Branch are generally higher than in most other nestlings in the state ( Jagoe et al. 2002).

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In 1991, structural anomalies in the Par Pond dam resulted in the partial drawdown of that reservoir, effectively reducing water levels by 6 m (20 ft) and surface area by 50 percent (Halverson et al. 1997). Bald eagle sightings increased in the years after drawdown, presumably due to greater prey availability, as fish were concentrated in a reduced area and protective cover for fish was diminished when the water level dropped below the macrophyte beds in the littoral zone of the reservoir (Bryan et al. 1996).

Historical Trends Bald eagles have been observed in the central Savannah River area since the early 1900s (Murphey 1937). The first record of an eagle on the SRS occurred in 1959, when a single bird was observed at the newly filled Par Pond (Norris 1963). Eagle occurrence increased in the 1970s and early 1980s (Mayer, Hoppe, and Kennamer 1985, 1986), and eagle nesting was first documented in 1986 at the Eagle Bay site (Mayer, Kennamer, and Brooks 1988). The second eagle nest was discovered in 1990 at the Pen Branch site. The SRS has monitored both nest sites regularly since their discovery. Ground observations occur approximately weekly through each breeding season, supplemented by aerial surveys. The Eagle Bay breeding pair was very successful during the first three years of monitoring but had sporadic success after 1988 and has not attempted to nest since 1998 (table 5.6). The Pen Branch breeding pair was consistently successful during its first nine years of monitoring but failed from 1999 to 2001 and has not attempted at that nest since (table 5.6). In late 2003, a new nest was discovered near the old Pen Branch nest site. It fledged one young in 2004. Causes for the recent reduced successes are not known but could be the result of disease (see “Avian Vacuolar Myelinopathy” below).

Management for Bald Eagles on the SRS Following the discovery of eagle nesting, the SRS developed specific management plans for both the Eagle Bay (Austin 1987) and Pen Branch breeding areas. These plans identified existing and potential conflicts (activities, events) and established management standards designed to obviate those conflicts. As suggested in the bald eagle management guidelines (U.S. Fish and Wildlife Service 1987), SRS delineated primary and secondary management zones around both nest sites intended to

Threatened and Endangered Species

299

Table 5.6 Number of nestlings fledged by bald eagle nesting pairs on the Savannah River Site, 1986–2000 Nest site Year 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 Total Average/yr attempted

Eagle Bay 2a 2 3 0b 0 0 0 1 0 0 1 0 0c 0c 0c 0c 0c 0c 9 0.8

Pen Branch

2a 2 2 2 1 1 2 2 2d 0 0 0 0c 0c 16 0.8

a First

year nest was known to exist. nestling produced, presumed lost when nest was dislodged during a windstorm. c No nesting was attempted. d The parents abandoned a fall breeding attempt but renested three months later and produced two young. Those young fledged prematurely but were rescued and taken to the S.C. Center for Birds of Prey at Charleston, where they were eventually “hacked” (released) back into the wild. b Single

promote optimum conditions for eagles by minimizing human activity (figure 5.8). The original primary zone for the Eagle Bay nest consisted of an 85-ha (210-ac) area within and adjacent to a 457-m (1,500-ft) radius from the nest site. Surrounding that zone was the 112-ha (275-ac) secondary zone to protect the integrity of the primary zone, as well as known flight corridors to feeding areas (primarily Par Pond and Lower Three Runs), and to protect potential nest, roost, and perch trees. In practice,

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the secondary zone (814 ha, or 2,011 ac) currently used for that nest surrounds the nest site by a 1.6-km (1-mi) radius. For the Pen Branch nest, consideration of flight corridors, feeding areas (primarily L Lake and Pen Branch), topographic, and other site-specific factors resulted in a primary zone of 241 ha (596 ac) and a secondary zone of 944 ha (2,333 ac). In addition to the primary and secondary zones for the Eagle Bay nest site, SRS identified sixteen key areas around Par Pond for management to provide for future eagle nesting and improved foraging opportunities. In 1986 and 1987, portions of those key eagle habitats received timber stand improvement (midstory removal and limited pruning) to improve eagle access for roosting, perching, and possible nesting. To optimize eagle habitat and avoid conflicting activities, SRS developed action items or management standards specific to each management zone and phase of the eagle reproductive cycle. Standards restrict aircraft use (vertical and horizontal from nest), road construction, timber (and other resource) management, prescribed burning, hunting, and nuisance animal control. Since development of management plans for the Eagle Bay and Pen Branch breeding areas, three additional eagle nest starts have been documented (A. Bryan, pers. obs., 1996; F. Brooks, U.S. Forest Service, retired, pers. obs., 1998; S. Czapka, U.S. Forest Service, pers. obs., 2001). The first two were along the east shore of Par Pond near Green Road, and the third was on the east shore of L Lake. The first two were not completed and have since disappeared. The third was completed, but eagles did not lay eggs and the nest was not active in 2002 or 2003. In the event that other potential SRS eagle habitat becomes occupied in the future, specific management strategies will be developed. In addition to maintenance of the management zones, SRS monitors existing nests and other potential nesting habitat and feeding areas by aerial and ground observations throughout the year. Occasionally, special management needs or opportunities arise. For example, in 1989 and 1994, high winds blew down the nest at Eagle Bay. On both occasions, SRS installed a nest platform in the original nest tree along with loosely arranged nesting materials, and successful eagle nesting ensued.

Avian Vacuolar Myelinopathy Avian vacuolar myelinopathy (AVM) is a frequently fatal neurologic condition of unknown origin affecting bald eagles and waterfowl, primarily American coots (Fulica americana), in the southeastern United States

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301

(Thomas, Meteyer, and Sileo 1998). Since 1994, more than eighty eagles and hundreds of coots have died in the United States from this affliction. Two eagles (an adult in 1998 and an immature in 1999) found dead on the SRS were confirmed as having AVM. Other coincidental aberrant eagle behaviors observed during this period include an eagle hanging upside down from a tree limb at the Eagle Bay nest site (December 1998), an eagle pair with hatched young abandoning a nesting attempt at Pen Branch (December 1998), an eagle pair with eggs abandoning a nesting attempt at Pen Branch (December 1999), and a dead eagle (immature, not analyzed for AVM) on the Pen Branch nest (2001). No direct link between nest abandonment and AVM has been established. American coots are a possible transmission vector between AVM and eagles. Occurrence of AVM in SRS coots has increased since its discovery in 1998. The SRS first documented coots with AVM during the winter of 1998–1999, when 36 percent collected on Par Pond tested positive for AVM. Coots collected on L Lake during that period did not have AVM. In 1999–2000, 46 to 60 percent of coots collected on both reservoirs were diagnosed with AVM, and in 2000–2001, 90 to 95 percent of coots collected on both reservoirs were diagnosed with AVM. We do not yet know the cause of this disease, but it probably does not result from known contaminants (cesium and mercury) associated with the SRS. It may be the result of natural algal toxins linked to fluctuating water levels. Regardless, it has likely affected recent eagle occurrence on the SRS; its potential impact on future eagle nesting at SRS is unknown.

Red-Cockaded Woodpecker Peter A. Johnston The red-cockaded woodpecker (Picoides borealis) is an inhabitant of the once extensive, fire-maintained longleaf pine savannas of the Southeastern Coastal Plain (Conner, Rudolph, and Walters 2001). It requires a mature pine forest with an open midstory. The loss of mature pine forests through logging and clearing for agriculture, as well as the suppression of fire, which serves to maintain the pine-savanna vegetation type, has led to the decline of this unique species (U.S. Fish and Wildlife Service 2003; Jackson 1986; Ligon et al. 1986; Walters 1991). Although historical records are vague and subjective, Audubon (1839) stated that red-cockaded woodpeckers were “found abundantly from Texas to New Jersey and as far

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inland as Tennessee.” In the mid-1900s, ornithologists still considered them “locally common,” although only one third to one half of the pine forests of the southeastern United States remained. Subsequent declines and the loss of nesting habitat promoted concern over the red-cockaded woodpecker’s future, and in 1970 it was listed as an endangered species. In 1979, in the first rangewide census of federal lands, the total population estimate was 2,677 pairs. The red-cockaded woodpecker is one of nine species of woodpeckers endemic to the southeastern United States. It is relatively small, about 18 cm (7 in) in length, and is distinguished from similar species by its white cheek patch. The red-cockaded woodpecker is the only North American woodpecker that excavates its cavities exclusively in living pine trees (Ligon et al. 1986). It is a cooperative breeder that lives in family groups of two to ten individuals, with males from previous generations and, in rare cases, females helping to care for the young. Each family group occupies a cluster of cavity trees, in which they roost year-round, with only one bird occupying each cavity. Cavity trees are typically 60 to 120 years old and must have adequate heartwood for the woodpecker to excavate. Older trees are more likely to have a fungal infection known as “red heart,” or “heart rot,” that rots trees from the inside out, making excavation easier. Once a red-cockaded woodpecker has established a cavity, it will maintain and defend it. The woodpeckers work on the bark surrounding the cavity entrance to make a “plate,” or an area around the entrance devoid of bark. They also maintain “resin wells” by pecking through the bark to the cambium layer to create a sap flow down the tree. They maintain the resin wells continually throughout the year to keep the sap flowing. The sticky sap apparently serves as a deterrent to predators that would climb the tree, primarily rat snakes (Rudolph, Kyle, and Conner 1990). Wood roaches (Parcoblatta spp.) are the most frequent prey delivered to nestling red-cockaded woodpeckers on the Savannah River Site (SRS), though wood borer larvae (Cerambycidae, Buprestidae), Lepidoptera larvae, spiders (Araneae), and ants (Formicidae) are also important dietary components (Hanula and Franzreb 1995; Hanula, Lipscomb et al. 2000). Red-cockaded woodpeckers typically forage on the largest trees available, preferring trees over 25 cm (10 in) in diameter at breast height (Zwicker and Walters 1999). Arthropod biomass per tree increases with longleaf pine stand age up to sixty-five to seventy years (Hanula, Franzreb, and Pepper 2000), but longleaf pine trees growing on old-field sites on SRS

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provide the same prey as those on relatively undisturbed sites in southern Georgia (Hanula and Engstrom 2000). Collectively, the nesting and foraging habits of red-cockaded woodpeckers indicate that the species is associated with mature pine habitat conditions.

Population History When the Department of Energy purchased the SRS in 1950, much of the land was being used for agricultural purposes (see chapter 1). Before the sale, residents logged much of the remaining standing timber. As a result, the SRS had relatively little habitat suitable for the red-cockaded woodpecker during the latter half of the twentieth century. A 1979 census estimated the SRS population at about seventeen groups. In 1980, there were ten groups. By 1986, only four birds remained, one breeding pair and two lone males. This precipitous decline was apparently caused by several interacting factors. In 1980, Jackson (1980) reported that the loss of red-cockaded woodpecker groups on SRS was attributable to the lack of adequate cavity trees; seven of eighteen groups in existence between 1974 and 1980 were lost from damage to cavity trees caused by lightning and pileated woodpeckers. Jackson later noted (1981, 1990) that none of the areas in which these groups lived had received prescribed burning for at least ten years prior to their abandonment by the woodpeckers, and that midstory hardwoods approached cavity height. Infrequent burning and the resulting midstory encroachment, combined with cavity loss to competitors and lightning and the lack of large trees to replace them probably all contributed to the decline of the SRS woodpeckers in the 1970s and early 1980s. In 1985, SRS initiated a cooperative red-cockaded woodpecker research and management program with the U.S. Forest Service Southern Research Station to restore the population. An intensive monitoring program included marking all birds on the SRS with color bands that identified each individual. To expand the population, SRS implemented several aggressive management strategies (see “Population and Habitat Management” below). The combination of these strategies and the maturing of pine trees on SRS has resulted in dramatic growth of the population since 1985 (table 5.7, figure 5.9). The SRS exceeded its short-term goal, set in 1986, of reaching thirty groups by 2000. Although not yet completely recovered, this red-cockaded woodpecker population represents a great success in endangered species management.

Table 5.7 Numbers of red-cockaded woodpecker fledglings and groups on the Savannah River Site, 1990–2003 Northern subpopulation

Southern subpopulation

Total

Year

Male:female

No. groups

Male:female

No. groups

Male:female

No. groups

1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003

2:NAa 1:1 2:1 0:2 2:2 3:2 2:3 2:3 7:4 6:9 10:7 7:13 11:9 7:14 17:15 12:23 11:17 23:19 12:20

3 1 1 2 2 4 5 6 6 7 10 12 13 17 20 22 26 28 30

0:0 1:1 1:3 0:2 3:1 2:2 1:5 4:4 7:4 11:6 10:9 14:9 10:10 7:14 8:14 14:7 8:16 7:11 8:17

2 2 2 2 2 3 3 4 5 6 8 10 11 11 11 12 11 14 15

2:NA 2:2 3:4 0:4 5:3 5:4 3:8 6:7 14:8 17:15 20:16 21:22 21:19 14:28 25:29 26:30 19:33 30:30 20:37

5 3 3 4 4 7 8 10 11 13 18 22 24 28 31 34 37 42 45

a NA

= not available.

Figure 5.9. Number of groups and size of post-breeding-season population of redcockaded woodpeckers on the Savannah River Site, 1975–2003. Population size was available only for 1985–2003.

Threatened and Endangered Species

305

Current Status During the 2003 breeding season, SRS had forty-five red-cockaded woodpecker groups, thirty-four of which attempted nesting. Twenty-nine groups successfully fledged at least one young. Sixty-nine young were banded in the nest, and fifty-nine young fledged, for an average of 1.74 young per nest. Following the 2003 breeding season, the total site population numbered 177 individuals, with an average group size of 2.6 adult birds. The groups are divided between northern (n = 30) and southern (n = 15) subpopulations (figure 5.10). The population had an unprecedented average annual growth rate of about 22 percent from 1991 to 2000.

Recovery Goal The federal red-cockaded woodpecker recovery plan has identified SRS as a “secondary core” population, which requires a viable population of 250 potential breeding groups (U.S. Fish and Wildlife Service 2003). A secondary core provides gene flow into a “primary core” population, the nearest being at Fort Stewart in Georgia and Francis Marion National Forest in South Carolina, and acts as a reserve against stochastic events, such as hurricanes and disease outbreaks. Assuming an annual population growth rate of 10 percent (Edwards et al. 2000), SRS can reach the 250group target within thirty-seven years. Current SRS research is addressing factors that affect colonization of new habitat, including recruitment stands, in order to further facilitate population growth and the merging of the northern and southern subpopulations.

Population and Habitat Management Management of red-cockaded woodpeckers at SRS includes both maintenance and development of suitable habitat, as well as direct management of the population. The SRS red-cockaded woodpecker management plan established a primary habitat management area (HMA; 34,831 ha, or 86,069 ac) and a Supplemental HMA (18,683 ha, or 48,167 ac), which together amount to approximately two thirds of the SRS (figure 5.10; Edwards et al. 2000). The SRS delineated these areas based on woodpecker distribution, potential longleaf pine distribution, and smoke management considerations. Within the HMA, loblolly pine is managed on 100-year rotations and longleaf pine on 120-year rotations. Rotation lengths are fifty years for both longleaf and loblolly pine in the Supplemental HMA.

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Figure 5.10. Location of active and inactive red-cockaded woodpecker (RCW) groups and recruitment stands within habitat management areas (HMA) during 2001 on the Savannah River Site.

Edwards et al. (2000) provide various guidelines on the size and type of timber harvest that can occur in each area. Specific red-cockaded woodpecker management strategies have included provision of artificial cavities and “recruitment stands,” midstory control, translocation, cavity restrictors, and southern flying squirrel control.

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Figure 5.11. Artificial cavity inserts, developed at SRS, have become a critical tool in red-cockaded woodpecker recovery efforts rangewide (U.S. Forest Service files).

Artificial Cavities and Recruitment Stands The availability of roosting and nesting cavities can be a limiting factor for red-cockaded woodpeckers, and it certainly was at the SRS. The shortage of suitable cavities, combined with the long time required for redcockaded woodpeckers to excavate natural cavities (several months to years), posed a serious impediment to restoring this population. These conditions led to the development at SRS of artificial cavities inserted into mature pine trees to promote colonization of unoccupied habitat (figure 5.11; Allen 1991). Red-cockaded woodpeckers at SRS readily accepted artificial cavities and reproduced successfully in them (Franzreb 1997). Artificial cavities are most often placed in clusters of suitable trees, which are then designated as recruitment stands. In addition to promoting group initiation in recruitment stands, SRS installs artificial

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cavities in active groups when the number of birds in the group exceeds the number of available cavities. When cavities are not available for roosting, red-cockaded woodpeckers will roost in the open (Hooper and Lennartz 1983), susceptible to nocturnal predation and weather. Artificial cavities provide roosting and nesting sites for the birds for several years, allowing them to reproduce while they create their own cavities. In 2000, there were 346 artificial cavities on the SRS, of which 231 were in 58 recruitment stands (figure 5.10). The remaining 115 artificial cavities were in active stands.

Midstory Control Prescribed fire is an essential tool for managing red-cockaded woodpecker habitat. In the absence of fire, hardwoods encroach to the height of the woodpecker cavities (figure 5.12). Then the birds abandon the cluster, presumably because the midstory provides access to the cavities by predators ( Jackson 1978; Van Balen and Doerr 1978; Costa and Escano 1989). Although prescribed burning was historically conducted during both dormant and growing seasons for red-cockaded woodpeckers at SRS (table 5.8), under the current management plan it is scheduled during the

Figure 5.12. A red-cockaded woodpecker cavity tree with an encroaching midstory below. Woodpeckers abandon cavity trees or clusters when the midstory gets too high (J. Kilgo).

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Table 5.8 Acreage receiving midstory control and prescribed burning for redcockaded woodpecker management on the Savannah River Site, 1990–2003 Growing-season Dormant-season Year

Midstory control

1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003

334 736 1,001 547 188 128 321 851 233 586 50 150 200 298

burn

burn

0 0 104 0 0 635 765 1,110 1,728 931 0 2,452 0 1,252

1,642 0 7,413 4,502 5,014 10,883 7,274 14,221 7,748 9,330 5,869 9,408 3,915 4,906

Total burn 1,846 807 7,517 4,502 5,014 11,518 8,039 15,331 9,476 10,261 5,869 11,860 3,945 6,158

Note: 1 ac = 0.405 ha.

growing season every four years for active woodpecker clusters. It is also conducted in recruitment stands and foraging areas. By reducing hardwoods, fire creates a more open habitat and encourages herbaceous growth in the understory. Because safe and effective prescribed burning must not violate air quality regulations or impact neighboring communities, appropriate burning weather limits the area that can be burned every year. To compensate for an irregular burning schedule, alternative methods of midstory control including mechanical removal and herbicides help maintain the quality of the stands (table 5.8).

Translocation Translocation of birds from other populations has played an integral role in the recovery of the red-cockaded woodpecker at the SRS (DeFazio et al. 1987; Allen, Franzreb, and Escano 1993; Gaines et al. 1995; Franzreb 1997, 1999). From 1986 to 2000, the SRS translocated thirty-six birds from other locations (table 5.9). By 1992, 87 percent of the birds on SRS either were translocated from an outside source or were offspring of such birds (Gaines et al. 1995). Red-cockaded woodpeckers were also translocated within SRS to facilitate group formation.

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Table 5.9 Number of red-cockaded woodpeckers translocated to the Savannah River Site, 1986–2000 Year

No. of birds

1986 1987 1988 1989 1990

3

Francis Marion National Forest (South Carolina)

5

Francis Marion National Forest (South Carolina)

3 1

Francis Marion National Forest (South Carolina) Fort Bragg (North Carolina)

2 3

Apalachicola National Forest (Florida) Apalachicola National Forest (Florida)

2

Carolina Sandhills National Wildlife Refuge (South Carolina)

1

Francis Marion National Forest (South Carolina)

6 7 1

Norfolk Southern Co., Brosnan Forest (South Carolina) Carolina Sandhills National Wildlife Refuge (South Carolina) Fort Jackson (South Carolina)

1991 1992 1993 1994 1995 1996 1997 1998 1999 2000

Source

Between 1986 and 1995, 51 percent of translocated birds (both from outside and within SRS) reproduced successfully (Franzreb 1999). Franzreb found that translocation success was positively related to the distance birds were moved and recommended that translocations be at least 7 km (4 mi), but the greater the distance the better. She concluded that neither the age of females translocated to resident males, nor the age, sex, or status of translocated pairs affected translocation success. From 1995 to 2000, a mobile aviary was used to encourage males to stay in their new location (Edwards, Dachelet, and Smathers 1997). The aviary was set up around a cavity tree and enclosed a bird for two weeks before its release. However, it did not significantly increase translocation success, and SRS abandoned the project. The SRS is no longer translocating red-cockaded woodpeckers from offsite populations. Translocations within the SRS are used to introduce young males to potential breeding territories or to pair young females with lone resident males. During winter, SRS groups with at least one helper male are targeted as sources for translocation. These juvenile males are trapped and moved to recruitment stands, where they may establish a territory.

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Cavity Restrictors To control cavity enlargement by pileated and red-bellied woodpeckers, SRS uses restrictor plates (Carter et al. 1989). These are 6×9-in (15×23-cm) perforated steel plates or mesh with an entry hole, placed over the cavity entrance. Cavity restrictors are placed on all artificial cavities upon installation and on natural cavities as needed, when evidence of cavity expansion appears.

Flying Squirrel Control Southern flying squirrels frequently usurp red-cockaded woodpecker cavities (“kleptoparasitism,” Kappes 1997). Red-cockaded woodpeckers tend to use the same cavity day after day for years at a time. In contrast, flying squirrels tend to be nomadic, using many different cavities. A single flying squirrel may evict several woodpeckers from cavities. Flying squirrels also occasionally prey on woodpecker eggs and nestlings (Conner et al. 2001). Laves and Loeb (1999) demonstrated that flying squirrels significantly impacted reproductive success of red-cockaded woodpeckers. To reduce flying squirrel kleptoparasitism, SRS developed “squirrel excluder devices,” or SQEDs (pronounced squed; Loeb 1996a). SQEDs consist of aluminum flashing, approximately 18 in wide, with flaps cut into the tops to prevent the sap from running over the surface, that creates a slick surface above and below the cavity entrance. SQEDs complement the sap flow created by the woodpecker as a predator deterrent. Initially, SQED installation targeted only inactive trees, then trees inhabited by auxiliary group members, and finally the trees inhabited by the breeding pair. Since group composition is dynamic and birds occasionally move from tree to tree, protection of the nesting tree was a continual process. In 2000, the SRS discontinued installation of SQEDs. Beginning in 1985, flying squirrels were removed from cavities during routine cavity inspections (table 5.10). DeFazio et al. (1987) concluded that this control was important for the small red-cockaded woodpecker population at SRS. Franzreb (1997) and Laves and Loeb (1999) reached the same conclusion. However, many workers (Mitchell, Carlisle, and Chandler 1999; Conner et al. 2001) now feel that while flying squirrel removal may benefit extremely small woodpecker populations, like those of the SRS during the 1980s and 1990s, squirrel removal is unwarranted in most populations. Considering the growth of its woodpecker population, the SRS reduced flying squirrel removal after 2001.

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Table 5.10 Number of southern flying squirrels removed from red-cockaded woodpecker cavities on the Savannah River Site, 1986–2003 Year

No. removed

1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003

69 27 126 96 107 89 104 135 167 512 731 712 878 375 284 369 92 68

Sensitive Animals William L. Jarvis A large and diverse assemblage of animals inhabits the Savannah River Site (SRS), including 87 fishes; 44 amphibian and 59 reptilian species; 259 birds, approximately 120 of which are breeding residents; 54 mammals; and thousands of invertebrates (see chapter 4). The SRS has designated thirty-two animals as sensitive. The term refers to animals and plants not federally protected under the Endangered Species Act (ESA) of 1973, whose population viability is a concern. The purpose of identifying, monitoring, and managing sensitive species is proactive, to ensure viability and to prevent any trend toward endangerment that could result in the need for federal listing under the ESA. The SRS reviews and updates its sensitive species list annually, based partially on the rarity and vulnerability rankings (global and state) of The Nature Conservancy and the South Carolina Department of Natural Re-

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sources (SCDNR). Typically, species having global rankings of G1, G2, or G3 or state rankings of S1, S2, or S3 (see table 5.3) are designated as sensitive. A question mark after the ranking indicates uncertainty in the rank. Species not federally listed but considered by the State of South Carolina to be threatened or endangered (under the South Carolina NonGame and Endangered Species Conservation Act of 1976) automatically are SRS sensitive. Species that SCDNR ranks “special concern” may or may not be listed as SRS sensitive, depending on their S ranking and local factors. The SRS also consults appropriate local and state authorities for the various taxa and local monitoring information. In addition to the thirty-two species, SRS has designated the headwater portion of Pen Branch (above Indian Grave Branch) as a stream worthy of protection due to its unique faunal characteristics. Surveys have revealed the presence of 341 aquatic insects, including 1 species never before found in the United States, 33 new species records for South Carolina, and 11 species new to science (Morse 1998). Unlike the similarly diverse Upper Three Runs, Pen Branch is not within a Department of Energy set-aside area. It should certainly receive protection from potentially harmful activities.

Mammals The current SRS list of sensitive animals includes seven mammals.

Southeastern Myotis The southeastern myotis (Myotis austroriparius), G3G4-S2S3, is listed as a state threatened species (SCDNR 2001, unpublished document). This bat typically roosts in caves, cavelike artificial structures, or hollow trees (W. M. Ford, U.S. Forest Service, pers. comm.) and forages over water bodies. Previous surveys at SRS had not revealed this bat’s presence (Cothran et al. 1991). However, Menzel (1998) captured this species during 1996–1997 surveys at SRS and has recorded it occasionally on recent surveys (Menzel, Menzel, Kilgo et al. 2003). Foraging activity is concentrated near the floodplain of the Savannah River and is highest in Carolina bays, bottomland hardwood forests, and forest gaps. The southeastern myotis probably roosts in tree cavities in bottomland hardwood forests on SRS (Menzel, Menzel, Kilgo et al. 2003). It may occur at SRS only seasonally (chapter 4).

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Little Brown Bat Like M. austroriparius, the little brown bat (Myotis lucifugus), G5-S3?, roosts in caves, but during summer it will roost under rocks, in piles of wood, and in trees (Fenton and Barclay 1980). However, the SRS is not in the normal range of the species (Menzel, Menzel, Ford, et al. 2003). Menzel, Menzel, Kilgo et al. (2003) reported the capture of one female near the Savannah River swamp in summer 1996 but concluded that this record was extralimital, so occurrence at SRS is probably accidental.

Rafinesque’s Big-Eared Bat Rafinesque’s (or southeastern) big-eared bats (Corynorhinus rafinesquii), G3G4-S2?, are state-listed in South Carolina as endangered (SCDNR 2001, unpublished). Roosting habitat includes caves, partially lit buildings, and trees (Barbour and Davis 1969). Menzel, Menzel et al. (2001) reported that seven of eight abandoned buildings surveyed on the Silver Bluff Audubon Sanctuary, 8 km (5 mi) northwest of SRS, contained reproductively active male big-eared bats. Their occurrence at SRS had been based solely on two specimens in the University of Georgia’s Museum of Natural History (Cothran et al. 1991), but Menzel, Menzel, Kilgo et al. (2003) reported one roosting in the Hog Barn near the Savannah River swamp in the late 1990s, and they reported the capture of seven adult females and one adult male. In 2003, S. Loeb (U.S. Forest Service, unpublished data) found big-eared bats roosting under five bridges at SRS, one of which supported a maternity group. Foraging habitat at SRS probably includes mature bottomland hardwood and swamp forests, brushy communities, and three- to five-year-old pine plantations (Menzel, Menzel et al. 2001; Menzel, Menzel, Kilgo et al. 2003).

Star-Nosed Mole The star-nosed mole (Condylura cristata), G5-S3?, a semi-aquatic species typically found at the edges of swamps, bays, and reservoirs (chapter 4), occurs on SRS (Cothran et al. 1991; McCay et al. 1999). Recording occasional captures in upland pines, McCay et al. suggested these were dispersing individuals. However, the star-nosed mole is not common and little is known about the species on SRS. The SRS population of this mole may be an isolated one; elsewhere in South Carolina it has been reported only along the coast and in the mountains (W. M. Ford, pers. comm.).

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315

Eastern Woodrat On SRS, eastern woodrats (Neotoma floridana), G5-S3S4, occur in a variety of hardwood habitats and near abandoned structures (Cothran et al. 1991), as well as in mature longleaf pine forests (Loeb 1999). W. M. Ford (unpublished data) reported the species to be generally uncommon on SRS but locally common in logging slash windrows and thick cane habitats of extensive bottomland hardwood stands.

Swamp Rabbit Despite extensive surveys (W. M. Ford, unpublished data), the swamp rabbit or canecutter (Sylvilagus aquaticus), G5-S3, is not a confirmed species for SRS, but it has been found immediately across the Savannah River in Columbia County, Georgia (Cothran et al. 1991). It may occur in the floodplain forests of SRS swamps.

Black Bear Although not established as a breeding species on SRS, the black bear (Ursus americanus), G5-S3, has been periodically observed since the SRS was established (Urbston 1972; M. Caudell, SCDNR, pers. comm.). South Carolina DNR heretofore has categorized the black bear as a transient species (between mountain and coastal populations) in the SRS area; but considering recent population growth in the upstate area, surveys to assess the current status of the species on SRS are planned (H. Still, SCDNR, pers. comm.).

Birds Eight species of birds have been designated sensitive at SRS.

American Swallow-Tailed Kite South Carolina lists the American swallow-tailed kite (Elanoides forficatus), G5-S2, as an endangered species (SCDNR 2001, unpublished). The primary breeding range of this swamp forest and marsh species is southern Florida, but it extends into the lower coastal plain of South Carolina (Hamel 1992). Several sightings of swallow-tailed kites occur annually on SRS, primarily near the Savannah River swamp. The U.S. Forest Service

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documented the first nesting record on the site in 2003, in the Savannah River swamp, approximately 500 m (1,640 ft) from the river. Efforts are underway to better assess the species’ breeding status on SRS.

American Kestrel Other than the endangered red-cockaded woodpecker (Picoides borealis), the American kestrel (Falco sparverius), G5-S4, is the cavity dweller requiring the greatest attention within the South Atlantic Coastal Plain; Partners in Flight ranks it regionally as a species of “highest priority” for conservation (Hunter, Peoples, and Collazo 2001). Little was known about the breeding status of kestrels on the SRS after Norris (1963) documented nesting in 1956. In 1991, the SRS erected thirty kestrel nest boxes in power lines, but no kestrel nesting occurred. In 1996, A. Beheler (Purdue University, pers. comm.) found a kestrel nest in a two-year-old longleaf pine plantation, the first known nesting on SRS since Norris’s 1956 record. The previous year, she had repeatedly observed eight kestrels on SRS using the same habitat type (Beheler and Dunning 1998).

Common Ground Dove The common ground dove (Columbina passerina), G5-S?, is a state-threatened species (SCDNR 2001, unpublished). Contrary to its name, it is somewhat rare on the SRS. Breeding Bird Censuses on the site found it to breed at a density of one to three pairs per 40 ha (100 ac) in a clear-cut, recently regenerated, longleaf pine stand (Irby, Gauthreaux, and Jarvis 1995, 1996).

Loggerhead Shrike Loggerhead shrikes (Lanius ludovicianus), G5-S3, once were reported as common on SRS (Norris 1963), perhaps due to the predominance of recently abandoned open shrubby fields. In recent years, this occupant of very open woods and large herbaceous openings with scattered thickets apparently has declined as a breeding resident. It has occurred rarely on breeding bird point counts conducted since 1992 ( J. Dunning, Purdue University, unpublished data). A few scattered breeding-season observations are reported each year, primarily along roadways (S. Wagner, Lander College, pers. comm.). The annual SRS Christmas Bird Count regularly

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317

documents wintering shrikes (C. Eldridge, Savannah River Ecology Lab, pers. comm.).

Swainson’s Warbler The Swainson’s warbler (Limnothlypis swainsonii), G4-S4, also was reportedly once common in suitable habitat (Norris 1963). Although ranked only G4-S4 in South Carolina, it is designated as sensitive on SRS due to its local rarity and high conservation priority ranking by Partners in Flight (Hunter, Pashley, and Escano 1993). It has been recorded only rarely in breeding bird censuses and point counts on SRS in recent years; though in dense switchcane and vine tangles in extensive bottomland hardwood forests, it occurs regularly ( J. Kilgo, U.S. Forest Service, pers. comm.). The species is highly area sensitive at SRS (Kilgo et al. 1996).

Painted Bunting The eastern painted bunting (Passerina ciris), G?S?, is one of Partners in Flight’s highest-priority species for conservation in the South Atlantic Coastal Plain (Hunter, Peoples, and Collazo 2001). Sporadic breedingseason records exist on SRS, where it uses the shrub-scrub habitat of young pine plantations and rights-of-way, primarily on the southern end of the site (pers. obs.). Areas of greatest abundance in South Carolina are near the coast, and SRS is near the inland-most extent of its distribution in the state.

Henslow’s Sparrow The Partners in Flight Bird Conservation Plan for the South Atlantic Coastal Plain (Hunter, Peoples. and Collazo 2001) lists Henslow’s sparrow (Ammodramus henslowii), G?S?, among the highest-priority land birds. The species breeds in the northeastern and midwestern United States but winters in grasslands of the Southeastern Coastal Plain. Little is known about the wintering ecology of this highly secretive bird. Henslow’s sparrows historically occurred in Aiken County (Sprunt and Chamberlain 1949), but Norris (1963) did not find them at SRS between 1950 and 1963. The species did not appear on SRS Christmas Bird Counts until 2001. Whether it went undetected or was absent and recently recolonized the SRS is unknown. P. Champlin and J. Kilgo (U.S. Forest Service, unpublished data) captured thirty-four birds on SRS during the winter of

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2002–2003 and determined that Henslow’s sparrows use areas of dense grass cover in herbaceous Carolina bays and power line rights-of-way.

Bachman’s Sparrow In the 1950s, Bachman’s sparrow (Aimophila aestivalis), G3-S3, was fairly common in SRS pine woods (Norris 1963) and remains so in appropriate habitats. It is associated with older pine stands that have an open grassy understory and with the grass-forb or seedling sere of recently regenerated pine stands (Droge et al. 1993). This sparrow is apparently declining in the Southeast, however, largely due to loss and fragmentation of the above two habitat types (Dunning et al. 2000). Landscape configuration appears to be an important factor controlling Bachman’s sparrow populations. Young pine stands (from about three years to seven to ten years in age, depending on planting density) provide suitable habitat, but colonization of such ephemeral patches is related to their distance and isolation from a source population (Dunning et al. 1995). Suitable sites on SRS often are not colonized before pine canopy closure reduces habitat quality.

Amphibians and Reptiles The SRS supports two sensitive amphibians and five sensitive reptiles.

Tiger Salamander The tiger salamander (Ambystoma tigrinum), G5-S2S3, is generally uncommon to rare in the Southeast (Wilson 1995). Breeding in permanent and temporary ponds such as Carolina bays, most of which are free of predatory fish, it largely remains in burrows in surrounding sandy uplands during the remainder of the year. It occurs in most temporary ponds and bays on SRS (see figure 4.20; Gibbons and Semlitsch 1991).

Gopher Frog The gopher frog (Rana capito), G3G4-S1, is a highly terrestrial frog, inhabiting burrows constructed by other animals or similar shelter under woody debris in pine and pine-oak uplands, but it also requires nearby breeding ponds (Wilson 1995). On SRS, Gibbons and Semlitsch (1991)

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319

reported hearing this frog vocalizing at many Carolina bays; they trapped it in at least five of those bays (see figure 4.20).

Gopher Tortoise The gopher tortoise (Gopherus polyphemus), G3-S1, is state-listed as endangered (SCDNR 2001, unpublished). Until recently, only two records of its occurrence existed for the SRS. In 2001–2002, the gopher tortoise was experimentally reintroduced to SRS (see chapter 4). Its preferred habitat of open pine stands on dry sandy soils is once again plentiful at SRS, where it was likely a resident (chapter 4) prior to the era of intensive agriculture and habitat alteration. The Savannah River Ecology Laboratory and U.S. Forest Service are currently evaluating the success of the reintroduction.

Southern Hognose Snake Although frequently observed on SRS (see figure 4.18; Gibbons and Semlitsch 1991), there is increasing concern for the southern hognose snake (Heterodon simus), G2-S?, throughout its range (chapter 4). This may be due to loss of preferred habitat areas of dry sandy pine and pine-oak uplands (Wilson 1995), as well as other factors.

Florida Green Water Snake The Florida green water snake (Nerodia floridana), G5-S2, is at the northern extent of its range at SRS (Wilson 1995), which is one of only two areas this snake occupies in South Carolina (Buhlmann and Gibbons 1997). This snake inhabits Carolina bays and other quiet waters, including reservoirs at SRS (see figure 4.19); it does not occur in streams or swamps (Gibbons and Semlitsch 1991). Buhlmann et al. (chapter 4) suggest that this snake may now be declining at SRS.

Pine Snake The pine snake (Pituophis melanoleucus), G4-S3S4, is a resident of xeric and open upland pine areas (Wilson 1995). The SRS, where it is more common than in surrounding areas (figure 4.18), appears to be an area of intergradation for the northern (P. m. melanoleucus) and Florida (P. m.

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mugitus) subspecies of the pine snake ( J. W. Gibbons, Savannah River Ecology Lab, pers. comm.).

Eastern Coral Snake Rare in South Carolina, the highly venomous eastern coral snake (Micrurus fulvius), G5-S2, is a rather secretive, burrowing animal, preferring loose sandy soils (Wilson 1995). It occurs at only a few locations on SRS, all in the far northern portion, in pine-hardwood habitats (figure 4.18).

Fishes The Atlantic sturgeon (Acipenser oxyrinchus), G3-S3, is the only sensitive fish that occurs at SRS. Bennett and McFarlane (1983) first reported it at SRS in larval form from an oxbow channel of the Savannah River. B. Marcy (Westinghouse Savannah River Co., pers. comm.) has observed it more recently in the main stream.

Invertebrates The SRS has designated nine invertebrates as sensitive, including eight mollusks and one insect.

Brook Floater A mussel of small, well-oxygenated, fast-flowing upland streams, the brook floater (Alasmidonta varicosa), G3-S?, is on the periphery of its range in South Carolina (Fuller 1979). The only pertinent information obtained came from M. Mulvey (Savannah River Ecology Lab, pers. comm., 1997), who indicated that this species was present on the SRS during the early to mid 1990s.

Brother Spike Mussel The brother spike mussel (Elliptio fraterna), G1G2-S1, is a state-endangered species (SCDNR 2001, unpublished). It was collected in the main channel of the Savannah River adjacent to SRS in 1972 (Fuller 1979). However, Mulvey (pers. comm., 1997) reported that it had not been found on SRS or in the adjacent reach of the Savannah River for at least the previ-

Threatened and Endangered Species

321

ous seven years. Fuller suggests it is “among the rarest of Nearctic naiades and possibly extinct.”

Mill Creek Elliptio The Mill Creek elliptio (Elliptio hepatica), unrated, is a locally endemic mussel species confined to the SRS’s Mill Creek and Tinker Creek, thirdorder tributaries of Upper Three Runs (Davis and Mulvey 1993).

Yellow Lance The yellow lance (Elliptio lanceolata), G2G3-S?, has been collected on SRS in the tributaries of Upper Three Runs, Pen Branch, Lower Three Runs, and the Savannah River (Britton and Fuller 1979). However, it has not appeared in more recent (1990–1997) SRS surveys (M. Mulvey, pers. comm., 1997).

Yellow Lamp Mussel The yellow lamp mussel or yellow mucket (Lampsilis cariosa), G3G4-S?, is known in the middle Savannah River, including reaches adjacent to SRS. It tolerates a variety of habitats but favors stable and muddy sands in larger bodies of water (Fuller 1979). This mussel continued to show up in SRS surveys during the early to mid 1990s (M. Mulvey, pers. comm.).

Rayed Pink Fatmucket Mussel The rayed pink fatmucket mussel or red mucket (Lampsilis splendida), G3-S?, was considered “plentiful in the middle Savannah River” (Fuller 1979) and was present in SRS surveys from 1990 to 1997 (M. Mulvey, pers. comm.).

Savannah Lilliput The Savannah lilliput or shore mussel (Toxolasma pullus), G2-S1S3, was known by only one living population, inhabiting sand bottoms stabilized by an admixture of mud in both the main stream and backwaters of the Savannah River on SRS (Fuller 1979). Mulvey (pers. comm.) also reported it present in the 1990s.

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Notched Rainbow Mussel According to Fuller (1979), little is known about the notched rainbow mussel (Villosa constricta), G3-S?, which occupies sandy stream beds sometimes stabilized by mud, silt, and detritus. Recently, Mulvey (pers. comm.) reported it present on or adjacent to SRS.

Sand-Burrowing Mayfly Morse (1998) reported the population of the sand-burrowing mayfly (Dolania americana), unrated, in Upper Three Runs as present and healthy. It is restricted to clean shifting sands in relatively unpolluted streams. This mayfly has previously been a state-threatened species in Florida, its primary range, while the SRS population appears to be disjunct (W. Specht, Westinghouse Savannah River Co., pers. comm.).

6

r

Harvestable Natural Resources Minerals Miles Denham

Commercial Forest Products John I. Blake and Ronald T. Bonar

Fishery of the Savannah River Barton C. Marcy, Jr.

Small Game John C. Kilgo

Waterfowl Robert A. Kennamer

Wild Turkey William F. Moore, John C. Kilgo, William D. Carlisle, and Michael B. Caudell

Furbearers John J. Mayer, Lynn D. Wike, and Michael B. Caudell

Wild Hog John J. Mayer

White-Tailed Deer Paul E. Johns and John C. Kilgo 323

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Outside of the Crackerneck Wildlife Management Area and Ecological Reserve (CWMA), the only natural resources currently used on the SRS are forest products, white-tailed deer, and wild hogs. The only public hunting on most of the SRS is for deer and wild hogs, as sanctioned under the deer and hog control programs. However, many other resources exist on SRS, primarily game animals, and they are described in this chapter. Miles Denham discusses mineral resources of the SRS, concluding that there are no known economically viable mineral deposits on the site. Kaolinite, sand, and gravel are mined in the vicinity of the SRS and occur in geologic strata beneath the SRS, but geologic and land-use conditions on the site make them unviable there. No mining of heavy minerals occurs in the vicinity of the SRS, but the area may be a potential source of the mineral monazite. The standing inventory of commercial forest products at SRS has increased about fourteenfold since 1951. John Blake and Ronald Bonar describe how the amount of timber harvested and the relative proportions of pine to hardwood and large to small round wood have increased dramatically in the last three decades. The annual volume sold is currently 5 to 6 million ft3. Thinning and partial cutting are a major component of harvesting operations. Since 1955, the SRS has harvested almost 160 million ft3 of wood, generating about $78 million in revenue through forest product sales, including $1.8 million for pine straw. The commercial forest program contributes significantly to the regional economy and provides a sustainable supply of wood to local manufacturers. The SRS reinvests revenue into land management, conservation, restoration, and research. Barton Marcy describes the fishery of the Savannah River adjacent to SRS and of Skinface Pond on CWMA. He discusses commercial and sport fishing for American shad, channel and white catfish, striped bass, and other species. Discussing small game animals on SRS, John Kilgo presents information on their population status and trends, CWMA harvest levels, and habitat use. He considers common snipe, American woodcock, mourning dove, northern bobwhite, eastern cottontail, marsh rabbit, and gray and fox squirrels. Robert Kennamer presents an overview of waterfowl use of SRS wetlands. Wood ducks and hooded mergansers nest on SRS. Kennamer and others have studied wood duck nesting ecology on SRS extensively through the use of nesting boxes. He estimates that the entire breeding population of wood ducks on SRS may exceed one thousand pairs. In addition, large numbers of wintering waterfowl use SRS impoundments, the most abundant species being lesser scaup, ring-necked duck, bufflehead, and ruddy duck. During the early 1980s, more individuals of these species used Par Pond than all inland bodies of water in South Carolina combined. Wild turkeys have increased dra-

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matically on SRS following reintroduction in 1973–1974, prior to which only a few turkeys occupied the site, primarily the portions along the Savannah River swamp. William Moore et al. outline the history of that population, its current status, and its habitat use. Through the trapping efforts of the South Carolina Department of Natural Resources, the SRS population has served as a source for restocking other areas since the late 1970s. John Mayer presents information on the furbearers that occur on SRS. He describes population status and habitat use of beaver, muskrat, coyote, red and gray foxes, raccoon, long-tailed weasel, mink, spotted and striped skunks, river otter, and bobcat. Mayer also outlines the history of wild hogs on SRS. Free-roaming hogs were present in the southwestern portion of SRS, primarily along the river swamp, at the time the Site was established. In the mid 1970s, a second population, the origin of which is unknown, was discovered in the north central portion of SRS. The two populations have expanded, and wild hogs currently occupy most of the site. Mayer estimates the current population at nine hundred animals. Due to the damage they inflict on ecological and forest resources, as well as concerns over hog-vehicle collisions, the SRS has operated a control program since 1953, and hogs have been taken on deer hunts since 1965. Like wild turkeys and wild hogs, white-tailed deer have expanded from the river swamp during the past fifty years and now occupy the entire SRS. Paul Johns and John Kilgo discuss the history of this intensively studied population. Since hunting was initiated in 1965, the population level has fluctuated from about 2,500 to 6,000 animals. The primary purpose of the deer hunt program is to control the population in an effort to reduce the number of deervehicle collisions. Through the either-sex, all-age harvest, the SRS deer herd has maintained a relatively even age structure and an almost 1:1 sex ratio, both positive characteristics in a deer population. However, the relationship between the population level and the number of deer-vehicle collisions is poor, and the authors describe recent management efforts aimed at reducing the number of collisions while maintaining the overall health of the deer population.

Minerals Miles Denham The Savannah River Site (SRS) is within the Upper Coastal Plain of the Atlantic Coastal Plain physiographic province. Beneath the SRS is a seaward dipping wedge of unconsolidated to semiconsolidated sediments.

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Ecology and Management of a Forested Landscape

These sediments are generally of shallow marine or fluvial origin and are mostly composed of interbedded sands and clays. The sands consist of quartz with minor amounts of feldspars and muscovite. Some of the sandy strata contain gravel. In places, the sands are relatively enriched in heavy minerals. Heavy minerals are those that have densities significantly greater than quartz and feldspar. The dominant clay mineral is kaolinite, which occurs in discrete beds and as pore-filling material and grain coatings in sandy units. Kaolinite and sand and gravel are mined in the vicinity of the SRS. Though no mining of heavy minerals occurs in the vicinity of the SRS, the area has been considered a potential source of the mineral monazite. However, there are no known economically viable mineral deposits on the Savannah River Site. Although kaolin, sand, and gravel occur within geologic strata beneath the SRS, geologic and land-use conditions make them unviable. Four factors determine whether a geologic material is an economic resource: purity, abundance, access, and price on the open market. The balance between the price on the open market and the first three factors determines whether it is economically viable to mine a raw material. The purity of the material is important because it bears directly on the cost of processing required to turn the raw material into a salable product. Costs of extracting the material from the ground are directly related to the abundance of the material and its ease of access. For example, sand and gravel deposits in Aiken County are easily accessible because they are near the ground surface. Equivalent deposits buried five hundred feet below ground surface may not be economically valuable. The thresholds of acceptable purity, abundance, and ease of access vary with the price of the raw material on the open market. If the price of sand and gravel rises considerably, it may be economically viable to mine deeper deposits. At SRS the purity, abundance, and ease of access of mineral resources do not warrant their consideration as economic resources. Several principal mineral materials occur in the vicinity of the SRS. The chemical formulas of these minerals appear in table 6.1.

Kaolin Kaolin is an important economic resource in Aiken County. According to U.S. Census data, the value of kaolin and ball clay shipments from South Carolina mines was $26.5 million in 1997 (www.census.gov). Aiken County is the largest producer of these products in the state. Paper pro-

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Table 6.1 Chemical formulas of minerals occurring at the Savannah River Site Mineral

Formula

Quartz Feldspar Alkali feldspar Plagioclase Kaolinite Ilmenite Monazite

SiO2 (K,Na)AlSi3O8 (Na,Ca)Al(Si,Al)Si2O8 Al2Si2O5(OH)4 FeTiO3 CePO4

duction consumes the largest amount of kaolin, along with rubber, paint, medicine, and ceramic products. Aiken County kaolin deposits occur in the updip portion of the Eoceneage Huber Formation. They generally occur in lenses that range from a few feet to tens of feet thick. Kaolin is a very pure form of the mineral kaolinite, generally a weathering product of feldspars and other aluminum silicate minerals. Originally, geologists thought a fluvial-deltaic environment produced Aiken County kaolin deposits. According to that hypothesis, kaolinite produced from intensive weathering of feldspar-rich sands settled in cutoff stream segments and areas where the energy of water flow was low (Bates 1969). Hurst and Pickering (1997) summarized more recent work, suggesting that kaolin deposits in South Carolina and Georgia are the result of weathering and diagenetic processes. These studies conclude that kaolin deposits occur where feldspar-rich sands to clays originally were deposited in a shallow marine environment. Intense weathering of nearsurface sediments and alteration by groundwater in recharge zones at the updip portions of these sediments produced massive kaolin deposits. The Congaree Formation beneath the SRS correlates with the updip Huber Formation in which the Aiken County kaolin deposits are found (Prowell 1994). However, the location of these sediments beneath the SRS would not have been conducive to the formation of economic kaolin deposits because they have not been subject to long periods of intense weathering or groundwater recharge.

Sand and Gravel The Mining Association of South Carolina (www.scmines.com) estimates statewide annual production of sand and gravel at $32 million. A portion is mined in Aiken County and in the vicinity of the SRS, primarily from

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Ecology and Management of a Forested Landscape

river terrace deposits and Cretaceous-age deposits. Deposits suitable for mining on the SRS have not yet been identified.

Heavy Minerals The “heavy minerals” are original depositional minerals with densities greater than those of quartz or feldspar. They generally occur in minor amounts but can become more concentrated by density separations during deposition. Water transports mineral grains and can concentrate minerals with higher density. At the inside of stream meanders, water loses energy and drops denser minerals. Likewise, heavy minerals may be concentrated in beach deposits when wave action winnows out less dense minerals. Such concentrations of heavy minerals are called placer deposits and can be economically valuable. Two minerals that occur in valuable placer deposits in the Southeast are ilmenite and monazite. Ilmenite, a source of titanium, is mined from placer deposits in northern Florida. Monazite, a source of thorium and the rare earth metals, has been mined from stream placers in upstate South Carolina (Overstreet et al. 1968). Elevated concentrations of monazite exist in the South Carolina Coastal Plain, but no locations have potential economic value (Mertie 1953; Dryden 1958). Though sediments beneath the SRS can contain elevated concentrations of ilmenite and monazite, there are no known locations of economic significance.

Commercial Forest Products John I. Blake and Ronald T. Bonar The Savannah River Site (SRS) sells both softwood trees (primarily loblolly, slash, and longleaf pines) and hardwood trees (including oak, sweetgum, sycamore, and yellow poplar; see appendix for scientific names). Pine straw is the only other forest product sold from the SRS. Forest product revenues indirectly support SRS management. These functions include ecological restoration of wetland and upland plant communities, research, wildlife monitoring, archeological surveys, and prescribed burning. Historically, the SRS has spent about 34 percent of forest product revenue on planting, stand management, and sale administration; 22 percent on prescribed fire management; 16 percent on

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administrative support functions; 16 percent on research and monitoring; and 12 percent on road building and maintenance.

Measurements In a sale area, the SRS estimates the commercial volume of sample trees in cubic meters (m3) of round wood to a variable top diameter by measuring the total height and the stem diameter at breast height (DBH, 1.4 m, or 4.5 ft). For pine, small round wood (SRW) is traditionally the volume in trees 10 to 24 cm (4.0–9.5 in) DBH and also the volume in the tops of larger-diameter trees. Hardwoods have greater DBH and top limits. SRW historically was used to produce pulp for paper, bags, and corrugated boxes. Recent improvements in manufacturing have allowed a large proportion of the volume in trees from 19 to 24 cm (7.5–9.5 in) DBH to be converted to lumber, plywood, and oriented strand board (A. Clark, U.S. Forest Service, unpublished data). Large round wood (LRW) is defined as volume in trees of more than 24 cm (9.5 in) DBH. These trees are suited to the production of lumber, plywood, and utility poles. Depending on DBH, defects, and sawing practices, one third to one half of the gross volume of a tree becomes chips for pulp, fuel, mulch, and other materials (Clark and McAlister 1998).

Effects of Historical Land Use on Forest Conditions At the time of European settlement, longleaf pine forests were predominant on about 80 percent of the non-wetland areas at SRS (Frost 1997). The balance of the landscape was in mixed hardwood, bottomland hardwood, and swamp forest. Land use from 1750 to 1950 was complex, but as much as 70 to 80 percent of the forest was converted to agricultural fields (White and Gaines 2000). In 1947, 64 percent and 42 percent of the land in Aiken and Barnwell Counties, respectively, was forested (McCormack and Cruikshank 1949). In 1951, 1,764 ha (4,358 ac) of farm fields on SRS had been planted to slash pine, but approximately 27,519 ha (68,000 ac) of open fields and up to 20,234 ha (50,000 ac) of cutover forest required some treatment (Savannah River Operations Office 1959). These figures exclude areas converted to roads, buildings, and infrastructure. In the forests surviving agricultural activities, selective removals repeatedly harvested longleaf pine in the uplands, bald cypress in the swamps, and white oaks in the bottomlands. The area currently

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Ecology and Management of a Forested Landscape

Table 6.2 Standing volume of pine and hardwood (hdwd) in millions of cubic feet (Mft3) at the Savannah River Site at intervals, 1952–2001 Year 1951a

1962

1972

1987

1992

2001

Forest land (ac) 120,400 183,275b 178,028c 181,477d 181,477 178,062e Volume (ft3/ac) 306.3 638.4 884.1 1,807.9 1,901.6 2,667.6 Pine-LRW (Mft3) 7.8 24.8 31.6 181.5 203.0 224.4 Pine-SRW (Mft3) 4.9 28.6 58.2 50.4 44.2 70.6 Total pine (Mft3) 12.7 53.4 89.8 231.9 247.2 295.0 Hdwd-LRW (Mft3) 17.7 35.6 35.3 62.6 64.6 108.9 Hdwd-SRW (Mft3) 6.5 28.0 32.3 33.5 33.3 71.1 Total hdwd (Mft3) 24.2 63.6 67.6 96.1 97.9 180.0 Grand total (Mft3) 36.9 117.0 157.4 328.1 345.1 475.0 Note: 1 Mft3 = 0.028 Mm3. Large round wood (LRW) approximates material that can be converted to solid wood products, and small round wood (SRW) approximates material that can be converted to pulp, paper, corrugated box, composites, and fuel. a Volume and area of forestland was estimated from the 1951 forest inventory (U.S. Army Corps of Engineers 1951). b Includes 17,556 ac nonforestland for facilities, roads, power lines. About 2,800 ac of mixed hardwood forest were lost when Par pond was constructed as a cooling water pond for P and R Reactors. c Area reduced as a result of transfer of 2,487 ac to Barnwell County and 6,021 ac to the Sumter National Forest. About 3,400 ac of nonforestland were included in the transfer. d Area increased as a result of transfer of 6,021 ac back to Department of Energy. e Actual forested area mapped is 182,420 ac, but no data on forest type are available for 4,358 ac in various inclusions.

within SRS supported numerous water-powered sawmills along Upper and Lower Three Runs prior to 1900 and several modern mills up to 1951. The overall condition in 1951 reflected poor-quality timber and low stocking levels. The estimated value of the SRS forest stands was $2,279,000. Average stocking on SRS was 21 m3/ha (306 ft3/ac), but stocking on pine lands averaged only 13 m3/ha (187 ft3/ac), whereas hardwood stocking averaged 32 m3/ha (459 ft3/ac). The 1947 average stocking in Aiken and Barnwell Counties was 605 and 774 ft3/ac, respectively (McCormack and Cruikshank 1949). Records indicate that landowners harvested the remaining forest areas at SRS prior to relinquishing ownership to the Atomic Energy Commission in 1951.

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Table 6.3 Approximate distribution (percent of land area) of the total forest area by stand age class and major commercial forest type using the Savannah River Site periodic stand mapping database Age class (years) Forest type Longleaf pine Slash pine Loblolly pine Mixed pine-hdwd Bottomland hdwd Cypress-tupelo Total

0–10

10–30

30–50

>50

Total

6.0 0.0 5.8 0.2 0.3 0.0 12.3

1.2 0.1 11.9 0.3 2.5 0.0 16.0

12.1 10.9 13.4 2.4 1.7 0.1 40.6

3.5 0.7 4.0 4.3 15.1 3.6 31.1

22.7 11.7 35.1 7.2 19.6 3.7 100.0

Forest Inventory Trends The SRS conducted forest inventories in 1958–1959 and about every five to ten years thereafter until the most recent in 2000–2001 (table 6.2). The SRS inventoried all forested land including potential harvest areas and areas in which harvesting is restricted (research areas, set-asides, and contaminated zones). The first inventories occurred in conjunction with tenyear plans to provide estimates of marketable products by forest cover types, age, and stocking in order to regulate the level of harvesting and estimate yields (Gates et al. 1967). In 2000, the modified forest survey provided additional information on wildlife habitat attributes (e.g., snags, cover) and fire-fuel loading, as well as merchantable forest products. From 1952 to 1992, the forested land base increased as old fields and cutover stands were planted, mostly to pines. Because the stands were young, large increments in pine growth were evident (see table 6.2). Small round wood pine volume has remained roughly the same in the last three decades because of thinning activities and transition of remaining trees into the LRW class. However, the volume of pine LRW has increased tenfold since the first inventory in 1962. Although hardwoods were harvested extensively until 1970, harvesting has dropped in recent decades because of wildlife habitat objectives and limited markets for certain hardwood species and those with defects (form, disease) resulting from pre-1951 logging practices. The volume of hardwood LRW has tripled since 1962, whereas SRW has increased slightly. Periodic stand mapping determines the approximate distribution of stand age classes by commercial forest type class (table 6.3). Resulting

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Ecology and Management of a Forested Landscape

from planting activities after 1951, the distribution shows a large proportion in the thirty- to fifty-year age class. Slash pine, which is not native to SRS, is no longer planted but has become established through prolific natural seeding. The percentage of stands in the more-than-fiftyyear age class reflects the average age of residual trees in contrast to an establishment age. Repeated selective cutting prior to 1951 often resulted in a few older trees of less desirable species or quality scattered among new regeneration. The oldest remaining pine in 1951 dated from the 1890s following abandonment of farms after the Civil War. The number of trees by species indicates the dominance of selected stand types, whereas the size distribution generally corresponds to the age distribution (table 6.4). The occurrence of hardwood and cypress trees over 51 cm (20 in) DBH results from better soil conditions and limited harvesting in wetlands and bottomland sites.

Volume Sold, Revenue, and Price Trends The annual volume of wood sold since 1955 increased steadily to almost 168,000 m3 (6 million ft3) until the mid-1970s, then declined to an average of about 112,000 m3 (4 million ft3) per year by the 1980s (figure 6.1). It remained at that level until 1997, when it increased to about 154,000 m3 (5.5 million ft3). Since the late 1970s, standing volume or growth per se has not determined annual volume sold. Rather, the amount sold has been an indirect consequence of area targets for regeneration, based on nominal rotation ages and residual stocking levels for thinning or partial cuts designed to meet overall wildlife management and habitat restoration objectives (Beavers et al. 1973; U.S. Department of Energy 1991). The relative proportion of the area thinned or partially cut compared to that clear-cut was about 5:1 from 1970 to 1980, declined to less than 2:1 from 1980 to 1990, and increased to more than 6:1 from 1990 to 2000. The increase in the total volume of pine LRW and average volume per tree has allowed an increase in total volume offered for sale since 1997, while the average area clear-cut declined dramatically (see chapter 3). As a consequence of the young age of the forest, harvests prior to 1970 generally consisted of pine in the SRW class and hardwood in the LRW class. From 1970 to 1980, the vast majority of the wood consisted of SRW pine. Extensive thinning operations during that period produced about two thirds of the pine volume, including 75 percent of the SRW and 25 percent of the LRW. Since the mid-1970s, the proportion of volume from the pine LRW class has increased steadily, so that it is now

51.7 174.1 29.7 4.0 1,187.6 715.0 639.0 116.0 226.0 364.0 97.0 319.0 40.0 257.6 738.1 474.9

29.8 298.3 22.7 59.7 6,590.4 2,714.7 3,664.0 1,073.9 537.0 445.0 567.0 1,989.0 298.0 170.4 6,324.0 5,758.0

Bald cypress Pond cypress Red cedar Sweet gum Black gumb Red maple Sweet bay Yellow poplar Water tupelo Elm Other hardwoodsc White oak Southern red oak Water oak Laurel oak

6,415.4 2,672.5 1,569.9

17,824.5 4,057.1 3,845.8

Loblolly pine Longleaf pine Slash pine Other softwoodsa

5–10

1–5

Species

31.8 85.0 1.2 2.0 371.7 332.0 158.1 42.0 106.0 192.0 42.0 34.0 19.2 61.4 211.4 192.0

2,297.1 1,355.6 1,164.1

10–15

7.5 18.7

28.8 17.0 7.0 1.5 21.7 22.0 2.8 1.2 1.4 4.2 5.0 22.0

127.2 161.0 26.0 4.0 56.0 82.0 9.7 20.0 11.7 7.7 30.5 40.0

128.0 9.8

20–25

9.2 97.5

824.2 212.3 69.7

15–20

DBH Class (in)

0.7 2.1

0.6

4.8 7.5

1.9 5.0 6.6

1.9

1.0 0.6

3.5

0.7

30–35

6.9 2.0 0.9

2.1 8.6

23.4

25–30

0.5

1.8

35+

(continued)

132.1 687.5 53.6 65.7 8,312.6 3,943.0 4,496.1 1,238.0 952.0 1,114.0 718.0 2,363.0 370.4 2,033.8 7,314.0 6,494.8

27,513.3 8,307.3 6,649.5

Total

Table 6.4 Estimated total number of trees (in thousands) by species and diameter class on the forested land area on the Savannah River Site in 1992. DBH = diameter of breast height.

2,893.7 567.0 627.0 3,908.0 2,983.0 2,682.0 2,953.4 656.3 535.0 2,682.3

1–5 24.0 48.0 40.0 5.0 92.2 220.0 11.0 8.6 5.0

78.0

10–15

91.0 171.0 25.3 279.0 385.9 548.0 213.1 20.8

5–10

0.7 3.0 6.8 16.0

22.4 49.0

20–25

3.0 28.0 17.0

15–20

DBH Class (in)

4.0

0.9

25–30

0.7 1.4

30–35

1.2

35+

3,011.0 814.0 712.0 4,192.0 3,491.6 3,521.0 3,177.5 685.7 535.0 2,765.2

Total

a Category

Note: See appendix for scientific names. includes shortleaf, pond, and Virginia pines in decreasing order of abundance. b This column includes upland and lowland black gum (swamp tupelo) combined. c Category includes black cherry, hackberries, black willow, and sycamore in decreasing order of abundance. d Category includes ash, bluejack oak, blackjack oak, red mulberry, river birch, Florida maple, scarlet oak, swamp chestnut oak, American beech, black oak, overcup oak, Shumard oak, and cherrybark oak in decreasing order of abundance. e Category includes dogwood, hornbeam, chinaberry, sourwood, and eastern hop-hornbeam in decreasing order of abundance.

Dwarf post oak Post oak Willow oak Turkey oak Hickory Otherd Holly Persimmon Sassafras Other small treese

Species

Table 6.4 (continued)

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Figure 6.1. Volume of wood in softwoods (pine) and hardwoods (hdwd) sold on the Savannah River Site, 1955–2003. Large round wood (LRW) approximates material that can be converted to solid wood products, and small round wood (SRW) approximates material that can be converted to pulp, paper, corrugated box, composites, and fuel (U.S. Forest Service, unpublished data).

the major component. Of the volume sold since 1955, approximately 93 percent has been pine and 7 percent has been hardwood. Approximately half of the net growth, or about 1.5 percent of the standing volume, is sold annually. The SRS produces 26 to 35 percent of all the softwood products in Aiken and Barnwell Counties and about 7 to 12 percent of all softwood products in the nine-county Central Savannah River Area (CSRA) of South Carolina and Georgia (U.S. Forest Service 1996). The SRS has historically marketed forest products to mills in twenty-six counties in South Carolina and Georgia. The production and sale of forest products contribute significantly to the annual economy ($19–$37 million) and employment (157–314 jobs) of the area (Teeter 2000). The SRS advertises all forest product sales regionally and solicits competitive sealed bids. The general demand for wood products and distance to primary manufacturing facilities dictate price. The unit price (dollars per acre) also depends on the total quantity offered for sale, the volume

Table 6.5 Comparative volume, value, and revenue sold from selected clear-cut or regeneration sales versus thinning or partial-cut sales 1987–1996 on the Savannah River Site Clear-cuts or regeneration cuts

Thinning or partial cuts

Fiscal year

Volume (CCF)a

Total value

Unit value ($/cubic ft)

Volume (CCF)a

1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 Average

21,907 23,132 23,973 30,691 23,340 17,842 22,893 19,293 15,017 24,790 22,288

$1,223,056 $1,563,980 $2,096,464 $1,741,779 $2,028,339 $1,882,903 $3,513,174 $2,266,363 $2,369,974 $3,219,121 $2,190,515

$0.56 $0.68 $0.87 $0.57b $0.87 $1.08 $1.53 $1.17 $1.58 $1.30 $0.98

5,482 15,041 14,857 3,958 20,531 13,334 12,572 12,403 24,057 22,185 14,442

Total value $267,292 $499,245 $805,145 $312,885 $1,043,708 $834,191 $1,156,530 $1,005,304 $2,013,959 $1,701,181 $963,944

Unit value ($/cubic ft) $0.49 $0.33 $0.54 $0.79 $0.51 $0.63 $0.92 $0.81 $0.84 $0.77 $0.66

Note: Data from mixed sales are not included, and therefore totals do not match values reported in figures 6.1 and 6.2. a CCF = hundreds of cubic feet (1 CCF = 2.8 m3). b Includes tornado salvage of >405 ha (>1,000 ac).

Figure 6.2. Total value of wood sold for all species on the Savannah River Site, 1955–2003, and the average unit price of the wood sold during each year (U.S. Forest Service, unpublished data).

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per acre, road access, average tree size, quality, and species composition. Unit prices are substantially higher for wood that can be harvested during winter months, when weather prevents access to many other sites. For the years 1987–1996, in comparison with clear-cuts or regeneration cuts, thinning or partial cuts contributed about 40 percent of the total volume sold, about 30 percent of the revenue as a result of higher logging costs and a higher proportion of SRW (table 6.5). The revenue from wood products sold has increased dramatically in the last two decades (figure 6.2). This increase is closely associated with the increasing unit price of wood, as well as an increase in the volume sold since 1997. The increase in unit price reflects larger and higher-quality material, as well as market conditions, and SRS wood demands comparatively high unit prices relative to other areas in the South (Timber Mart South 1999).

Minor Forest Products Trends Pine straw is sold by competitive bid each year. The SRS receives a relatively high unit price for pine straw, as landscapers and homeowners prefer longleaf pine straw. The annual area raked and the total revenue received varied considerably from 1991 to 2002 (table 6.6). Old-field stands are normally raked because the understory is relatively clean. Contractors may rake only “red” straw, which is the needle fall from the previous one to two seasons. They rake about once every ten years, usually just prior to Table 6.6 Area raked, total sales revenue, and unit value per acre for pine straw harvest at the Savannah River Site, 1991–2002 Year

Area (ac)

Revenuea

Unit ($/ac)

1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001

526 0 250 435 161 325 182 257 449 505 324

$80.5 $0.0 $43.8 $89.5 $35.0 $75.9 $32.4 $56.0 $83.9 $99.1 $60.4

$153 $0 $175 $206 $217 $234 $178 $218 $187 $196 $186

2002

237

$36.1

$152

a

In thousands of dollars.

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Ecology and Management of a Forested Landscape

commercial thinning. Studying the response to raking, fertilization, and prescribed burning, Ross, McKee, and Mims (1995) did not detect a reduction in pine growth when red straw was raked every three years.

Fishery of the Savannah River Barton C. Marcy, Jr. The Savannah River Site (SRS) contains several lakes and streams that support excellent fish stocks. However, only the fisheries located on the Crackerneck Wildlife Management Area and Ecological Reserve are exploited. Skinface Pond, a 3-ha (8-ac) pond on Crackerneck is currently managed for public fishing per agreement between the U.S. Department of Energy (DOE), the South Carolina Department of Natural Resources (SCDNR), and the U.S. Forest Service–Savannah River (USFS) in 1995. It was open to public fishing and was stocked annually by USFS from 1977 to 1984, when DOE reclaimed the Crackerneck land area. The pond was open on a limited basis to public fishing until 1999, when it was drawn down. It was restocked with bluegill (see table 4.16 for scientific names), redear sunfish, and largemouth bass in April 2000 and was reopened to fishing in September 2001. This section covers commercial and sport fisheries of the Savannah River. Many of these fisheries are confined to the marine and brackish waters of the coastal regions of South Carolina and Georgia. The fish of the SRS are discussed as a biotic community in chapter 4 (see also Marcy et al. 2005).

Commercial Fishing The commercial fishes of significance near SRS are American shad and channel and white catfish. Nonprofessional local fishermen exploit these species to a limited degree. Commercial and recreational fisheries for blueback herring exist in South Carolina (Ulrich et al. 1978), but Georgia restricts commercial netting.

American Shad American shad stocks in the Savannah River appear to be healthy and productive. Music (1981) reported that commercial catches in the Savannah River in 1980 represented 51 percent of Georgia shad landings

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in that year, yet only 13 percent of Georgia’s commercial shad fishermen operated in the Savannah River. Thus, American shad stocks in the Savannah River may be less heavily exploited and relatively more abundant than stocks in other Georgia rivers.

Striped Bass Paller et al. (1984), Paller, O’Hara, and Osteen (1985), and Paller, Saul, and Hughes (1986) have documented striped bass spawning upstream of tidally influenced regions of the river. Nevertheless, Gilbert, Larson, and Wentworth (1986) suggested that striped bass spawning occurs primarily in the tidally influenced portions of the river. Van Den Avyle and Maynard (1994) reported that the major spawning area is between river km 16 and 50 (river mi 10 and 31) and that a decline in the abundance of adult striped bass paralleled a reduction in striped bass egg density in the estuarine area. Unpublished data collected by the Georgia Department of Natural Resources (GDNR) show that angler catch rates of striped bass in the Savannah River declined by 89 percent during 1980–1988, and electrofishing catch also declined by 96 percent between 1980 and 1989. These patterns suggest recurring recruitment failure in the population during the 1980s and appear linked to the operation of a tide gate that altered the salinity in the spawning area. Restoration of conditions suitable for spawning success, such as maintenance of freshwater on the spawning grounds, is underway (Van Den Avyle and Maynard 1994).

Sport Fishing Sport fishermen are the principal consumers of river fishes, mostly American shad, sunfish, and catfish. Striped bass, which is classified as a game fish in South Carolina and Georgia (Ulrich et al. 1978), is a favorite quarry of fishermen in the Augusta, Georgia, area. Boltin (1999) evaluated the sport fishery from the New Savannah River Lock and Dam area during 1999. Anglers caught a total of twenty-five species (table 6.7). The dominant species in the sport harvest were American shad (31.2 percent), redbreast sunfish (18.6 percent), and bluegill (10.1 percent). The composite category of sunfishes was 32.8 percent, and catfish 8.5 percent, of the total angler catch. Anglers in the freshwater section of the Savannah River fish predominantly for bream and largemouth bass (Schmitt and Hornsby 1985). Based on electrofishing studies, the relative abundance of bream in the

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Ecology and Management of a Forested Landscape

Table 6.7 Estimate of percentage of fish species harvested from New Savannah Bluff Lock and Dam on the Savannah River during the 1999 access creel census Species American eel Redbreast sunfish Bluegill Warmouth Redear sunfish Largemouth bass Black crappie Yellow perch Brown bullhead Channel catfish Blue catfish Chain pickerel American shad

Percent 0.1 18.60 10.10 0.60 3.50 0.60 3.00 5.00 0.30 2.50 5.00 0.20 31.20

Species Striped bass Hybrid striped bass Quillback Gizzard shad Flathead catfish Bowfin Black bullhead Spotted sucker Striped mullet White bass White perch Yellow bullhead

Percent 0.20 0.20 0.10 0.40 0.10 0.10 0.10 2.80 12.30 2.00 0.40 0.60

Source: Boltin 1999.

freshwater section of the river is high, as is the actual angler success rate. The lower abundance of largemouth bass in the freshwater section results in a relatively low angler harvest of this species. Sunfishes showed the highest fishing effort by anglers at 1.37 catches per unit effort (CPUE; number harvested + number released/hr), with American shad second at 0.42 CPUE (Boltin 1999).

SRS Impact to Savannah River Fisheries Historically, SRS impacts to the populations of commercially and recreationally important fish species in the river were primarily from impingement and entrainment losses of fish eggs, larvae, and adults during the intake of cooling water (see chapter 4). The overall rates of impingement at the SRS intakes were low relative to other cooling water intake facilities in the southeastern region, and impingement losses were concentrated among species of low commercial or recreational value (U.S. Department of Energy 1988). Cessation of reactor operation and the concomitant lack of need for large cooling-water withdrawals from the Savannah River have reduced impacts substantially.

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Small Game John C. Kilgo Although small game currently is not harvested on the Savannah River Site (SRS) outside of the Crackerneck Wildlife Management Area and Ecological Reserve (CWMA), several species of small game occur on SRS. These include common snipe (Gallinago gallinago), American woodcock (Scolopax minor), mourning dove (Zenaida macroura), northern bobwhite (Colinus virginianus), eastern cottontail (see table 4.24 for scientific names of mammals), marsh rabbit, gray squirrel, and fox squirrel. Swamp rabbits are not known to occur at SRS (see chapter 5). Although representatives of this group occupy virtually every habitat on SRS, they vary in their seasonal occurrence and abundance. Some are resident (bobwhite and the mammals), and some are migratory (snipe, woodcock, and mourning dove); some are common (mourning dove and gray squirrel), and some are rare (snipe and marsh rabbit). In general, little information is available on the status of these species on SRS, and limited research has been conducted on them there. The annual Christmas Bird Count, coordinated by the National Audubon Society and conducted by volunteers, provides the most useful data available on population trends of the birds since 1979. Although the Christmas Bird Count contains many inherent biases, it is the most uniform long-term dataset available for these species on SRS. A few communitylevel, breeding-season studies also have noted the birds. Similarly, various research projects have incidentally noted some of the mammals, particularly the squirrels. The annual furbearer census from 1954 to 1982 (see “Furbearers” section in this chapter) occasionally recorded eastern cottontails and gray squirrels, but none of these surveys were designed to assess their populations. Harvest records from CWMA may reflect population trends for that area, but small game hunting is not intensive there, and harvests generally are very low. Therefore, much of the information contained herein is anecdotal or based on general knowledge of the species, obtained from beyond the SRS.

Common Snipe The common snipe occurs at SRS from fall through spring, arriving from northern breeding grounds in early October and departing in early May (Norris 1963; Mayer et al. 1997). It uses shallow wetlands, including

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Ecology and Management of a Forested Landscape

Table 6.8 Christmas Bird Count data for small game birds at the Savannah River Site, 1979–2002 Species Year

Common snipe

1979 1980 1981 1982 1983 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 a Species

American woodcock

1 2 1 1

1 2 1 10 11 8 12 2 5 3 5

1 3 11 4 5 5 3 2 1

Mourning dove Northern bobwhite 13 17 55 1 22 65 33 65 41 39 64 232 30 72 472 75 99 157 64 110 43 75 38 50

57 46 6 1 6 2 24 10 37 2 54 9 5 24 cwa 18 18 cw 5 32

detected during the week of the count but not on the count day.

marshes and wet, herbaceous meadows (Arnold 1994), and probably Carolina bays with herbaceous cover. No reliable information is available on continental or regional population status or trends (Arnold 1994). Norris (1963) characterized snipe as “fairly common” at SRS. In recent years, the Christmas Bird Count has recorded snipe regularly, but from 1979 to 1993, they were recorded in only five years (table 6.8). However, the recent increase in observations more likely reflects an increase in survey effort than an actual population trend. Snipe have been neither observed nor harvested at CWMA, most likely because suitable habitat there is extremely limited (M. Caudell, South Carolina Department of Natural Resources, pers. comm.).

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American Woodcock Although no nesting records exist for SRS, woodcock breed locally within South Carolina (Post and Gauthreaux 1989). Occasional breeding at SRS may occur, as woodcock have appeared there during summer (M. Caudell, pers. comm.). During fall and winter, more northerly migrants augment southern breeding populations. Norris (1963) considered woodcock rare on SRS during the 1950s, citing an individual killed on South Carolina Highway 125 as the only record. The Christmas Bird Count recorded woodcock in only three years prior to 1994 but recorded them in every year since, except 2000 (table 6.8). No woodcock were harvested at CWMA between 1984 (the first year harvest was monitored) and 1991, but they have been harvested in five of the twelve years since (table 6.9). They are common on CWMA during winter, but few hunters pursue the species (M. Caudell, pers. comm.). However, as with snipe, it is doubtful that these patterns reflect an increase in the wintering population of woodcock on SRS, as the species experienced annual declines of 2.5 percent region-wide (eastern United States) between 1968 and 1996 (Brugginck 1996). Mayer et al. (1997) still considered woodcock rare at SRS in the mid-1990s. During winter, woodcock use moist forests, typically bottomland hardwoods, with dense understories (Straw et al. 1994) for foraging during the day. Although some birds remain in forested habitat at night, they often move to open habitats. Berdeen and Krementz (1998) reported that approximately half of the nocturnal radio-locations of woodcock in the Georgia Piedmont were in one- to three-year-old clear-cuts or fallow fields; woodcock used those habitats more frequently than other open habitats. Woodcock preferred clear-cuts larger than 5.5 ha (13.6 ac) that had dense foliage at 0.8 to 2.0 m (2.6–6.6 ft) in height, combined with a high percentage of bare soil (Berdeen and Krementz 1998).

Mourning Dove Among South Carolina hunters, the mourning dove is the second most popular species of choice behind white-tailed deer (Responsive Management 2001). The statewide harvest of doves during the 1999–2000 season was just under 1.5 million birds. Doves are common year-round on SRS (Mayer et al. 1997), nesting in nearly all upland habitats on site, though abundance is probably greatest during winter, when northern migrants join resident birds.

Table 6.9 Small game harvest at Crackerneck Wildlife Management Area and Ecological Reserve, Savannah River Site, 1984–2003 Species

Year 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003

Woodcock

Mourning dove

Bobwhite

Rabbit

1 2

3

8 2 8

1

1 2 36 3

1 6 9 28 24 13 44 49 12 8 13 17 18 17

1 3 7 2 2 1 5 6 30 11

Gray squirrel

105 103 85 28 27 75 37 2 12 34 37 35 56 38 66 232 47 121

Fox squirrel

6

4

As granivorous ground feeders, mourning doves are typically most abundant in agricultural areas (Lewis 1993). During the breeding season, they are more than four times as abundant in the counties surrounding SRS than they are on SRS (Kilgo et al. 2000). However, with young pine plantations; road, railroad, and transmission line rights-of-way; and the lawns surrounding facilities, the amount of open habitat on SRS is adequate to maintain a substantial population. Despite their abundance on site relative to other game birds, only forty doves have ever been harvested at CWMA, thirty-six of which were in one year (see table 6.9). Doves are typically hunted around agricultural fields, and no managed dove fields currently exist on CWMA. From 1991 to 1995, the partial drawdown of Par Pond for repairs to the retaining dam exposed sediments contaminated by low-level radiocesium (137Cs). Doves and other wildlife foraged on vegetation that grew

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on those sediments. Kennamer et al. (1998) analyzed the risk to a hypothetical hunter of consuming doves from Par Pond. Using the maximum concentration of 137Cs observed in doves in the study, they calculated that a hunter would have to consume forty-one such doves per year to exceed the U.S. Environmental Protection Agency’s action level of excess cancer risk. As only 1 of 102 doves collected from Par Pond exhibited the contamination level used in their calculation, Kennamer et al. determined that it was unlikely that the hypothetical hunter could have harvested and consumed more than 40 such doves, even if he or she harvested the entire legal season limit of 840 doves (12 per day × 70 days in the season), hunting only at Par Pond. Hunters in the vicinity of Jackson, South Carolina, immediately adjacent to SRS, would have to consume more than 3,800 doves per year to exceed the EPA risk-action level (Kennamer et al. 1998).

Northern Bobwhite The northern bobwhite, or bobwhite quail, is resident at SRS year-round. Although it is still common (Mayer et al. 1997), its population on SRS has declined since 1950. Golley (1962) reported that bobwhite numbers increased by 100 percent from 1952 to 1961. Abundance on SRS in 1961 was comparable to that in Alabama and southwest Georgia ( Jenkins and Provost 1964) where intensive management for the species occurred. Covey size averaged seventeen birds in 1960–1961 ( Jenkins and Provost 1964). The population apparently peaked in 1961 and declined thereafter, as the extent of pine plantations increased on SRS. Declining trends have occurred throughout the southeastern United States during the past forty to fifty years. The primary cause of the declines has been the extensive land-use conversion in the region during that period. The invasion of the red imported fire ant (Solenopsis invicta) into the United States, as well as an increase in predators resulting from both raptor protection and a decline in commercial furbearer trapping, may have impacted quail production, especially in marginal habitats. Habitat loss has likely been an especially important factor at SRS, given the dramatic change in land use on site from a primarily agricultural to a primarily forested landscape (see chapter 1). As is the case with mourning doves, Kilgo et al. (2000) reported that quail were more than four times as abundant in the region surrounding SRS, where a significant component of the landscape remains agricultural, than on SRS. Fire ants and predators may also limit quail populations at SRS.

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Quail use early-successional edge habitats and open woods (Mahan 1995). On SRS, they use recently regenerated pine plantations and rightsof-way ( J. Dunning, Purdue University, unpublished data) because so little area remains in fields. Older, frequently burned pine forests with well-developed grass-forb layers constitute the most suitable quail habitat at SRS. Native legumes and grasses occurring in such stands provide the most important food resources for quail during much of the year (Landers and Johnson 1976). The CWMA plants bicolor lespedeza and manages food plots for quail. During the brood rearing period, quail make greater use of herbaceous cover in open habitats, which provides the invertebrate prey that constitutes more than 80 percent of the diet of young quail. The CWMA maintains areas with low herbaceous cover as brood habitat. Quail call counts on CWMA from 1991 to 2001 indicate fluctuating numbers (South Carolina Department of Natural Resources, unpublished data), probably in response to localized timber harvest and quail habitat management activities occurring along the count route. The first quail was harvested at CWMA in 1989. Annual harvest generally increased until its peak in 1995 at forty-nine birds, likely reflecting increased hunter effort, but has declined since (table 6.9).

Eastern Cottontail The eastern cottontail is abundant at SRS (Cothran et al. 1991). During the early 1960s, Jenkins and Provost (1964) estimated densities at 0.7 rabbits per ha (0.3 per ac), though numbers have likely declined, since their preferred habitat has diminished. Cottontails most commonly occur in thick grass and thickets in upland habitats on SRS, regardless of forest type. Lower densities occur in sandhills, and cottontails are virtually absent in extensive areas of bottomland habitat (Cothran et al. 1991), such as the Savannah River swamp and Upper Three Runs. Rabbits (both marsh and cottontail have been taken sporadically at CWMA, though harvest seems to have increased in recent years (table 6.9).

Marsh Rabbit Marsh rabbits are primarily a coastal species, occurring in coastal lowlands and brackish marshes of the southeastern United States. They are considered uncommon on SRS, where they replace cottontails in bottomland habitat (Cothran et al. 1991). Little is known of their status on

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SRS, though they likely constitute a significant portion of the harvest at CWMA, which includes extensive bottomland hardwood habitat.

Gray Squirrel Gray squirrels are abundant on SRS. They occur most commonly in hardwood forests containing oaks and hickories, but they also use pine and mixed pine-hardwood forests (Cothran et al. 1991). Jenkins and Provost (1964) estimated densities in the Savannah River swamp at more than 2.5 per ha (1 per ac). Squirrel populations likely fluctuate annually with the abundance of mast crops. Gray squirrels were the fourth most popular species hunted in South Carolina in 1999–2000 (Responsive Management 2001). On CWMA, annual harvest of gray squirrels has averaged sixty-three since 1986 (table 6.9).

Fox Squirrel Fox squirrels occur in both pine and upland hardwood habitat at SRS. Generally, they prefer habitats with large trees and sparse understories (Loeb and Moncrief 1993). The literature suggests limited use of bottomland hardwoods, primarily where they occur as stringers along small streams within an upland matrix (Edwards, Guynn, and Lennartz 1989; Loeb and Moncrief 1993). They are most common on the plateaus and upper terraces of SRS (Cothran et al. 1991). Fox squirrels have been declining throughout much of the Southeast, likely due to the loss of mature pine forest habitat through conversion to short-rotation silviculture (Weigl et al. 1989; J. Barnes, South Carolina Department of Natural Resources, pers. comm.). The longer-rotation management characteristic of much of the SRS (chapter 3) has probably benefited fox squirrels on site, though no long-term population data are available.

Waterfowl Robert A. Kennamer Waterfowl are among the most economically important wildlife occurring on the Savannah River Site (SRS). On an annual basis, three million people in the United States spend $700 million on sport hunting of migratory birds, with about one third of that activity directed toward duck and

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goose hunting (U.S. Department of the Interior et al. 1993). During the 1960s, estimated numbers of 226,000 to 750,000 ducks passed through the Savannah River drainage each winter (Bellrose 1980), making the area a major route for migratory waterfowl within the Atlantic Flyway. More recently, midwinter waterfowl surveys in South Carolina during the early 1990s have shown reduced numbers of ducks within the state, ranging from 124,000 to almost 219,000 (Serie 1992, 1993). On the SRS, large numbers of waterfowl have occurred since closure of the site to the public in the early 1950s ( Jenkins and Provost 1964; Mayer, Kennamer, and Hoppe 1986). Twenty-eight species of North America’s native ducks, geese, and swans, as well as several other aquatic bird species that are often closely allied with waterfowl, have been identified on the SRS between 1952 and 1997 (Halverson et al. 1997; table 6.10). Wood ducks (see table 6.10 for scientific names) and hooded mergansers are the only waterfowl known to breed on the SRS (Mayer, Kennamer, and Hoppe 1986), and both species require cavities in which to nest. Waterfowl are present in most suitable SRS aquatic habitats (table 6.10; Norris 1963; Mayer, Kennamer, and Hoppe 1986; Halverson et al. 1997; Kennamer, unpublished data), including those contaminated by nuclear materials production activities (e.g., reactor cooling reservoirs and seepage and settling basins).

Breeding Wood Ducks Wood ducks ranked among the top four duck species harvested in the United States and accounted for 36 percent of the 1999 duck harvest in South Carolina (Martin and Padding 2000). On the SRS, wood ducks are the most common year-round resident species of waterfowl, occupying virtually all wetland types (table 6.10; Mayer, Kennamer, and Hoppe 1986). Because of their requirement for nest cavities, breeding wood ducks typically inhabit forested wetlands. Natural populations of wood ducks on the SRS are closely associated with forested areas, particularly riparian and lowland hardwood forests. Wood ducks also readily nest in small isolated wetlands with suitable nest sites, or even in tree cavities well away from water, thus necessitating overland movement by females with their broods. Nest boxes have provided additional nest sites for wood ducks on the SRS since the early 1970s (Fendley 1978). By the early 1990s, more than 275 nest boxes were located across the site (figure 6.3). From 1979 to 1996, one of the longest continuous studies of box-nesting wood ducks in North America took place on the SRS (Kennamer and

Waterfowl Tundra swan White-fronted goose Blue/snow goose Canada goose Wood duck Green-winged teal American black duck Mallard Northern pintail Blue-winged teal Northern shoveler Gadwall American wigeon Canvasback Redhead Ring-necked duck Greater scaup Lesser scaup

Common name

Cygnus columbianus Anser albifrons Chen caerulescens Branta canadensis Aix sponsa Anas carolinensis Anas rubripes Anas platyrhynchos Anas acuta Anas discors Anas clypeata Anas strepera Anas americana Aythya valisineria Aythya americana Aythya collaris Aythya marila Aythya affinis

Scientific name

+ + + + + + + + + + + + + + +

+

Par Pond

+ + + + + + + + + + + + + + +

L Lake

+

+

+ + + +

+ + + + +

+

Pond B

+

+ + + + + +

+ +

+ +

Pond C

+

+ +

+

+ + + +

+

+ +

+

+ + + +

+

+ +

+ + + +

+

+

+ + + + + + + + +

Beaver Dam Fourmile Pen Steel Creek Branch Branch Creek

+

+ +

+ +

(continued)

+

+ + + + + +

+ + + +

+ + + + + + + + + + +

+

Upper Three Carolina Runs Bays Basins

Table 6.10 Locations on the Savannah River Site where waterfowl and other selected aquatic birds have been observed (“+”), 1952–1997

Waterfowl (continued) Oldsquaw Black scoter Surf scoter White-winged scoter Common goldeneye Bufflehead Hooded merganser Common merganser Red-breasted merganser Ruddy duck Other species Common loon Pied-billed grebe Horned grebe Red-necked grebe Purple gallinule Common moorhen American coot

Common name

Table 6.10 (continued)

+ + + + + + + + + + + + + + + + +

Clangula hyemalis Melanitta nigra Melanitta perspicillata Melanitta fusca Bucephala clangula Bucephala albeola Lophodytes cucullatus Mergus merganser Mergus serrator Oxyura jamaicensis

Gavia immer Podilymbus podiceps Podiceps auritus Podiceps grisegena Porphyrula martinica Gallinula chloropus Fulica americana

Scientific name

Par Pond

+ +

+ + +

+

+

+ +

+ +

+ +

+ +

Pond C

+ +

Pond B

+ + +

+ + + + + +

+

L Lake

+

+

+

+ +

+

+ +

Beaver Dam Fourmile Pen Steel Creek Branch Branch Creek

+

+ + +

+ +

+

+ + +

+ +

+ +

+ + + + +

Upper Three Carolina Runs Bays Basins

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Figure 6.3. Habitats used by waterfowl and locations of nest boxes for breeding wood ducks and hooded mergansers on the Savannah River Site.

Hepp 2000). Nest boxes were placed in Carolina bays, beaver ponds, and reservoirs, as well as along several stream systems that drain from the SRS into the Savannah River. Although the numerous nest boxes throughout the SRS have increased the local population of breeding wood ducks (estimated at more than three hundred pairs using all 275 SRS nest boxes), many more breeding wood ducks use natural cavities found in the SRS’s extensive forested wetlands. No studies to date have quantified natural cavity use by wood ducks on the SRS. However, considering the extent of SRS wetlands, including the Savannah River swamp system (SRSS; 3,800 ha; figure 6.3), the total SRS population of wood ducks could easily exceed one thousand breeding pairs.

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Ecology and Management of a Forested Landscape

Wood ducks breeding on the site have the longest nesting season known for the species, with nests starting as early as January 11 and as late as July 7; nest hatch occurs as early as March 4 and as late as July 31. Because of this extraordinarily long breeding season, as much as 19 percent of the SRS breeding population can have two successful nests in a single season (Kennamer and Hepp 1987; Kennamer and Hepp 2000), a phenomenon quite rare for other North American waterfowl. Annual variation in SRS wetland conditions (as indexed by water levels) influences wood duck productivity. In wet years, onset of the nesting season is early (average wet season onset is January 23), and females produce an average of 9.8 ducklings (Kennamer 2001). Conversely, in dry years, the nesting season onset is generally later (average dry season onset is February 11), and productivity averages 8.6 ducklings per female (Kennamer 2001). In general, females that nest earlier in the breeding season are in better body condition and lay larger clutches than females nesting later (Hepp and Kennamer 1993). Wood duck use of about 126 SRS nest boxes in the long-term study averaged 66 percent, increasing from an average use of about 50 percent in the early 1980s to about 80 percent in the mid-1990s. Over that period, females laid more than 26,250 eggs. Average clutch size from 1,876 nest attempts on the SRS was 14 eggs (range: 1 to 41), and each nesting female laid an average of 20 eggs per year. Nests were successful in producing ducklings 54.6 percent of the time. For every thirty days of delay in nest initiation, females were about 1.25 times more likely to have nests preyed upon (Hepp and Kennamer 1993), the major predators being rat snakes and raccoons. Within wood duck nests on the SRS, hatching success averaged 72.7 percent. More than 11,880 ducklings hatched from 1982 to 1996, but because of a high mortality rate typical for young duck broods, only about three hundred female ducklings survived to adulthood over the study period (based on an estimated breeding female recruitment rate of 5.2 percent; Hepp, Kennamer, and Harvey 1989). From one year to the next, female wood ducks exhibit a high level of fidelity to nest sites (Hepp and Kennamer 1992), so capture-recapture studies on SRS have produced relatively precise estimates of population parameters (Hepp, Hoppe, and Kennamer 1987; Kennamer and Hepp 2000). Numbers of female wood ducks nesting in the approximately 126 long-term monitored nest boxes increased from about thirty individuals in 1980 to more than one hundred in the mid-1990s (figure 6.4a). Due to difficulty in censusing this highly secretive species, precise estimates

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do not exist of population size at larger geographic scales (e.g., Atlantic Flyway population, southeastern subpopulation); however, harvest rates of wood ducks suggest that southern Atlantic Flyway subpopulations are increasing (Serie and Chasko 1990). Thus, an increasing female population using SRS nest boxes likely indicates both local natural population expansion as well as progressive saturation in use of available nest boxes. Annual survival rate estimates for breeding female wood ducks on the SRS averaged 0.59, ranging from 0.41 to 0.77 (figure 6.4b). Survival rates estimated similarly for box-nesting wood ducks across Florida averaged 0.49 (Brakhage and Eggeman 1998). Closure of the SRS to public waterfowl hunting and the sedentary nature of breeding wood ducks in the deep South may contribute to the apparently higher survival of female wood ducks on the SRS. Estimates of recruitment (i.e., births and immigrations) into the breeding female population that used SRS nest boxes averaged thirty-six birds per year, ranging from ten to sixty-one individuals (figure 6.4c). New breeding recruits accounted for an average of 44.6 percent (range: 26.7–58.5 percent) of the breeding population annually, and there was no long-term trend for either increasing or decreasing recruits as a proportion of the overall population. Female wood ducks on the SRS generally attained sexual maturity as yearlings, but an average 25 percent of yearlings deferred breeding until after the first year (usually breeding by the third year; Kennamer 2001). Yearling females that deferred breeding ranged from zero to 66.7 percent annually, and the proportion was highest when dry wetland conditions prevailed. Females that delayed reproduction until two years of age or later had a significantly longer life span than females first breeding as yearlings, but females that reproduced as yearlings had higher individual fitness (Oli, Hepp, and Kennamer 2002). As population size of wood ducks using nest boxes on the SRS increased, nesting efficiency (i.e., the proportion of all eggs laid in a given year that hatched) decreased. As the population increased, both total nesting attempts and numbers of parasitized nests (i.e., those nests in which multiple females laid eggs) also increased. Hatching success was lower in parasitized nests (68.8 percent) than in nonparasitized nests (81.5 percent) in every year, thus explaining the lower nesting efficiency at higher population densities. Because wood ducks are abundant on the SRS and because they readily use nest boxes, this species has been the focus of numerous contaminant studies on the site (see Fendley, Manlove, and Brisbin 1977;

Figure 6.4. Population parameter estimates (±95 percent confidence intervals) from Jolly-Seber capture-recapture models for female wood ducks (WODU) using nest boxes on the Savannah River Site. Given are the estimated number of breeding females in the nest box population 1980–1994 (a), survival estimates of those females 1979–1993 (b), and the estimated number of new females recruited into that breeding population 1980–1993 (c).

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Kennamer, McCreedy, and Brisbin 1993, 1995; Colwell, Kennamer, and Brisbin 1996). Both wood ducks and their eggs have been successfully used as monitors of radiocesium (137Cs) and mercury at Pond B, Par Pond, Steel Creek, and other areas of the SRS.

Breeding Hooded Mergansers During the postbreeding and winter periods, hooded mergansers occupy virtually all wetland habitat types on the SRS. However, like wood ducks, breeding hooded mergansers typically occupy forested wetlands because they require cavities for nesting and therefore depend on forest resources in riparian and lowland hardwood forests. Compared to wood ducks, hooded mergansers are apparently more restrictive in their use of nest boxes in isolated wetlands, particularly those lacking woody species; hooded mergansers may be less likely than wood ducks to trek overland with broods to suitable rearing habitats. Densities of breeding hooded mergansers in the southeastern United States are generally considered low (Bellrose 1980). On the SRS, Kennamer, Harvey, and Hepp (1988) reported only five total nests for the period 1982–1988, with a pair nesting about every other year and nest box use averaging 0.6 percent annually. During 1989–1996, however, nest box use by hooded mergansers more than tripled, to 2.2 percent annually, with an average of three nesting attempts each year (Kennamer 1997). Hooded mergansers also laid eggs parasitically in twenty nests of wood ducks, with increasing frequency in recent years. These results suggest modest growth of the SRS breeding hooded merganser population, though breeding densities continue to be low. Nest box use by hooded mergansers is low relative to that by wood ducks, and natural cavity use by these two species might be proportionately similar. Therefore, considering the extensive forested wetland habitats on the site, the total SRS population of hooded mergansers could number fifty to one hundred breeding pairs. Harvest statistics for hooded mergansers further suggest their relatively low abundance. In 1999, hooded mergansers accounted for only about 1 percent (fewer than 2,300 individuals) of the 1999 duck harvest in South Carolina, while contributing to only about 0.5 percent of the total United States duck harvest (Martin and Padding 2000). Nest initiation dates for hooded mergansers on the SRS ( January 18–March 22) occurred only within the first half of the wood duck nesting season. Clutch size for twenty-one complete clutches of hooded mergansers on the SRS averaged eleven eggs (range: eight to nineteen). For

356

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sixteen successful nests, average brood size at hatching was ten, with a hatching success rate of 86 percent (Kennamer 1997).

Winter Waterfowl Populations During fall and winter, migrating waterfowl use the SRS extensively for foraging, loafing, and roosting (Costanzo 1980; Mayer, Kennamer, and Hoppe 1986; Bergan, Smith, and Mayer 1989). Their primary habitats include the site’s former cooling reservoirs and the wetlands that make up the SRSS (figure 6.3), both of which received heated water during periods of reactor operations. For example, within five years after the 1958 completion of the 1,012-ha (2,500-ac) Par Pond, Jenkins and Provost (1964) estimated that ten thousand ducks and American coots (hereafter coots) were wintering on that impoundment. At the same time, about two thousand ducks and coots were using the SRSS ( Jenkins and Provost 1964). Since 1982, weekly aerial surveys (November–March) have assessed abundance and distribution patterns of SRS waterfowl. Consistently, four species of diving ducks have dominated the waterfowl assemblage using SRS reservoirs: lesser scaup, ring-necked ducks, buffleheads, and ruddy ducks. In addition, coots typically use these reservoirs in numbers similar to those of all ducks combined. In the SRSS, the major waterfowl species include mallards and wood ducks, with large numbers (more than a thousand) of ring-necked ducks present during winters of exceptionally high water. In the early 1980s, maximum combined numbers of the four dominant diving duck species on Par Pond totaled three thousand to five thousand birds (figure 6.5a), plus an additional four thousand to eight thousand coots. During that period, in U.S. Fish and Wildlife Service– sanctioned midwinter surveys of the Atlantic Flyway, more diving ducks occurred on Par Pond than on all surveyed inland bodies of water in South Carolina combined. Studies of food habits (Hoppe, Smith, and Wester 1986) and resource availability (Smith et al. 1986) indicated that lesser scaup and ring-necked ducks consumed large amounts of mollusks from Par Pond and tended to deplete that food resource as winter progressed. In 1985, the completion of the 405-ha (1,000-ac) L Lake provided additional SRS habitat for migratory waterfowl. By the winter of 1988–1989, lesser scaup and ring-necked ducks were using this new reservoir heavily (figure 6.5b), primarily during late winter, as birds moved from Par Pond, presumably when food resources there fell below some threshold level.

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In late summer 1991, a forced partial drawdown of Par Pond exposed about 520 ha (1,285 ac) of the reservoir’s bottom sediments, decimating the aquatic macrophyte community and the particularly important mollusk populations. Waterfowl and coots that arrived in the fall of 1991 to feed on those resources immediately dispersed from Par Pond to other locations (figure 6.5a). Lesser scaup and ring-necked ducks moved to L Lake, as much as its carrying capacity allowed; coots, by the thousands, simply moved off the site. Over the course of the three-year drawdown, waterfowl numbers on Par Pond gradually increased (figure 6.5a). The refill of Par Pond took place during the winter of 1994–1995, and the following winter, lesser scaup and ring-necked duck numbers again plummeted, leaving L Lake as the primary reservoir used (figure 6.5a, b). Recently (winter 1999–2000), the single-flight maximum number of combined waterfowl and coots using SRS reservoirs totaled roughly 8,200 individuals, with about 80 percent lesser scaup and ring-necked ducks. Maximum numbers of coots peaked that winter at over 5,500. Waterfowl numbers using Par Pond have increased (figure 6.5a) as the reservoir’s aquatic macrophytes and benthic invertebrate populations returned to pre-drawdown levels. As in the early 1980s, the former reactor-cooling reservoirs of the SRS have become a major inland destination for migratory waterfowl in the Southeast. In the SRSS, maximum waterfowl numbers in recent years ranged from a few hundred to more than 1,200 birds, varying as fluctuating Savannah River levels affect suitable habitat. Waterfowl trapping efforts on Par Pond and L Lake from 1985 to 1995 resulted in the capture, banding, and release of 5,672 ring-necked ducks. Recovery of 594 banded birds during annual waterfowl hunting seasons (1985–2002) has provided information on the geographical extent and patterns of migration of ring-necked ducks wintering on the SRS (figure 6.6). Most hunter recoveries took place within the Atlantic Flyway as expected, although some limited exchange with the Mississippi Flyway was evident. Direct recoveries (104 of 594; those occurring in the same winter as banding) occurred only in South Carolina (80 percent), Georgia (13 percent), Florida (6 percent), and Alabama (1 percent). An estimated 2.5 percent of all ring-necked ducks that visit SRS reservoirs each winter are harvested in that same winter. Avian vacuolar myelinopathy (AVM), a neurologic syndrome of currently unknown origin affecting bald eagles (Haliaeetus leucocephalus) and certain waterfowl species, was first observed nationally during the winter of 1994–1995 on DeGray Lake in Arkansas. It was first diagnosed on

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Figure 6.5. Maximum numbers of ring-necked ducks (RNDU), lesser scaup (LESC), buffleheads (BUFF), and ruddy ducks (RUDU) observed per year during aerial surveys of Par Pond (a) and L Lake (b) on the Savannah River Site, 1982–2003.

the SRS in the winter of 1998–1999 and has been confirmed in both bald eagles and coots on the site. Bryan and Jarvis (chapter 5, “Bald Eagle”) provide additional details on AVM. Numerous contaminant studies have used wintering waterfowl on the SRS as subjects (Brisbin, Geiger, and Smith 1973; Clay et al. 1980; Potter

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Figure 6.6. Hunter recovery locations in the eastern United States of 594 ringnecked ducks originally banded on the Savannah River Site, 1985–2002.

et al. 1989; Brisbin and Kennamer 2000). Much of this research has focused on radiocesium and mercury levels in waterfowl using Par Pond and Pond B.

Wild Turkey William F. Moore, John C. Kilgo, William D. Carlisle, and Michael B. Caudell Wild turkeys (Meleagris gallopavo) were once abundant throughout the Southeast, but unregulated hunting and habitat destruction greatly reduced populations to a few thousand birds by 1930 (Hurst and Dickson 1992). Through intensive restocking efforts beginning in the 1950s, protection from hunting, and reforestation, southeastern turkey populations have rebounded to an estimated one million birds (National Wild Turkey Federation 1986). Biologists once believed that wild turkey populations required large areas of remote, undisturbed forest (Mosby and Handley 1943; Hurst and Dickson 1992). However, over the years, turkeys have

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proven adaptable to various types of habitats and now thrive in areas once thought only marginal (Little 1980).

SRS Population History When the Savannah River Site (SRS) was established in 1951, wild turkeys were extremely rare on the site and were restricted to the Savannah River swamp ( Jenkins and Provost 1964). A total of eight turkeys (mainly single birds) were observed from 1951 to 1961. In the early 1970s, the South Carolina Department of Natural Resources (SCDNR) reintroduced wild turkeys on SRS to establish a large source population for restocking other areas of the state. In the winters of 1973 and 1974, SCDNR trapped forty-eight turkeys in the western and central Piedmont of South Carolina and released them at four locations on the site. By 1977, SCDNR deemed the stocking effort a success, and that winter they began trapping SRS turkeys for translocation to other regions of South Carolina. Initial efforts in the original release areas during 1977 trapped only eight birds, but by the early to mid 1980s, trapping success began to increase (table 6.11). It declined again in the mid to late 1980s but was good from then until 2000, after which turkeys were no longer needed for restocking other areas. From 1991 to 2000, the number of wild turkeys trapped annually on SRS for restocking purposes ranged from 31 to 108 and averaged 58. Turkeys have not been hunted on SRS since the Site was established in 1951. However, in the western portion of SRS, Crackerneck Wildlife Management Area and Ecological Reserve (CWMA) allows spring gobbler– only hunting. Since CWMA opened for hunting in 1983, the annual harvest has ranged from one to forty-three (table 6.12). Until 1992, annual harvest was well below the long-term average of thirteen birds. However, from 1993 to 2002, an average of twenty-two turkeys were killed each year. The CWMA harvest data and SRS trapping success data, combined with data from annual wild turkey summer brood surveys conducted by SCDNR, indicate that the SRS turkey population increased between 1993 and 2003 (figure 6.7). From 1974 to 1992, an average of 68 adult turkeys and 77 poults were seen each year, whereas an average of 451 adults and 308 poults were observed annually from 1993 to 2003. The current estimated population size on SRS is 2,000 to 2,200 birds and appears to be stable or increasing. Turkeys now occupy all portions of the site, with greatest densities in portions adjacent to the Savannah River swamp.

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Table 6.11 Number of turkeys trapped on the Savannah River Site by the South Carolina Department of Natural Resources for off-site restocking programs, 1978–2000 Year

Hens

1978 1979 1980 1981 1982 1983 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 Total

0 6 0 6 0 19 38 11 8 0 0 22 0 9 66 28 39 12 50 92 32 0 25 467

Gobblers 8 6 6 5 0 33 36 12 4 0 0 9 8 33 38 11 43 19 17 16 4 28 18 362

Total 8 12 6 11 0 52 74 23 12 0 0 31 8 42 104 39 82 31 67 108 36 28 43 829

Population Influences Moore et al. (2002) reported survival rates for 102 radio-instrumented turkeys monitored for three years on SRS. Annual survival rates of hens (0.60) and gobblers (0.71) do not differ significantly. Most mortality for both sexes occurs during spring and early summer, when gobblers are preoccupied with breeding and hens are nesting. The primary predators of both gobblers and hens on SRS are bobcats and coyotes (table 6.13). Other potential predators include gray fox, hawks, feral dogs, and owls. Roadkills accounted for 8 percent of the mortalities of radio-instrumented turkeys. For gobblers in the CWMA population, hunting is also a significant mortality source. The annual survival rate of CWMA gobblers (0.55)

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Table 6.12 Wild turkey harvest data recorded on Crackerneck Wildlife Management Area and Ecological Reserve, 1983–2003 Year

Gobblers

Jakes

1983a

0 3 0 1 4 4 5 4 2 4 10 2 14 10 11 17 24 15 27 19 6

1 0 2 1 0 0 0 0 2 4 0 4 8 5 4 2 8 3 3 8 0

1984 1985b 1986c 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003e

Total 1 3 2 2 4 4 5 4 4 8 11d 6 22 15 15 19 32 18 35 43 6

a Initial

year of hunting, with season from April 1 to May 1. season. c Expanded to half-day hunts on Fridays and Saturdays April 1–April 30. d Includes an illegally harvested hen with no beard. e Season was shortened due to elevated security concerns on SRS. b Three-day

is significantly lower than that of gobblers in the unhunted SRS population (0.71). Nesting success of hens varies greatly on SRS from year to year. In 1998, 92 percent of radio-marked hens nested successfully; ten of the thirteen hens that attempted nesting hatched broods successfully on their first attempt, and two others were successful on their second attempt (Moore et al. 2002). Accordingly, the number of poults observed during the SCDNR sitewide summer brood survey that year was among the highest on record for SRS (figure 6.7). In contrast, nesting success of radio-marked hens in 1999 and 2000 was extremely poor; of seventeen

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Figure 6.7. Wild turkey observations recorded during South Carolina Department of Natural Resources summer brood surveys 1974–2003 on the Savannah River Site (S.C. Dep. Nat. Resources, unpublished data).

Table 6.13 Causes of mortality (number and percent) among 132 radio-instrumented wild turkeys on the Savannah River Site and the Crackerneck Wildlife Management Area and Ecological Reserve (CWMA), 1998–2001 Gobblers Cause Bobcat predation Coyote predation Unknown predator Harvest Road kill Total

Hens 9 2 9 0 2 22

(41%) (9%) (41%) (9%)

SRS (unhunted) CWMA (hunted) 11 (61%) 0 5 (28%) 0 2 (11%) 18

5 (42%) 0 2 (17%) 5 (42%) 0 12

Total 25 (48%) 2 (4%) 16 (31%) 5 (10%) 4 (8%) 52

Source: Moore et al. 2002, J. C. Kilgo, U.S. Forest Service, unpublished data.

hens that attempted nesting, only one successfully hatched a brood (Moore et al. 2002). In addition to an extremely high nest predation rate of 81 percent over the two years, most radio-marked hens in 1999 (fourteen of fifteen) either did not attempt to nest or their nests were depredated during the laying period (before researchers located them). None of the fourteen renested. Although the summer brood surveys indicate

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that nesting success was not as poor in the general population as among the radio-marked hens, approximately 40 percent fewer poults were observed in those years than in 1998 (figure 6.7). Nesting success of radiomarked hens was only slightly better in 2001, when three of ten hens (30 percent) were successful (Carlisle 2003). The summer brood surveys reflected this slight increase in productivity. Over the four years of study, nesting success was 40 percent. Nest predators on SRS include raccoons, opossums, and snakes. Clutch sizes of first nesting attempts averaged eleven eggs during all years, while renests averaged eight eggs. To evaluate the effect on turkeys of prescribed burning during the growing season, Moore et al. (2002) and Carlisle (2003) monitored twenty-two hens on a portion of the SRS subjected to growing-season prescribed fire on a three-to-five-year frequency. Only two hens (9 percent) had nests destroyed by prescribed burns. One of the hens attempted to renest, but her second attempt was depredated. Given the small sample, the impact on productivity remains unclear, but it appears that the SRS turkey population is minimally affected, especially considering the limited area currently burned during the growing season (less than 1,000 ha, or 2,471 ac; see chapter 3). The wide variety of habitats selected for nesting (see below) further limits nest exposure to fire, as most growingseason burning is in mature pine stands. The percent cover of preferred turkey food plants was similar in stands burned during growing and dormant seasons (W. F. Moore, unpublished data), perhaps due to the fact that the areas sampled had only recently come under a growing-season burning regime. Long-term use of growing-season burning may enhance development of more typical fire-maintained herbaceous communities, which may provide greater benefit to turkeys.

Habitat Use Throughout most of the wild turkey’s range, hardwoods are an essential habitat component, particularly during the winter months, when hardwood mast is their primary food source. In the Southeast, many studies have shown that areas dominated by hardwoods are the preferred winter habitat for turkeys (Everett, Speake, and Maddox 1979; Kennamer, Gwaltney, and Sims 1980; Everett, Speake, and Maddox 1985; Smith and Teitelbaum 1986; Hurst and Dickson 1992). Providing such areas for winter habitat helps maintain a year-round wild turkey population (Hurst and Dickson 1992).

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Though turkey populations seem to be highest in areas with extensive stands of mature hardwoods, turkeys can exist in areas dominated by pine plantations when plantations are relatively small (about 40 ha, or 100 ac) and the ages of adjacent stands are diverse (Hurst and Dickson 1992). Some mature hardwoods are needed for roosting habitat and for mast production during winter. Openings or early-successional areas are required for brood habitat. Turkey habitat in pine plantations is greatly improved when burned on a three-to-five-year cycle and thinned frequently (Hurst and Dickson 1992). Turkeys are apparently adaptable to many types of small-scale forest disturbances. Wild turkeys on SRS use a wide variety of upland and bottomland habitats throughout the year. During spring and summer, they exhibit few habitat preferences (W. F. Moore, unpublished data), although they— especially hens with broods—forage extensively for insects in herbaceous areas such as grassy rights-of-way. However, during fall and winter, turkeys prefer hardwood habitats, including upland, bottomland, and mixed pine-hardwoods (W. F. Moore, unpublished data), where they forage for mast. Year-round, roosting sites tend to be in hardwood forests near a water source, such as a creek or pond. Hens nest in virtually every habitat on SRS, including pine stands of all ages, upland hardwoods, bottomland hardwoods, mixed pine-hardwoods, blackberry thickets, and power line rights-of-way (Moore et al. 2002). Vegetation around monitored nest sites from 1998 to 2000 varied widely in species composition and density, and there were few similarities among nest sites. However, 95 percent of monitored nests were located less than 100 m (328 ft) from a road or firebreak. Hens may nest near roads so they can more easily lead poults to herbaceous feeding areas after hatching.

Home Range and Movements Home range sizes of turkeys on SRS average approximately 728 ha (1,800 ac) for gobblers and 526 ha (1,300 ac) for hens (Moore et al. 2002). Weekly movements of gobblers are greater in late winter and early spring, during the breeding season, while movements of hens are usually greater during late spring and early summer, when they are searching for nest sites. Several monitored hens on SRS moved great distances (more than 6.4 km, or 4 mi) in a few days. Gobblers captured and banded on SRS have been harvested by hunters on private property up to 19 km (12 mi) from

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their capture sites. Many of these movements are temporary. For example, hens occasionally moved outside their home ranges to nest or for other unknown reasons but eventually returned to their home range. Some turkeys, however, made long-distance dispersal movements and established new home ranges. Thus, although trapping by SCDNR for its restocking program has not been needed since 2000, SRS continues to be a source of turkeys, if only for the local area.

Furbearers John J. Mayer, Lynn D. Wike, and Michael B. Caudell Furbearers are mammals with marketable pelts that represent a potential economic resource. Several regionally significant furbearers occur on the Savannah River Site (SRS). In spite of their economic importance, these species have not been commercially harvested on SRS since its establishment. Since 1954, researchers have studied several individual furbearer species on SRS. In addition, two long-term surveys of SRS furbearer numbers have been conducted: the Small Furbearer Survey, by the University of Georgia and the Savannah River Ecology Laboratory from 1954 to 1982; and the Furbearer Scent Station Survey, by the South Carolina Department of Natural Resources (SCDNR) from 1984 through the present. Furbearers on SRS historically include Virginia opossum (see table 4.24 for scientific names), beaver, muskrat, coyote, red fox, gray fox, raccoon, long-tailed weasel, mink, eastern spotted skunk, striped skunk, river otter, and bobcat. All species except the coyote were present when the government acquired the property. The following individual species accounts discuss current population levels, factors controlling distribution on SRS, and the historical population trends and environmental impacts of each of these species.

Virginia Opossum The Virginia opossum is the only marsupial native to North America. This species has continued to gradually expand its range northward and has been introduced on the west coast of the United States. The opossum pelt is of low quality but is an abundant item in fur markets. This species uses a wide variety of habitats and is common throughout the SRS (Cothran et al. 1991). Jenkins and Provost (1964) stated that the opos-

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Figure 6.8. Number of Virginia opossum, raccoon, and striped skunk captured per year during the Small Furbearer Survey, Savannah River Site, 1954–1982 (Cothran et al. 1991).

sum population was approximately the same size as the raccoon population at SRS (i.e., roughly 13,000 animals). Opossums were overall the second most commonly captured species in the Small Furbearer Survey and increased to become the most frequently trapped species in that study during the late 1970s and early 1980s (figure 6.8). More recent data on their relative abundance on SRS is unavailable. However, from 2000 to 2003, opossums were the most frequently killed furbearers on SRS’s and the surrounding counties’ roads, accounting for 59 percent of all furbearer roadkills (Mayer, unpublished data).

Beaver As the largest native North American rodent, beaver frequently weigh more than 27 kg (60 lbs). Although fairly common on SRS, no population estimate exists for beavers there. Beavers are aquatic mammals, living in streams and lakes where suitable water and food are available. In spite of their present abundance, beavers were not abundant on SRS in the early 1950s. Jenkins and Provost (1964) estimated a minimum of two hundred beavers in fifteen colonies on SRS in the mid 1960s. The popu-

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lation increased to a minimum of twenty-four colonies by the late 1970s, and reports of negative beaver impacts to the environment increased concurrently. Because of an increase in nuisance flooding and damage to timber, SRS implemented a control program for beavers in 1983. Between 1983 and 2003, SRS removed 4,028 beavers from its watersheds (table 6.14). Centers of highest beaver activity on SRS include Upper and Lower Three Runs, the swamps along the Savannah River, and the areas around Par Pond and L Lake ( Jenkins and Provost 1964; Fitzgerald 1979; Cothran et al. 1991).

Muskrat A large semi-aquatic rodent found largely in the Blue Ridge and Piedmont regions of South Carolina, the muskrat has extended its range into the coastal plain along large river corridors, primarily in the northeastern corner of the state (Golley 1966; Webster, Parnell, and Biggs 1985). Muskrats are rare on SRS, which is at the edge of their distribution. They require permanent wetlands with an abundance of aquatic plants and animals. No estimates currently exist for the SRS muskrat population size, and little is known about the species on the site. Muskrats have been observed on SRS in only a few instances, and no field sign (e.g., cuttings, feeding platforms) has ever been reported on the site ( Jenkins and Provost 1964; Cothran et al. 1991).

Coyote A canid species native to the western United States, the coyote has only recently expanded its range into the area of South Carolina encompassing SRS (Webster et al. 1985). Local sportsmen stocked coyotes into Aiken County prior to the mid-1900s (Golley 1966), but we do not know whether they became established at that time. To date, there have been no population estimates or published studies on SRS coyotes. The coyote is an adaptable omnivore, able to occupy a variety of undeveloped and developed habitats. Its prey at SRS includes animals as large as wild turkeys and probably deer, but no environmental impacts have been reported. Hunters have harvested a few coyotes on Crackerneck Wildlife Management Area and Ecological Reserve. The earliest known sighting of a coyote on SRS was on December 3, 1986, along SRS Road C near the Upper Three Runs drainage corridor. Since then, coyote sightings and

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Table 6.14 Annual number of beaver trapped on the Savannah River Site, 1983–2003 Year

Beavers trapped

1983 1984 1985 1986 1987 1988–91a 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 Total

196 44 192 148 84 0 153 262 327 489 519 604 670 221 44b 35b 21b 19b 4,028

a Trapping b Some

not conducted. of these beaver were shot as opposed to being trapped.

road-killed individuals have steadily increased each year. Coyotes killing livestock and eating watermelons in areas surrounding SRS have become a significant problem.

Red Fox A medium-sized canid, the red fox commonly occurred on SRS in the early 1950s. This species expanded its range into the southeastern United States during colonial times, but it did not occur in South Carolina before the mid-1800s. Fox hunters reportedly introduced the species into Aiken County prior to the 1950s (Golley 1966; Webster, Parnell, and Biggs 1985). The red fox is associated with open habitats and rarely occurs in densely wooded areas. As the SRS shifted from a mixed farmland–wooded mosaic to predominantly forested habitat, the numbers of red fox on the site declined dramatically. The Small Furbearer Survey cap-

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Figure 6.9. Number of red fox, gray fox, and bobcat captured per year during the Small Furbearer Survey, Savannah River Site, 1954–1982 (Cothran et al. 1991).

tured no red fox after 1977 (figure 6.9), and more recent surveys have not documented this species on SRS. Red fox may still occur on the edge of the SRS where it borders neighboring farmlands.

Gray Fox The gray fox, the smallest native canid on SRS, is currently very abundant on the site. This species occupies a variety of habitat types but prefers early-successional woodlands (Webster, Parnell, and Biggs 1985). Several studies have described the age structure, productivity, behavior, movement, and habitat use of SRS gray foxes (Wood 1958; Jeselnik 1982; Sawyer 1988; Weston 2001). As the SRS has shifted to primarily woodland habitats, the site’s gray fox population has increased. This species was the most common species captured in the Small Furbearer Survey (figure 6.9). Weston (2001) studied the SRS gray fox population as an unharvested baseline for comparison with harvested populations off-site. She found that the SRS population had a higher density (0.97 foxes/km2, or 2.51 foxes/mi2; as compared to 0.15–0.83 foxes/km2, or 0.39–2.15 foxes/mi2 elsewhere); a sex ratio biased toward females (1:1 elsewhere); smaller litter sizes (3.6 young/litter as compared to 3.8–4.6 elsewhere); and an older

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average age (2.97 years as compared to 1.78 years elsewhere) than the harvested populations off site. The SRS gray fox population ranges in size from 355 to 765 individuals (Weston 2001) and may serve as a recruitment source for populations in the surrounding areas. The gray fox is a vector of concern for rabies in the Southeast (Davidson and Nettles 1988), and at least one case of rabies in gray fox has been verified on SRS ( J. Weston, Savannah River Ecology Lab, pers. comm.).

Raccoon With its black bandit mask, thick fur, and ringed tail, the raccoon is an easily identifiable furbearer and is abundant on SRS. It is omnivorous and prefers bottomland hardwood and swamp forest habitats that offer abundant hardwood den trees and water for foraging sites (Kinard 1964). However, raccoons occur in almost every habitat on SRS. In 1962, Cunningham estimated that the SRS could have been supporting a raccoon population of roughly fifteen thousand animals. They were the third most common species taken during the Small Furbearer Survey (figure 6.8). Densities as high as one raccoon per 4 ha (10 ac) have occurred on SRS (Cunningham 1962; Kinard 1964; Cothran et al. 1991). Raccoons populations in the extreme southeastern United States have long exhibited enzootic rabies infection (Davidson and Nettles 1988).

Long-Tailed Weasel The long-tailed weasel is the most common weasel in both South Carolina and Georgia. A highly efficient predator, active year-round, it occupies many habitats (Webster, Parnell, and Biggs 1985). Highly secretive, it is rarely seen on the SRS ( Jenkins and Provost 1964), and it has not been studied there (Cothran et al. 1991). However, it is probably more common than suspected. Between 1993 and 2000, four long-tailed weasels were inadvertently live-trapped during small mammal studies in either the southeastern portion or the northeastern corner of the site (S. Loeb, U.S. Forest Service, pers. comm.).

Mink The mink is a medium-sized member of the weasel family that occurs throughout South Carolina. It is a mostly nocturnal, secretive mammal that seldom interacts or comes into contact with humans (Cothran et al. 1991). Although it is probably not rare, few observations exist for SRS

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( Jenkins and Provost 1964), and no SRS population estimates are available. Mink are semi-aquatic mammals that use wetland habitats such as streams, ponds, lakes, swamps, and marshes, where they prey on a variety of invertebrate and vertebrate animals (Webster, Parnell, and Biggs 1985; Cothran et al. 1991). Their presence on SRS is based on four records of occurrence in bobcat scats (Kight 1962) and a few sightings by field personnel ( Jenkins and Provost 1964). In a mink survey on SRS in the late 1980s, SCDNR placed scent stations on sandbars under bridges but found no evidence of any mink on the site.

Eastern Spotted Skunk The eastern spotted skunk has four to six solid white stripes on the head and neck and a series of irregular white spots along the length of the body. It is distinctly smaller than the more familiar striped skunk (see below; Webster, Parnell, and Biggs 1985). The spotted skunk is primarily restricted to the western portions of South Carolina, and the SRS is on the edge of its range (Golley 1966). Spotted skunks were fairly common in lowland swamps and adjacent upland ridges of the site during the 1950s and early 1960s ( Jenkins and Provost 1964). Typically, they outnumber the striped skunk where both species are present (Webster, Parnell, and Biggs 1985), and early trapping studies on the SRS indicated that spotted skunks were three times more abundant than striped skunks ( Jenkins and Provost 1964). Although the Small Furbearer Survey captured striped skunks, it never captured spotted skunks, however (Cothran et al. 1991). Their current status on SRS is unclear.

Striped Skunk The striped skunk is a well-known housecat-sized mammal. Its coloration pattern is conspicuous, with long black fur and a broad white stripe that begins on the head and typically splits into two parallel stripes down its back. The bushy tail may be tipped with white (Webster, Parnell, and Biggs 1985). This omnivorous species feeds primarily on insects but also eats fruits, berries, and small animals such as mice, frogs, and snakes, as well as bird eggs. Striped skunks are generally nocturnal and occupy a variety of habitats. Fairly common on SRS, they are more abundant in low swampy areas than on sandy uplands ( Jenkins and Provost 1964; Cothran et al. 1991). The Small Furbearer Survey took small numbers of striped skunks (figure 6.8).

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River Otter The river otter is a large, aquatic mustelid well known for its playful nature. Otters occupy a variety of free-flowing to impounded aquatic habitats with good food supply, clean water, and relatively low levels of human disturbance. They prey on a diversity of fish, crustaceans, and amphibians (Webster, Parnell, and Biggs 1985; Cothran et al. 1991). Although otters have declined throughout their native range in the Southeast (Webster, Parnell, and Biggs 1985), they are still fairly common on SRS ( Jenkins and Provost 1964; Cothran et al. 1991). An estimated seventy-five to one hundred otters occurred on SRS in the mid-1960s ( Jenkins and Provost 1964). In 1984, four otters were live-trapped on SRS and transported to West Virginia as part of a restocking program. In spite of their secretive nature, otters regularly appear in waterways and impoundments on SRS.

Bobcat The bobcat is the largest wild felid known to exist on SRS at present. Bobcats were historically more abundant on SRS than in most areas of the southeastern coastal states (Cothran et al. 1991), though they have been uncommon to rare in most areas of the Carolinas (Webster, Parnell, and Biggs 1985). The SRS bobcats are probably among the most studied populations of this species in the eastern United States (Cothran et al. 1991). They prefer the edges of swamps and streams, young pine plantations, and upland hardwoods (Kight 1962; Buie 1980). Because bobcats are highly territorial, the availability of suitable habitat limits their population size (Buie 1980). Kight (1962) estimated a density of 0.8 to 1.2 bobcats/km2 (2–3 bobcats/mi2) in the more pristine swamps on SRS in the early 1960s. However, the number of bobcats captured on the Small Furbearer Survey declined after 1970 (figure 6.9). The widespread conversion of old fields to mature pine forest reduced the quality of SRS as habitat for bobcats (Buie 1980). In the mid to late 1970s, an outbreak of feline panleukopenia (feline distemper) also temporarily reduced the number of bobcats on the site (T. Fendley, Clemson University, pers. comm.). Cothran et al. (1991) estimated adult bobcat density on SRS in the late 1980s at 0.1 bobcat/km2 (0.3 bobcat/mi2), only 8 to 12 percent of what it had been twenty to thirty years previously. The Furbearer Scent Station Survey recorded bobcats during the 1980s and 1990s but not recently, indicating that although bobcats and their sign are observed regularly on SRS, their numbers remain relatively low. However, Moore et al. (2002) reported that bobcats were the primary predators of wild turkeys on SRS from 1998 to 2001.

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Wild Hog John J. Mayer Wild hogs (Sus scrofa) did not historically occur on the Savannah River Site (SRS). Not native anywhere in the Western Hemisphere, they were introduced into the United States by humans (Mayer and Brisbin 1991). Introductions have included Eurasian wild boar, feral hogs (free-living wild hogs solely of domestic ancestry), and hybrids between those two types. Long-term feral hogs are those in populations that became wild prior to 1800. After that date, intensive swine breed improvement began in the United States, which forever changed the appearance of American domestic swine. Short-term feral hogs, those in populations established from domestic stock after 1800, are physically different from their longterm counterparts. Both early colonial domestic swine and long-term feral hogs are physically smaller, with proportionately longer snouts, legs, and hair, higher shoulders, and shorter bodies (Mayer and Brisbin 1991). The SRS wild hogs date back to the initial governmental acquisition in 1951. They derive from a small population of free-ranging recent or modern-day domestic swine that local farmers did not remove before the 1952 deadline (Jenkins and Provost 1964). Physically, these animals in and around the SRS river swamp closely resemble other populations of shortterm feral hogs in the United States. Subsequent introductions of other types of wild hogs (e.g., wild boar × feral hog hybrids) have increased the morphological diversity in the SRS population (Mayer and Brisbin 1991). Wild hogs are one of the most controversial wildlife species on SRS. Many public agencies and private individuals consider them serious undesirable exotic pests that cause extreme ecological and economic damage. At the same time, many sport hunters hold the wild hog in high regard as a big game animal and meat source.

Population History In 1952, one hundred to two hundred free-ranging hogs roamed the SRS river swamp, upland areas bordering the swamp, and adjacent drainage corridors ( Jenkins and Provost 1964; Mayer, unpublished data). Over the ensuing years, these animals thrived and multiplied. In spite of control efforts, the population continued to increase in the 1960s and early 1970s, though the general distribution of these animals remained unchanged. In the mid-1970s, a second population of wild hogs, the ori-

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Figure 6.10. Expansion of wild hog distribution on the Savannah River Site, 1975– 2003. The shaded area indicates the 1952-to-present distribution of the river swamp population. The dated, enclosed contours represent the expanding distribution of the upland population. Updated and adapted by permission from Mayer and Brisbin 1991, © 1991 by University of Georgia Press.

gin of which remains unknown, was discovered in the more upland, north-central portion of the Site. Based on morphological data, these animals appear to be hybrids between Eurasian wild boar and long-term feral hogs; they did not stem from the established population in the SRS river swamp (Mayer and Brisbin 1983). The upland population subsequently expanded throughout the northern half of the SRS, and by 1986, it became contiguous with the original population (figure 6.10; Mayer and Brisbin 1983).

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Since 1965, wild hogs have been taken on SRS public deer hunts, held annually from October through December. Before the early 1980s, all the wild hogs from the river swamp showed the physical characteristics of short-term feral hogs. In 1983, wild hogs taken on hunts around Ellenton Bay and the mouth of Upper Three Runs exhibited characteristics of Eurasian wild boar × feral hog hybrids. The origin of these animals was traced to a release of hybrid wild hogs on adjacent private property. The percentage of wild hogs showing these mixed characteristics continued to increase in the river-swamp hunt compartments during the mid1980s. By 1989, the hybrid phenotype had expanded throughout the SRS river swamp (Mayer and Brisbin 1991). In 1981, SRS imposed a one-year moratorium on harvest of wild hogs during hunts in the river-swamp hunt compartments. This was done in an effort to protect several wild hogs that were instrumented with radiotracking collars as part of a telemetry study conducted by Clemson University. The moratorium resulted in a subsequent doubling of wild hog population size in that area of the SRS. Because of the damage that wild hogs cause, SRS has used a variety of control efforts to manage their population numbers. These efforts began in 1952 after workers noted hog damage to planted pine seedlings. The early control program included both opportunistic shooting and live trapping using wooden corral traps. Those efforts were discontinued in the late 1960s, after several hundred wild hogs had been removed from the site ( Jenkins and Provost 1964). Between 1965 and 2003, the public harvested 3,009 wild hogs on SRS deer hunts. The number of wild hogs taken during hunts increased from 1982 until the mid-1990s (table 6.15). More recently, that number has declined, with a yearly average of seventyeight animals taken between 1996 and 2003. Because of the population increase in the early 1980s, SRS implemented a subcontracted controland-removal program in 1985. Initially using only welded-wire corral traps, in the early 1990s this program began to use trained hunting dogs to catch and remove wild hogs. From 1999 to 2001, SRS temporarily suspended the use of hog-control subcontractors, and U.S. Forest Service personnel operated corral traps. Subcontractors resumed hog control in 2001, at which time limited public hog hunts were also initiated to supplement control efforts. During January 2001, hunters removed 121 wild hogs. In response to the terrorist incidents of September 11, 2001, the public hunts and subcontracted control efforts were greatly curtailed during the remainder of that year. Those management activities were fully

Table 6.15 Number of wild hogs removed annually from the Savannah River Site, 1965–2003, on public deer hunts and by U.S. Forest Service–Savannah River (USFS-SR) subcontractors Year 1965–69 1970 1971 1972 1973 1974 1975 1976 1977 1978 1979 1980 1981 1982 1983 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 Total

Deer hunts 36 34 10 17 12 38 45 176 57 28 61 32 33 189 133 104 79 123 123 146 179 134 126 168 148 105 46 107 85 62 45 38 6 174 110 3,009

USFS-SR subcontractor

160 238 170 326 177 302 183 503 326 627 907 876 1,004 1,000 650 61 240 259 272 8,281

Total annual removal 36 34 10 17 12 38 45 176 57 28 61 32 33 189 133 104 239 361 293 472 356 436 309 671 474 732 953 983 1,089 1,062 695 99 246 433 382 11,290

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resumed the following year. A second limited public hog hunt held during January 2003 removed fifty-two animals. Overall, SRS wild hog control has been very successful, removing an annual average of 541 and a total of 10,285 wild hogs between 1985 and 2003 (table 6.15). Established populations of wild hogs, such as the one on SRS, are usually difficult to control, and to be completely effective, control efforts must be intensive and continuous. In general, annual removal of 30 to 50 percent of a wild hog population is necessary to keep numbers either stable or decreasing in a given area (Tipton 1977). The estimated size of the SRS wild hog population during the past ten years has fluctuated between about eight hundred and two thousand animals. Wild hogs currently occupy approximately 91 percent of the SRS, with a sitewide average density of approximately 1 hog/km2 (3 hogs/mi2).

Present Population Size and Distribution In 2003, the SRS wild hog population was estimated at approximately nine hundred animals (Mayer, unpublished data), making them second only to white-tailed deer as the most common large mammal on the SRS. Over the past decade, the number of wild hogs on the SRS has been declining slowly due to control activities. Both population size and distribution of SRS wild hogs are ultimately determined by two primary factors: availability of suitable habitat and population management. The variety and quality of habitats at SRS generally allow for an increase in the number of wild hogs and the areas they occupy. In contrast, SRS natural resources agencies implement management to reduce the number and distribution of wild hogs on the site. Wild hogs are generalists with respect to habitat requirements. They occupy most terrestrial and many wetland habitats on SRS. During fall and winter, wild hogs on SRS prefer areas dominated by mast-producing species, particularly bottomland hardwood forests (Sweeney 1970; Kurz 1971; Crouch 1983; Hughes 1985), and on a year-round basis, they seek areas with well-distributed water and escape cover. The mast produced by oaks and hickories in both upland and bottomland hardwood forests plays an important role in determining the annual cycles of nutritional status and reproductive success of wild hogs. Further, their level of habitat use is directly proportional to the density of escape cover in a given area (Barrett 1978). Escape cover also provides preferred bedding habitat for wild hogs (Conley, Henry, and Matschke 1972).

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Human activities have historically caused approximately 88 percent of the annual attrition of SRS wild hogs. The wild hog control program and public deer hunts account for most of that. However, collisions with vehicles, illegal poaching, control shooting by South Carolina Department of Natural Resources personnel, and specimen collection by Savannah River Ecology Laboratory researchers have also taken a number of wild hogs. Of lesser importance, disease and natural predation by bobcats, coyotes, and American alligators also remove a small portion, mostly among very young and very old animals within the population.

Effect on the SRS Environment In general, wild hogs have a negative impact on the SRS environment. Rooting causes the most widespread damage. Excessive hog rooting can destabilize surface soils and increase soil erosion, damaging stream channels, seeded roadbeds, and ditch banks. Since the early 1950s, wild hogs have damaged pine plantations on the site. Hogs dig up and chew the rootstock of loblolly and longleaf pine seedlings, sometimes destroying entire regeneration plots. Similar depredations on planted hardwood seedlings recently occurred in a wetland restoration area (Mayer, Nelson, and Wike 2000). Hogs may also negatively affect native plant communities through rooting disturbance and direct foraging, and native wildlife by competing for food. Hogs compete with white-tailed deer (Odocoileus virginianus), wild turkeys (Meleagris gallopavo), and other animals for the mast crop. Wild hogs also have some positive impacts on SRS environments. Rooting aerates compacted forest floor soils, promoting the propagation and regeneration of certain tree seedlings. It can increase tree growth in some species (Lacki and Lancia 1986), though it also damages tree roots and increases the amount of sprouting and root suckers in a few hardwood species (Huff 1977). Because wild hogs have a high reproductive potential and become wary with hunting pressure, they are difficult to control, much less eradicate. Populations on properties surrounding SRS could repopulate any portion of the SRS where they have been eliminated. Control of the SRS wild hog population will likely be an ongoing effort because of the destructive nature of this introduced species. At the same time, wild hogs also will continue to be a highly prized big game animal on annual public hunts.

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White-Tailed Deer Paul E. Johns and John C. Kilgo From a public relations standpoint, the white-tailed deer (Odocoileus virginianus) is probably the most important wildlife species occurring on the Savannah River Site (SRS). The SRS deer herd has been the subject of more scientific investigations than any comparable deer population in the world, resulting in more than 125 published papers. Each year more than 5,500 people apply to be drawn for one of the public hunts, and with articles in hunting magazines such as Buckmasters (Handley 2000), hunters have applied from as far away as Alaska and Italy. In thirty-six years on the SRS, over 150,000 hunters have harvested over 40,000 deer. Each deer harvested in South Carolina brings an estimated $1,500 into state and local economies (U.S. Department of Interior et al. 1997). The current SRS deer population grew from a few individuals that were present in 1950. Early workers realized that the study of a young, rapidly expanding population would provide invaluable insights into the basic biology of the species (Urbston 1967). Accordingly, researchers have collected a broad base of data on nutrition, reproduction, antler growth, parasites, genetics, and movement for this population since the early 1960s. Such a large database exists for no other deer population in the world.

Population History When the Atomic Energy Commission, later Department of Energy (DOE) acquired the SRS during 1950 and 1951, deer were practically unknown in the area. Overworked farmland provided little suitable upland habitat, and continual pressure by the public had all but extirpated the species. In 1950, an estimated one to two dozen animals occupied the inaccessible portions of the Savannah River swamp ( Jenkins and Provost 1964). The DOE closed SRS to the public on December 14, 1952, and until 1965 there was no public use of the wildlife resources. Except from limited poaching, the deer population had complete protection. Deer habitat quickly improved, and by 1965, range conditions were considered excellent over most of the SRS (Urbston 1967). Land management converted farm fields to pine plantations, providing needed cover. Hardwood mast was readily available in the extensive bottomland hardwoods, along old fencerows, and at old house sites (Wiggers et al. 1978). In 1963, the

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deer population was approximately 1,400 animals ( Jenkins and Provost 1964). Within fifteen years, deer had expanded to all areas of the SRS (Urbston 1967). During the spring of 1965, estimated deer density exceeded 8 per km2 (20 per mi2) in some areas such as the river swamp (Payne, Provost, and Urbston 1966). Although sitewide numbers remained low, browse lines had developed in these areas, the physical condition of deer had declined, and there was an increase in deer-vehicle accidents on the site (Urbston 1967). As a result, SRS initiated public hunts on a limited area of the site during the fall of 1965. The hunts used dog drives (hereafter, dog-hunting), a traditional method of hunting deer in the South Carolina Low Country. Each hunt consisted of about 150 hunters and over three hundred dogs on units that averaged 1,851 ha (4,574 ac). Hunters harvested both sexes and all ages of deer with no bag limit (Payne, Provost, and Urbston 1966). Because of buck-only harvest laws elsewhere in the state, most hunters had never had the opportunity to shoot deer of any sex or age, and word spread about the number and quality of deer taken on the early SRS hunts. Dog-hunting effectively removed large numbers of deer from hunted areas in a short time. It also satisfied security and safety concerns, because SRS could control hunter location and hunters used shotguns instead of high-powered rifles. In 1968, SRS initiated still-stalk hunts (hereafter, still-hunting) on two areas. Those areas, outside the fenced security areas, were on the north and southeast sides of the Site and included about 19,100 ha (47,200 ac). Two to three times each year, between two hundred and four hundred hunters were allowed one day to scout the area and the next three days to hunt. Although still-hunting was less efficient than dog-hunting (an 11 percent versus a greater than 25 percent hunter success rate; Novak et al. 1991), in 1980, SRS expanded it to most areas to reduce the personnel needed to run hunt operations. After a shooting accident during a hunt the following year, SRS eliminated still-hunting, however, and dog-hunting has been the only method used since. During the still-hunting period, the number of hunters and the annual harvest varied yearly. Hunters removed more deer, and hunter success was much higher in the dog-hunted area than in the still-hunted area. In addition, with the initiation of dog-hunting in the previously still-hunted area, total harvest and hunter success increased to a level approximating that of the previously dog-hunted area (Scribner et al. 1985). From 1982 to 2000, the estimated prehunt population of the site fluctuated

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between 3,200 and 5,900 deer, with an average of 4,311. Annual harvest during the same period has ranged from 294 to 2,063, with an average of 1,180. Several changes in the operation of the dog-hunts accompanied the cessation of still-hunting in 1982. The SRS increased the minimum distance between hunt stands from 122 to 183 m (400 to 600 ft). The number of standers and dog packs used in each hunt increased, as well as the number of hunts. In 1994, because of increased safety concerns, SRS again increased the distance between stands from 183 to 274 m (600 to 900 ft). In 1996, in an effort to raise efficiency and lower cost, the number of dog packs again increased, by as many as twenty-five on some hunts. Recent work indicates that deer rarely leave their home range when pursued by dogs, and those that do return within less than twentyfour hours (D’Angelo et al. 2003).

Population Dynamics Data on the demographics of the SRS deer population help form management strategies. The extensive database from harvest records beginning in 1965 includes the location, age, sex, weight, antler development, lactation status, and in utero number of fawns (when discernible) for each deer harvested. Researchers have derived the age structure and sex ratio of the population, as well as location-, age-, and sex-specific fecundity rates (Payne, Provost, and Urbston 1966; Johns et al. 1977; Rhodes et al. 1985). Novak et al. (1991) derived the 1965 population size (the first year of the hunts); subsequently, using a life table model, Novak, Johns, and Smith (1999) retrospectively estimated population size for 1965 through the early 1990s. Since that time, researchers have used this model annually to predict the size of the prehunt population and thereby help formulate annual harvest strategies (figure 6.11). The number of births relative to the number of deaths determines the size of the SRS deer population; immigration and emigration are negligible because of the size of the SRS ( J. Novak, Savannah River Ecology Lab, pers. comm.). The number of births is determined by the sex ratio (i.e., used to derive number of does in the population), the age structure of the doe population, and age-specific fecundity rates. The sex ratio of 0.96 does per buck approaches evenness, represented by 1.0 (i.e., a 1:1 ratio). This is attributable to the either-sex harvest and has not varied significantly over time (Novak, Johns, and Smith 1999). In contrast, the age structure of the female component of the population shifted modestly between the

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Figure 6.11. Estimated size of the deer population and number of deer harvested on the Savannah River Site, 1965–2003.

periods 1985–1989 and 1995–1998, with a decrease in the number of fawns (0.5-year) and yearlings (1.5-year) and a concomitant increase in the number of 2.5-year-old does (Novak, Johns, and Smith 1999). Longterm averages for age-specific fecundity rates (fawns per pregnant female) are 1.06 for 0.5-year-olds, 1.56 for 1.5-year-olds, 1.73 for 2.5-year-olds, and 1.76 for 3.5+-year-olds (Rhodes et al. 1985). With the exception of the swamp population during the 1960s, these figures have varied little across the population levels that have existed at SRS (Rhodes et al. 1985). Nearly 100 percent of adult females (1.5+ years) conceive. However, the most important factor that has influenced the ability of the population to sustain high levels of harvest and to recover from overharvest has been the conception rate of doe fawns (i.e., 0.5 years old). As the population size decreases, the number of fawns that breed increases ( Johns et al. 1977). At high population levels, fewer fawns breed; whereas at low levels, the incidence of fawn breeding approaches 40 to 50 percent (Urbston 1967). As fawns may account for as much as 34 percent of the doe population (Novak, Johns, and Smith 1999), their breeding can have a significant impact on total annual production. The number of deaths in the population is largely determined by harvest level, as Novak et al. (1991) found that natural mortality is minimal. Harvest has been able to control the SRS deer population (figure 6.11).

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Due to a misunderstanding of certain effects, some hunt units were overharvested during the mid to late 1970s. The population had increased between 1952 and 1974, but in 1975 it began a decline that continued through 1978. After 1978, SRS reduced dog-hunting effort and did not hunt some units for a couple of years. With more still-hunts over the next three years (1979–1981), the population increased, due to the lower efficiency of that hunt method. However, with the return to dog-hunts as the sole method of harvest in 1982, combined with the belief that the population could not be overharvested, the number of both stand and dog-hunters increased. As a result, by 1987, the population had declined to levels not observed since the late 1960s. By lowering the total number of hunts and skipping hunts in certain units in 1987, the population began to increase once more. In 1989, hunts resumed at previous levels, with two to five units “rested” (i.e., not hunted) each year. Under that system, the population increased until 1992 and remained fairly high until the mid-1990s. In 1995, SRS again increased the number of dog packs used per hunt in an effort to remove more deer. This strategy was so efficient that by 2000, the deer population had again declined to mid1960s levels. During the 2000 season, all hunts except two that targeted high deer-vehicle accident areas were buck-only. Within two years, the population increased by 61 percent. Thus, knowledge of reproduction and harvest facilitate estimation of population size. Given the current year’s prehunt population size, managers can predict next year’s prehunt population by determining the number of bucks and does in the population, subtracting the harvest of each, and adding the expected reproduction. Annual reproduction is simply the sum of age-specific productivity, determined by multiplying the number of does in each age class by the age-specific fecundity rates. Without annual harvest, the SRS deer population is theoretically capable of more than doubling in two years. In recent years, two factors may have complicated the methods described above for estimating population size. First, coyotes colonized the SRS during the late 1980s and 1990s and now are common. Although predation of adults is probably rare, together with bobcats, they could affect fawn survival. Second, the region experienced severe drought from 1999 to 2002. The extent to which drought conditions may have affected habitat quality, and hence productivity, is unknown. However, although Novak et al. (1991) determined that nonhunting mortality was insignificant in the SRS population prior to their study, the recent changes in predator populations and possible changes in habitat conditions con-

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ceivably could have impacted annual recruitment. The only data available to evaluate that possibility are annual spotlight surveys conducted on SRS. In recent years, population estimates derived from the spotlight counts have been somewhat lower than the predicted population size. Spotlight estimates are based on actual counts of deer, but spotlight censusing includes some potential biases. The predictive model is based on robust statistical procedures and sound data, but it does not consider nonhunting mortality. Whether recent low spotlight estimates reflect normal sampling error or true population declines resulting from depressed recruitment is unknown. However, if the latter is true, harvest guidelines (which are based on population model predictions) may have been excessive, further compounding the problem. This issue warrants further investigation. An interesting characteristic of the SRS population is the difference between river-swamp and upland deer. During the mid to late 1960s, the river swamp that had served as a refuge for the founding individuals became overpopulated, and Urbston (1967) noted evidence of decreased body condition. However, on the remainder of the SRS, the population was still expanding and had not reached carrying capacity when intensive hunting began (Urbston 1967). The deer in the swamp differed demographically and genetically from those in the upland (Urbston 1967, 1976; Urbston and Rabon 1972; Johns et al. 1977; Dapson et al. 1979; Ramsey et al. 1979). For example, fecundity, body size, and antler development were lower in the swamp than in the upland. Most of these differences occurred during the early expansion phase of the herd, and though some still exist, they have decreased over time. Seasonal home range size of adult does at SRS averages 188 ha (465 ac; D’Angelo et al. 2004).

Population Management Deer management on SRS is an ever evolving process. Prior to 1991, SRS conducted the hunts—as in most locations—without information on the population’s size. Harvest was occasionally adjusted, as described above, based on perceived changes in population density, as well as in response to numbers of deer-vehicle accidents, but no long-term goal existed for population size. By 1991, estimates of population size had become available, and the SRS deer management team developed a long-term goal of five thousand deer in the prehunt population. The current SRS Deer Management Plan (U.S. Forest Service–Savannah River 2000, unpublished) states that the purpose is “to maintain the population at a level that

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minimizes both the number of deer-vehicle accidents and damage to the SRS landscape (i.e., native plant communities, timber plantations), yet supports a quality hunt program that benefits the economies of local communities.” This plan prescribes a long-term prehunt population goal of four thousand deer. The adjustment of the population goal from five thousand to the current figure of four thousand resulted from a combination of factors. The primary objective of the deer hunts at SRS has always been to minimize the number of deer-vehicle accidents on site. The original population goal was based on two assumptions: that hunting controls population size and that the number of deer-vehicle accidents is a function of the population size. The first assumption has largely been valid at SRS. Recent analyses, however, indicate problems with the second assumption. Population size explains only 34 percent of the annual variation in the number of deer-vehicle accidents (figure 6.12a). Although low population levels occasionally result in fewer accidents and high population levels occasionally result in more accidents, the relationship does not hold at intermediate population levels. Therefore, other factors affect the number of deer-vehicle accidents per year. For example, the size of the SRS workforce (as an index to traffic volume) explains 42 percent of the variation in accident numbers (figure 6.12b), indicating that workforce size is at least as good a predictor of the number of accidents as deer population size. Although an extremely low deer population may result in fewer accidents, such a population would not support an annual harvest sufficient to attract enough hunters to control the population over the long term. Therefore, management for such a small population is undesirable. The current long-term management goal may result in slightly fewer accidents while allowing for a long-term sustainable harvest of approximately nine hundred deer, assuming maintenance of the historical even sex ratio. Such a harvest would allow a more stable long-term population well below the carrying capacity of the habitat, allowing for maximum productivity of does and quality antler and body development of bucks. A prehunt population size of 4,000 approximates the long-term mean of 4,285 for the period 1965–2000.

Deer-Vehicle Accidents The annual number of deer-vehicle accidents reported on SRS has ranged from 16 to 104, with an average of 53 during the period 1965–2003. Comparison of accident figures over time, is problematic, however. For

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Figure 6.12. Relationship between the number of deer-vehicle accidents and (a) the estimated size of the deer population and (b) the size of the workforce on the Savannah River Site, using comprehensive accident data 1992–2003.

example, factors such as the number of roads open to traffic and the particular roads monitored for accidents confound assessment of potential trends, so the data are not exactly comparable among years. Also, the proportion of total number of accidents actually reported has fluctuated dramatically, according to changes in insurance reporting laws. Thus, long-term accident figures underrepresent the true number of accidents that occurred each year by an unknown and variable percentage. Therefore, since 1991, the Savannah River Ecology Laboratory has recorded all known deer-vehicle accidents on SRS, including those for which no

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official accident report was prepared. During the period 1992–2003 (which included some of the highest and lowest population levels recorded on SRS), the number of known accidents per year has ranged from 69 to 128, with an average of 95 ( Johns, unpublished data). The number of accidents reported underestimates the actual number of accidents by at least 34 percent. This more comprehensive database also has identified several patterns in the incidence of deer-vehicle accidents. For example, most accidents occur around dawn (50 percent) and dusk (30 percent), and more than half of all accidents occur during the fall (53 percent), when the rut occurs. Thus, accidents tend to be most frequent when peak traffic volumes (due to shift change) coincide with high deer activity. During this period, mature bucks cause 71 percent of the accidents. Accident “hot spots” shift from year to year along any given stretch of roadway, indicating that localized placement of deer crossing signs may not reduce the number of accidents. Thus, factors that affect the number of accidents include the number of vehicles on the road, the pattern in time of traffic flow, the particular roads open to traffic, and the demographic structure and spatial distribution of the deer population. The number of accidents increases in areas where hunters are farthest from roadways. The area of the SRS contained in the unhunted 274-m (300-yd) safety buffer along either side of roadways is 8,425 ha (20,819 ac), or 10.5 percent, of the entire area of the SRS. Since deer densities may be higher in corridors along roadways as a result of the safety buffer, experimental hunts along three SRS roads during 2000–2002 specifically targeted the protected buffers by closing roads during hunts. Current research (C. Comer, University of Georgia) is examining whether SRS deer exhibit a social structure that might allow this intensive localized removal to result in a reduced density along roads that is sustainable over the long term. If so, such hunts might ultimately reduce the number of deer-vehicle accidents. This work may also explain why the occasionally heavy removal of deer in areas away from roadways, while necessary to control the sitewide population level, has little impact on the number of deer-vehicle accidents.

Radiological Concerns Some hunters have voiced concerns over the health risk of consuming venison taken from the site. Deer at SRS generally exhibit radiation levels (i.e., radiocesium, 137Cs) no higher than normal background levels in

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deer from similar pine-hardwood habitats across the southeastern United States ( Jenkins and Fendley 1971; Savannah River Ecology Laboratory 1999). The primary source of radiocesium in southeastern deer comes not from SRS operations, but rather from fallout from the above-ground nuclear weapons testing that has occurred worldwide since the 1950s (Haslow 1991; Wentworth 1998). All animals harvested on SRS hunts are monitored for radiological contamination, and the radiocesium levels of all deer taken by an individual hunter are tracked over the course of each hunting season. No hunter is allowed to receive a cumulative dose of more than 100 millirem (mrem) of cesium. Thus, SRS confiscates any deer harvested by a hunter that would put that individual over the 100-mrem limit for the year. This threshold dose level for confiscation is more stringent than the guideline set by the Environmental Protection Agency for consumption of fresh meat (U.S. Environmental Protection Agency 1989). Of more than forty thousand deer harvested at SRS, only one has ever been confiscated (Savannah River Ecology Laboratory 1999). No other deer have even approached radiocesium levels that would trigger confiscation.

7 Conclusion

r

John I. Blake and John C. Kilgo

In this book, experts from many fields have reviewed and synthesized a vast body of information on the ecology and management of the Savannah River Site (SRS) collected over more than fifty years. In this final chapter, we explore, in general terms, how science has helped guide management of the site, the prospects for long-term recovery of the Site, and what the future might hold.

Important Research in SRS Land Management Scientists and other workers at SRS have generated thousands of research publications and environmental studies in a variety of scientific fields. Many have been in basic sciences and have dramatically advanced scientific knowledge and understanding of ecology. Indeed, much of the work of Eugene Odum, which earned him a reputation as “the father of ecosystem ecology” (Craige 2003), was conducted at SRS. This body of work profoundly affected our understanding of the natural world in general and of SRS in particular, and as such, indirectly informs all decision making at SRS. For managers who must implement policies and procedures on the ground, science often is most immediately relevant when conducted in conjunction with operational projects that evaluate alternatives that directly affect decision making. Work that tests predictive models of processes or relationships is also directly beneficial to land managers. Thus, the following selection of important SRS research includes examples that have most directly impacted on-the-ground management of the site. Also, some work that was not so directly relevant to manage390

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ment, such as the early surveys by Odum and many others during the 1950s, provided critical baselines for measuring future progress. Several studies were key to the successful reforestation and subsequent timber management of SRS. The early reforestation work of Shipman (1958) greatly improved the ability of SRS managers to reforest the old fields and cutover forest areas. Studies that improved seedling quality and refined practices to reduce competition led to increases in tree survival. Research on hardwood regeneration by Kormanik, Sung, and Kormanik (1994) played a critical role in restoring areas like Pen Branch. Recent work by R. H. Jones (Virginia Polytechnic Institute, unpublished data) on hardwoods has elucidated the critical importance of root competition and the need for eliminating overstory competition on Sandhills sites. Studies on abandoned spoil piles and borrow pits conducted by a number of scientists (e.g., Berry and Marx 1980) identified critical aspects affecting revegetation of severely disturbed sites. Considerable work has aided landscape restoration efforts at SRS. Historical and archeological studies (Brooks and Crass 1991) helped create a broader perspective for landscape restoration by identifying postsettlement land-use legacies that are not always apparent. White and Gaines (2000) and White (2004) documented the degree and extent of human impacts to the area prior to SRS establishment. That work combined with efforts by Sassaman et al. (1990) and Frost (1997) to better understand the presettlement landscape enabled managers to articulate a broader strategy, particularly for forested savannas, and argue the case for expanding the recovery area for the red-cockaded woodpecker. Duncan and Peet (1996) showed that patterns in native savanna plant community composition were related to underlying edaphic, topographic, and hydrological features. That relationship was critical in identifying sites with the greatest potential for restoration, given that for old-field sites the only remaining template for restoration is residual soils and topography. Two other studies have had strong influence on savanna restoration. Harrington, Dagley, and Edwards (2003) showed a dramatic response of recently established plants to overstory stand density. Unexpectedly, development and reproduction of savanna plants were found to be very sensitive to even low pine tree densities. Ongoing work by Marshall, Imm, and Foster (unpublished data) is developing techniques for collecting, growing, and establishing dozens of herbaceous species and exploring the processes of natural dispersal. Extensive research and monitoring were conducted before, during, and after hot water discharge to various streams and cooling ponds at

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SRS. This large body of work had significant impacts on regulatory issues far beyond the SRS. It demonstrated, among many other things, that many species of riparian and aquatic plants, invertebrates, and fish could naturally recolonize even severely disturbed systems (Marcy et al. 2005). However, the overall species assemblages often were drastically different from those in predisturbance systems. Opportunities to conduct research and monitoring in conjunction with the active restoration of two other disturbed systems, Lost Lake and Pen Branch (Halverson et al. 1997; Nelson, Kolka et al. 2000), generated additional insights into the potential of wetland systems to recover from severe impacts. As the Lost Lake and Pen Branch efforts were under way, managers considered possibilities for restoring other wetland systems. A study by Kirkman and Sharitz (1994) demonstrated that a large number of plant species sequestered in the seed bank of Carolina bays could be stimulated following soil disturbance. Given the history of agricultural impacts to these systems (Kirkman et al. 1996) and their importance to rare flora and several amphibian species (Sharitz and Gresham 1998), plans were developed for bay restoration on a large scale. This effort involved three key elements: restoring hydrology, planting obligate wetland species, and introducing mechanical and fire disturbance. This research has demonstrated the benefit of simple, well-focused strategies. Considerable research on reptiles and amphibians (e.g., Bennett, Gibbons, and Glanville 1980; Buhlmann and Gibbons 2001) documented that several species occupying bay wetlands also require the surrounding uplands for portions of their life cycles. Thus, an additional component of the bay restoration project included simultaneous management of the adjacent uplands. The turning point for the recovery of the endangered red-cockaded woodpecker, regionwide as well as at SRS, was the development of artificial cavity inserts (Allen 1991) and techniques to successfully translocate birds (Allen, Franzeb, and Escano 1993). Later work by Hanula, Franzreb, and Pepper (2000) determined that the food base for red-cockaded woodpeckers largely consisted of arthropods that move up trees from detrital materials on the forest floor. This finding changed how managers viewed the importance of live pine tree density to woodpecker foraging requirements, and thereby affected forest management on a large scale. Strategies for management of other SRS fauna depend on an understanding of the relationship between measurable habitat characteristics and species abundance or community composition. Traditional ecological ordination models can provide important insights into critical habitat features, but they are most helpful to managers when the axes of the

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ordination can be readily interpreted as variables that can be managed. For example, the work of Aho et al. (1986) and Meffe and Sheldon (1988) demonstrated a strong relationship between fish community structure and stream channel features. Coupled with knowledge of the importance of other features such as woody debris and channel cover, that work enabled managers to develop a simple predictive model to guide restoration of degraded stream systems. Similar efforts to test and refine habitat models for birds (Kilgo et al. 2002) and to identify relationships between habitat structure and avian demography (Liu, Dunning, and Pulliam 1995; Krementz and Christie 1999; Moorman, Guynn, and Kilgo 2002) are guiding savanna and hardwood management strategies. This work, together with much more like it, has guided and improved land management practices at SRS during the last fifty years. Given future challenges, the Site will continue to rely on sound research and monitoring to inform land management decisions in an increasingly complex environment.

Missions for the Next Decade The Department of Energy (DOE) mission at SRS is to “serve the nation through safe, secure, cost-effective management of our nuclear weapons stockpile, nuclear materials, and the environment” (U.S. Department of Energy 2000, 1–4). The SRS, like other DOE sites, is operating under an accelerated environmental cleanup and closure schedule for various waste sites that currently do not meet regulatory standards. The SRS long-range comprehensive plan (U.S. Department of Energy 2000) provides projected timelines for various tasks associated with cleanup and closure. For example, completion of environmental remediation activities is expected by 2017, vitrification of all high-level waste is expected by 2023, and disposal of that waste to federal repositories is expected by 2038. Despite the priority of Resource Conservation and Recovery Act and Comprehensive Environmental Response, Compensation, and Liability Act mandates, both regulators and managers are aware that the costs and adverse ecological impacts of existing technologies for removal of dispersed low-level metals, volatile organic carbons, and radionuclides can be high relative to the real risks posed to human health if they are left in place (Whicker et al. 2004). As a result, greater emphasis is being placed on enhancing natural remediation strategies (Looney, Vangelas, and Sink 2004). Coupled with the accelerated cleanup are the decontamination and decommissioning of older facilities, driven primarily by the desire to reduce maintenance costs. The result will

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ultimately be the elimination of most of the infrastructure associated with the primary missions of the Site during the Cold War era. An example, perhaps unique, of what this has led to at other sites in the DOE complex is the conversion of Rocky Flats in Colorado to a national wildlife refuge. The future of the SRS landscape and the details of its ecology and management are difficult to predict with precision. While restoration as an explicit goal of SRS land management was not formalized in 1951, it has gradually become an important component of the SRS land management strategy. It was articulated in 1993 in the goals of the Biodiversity Research Program, and many restoration projects, both research and operational in nature, have been conducted to meet these goals. The Natural Resource Management Plan (U.S. Department of Energy 2005) for the future retains the restoration theme, stating that “management is designed to promote conservation and restoration, to provide research and educational opportunities, and to generate revenue from the sale of forest products.” Thus, in the near term, management will continue to actively conserve and restore species, communities, and habitats such as firemaintained savannas, isolated wetlands, hardwood forests, and streams. Some restoration or recovery actions, such as environmental cleanup and endangered species management, are mandated by federal legislation, whereas others are implemented proactively in an effort to avoid regulatory problems and high costs in the future.

Is Restoration to Presettlement Conditions Realistic? Reforestation was the major goal in the early period of SRS. Many species recovered simply through the reduction of direct human presence and through the increasing amount of forest cover ( Jenkins and Provost 1964). Others were the focus of specific restoration efforts (e.g., wild turkey, red-cockaded woodpecker, gopher tortoise) and planting programs (e.g., oaks, savanna grasses, and herbaceous plants). Still others benefited from the intentional creation of a particular habitat structure (e.g., snags, grassy savannas, riparian cover) or process (e.g., fire, wetland hydrology). These first-order solutions were based on fairly robust scientific information, but implementation was often difficult. Given the progress over the past fifty years, what additional gains can be made in the future? Even if all of the native species present at the time of European settlement still existed, it is doubtful whether any amount of effort or time would allow presettlement conditions to be recreated. Our knowledge of the southeastern landscape during that time is impre-

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cise, and our understanding of the historical scope and intensity of ecological processes is limited. Except for extinct species, the most obvious missing components of the former southeastern fauna at SRS are the large predators—the red wolf, cougar, and black bear. Even the relatively large size of SRS is most likely too small to sustain populations of these species, however. Social and political considerations off the site could also be problematic. As the Yellowstone wolf and grizzly bear situations illustrate, large predators can be perceived by adjacent landowners as presenting numerous threats. Significant constraints are imposed by considerations in the surrounding region. The Strom Thurmond Reservoir upstream on the Savannah River is designed to regulate flows to protect lives and property. Therefore, the timing, extent, and duration of flooding in the Savannah River swamp, a critical process in that ecosystem, is beyond the control of SRS managers. Similarly, difficulties exist in the use of fire. Wildfires must be controlled to prevent damage and loss, and regional air pollution standards to protect human health have led to stringent regulations on smoke emissions from prescribed fire. Coupled with SRS liability and safety concerns, the extent that prescribed fire can be used to sustain forested savannas is limited. Taken together, these continuously changing social, environmental, and economic considerations present significant challenges to future substantive restoration efforts. However, SRS managers continue to pursue restoration opportunities using an adaptive management approach and inexpensive technologies to offset the limitations on natural processes. Reintroduction of extirpated species will likely be limited, making natural dispersal into the area the most probable mechanism by which the species pool would increase. In fact, since the early surveys in the 1950s, the number of species and their known extent on the SRS have increased, particularly among plants, fish, amphibians, and reptiles. This is in large part the result of intensive survey efforts that have created a better understanding of existing distributions. For example, many ecologists have been surprised by the diversity of plants and animals found in managed old-field pine stands, once dismissed as “ecological deserts.” While midrotation pine plantations can certainly be depauperate in terms of species richness, recent discoveries of sensitive plant populations have demonstrated that many species have persisted in spite of land-use legacies (see chapter 5). Other species have colonized the SRS unassisted. For example, several bird species (ovenbird, blue-headed vireo, black-andwhite warbler) have expanded their ranges southward during the past fifty years and now occur on SRS (chapter 4).

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Is There a More Appropriate Theme or Model? As indicated above, conservation and restoration in general are goals of SRS land management. Can that be more explicitly stated in terms of current ecological paradigms such as ecosystem management, sustainability, naturalness, presettlement conditions, the range of natural variation, ecological integrity, functional processes, and biodiversity indices? Any of these can be useful as general guiding concepts in a qualitative sense. The problem they present for land managers lies in attempts to translate their often esoteric aspects into meaningful actions on the ground with distinct metrics for success. This process generally leads to vigorous debates, rife with multiple opposing interpretations. A large proportion of an agency’s budget can be spent on planning, meetings, staffing, and writing and still result in little meaningful implementation. While organizational bureaucracy is partially to blame for this inertia, these issues remain difficult to resolve and are debated even in the scientific literature from which they derive. Success at SRS at the level of individual projects or initiatives often is associated with close collaboration between research and management personnel. This is particularly true when objectives and metrics for success are made simple and tangible. For example, rather than stating a goal as restoring a specific site to “presettlement conditions,” it may be more appropriate to state it as restoring “the habitat structure and species composition of longleaf savanna.” Such a specific statement is facilitated by research information about the presettlement conditions, and its precision makes success easier to monitor. While this may appear to be a matter of semantics, precise goals at the project level eliminate the guesswork in assessing success.

Long-Term Management of SRS Department of Energy missions at SRS are continually evolving. An SRS manager was once asked about the long-term vision for SRS, and he responded, “My short-term vision is Friday of this week, and my long-term vision is Monday of next week.” He was attempting to emphasize the dynamic political, social, and economic environments influencing the Site’s primary missions and resources following the Cold War. Security changes following the terrorist events of September 11, 2001, and the subsequent acceleration of waste unit closure added further complexity. Regarding future land use, the Long Range Comprehensive Plan (U.S. Department of Energy 2000) offers numerous guidelines that “will be

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considered to the greatest extent possible.” These include, among others, the following: SRS boundaries shall remain unchanged, and the land shall remain under the ownership of the federal government. The Site’s designation as a National Environmental Research Park (NERP) will continue. . . . SRS land should be available for multiple use wherever appropriate and non-conflicting. . . . Natural resources shall be protected and managed, with biodiversity being a primary goal. Disturbance of undeveloped land and valuable ecological habitats shall be minimized. . . . Recreational opportunities should be considered and increased, as appropriate” (U.S. Department of Energy 2000, 3-2). Perspectives on the most appropriate long-term role for the SRS are influenced by several aspects of the significance of the Site: its role in the safety and security of national nuclear programs, its contribution to local and regional economies, its diverse biological communities, and its relatively nonfragmented state compared to adjacent lands (U.S. Department of Energy 2000). It is within this environment that long-range natural resource planning must occur. For example, the most recent management plan for the red-cockaded woodpecker (Edwards et al. 2000) was designed to balance industrial missions and operations with ecological conditions and the biological requirements of the bird. Ultimately, the public and the federal government will determine whether the integrity of SRS will be maintained. In order for that to happen, stakeholders must find ways to balance competing interests, values, and benefits. If the whole is not valued as greater than its parts, the integrity of the site may be compromised. As long as primary missions are active, security and safety requirements will limit incursions of the current boundary. Despite increased security in recent years, public pressure for greater access is increasing. The Department of Energy’s response has included expansion of the Crackerneck Wildlife Management Area and Ecological Reserve, encouraging national science programs, facilitating controlled access for hands-on education and outreach programs, and the offering in 2004 of a turkey hunt for mobility-impaired hunters.

Some Threats to the Integrity and Recovery of SRS Direct pressures on SRS include efforts to have parcels transferred to state or local entities, or in some cases, individuals (Aiken Standard 2004). The development of the National Environmental Research Park concept in

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Ecology and Management of a Forested Landscape

the early 1970s was in part a response to such pressure. Tracts were transferred to an adjacent industrial park and to the USDA Forest Service, though the latter was later returned to DOE ownership. Whether the National Environmental Research Park concept is sufficiently compelling on its own to sustain the integrity of the SRS is debatable. The unique assets of the site enable research that could occur at no other location in the country (e.g., Pechmann et al.1991; Tewksbury et al. 2002). Still, even an innovative, cutting-edge program addressing environmental science questions of national importance is not—on its own—likely to justify preserving the integrity of the Site. Other pressures beyond the control of SRS managers include the degradation of environmental conditions in the landscape immediately surrounding the Site, as well as in the larger region. Climate change may affect the ecology of the SRS, as everywhere. Despite the size of the SRS, human population growth in the area and the resulting fragmentation of habitat could potentially impact ecological processes on the site; increased isolation of the Site may well lead to the loss of additional species. Invasive species (e.g., coyotes, hogs, fire ants, kudzu, tall fescue, zebra mussel) and disease complexes (e.g. dogwood anthracnose, oak decline) could cause native species to decline or could prevent their recovery, although there are no documented cases on SRS in which native species have been extirpated by invasives, other than humans. These are genuine concerns, however, and they require continued vigilance. Off-site land use may also directly degrade water quality, facilitate the dispersal and introduction of exotic species, or impair critical metapopulation processes for species with large regional habitat needs, such as the bald eagle. Of particular concern is municipal and agricultural runoff discharged to Upper Three Runs and industrial discharge to the Savannah River. Finally, poor management decisions can adversely impact ecological conditions and natural resources. In hindsight, one can point to a multitude of good and bad decisions made over the last five decades. No model assures good decisions. However, some circumstances may encourage sound land management. When managers are able to view new initiatives resulting from changing public values and new science as opportunities, they may be more inclined to adapt their positions. When sustainable economics are applied as an incentive for conservation and restoration, traditional forest managers can more easily see the benefits. When organizations reward decisions and achievements that are consistent with new goals, they are more likely to see such accomplishments. When

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scientists and conservationists are willing to question ecological and environmental paradigms that may sometimes be overgeneralized, managers may perceive them as more cooperative. Environments in which these conditions are fostered tend to improve communication between parties on both sides of issues.

Research Priorities for the Future The future of research at SRS will depend on mission mandates and available funding for both on-site and off-site organizations. The Savannah River Ecology Laboratory was recently moved administratively to the DOE’s Office of Science to conduct basic science related to environmental management. The pursuit of extramural funding for ecological and environmental studies has become a necessity. The Savannah River Technology Center was recently converted to the Savannah River National Laboratory under the Department of Energy’s Environmental Management Office. The USDA Forest Service–Savannah River continues to conduct research through extensive partnerships with various universities, state and federal agencies, and private organizations to foster stewardship of natural resources. The National Environmental Research Park concept remains viable, but the research theme will need to evolve with current national science priorities. Using the SRS as a large experimental landscape for research that addresses sustainable development and management, conservation, restoration, and environmental management technology has merit and value to the nation. Future natural resource research will continue to emphasize simple restoration technologies and strategies for sensitive species and groups. Basic habitat relations, not to mention relationships between habitat quality and demography, remain poorly understood for many species or groups. This work will necessarily be done at scales from within stands to across the larger landscape. Understanding processes that interact to affect species establishment, dispersal, and population expansion will be important research areas. For example, it is clear that many components of the savanna flora are difficult to establish. How their establishment is affected by fire, other species, landscape variables, disease, and a multitude of site factors remains unclear. Long-term monitoring of both flora and fauna must be designed to address questions related to the temporal and spatial dynamics of these populations in relation to their persistence on the landscape. Identification of simple, low-cost technologies

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that capitalize on links between limiting ecological factors and natural ecological processes to expand and sustain species and communities at the landscape scale is critical. The SRS offers a unique large-scale laboratory in which unparalleled research can be conducted in a variety of fields. Studies on principles of environmental chemistry, radioecology, and ecological toxicology can be applied to the restoration of severely contaminated areas. Environmental restoration technologies can be developed, tested, and applied to contaminant remediation. The site provides opportunities to investigate land-use impacts on global carbon sequestration, as well as strategies that might mitigate CO2 increases. The sustainability of ecological restoration efforts at SRS depends in part on interrelationships between the Site and the surrounding landscape, a dramatic contrast that provides unique research opportunities. Some of the largest experimental landscape studies in the United States are being conducted at SRS. Studies on the impacts of management practices will continue but with increasing sophistication and complexity. Studies that model population and environmental processes will enable predictions over broader temporal and spatial scales.

The Long-Term Importance of SRS This book has demonstrated the ecological value of the SRS. That value can be appreciated not just at the local scale but at regional, continental, and global scales, as well. From a conservation perspective, the example of the longleaf savanna and red-cockaded woodpecker management programs perhaps best illustrates the value of sites like SRS and comparable lands, such as military installations under the Department of Defense. The current regional recovery plan (U.S. Fish and Wildlife Service 2003) for the red-cockaded woodpecker considers many of these areas to be significant in the recovery of this endangered species. Although some, like SRS, are officially designated as supporting “secondary core populations,” they are nonetheless critical to the long-term viability of the species. Many of these locations support significant rare plant populations associated with fire-maintained savannas. Because these are often very large areas with restricted access, they offer protection from impacts of uncontrolled recreation and use, such as unregulated botanical harvests or poaching, that neither national parks nor national forests can easily achieve. However, the capability to provide multiple benefits to the public from maintaining the integrity of these landscapes will weigh significantly in decisions about their future management, and even their existence.

Appendix: Habitat Preference Matrix for Savannah River Site Plants Species are organized taxonomically within growth forms (column 1); family names are capitalized. Species nomenclature follows Radford, Ahles, and Bell (1968). The key below provides an explanation of the codes used for “Growth Form,” “Relative Abundance,” and the lettered columns of “Habitat Type.” Under those lettered columns, marginal habitat for a species is designated by “M,” suitable habitat for a species by “S,” and optimal habitat for a species by “O.” Growth Form: AQ Aquatic GF Ground fern and lower plant GG Ground graminoid GH Ground herb SW Woody shrub TE Epiphyte TW Woody tree VH Herbaceous vine VW Woody vine

Relative Abundance: A Abundant C Common O Occasional U Uncommon R Rare Z Reported

Habitat Type: A Streamheads, seeps, pocosins, bogs, and bayheads B Moist small stream bottoms C Moist to wet blackwater stream bottoms D Stream and river swamps E Moist to wet river bottomlands F Disturbed and successional bottomlands G Stream bottoms and margins H Stream and delta marshes I Lakes and ponds J Carolina bay ponds and drawdown zones K Carolina bay interior meadows and savannas

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401

Forested Carolina bays and moist bay margins Open pine savannas Upland pine plantations and forests Pine flatwoods and wet pine savannas Xeric sandhill woodlands and scrubby flatwoods Dry post oak woodlands Hardwood slopes, bluffs, and coves Southern mixed hardwood and mesic bottoms Successional upland mixed forests Abandoned home sites Upland meadows and old fields Roadsides New fields and disturbed areas Planted areas

402

Species

BRYOPHYTES Atrichum spp. Cladina spp. Cladonia spp Cladonia spp. Dicranum spp. Dicranum condensatum Sphagnum spp. ACANTHACEAE Dyschoriste oblongifolia Justicia ovata Ruellia caroliniensis ACERACEAE Acer floridanum Acer negundo Acer rubrum Acer saccharinum AMARYLLIDACEAE Agave virginica ALISMATACEAE Echinodorus cordifolius Echinodorus tennellum var. parvulus Sagittaria australis Sagittaria graminea Sagittaria isoetiformis Sagittaria lancifolia Sagittaria latifolia Sagittaria subulata AMARANTHACEAE Alternanthera philoxeroides Amaranthus palmeri Froelichia floridana Froelichia gracilis AMARYLLIDACEAE Narcissus pseudo-narcissus Narcissus tazetta × poeticus Zephyranthes atamasco ANACARDIACEAE Rhus aromatica Rhus copallina Rhus glabra Rhus radicans Rhus toxicodendron Rhus vernix

Common Name

MOSS Moss Hanging reindeer moss, old-man’s beard British soldiers Reindeer moss Feather moss Feather moss Sphagnum moss RUELLIA Pineland dyschoriste Water willow Wild petunia, Carolina wild petunia MAPLE Florida maple, southern sugar maple Box elder, ash-leaved maple Red maple Silver maple AGAVE Agave ARROWHEAD Creeping bur-head Little bur-head Arrowhead Duck potato, duckmeat Slender arrowhead Wapato Arrowhead Arrowhead AMARANTH Alligator weed Pigweed, amaranth, careless weed Cottonweed Slender cottonweed AMARYLLIS Daffodil, buttercup Narcissus, primrose-peerless Easter lily, common atamasco lily CASHEW Aromatic sumac Winged sumac Smooth sumac Poison ivy Poison oak Poison sumac C C C C O O C O C U R O A U U O R O U R U C C O O O R C O O R A U A C U

GH SW GH TW TW TW TW SW AQ AQ AQ AQ AQ AQ AQ AQ AQ GH GH GH GH GH GH SW SW SW VW SW SW

Growth Form GF TE GF GF GF GF GF

Relative Abundance

O

O

D O S

E

S

S

S

S S

S

S

S

S

M M M M S S S M S S

S

S S S

S

S S S S

O S

C

O S

B

M

S

S S S

S

S

O

F

M M S S S M S O M M M M M O S

M

S

O

S

O S

A

S

S S S

O

O

S S

S S

S

S

O

G H

S S

O

I

S

O

J

S

S

S

O

K

S

O

L

S

S

S

S

S

S S

O

S

M S

S

S

M S S

O

S

S

S

S

O

M N O

Habitat Type

S

S

S S

S

S S S

O

P

S

S

S

S

S

O

Q

O S M S

S S

S

S

S

M

S

S

S

O

S

S

S

S

S

O S

R

S

M

S

S

O

T

S

S

S

S

O S

U

S S

S

S

S

S

O

S

S

S S M M

S

S

S

S

O S

S

S S

S S

S

S

S

S

O

V W X

S

O

Y

403

Species

ANNONACEAE Asimina parviflora Asimina triloba APIACEAE Angelica venenosa Apium leptophyllum Centella asiatica Chaerophyllum tainturieri Cicuta maculata Daucus carota Eryngium integrifolium Eryngium yuccifolium Hydrocotyle umbellata Hydrocotyle verticillata Osmorhiza claytonii Ptilimnium capillaceum Sanicula canadensis Sanicula smallii Spermolepis divaricata Spermolepis echinata Thaspium barbinode Trepocarpus aethusae APOCYNACEAE Amsonia ciliata Amsonia tabernaemontana Apocynum cannabinum Asclepias amplexicaulis Asclepias humistrata Asclepias obovata Asclepias perennis Asclepias tomentosa Asclepias tuberosa Asclepias verticillata Asclepias viridiflora Asclepias viridis Matelea gonocarpa Matelea suberosa Nerium oleander Trachelospermum difforme Vinca minor AQUIFOLIACEAE Ilex ambigua Ilex amelanchier Ilex cassine Ilex cassine ssp. myrtifolia Ilex coriacea

Common Name

PAWPAW Little pawpaw, dwarf pawpaw Common pawpaw, Indian banana CARROT Hairy angelica Marsh parsley Asian coinleaf Southern chervil Water hemlock Queen Anne’s lace, wild carrot Savanna eryngo, simple-leaf eryngo Rattlesnake master, button snakeroot Marsh water pennywort Water pennywort Sweet cicely Atlantic bishop weed Large sanicle Southern snakeroot, Small’s sanicle Southern spermolepis, roughfruit spermolepis Bristlefruit spermolepis, hooked spermolepis Meadow parsnip Trepocarpus MILKWEED Blue-star, broadleaf sandhill blue stars Blue stars Indian hemp, hemp dogbane Clasping milkweed Fleshy milkweed Obovate milkweed Swamp milkweed, thinleaf milkweed Sandhills milkweed Butterfly weed, pleurisy root Whorled milkweed Green milkweed Green milkweed Common anglepod Atlantic anglepod Oleander Climbing dogbane Lesser periwinkle HOLLY Carolina holly Sarvis holly Dahoon Myrtle-leaf holly, myrtle holly Big gallberry, sweet gallberry U R O O O O U A U U O U R O O U O U U R U U O O C R C U C U R R U U U C O U R U R O

GH GH GH GH GH GH GH GH GH GH GH GH GH GH GH GH GH GH GH GH GH GH GH GH GH GH GH GH GH GH VW VW SW VW VW SW SW SW SW SW

RA

SW SW

GF

S

S

S

A

C

S

S

S

S

S

S

M

S

S

S

S

S

S

S

S

S

S S S

S

S

S

S

S S

S

M

S

S

S S

M M S M

O S

M

S

M M

M S

E

S

D

S

M M M

B

S

S

S

M

S

S

S

M

S S

S

G H

S S

S

S

F

I

J

S

S

K

S

S

S

L

S

M S S S S

S S S S

M

S

S

S

S

S S S

S

S S

S

S S

S

S S

S

S

M N O

S S S

S S

S

S

P

S S S

S S S

S

S

Q

S

S

M M M

M

M S M

S M

S S

M M S

S

S S

R

S

S

S

S

S S S

S S

S

S

S

S S

S

S S

S

T

M

S

S

U

S

S S

S S S

S

S

S

S S

S S S

S

S

S S

S

S S S

V W X

S

Y

404

Species

Ilex decidua ssp. decidua Ilex glabra Ilex laevigata Ilex opaca Ilex verticillata Ilex vomitoria ARACEAE Acorus calamus Arisaema dracontium Arisaema triphyllum Orontium aquaticum Peltandra virginica Pistia stratiotes ARALIACEAE Aralia hispida Aralia nudicaulis Aralia spinosa Hedera helix ARECACEAE Sabal minor ARISTOLOCHIACEAE Aristolochia macrophylla Aristolochia serpentaria Aristolochia tomentosa Hexastylis arifolia ASPENIACEAE Asplenium platyneuron ASTERACEAE Acanthospermum australe Achillea millefolium Ambrosia artemisiifolia Antennaria plantaginifolia Arnica acaulis Artemisia caudata Aster bifoliatus Aster concolor Aster dumosus Aster hemispherica Aster patens Aster paternus Aster pilosus Aster tortifolius Aster undulatus

Common Name

Possumhaw, deciduous holly Gallberry, inkberry Smooth winterberry American holly Common winterberry Yaupon ARUM Sweet flag Green dragon, dragon arum Jack-in-the-pulpit Golden club, never-wet, bog torches Arrow arum, green arrow arum Water lettuce GINSENG Bristly sarsaparilla Wild sarsaparilla Hercules’-club, devil’s walking-stick English ivy, common ivy PALM Swamp palmetto, palmetto, dwarf palmetto GINGER Dutchman’s-pipe Turpentine root, southern birthwort Pipe vine, woolly Dutchman’s-pipe Wild ginger, little brown jug SPLEENWORT FERN Ebony spleenwort COMPOSITE Sheep bur, Paraguay bur Yarrow, milfoil Common ragweed Plantain pussytoes Leopard’s bane, southeastern arnica White sage Zigzag aster Eastern silvery aster Bush aster, long-stalked aster Tennessee aster Skydrop aster, late purple aster Toothed white-topped aster Aster Twisted-leaf white-topped aster Wavy-leaved aster R R R U A O C O C U U C U O C U C O O U

VW GH VW GH GF GH GH GH GH GH GH GH GH GH GH GH GH GH GH GH

R U O O

SW SW SW VW U

R U O U U U

AQ GH GH AQ AQ AQ

SW

C A U A O U

Growth Form SW SW SW TW SW SW

Relative Abundance M

O

M

S S

S

M

S

S

S

S S

S O S S S

C

S

S

S

S S

S S

B

M

A

M

S M

S

M S

D

M

S S

S

O

S S

S

O

E

S

S

M

S

S

M M

F

S

S

S

I

S

M M S S S

S

G H

J S

K

M

S

S

L

S

S

S

S

S

S

S

S S

S S

S

S

S

S S

S

S

M S S S

S S

S

P

S S S S S

S S S

S

M M M

S

S

S

S

S

M N O

Habitat Type

S S

S S

S

S

S

S

Q

S

S

S

S

S

S

S

S

S

S S

M M M M M M S

S

S S M M M S S

S

S S S

S

S S M

S

R

S

S

S

S

S

T

S

U

S

S

S

S S S

S

S S

S S

S S S

S

S

S

V W X

Y

405

Species

Baccharis halimifolia Bellis perennis Berlandiera pumila Bidens aristosa Bidens bipinnata Bidens discoidea Bidens frondosa Boltonia asteroides Boltonia caroliniana Boltonia diffusa Cacalia atriplicifolia Cacalia muhlenbergii Carphephorus bellidifolius Carduus nutans Carphephorus tomentosus Centaurea benedicta Centaurea cyanus Chaptalia tomentosa Chrysanthemum leucanthumum Chrysogonum virginianum Cichorium intybus Cirsium lanceolatum Cirsium muticum Cirsium nuttallii Cirsium repandum Cirsium horridulum Cirsium virginianum Coreopsis basalis Coreopsis lanceolata Coreopsis major ssp. major Coreopsis rosea Coreopsis verticillata Echinacea laevigata Eclipta alba Elephantopus carolinianus Elephantopus nudatus Elephantopus tomentosus Erechtites hieracifolia Erigeron annuus Erigeron canadensis Erigeron philadelphicus Erigeron strigosus Eupatorium album Eupatorium aromaticum Eupatorium capillifolium Eupatorium coelestinum

Common Name

Saltbush, groundsel tree, silverling English daisy Green eyes Midwestern tickseed-sunflower Spanish needles Few-bracted beggar-ticks Devil’s beggar-ticks Eastern doll’s-daisy, white boltonia Carolina doll’s-daisy Southern doll’s-daisy, smallhead boltonia Pale Indian plantain Indian plantain Carphephorous Nodding thistle Soft carphephorous Blessed thistle Cornflower, raggedy-buttons, raggedy-sailors Sunbonnets, pineland daisy, bog dandelion Oxeye daisy Green-and-gold Chicory, blue-sailors Bull thistle Swamp thistle Thistle Sandhill thistle Yellow thistle Virginia thistle Texas coreopsis Longstalk coreopsis, lanceleaf coreopsis Woodland coreopsis Rose coreopsis Threadleaf coreopsis Smooth purple coneflower Yerba-de-tajo Carolina elephant’s foot Elephant’s foot Elephant’s foot Fireweed Daisy fleabane, annual fleabane Horseweed, common horseweed Fleabane, Philadelphia daisy Rough fleabane White-bracted throughwort Small-leaved white snakeroot Dog fennel Mistflower, ageratum

SW GH GH GH GH GH GH GH GH GH GH GH GH GH GH GH GH GH GH GH GH GH GH GH GH GH GH GH GH GH GH GH GH GH GH GH GH GH GH GH GH GH GH GH GH GH

GF C U C U U U O O O R O U O U R U C U O O A U U U C O U C O C R O R O U U C A U A A C O U A O

RA

S

A

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V W X

Y

406

Eupatorium compositifolium Eupatorium cuneifolium Eupatorium fistulosum Eupatorium hyssopifolium Eupatorium leucolepis Eupatorium perfoliatum Eupatorium pilosum Eupatorium rotundifolium ssp. rotundifolium Eupatorium rugosum Gaillardia aestivalis Gnaphalium chilense Gnaphalium helleri Gnaphalium obtusifolium Gnaphalium purpureum ssp. americanum Gnaphalium purpureum ssp. purpurea Haplopappus divaricatus Helenium amarum Helenium autumnale Helenium flexuosum Helianthus angustifolius Helianthus debilis Helianthus strumosus Heliopsis helianthoides Heterotheca gossypina Heterotheca graminifolia Heterotheca mariana Heterotheca nervosa Heterotheca pinifolia Heterotheca subaxillaris ssp. latifolia Hieracium gronovii Hieracium pilosella Hymenopappus scabiosaeus Hypochaeris glabra Ionactis linariifolius Iva microcephala Krigia dandelion Krigia oppositifolia Krigia virginica Kuhnia eupatorioides Lactuca canadensis Lactuca graminifolia Liatris earlei

Yankee weed, coastal dog fennel Wedgeleaf eupatorium, bushy throughwort Joe-pye weed, queen-of-the-meadow Hyssop-leaf throughwort Savanna throughwort Boneset Ragged throughwort Roundleaf throughwort

Cudweed, spoonleaf purple everlasting False dandelion, scratch daisy Bitterweed Common sneezeweed Southern sneezeweed Narrowleaf sunflower Sunflower Roughleaf sunflower Eastern sunflower-everlasting Camphor weed Grass-leaved golden aster Camphor weed, Maryland golden aster Silk grass Grass-leaved golden aster Common camphor weed Hairy hawkweed, beaked hawkweed Mouse-ear hawkweed Sandhills woolly-white Smooth cat’s-ear Stiff-leafed aster, savory-leaf aster Small-headed marsh elder Colonial dwarf dandelion Opposite-leaf dwarf dandelion Virginia dwarf dandelion Eastern false boneset Wild lettuce Wild lettuce Earle’s blazing star

White snakeroot, common milk-poison Sandhills galliardia Rabbit tobacco Rabbit tobacco Fragrant rabbit tobacco Cudweed, American everlasting

Species

Common Name A C O U O O O C U U U R U O U O A C C U U R O A O O A O O O C O O C R R U O O C O O

GH GH GH GH GH GH GH GH GH GH GH GH GH GH GH GH GH GH GH GH GH GH GH GH GH GH GH VW GH GH GH GH GH GH GH

Growth Form GH GH GH GH GH GH GH

Relative Abundance S

S

A

D

S

E

S S M

M M M

C

S S S S M M

B

S S S

S

S

M

F

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G H

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S S S M

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S S S S S S S M M M M

S

S S S

S

S

S S

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S

S

S

S

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P

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S M

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M N O

Habitat Type

S S S

S

S

S

S

M

S

S

S M

S S

S

S S

S

S

S

S

S S S S

S

S S

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S

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S

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S

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S

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S

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M S

S S

S

S S

S S

S

S

S

S

S

S

S

S

S

S

S

S

V W X

Y

407

Species

Liatris elegans Liatris graminifolia Liatris secunda Liatris tenuifolia Marshallia obovata Melanthera hastata Mikania scandens Packera aurea Packera glabella Packera obovata Packera anonyma Packera tomentosa Pluchea camphorata Pluchea foetida Pluchea rosea Polymnia uvedalia Prenanthes altissima Prenanthes serpentaria Pterocaulon pycnostachyum Pyrrhopappus carolinianus Rudbeckia fulgida Rudbeckia hirta Sclerolepis uniflora Senecio vulgaris Sericocarpus linifolius Silphium compositum Silphium dentatum Solidago altissima Solidago auriculata Solidago caesia Solidago fistulosa Solidago gigantea Solidago leavenworthii Solidago microcephala Solidago nemoralis Solidago odora Solidago petiolaris Solidago rugosa Solidago stricta Solidago tenuifolia Sonchus asper Spilanthes americana Trilisa paniculata Verbesina virginica Veronia altissima Veronia angustifolia

Common Name

Showy blazing star Blazing star Blazing star Blazing star Barbara’s-buttons Melanthera Climbing hempweed, climbing boneset Golden ragwort, heartleaf ragwort Butterweed, smooth ragwort Roundleaf ragwort, running ragwort Southern ragwort, Small’s ragwort Woolly ragwort Camphor pluchea Marsh fleabane, stinking fleabane Marsh fleabane Bearsfoot Tall rattlesnake root Lion’s-foot, gall-of-the-earth Blackroot, wingstem False dandelion Common eastern coneflower Woodland black-eyed susan Sclerolepis common ragwort, common groundsel Narrow-leaf white-topped aster Compass plant, rosinweed Rosinweed Common goldenrod Eared goldenrod Blue-stem goldenrod, axillary goldenrod Hairy pinewoods goldenrod Smooth goldenrod Leavenworth goldenrod Flat-topped goldenrod Southern gray goldenrod Licorice goldenrod Goldenrod Wrinkle-leaf goldenrod Wand goldenrod Slender-leaved flat-topped goldenrod Sow thistle, spiny-leaved sow thistle Spot flower, creeping spot flower Panicled carphephorous Common frostweed Tall ironweed Ironweed

GH GH GH GH GH GH VW GH GH GH GH GH GH GH GH GH GH GH GH GH GH GH GH GH GH GH GH GH GH GH GH GH GH GH GH GH GH GH GH GH GH GH GH GH GH GH

GF U U U C U U C U O U A O O C U O O O O C C O U U R C U U R O U O U O O C U U C U C R R U R O

RA

S S

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A

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M M

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D

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M M

S

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M M S

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S S S

S

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S M M

S

M

S S

S S

S

V W X

Y

408

Species

AZOLLACEAE Azolla caroliniana BALSAMINACEAE Impatiens capensis Impatiens pallida BERBERIDACEAE Nandina domestica Podophyllum peltatum BETULACEAE Alnus serrulata Betula nigra Carpinus caroliniana Ostrya virginiana BIGNONIACEAE Anisostichus capreolata Campsis radicans Catalpa bignoniodes BLECHNACEAE Woodwardia areolata Woodwardia virginica BORAGINACEAE Heliotropium amplexicaule Lithospermum caroliniense Myosotis verna Onosmodium virginianum BRASSICACEAE Arabidopsis thaliana Brassica hirta Camelina microcarpa Capsella bursa-pastoris Cardamine hirsuta Cardamine parviflora Descurainia pinnata Draba brachycarpa Lepidium virginicum Raphanus raphanistrum Rorippa islandica Rorippa sessiliflora Warea cuneifolia BROMELIACEAE Tillandsia usneoides BUXACEAE Pachysandra terminalis CABOMBACEAE

Common Name

MOSQUITO FERN Carolina mosquito fern BALSAM Orange jewelweed, spotted touch-me-not Yellow jewelweed, pale touch-me-not BARBERRY Nandina, sacred bamboo Mayapple, American mandrake BIRCH Tag alder, smooth alder River birch Hornbeam, ironwood, muscle tree Eastern hop hornbeam, ironwood BIGNONIA Cross vine Trumpet creeper, cow-itch Southern catalpa CHAIN FERN Netted chain fern Chain fern BORAGE Wild heliotrope Carolina puccoon, coastal-plain puccoon Early forget-me-not Virginia marble-seed MUSTARD Mouse-ear cress White mustard, yellow mustard False flax, lesser gold-of-pleasure Shepherd’s purse Toothwort, hairy bittercress Sand bittercress Southeastern tansy-mustard Short-fruited draba Peppergrass, poor man’s pepper Wild radish, jointed charlock, white charlock American marshcress Creeping marshcress Carolina pineland cress, Carolina warea BROMELIAD Spanish moss BOX Allegheny spurge CABOMBACEAE O C R U U A C C O C C U C A U C O R O U U O O O O U A C U R U C U

AQ

SW GH SW TW TW TW VW VW TW GF GF GH GH GH GH GH GH GH GH GH GH GH GH GH GH GH GH GH TH SW

Growth Form VH VH

Relative Abundance O

A

S

S

O O

S

S

S S

B

S

S S

O O

S M

S S S M

S S

C

S M

D

S

S

O S

S M

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S

S

E

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S

S S

S

S

F S

S

S

G H S

I

J

S

K

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L

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S

S

S

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M

M N O

Habitat Type

S

S S

S

Q

S

S M

S S M

S

S

S

S S

S

S

M M S

S

S S

M

M M M

R

T

S

S

U

S

S S

S

S S

S

S

S S S S S S S S S M M S S S S S S S S M S S

S

S S

S

S

V W X

M

Y

409

Species

Brasenia schreberi Cabomba caroliniana CACTACEAE Opuntia compressa CALLITRICHACEAE Callitriche heterophylla CALYCANTHACEAE Calycanthus fertilis Calycanthus floridus CAMPANULACEAE Lobelia boykinii Lobelia cardinalis Lobelia elongata Lobelia nutallii Lobelia puberula Lobelia spicata Specularia perfoliata Sphenoclea zeylandica Wahlenbergia marginata CAPRIFOLIACEAE Lonicera japonica Lonicera sempervirens Sambucus canadensis Viburnum acerifolium Viburnum cassinoides Viburnum dentatum Viburnum nudum Viburnum obovatum Viburnum prunifolium Viburnum rufidulum CARYOPHYLLACEAE Arenaria caroliniana Cerastium glomeratum Paronychia americana Paronychia riparia Saponaria officinalis Scleranthus annuus Silene antirrhina Silene caroliniana Stellaria media Stipulicida setacea CELASTRACEAE Celastrus orbiculatus Euonymus americanus Euonymus europaeus Euonymus fortunei

Common Name

Water shield, purple wen-dock Fanwort CACTUS Eastern prickly pear CALLITRICHE Water starwort SWEETSHRUB Common allspice, smooth sweetshrub Sweetshrub, hairy allspice BELLFLOWER Boykin’s lobelia Cardinal flower Lobelia Nuthall’s lobelia Lobelia Lobelia Venus looking-glass Venus looking-glass Wahlenbergia HONEYSUCKLE Japanese honeysuckle Coral honeysuckle, trumpet honeysuckle Common elderberry Maple-leaved viburnum Withe rod, northern wild raisin Carolina arrowwood Possumhaw viburnum, southern wild raisin Southern nannyberry, small-leaf viburnum Smooth blackhaw Rusty blackhaw, southern blackhaw PINK Carolina sandwort Sticky mouse-ear American nailwort Perennial dune whitlow-wort Soapwort, bouncing bet Knawal, annual knawal Catchfly, garter pink, sleepy catchfly Northern wild pink, sticky catchfly Common chickweed Florida wire plant, spider plant BITTERSWEET Bittersweet, oriental bittersweet American strawberry bush, hearts-a-burstin European strawberry bush Climbing euonymus, wintercreeper

C U C O U U R U U O O O A U U A C C R U O C U U C U A R U O A U U A C U U O U

SW AQ SW SW GH GH GH GH GH GH GH GH GH VW VW SW SW SW SW SW SW SW SW GH GH GH GH GH GH GH GH GH GH VW SW SW SW

RA

AQ AQ

GF

M

A

S

S

S

S S

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B

M M S S S S S S S

S

S

S

M M M M S S S S S

M M

F

M

S S

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M S S S M S

D

M S S M

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S

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G H

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S

S S

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S S S

S

S S S

S

S

S

S S S

S

S S S

S

S

V W X

S

Y

410

Species

CELTIDACEAE Celtis laevigata Celtis occidentalis ssp. tenuifolia CERATOPHYLLACEAE Ceratophyllum demersum CHENOPODIACEAE Chenopodium album Chenopodium ambrosioides Cycloloma artriplicifolium CISTACEAE Helianthemum canadense Helianthemum carolinianum Helianthemum rosmarinifolium Lechea minor Lechea patula Lechea tenuifolia Lechea villosa CLETHRACEAE Clethra alnifolia COMMELINACEAE Aneilema keisak Commelina communis Commelina diffusa Commelina erecta Commelina virginica Tradescantia ohiensis Tradescantia rosea Tradescantia roseolens Tradescantia virginiana CONVOLVULACEAE Bonamia aquatica Bonamia humistrata Bonamia patens Bonamia pickeringii Calystegia sepium Dichondra carolinensis Ipomoea hederacea Ipomoea lacunosa Ipomoea pandurata Ipomoea purpurea Ipomoea trichocarpa Jacquemontia tamnifolia CORNACEAE

Common Name

HACKBERRY Sugarberry, southern hackberry Georgia hackberry, upland hackberry HORNWORT Coontail, hornwort PIGWEED Lamb’s-quarters, pigweed Mexican tea Winged pigweed FROSTWEED Canada frostweed, rockrose Carolina frostweed Rosemary sunrose Thymeleaf pinweed Pinweed Pinweed Pinweed PEPPERBUSH Sweet pepperbush, coastal white alder SPIDERWORT Handle-mazzetti Asiatic dayflower, common dayflower, Creeping dayflower Slender dayflower, erect dayflower Virginia dayflower, annual dayflower Smooth spiderwort, Ohio spiderwort Roseling spiderwort Sandhill spiderwort Virginia spiderwort MORNING GLORY Pineland breweria, water dawnflower Southern dawnflower Common dawnflower Pickering’s breweria, Pickering’s dawnflower Hedge bindweed Carolina ponyfoot Ivy-leaved morning glory Small-white morning glory Wild potato vine, man-of-the-earth, man-root Common morning glory Morning glory Jacquemontia DOGWOOD C C U U O C O R R C O C O O R A U C C O O U U U O O R A O O U C C U C

AQ GH GH GH GH GH GH GH GH GH GH SW GH GH GH GH AQ GH GH GH GH VH VH VH VH VH VH VH VH VH VH VH VH

Growth Form TW TW

Relative Abundance A

S S

S

S

M

S

S

C

S S

S

B

M

S

F

S

S S

M S

S S

M M

S

E

M M M

S

D

M

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G H

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S S S S

S M M

S S

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S S S S M

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S S

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S S S S S S S

S

S

M N O

Habitat Type

S S

S

S

S

S

P

S

S M S

S S S

S

S S

S

S

Q

S S M M S S

S M

M

M S

R

S S S

S S S S S S

S S

S

S S

S

S

S

S

T

S

S

U

S

S S

S

S

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S S S

S S

S S S

S S

S

S S S

S

S

S

S

S

S S

S

S

S S S

S S

S

S

S

V W X

Y

411

Species

Cornus amomum Cornus florida Cornus stricta CRASSULACEAE Penthorum sedoides CUCURBITACEAE Lagenaria vulgaris Melothria pendula CUPRESSACEAE Chamaecyparis thyoides Juniperus communis Juniperus virginiana Taxodium ascendens Taxodium distichum CUSCUTACEAE Cuscuta campestris Cuscuta compacta Cuscuta gronovii Cuscuta pentagona CYPERACEAE Bulbostylis barbata Bulbostylis capillaris Bulbostylis ciliatifolia Bulbostylis stenophylla Carex albolutescens Carex atlantica Carex chapmanii Carex collinsii Carex comosa Carex complanata Carex debilis Carex decomposita Carex digitalis Carex festucacea Carex folliculata Carex howei Carex intumescens Carex jooriii Carex laevivaginata Carex laxiflora Carex louisianica Carex lurida Carex muhlenbergii Carex nigromarginata Carex oligocarpa Carex retroflexa

Common Name

Silky dogwood, silky cornel Flowering dogwood Southern swamp dogwood, stiff dogwood STONECROP Live-forever CUCUMBER Bottle gourd Creeping cucumber ARBORVITAE Atlantic white cedar Creeping juniper Eastern red cedar Pond cypress Bald cypress DODDER Field dodder Compact dodder Dodder Love vine SEDGE Old-world hairsedge Common hairsedge Capillary hairsedge, savanna hairsedge Hairsedge Bay sedge Prickly bog sedge Chapman’s sedge Collins sedge Sedge Hirsute sedge White-edge sedge Cypress-knee sedge Slender wood sedge Sedge Long sedge Howe’s sedge Bladder sedge Cypress-swamp sedge, Joor’s sedge Sedge Sedge Louisiana sedge Sedge Muhlenberg sedge Black-edge sedge Eastern few-fruit sedge Reflexed sedge

U C C U O O R R O O A C O O O O O O U U O R R O U U R O U U C O C O O C O O O R O

GH VH VH TW SW TW TW TW VH VH VH VH GG GG GG GG GG GG GG GG GG GG GG AQ GG GG GG GG GG GG GG GG GG GG GG GG GG GG

RA

SW TW SW

GF

S

S S S

C

M M

S S

B

S

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S

S

S

S

S M

S

S

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S M M M M M S

S

A

S S S S S

S

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S O

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S

M

S

S M S

F

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M S

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G H

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L

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M N O

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M

M

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M M

S

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S

S

S

S

S

S S

S

O

S

S

S

S

S

S S S S

S

S

V W X

S

S S S

Y

412

Species

Carex seorsa Carex tenax Carex tribuloides Carex typhina Cyperus esculentus var. sativus Cyperus ferruginescens Cyperus filiculmis Cyperus haspan Cyperus iria Cyperus ovularis Cyperus plukenetii Cyperus pseudovegetus Cyperus retrofractus Cyperus rotundus Cyperus strigosus Cyperus virens Dulichium arundinaceum Eleocharis acicularis Eleocharis equisetoides Eleocharis melanocarpa Eleocharis microcarpa Eleocharis obtusa Eleocharis quadrangulata Eleocharis robbinsii Eleocharis tortilis Eleocharis tricostata Eleocharis tuberculosa Fimbristylis autumnalis Fimbristylis dichotoma Fimbristylis spadicea Fuirena pumila Fuirena squarrosa Rhynchospora caduca Rhynchospora chapmanii Rhynchospora corniculata Rhynchospora globularis Rhynchospora glomerata Rhynchospora grayi Rhynchospora inundata Rhynchospora macrostachya Rhynchospora rariflora Rhynchospora tracyi Scirpus cyperinus Scirpus etuberculatus

Common Name

Sedge Sedge Bristle-bract sedge Cattail sedge Chufa Bay flatsedge Slender flatsedge Flatsedge, umbrella sedge Flatsedge, umbrella sedge Globe flatsedge Flatsedge, umbrella sedge Marsh flatsedge Flatsedge, umbrella sedge Coco grass False nutgrass Flatsedge, umbrella sedge Three-way sedge Spike rush Horsetail spike rush Sandhill spike rush, black-fruited spik erush Spike rush spike rush Spike rush Robbins spike rush Twisted sedge Three-angle spike rush Spike rush Fimbry Fimbry Fimbry Dwarf umbrella sedge Hairy umbrella sedge Angle-stem beaksedge Chapman’s beaksedge Short-bristle horned beaksedge Globe beaksedge Clustered beaksedge Gray’s beaksedge Drowned horned rush Tall horned beaksedge Few-flower beaksedge Tracy’s beaksedge Woolgrass bulrush Canby’s bulrush

Growth Form GG GG GG GG GG GG GG GG GG GG GG GG GG GG GG GG GG GG GG GG GG GG GG GG GG GG GG GG GG GG GG GG GG GG GG GG GG GG AQ GG GG GG AQ GG

O R U O O R C O O O C C O O C O O O R U O O O R O R C O U O O O U U U U U U R U O R A R

Relative Abundance S

S S

A

B

S

S S

S

M S S

S

S

S

S

S S

S

S

S

S

S

S S S

S S

S S

S S S

S

S

F

S

S

E

S

S

S

D

S

C

S

S

S S S

S S

S S

S S S S

S S S

S

S

S S S S S S S

S

G H

S

S

S

I

S

J

S S

S S S

S

S

S

S

S

K

L

S

S

M

M

S

S

S

S

S

S

S

S S

S

S

S

M N O

Habitat Type P

S

S

S

Q M

R

S

S

S

S

T

U

S S

S

S

S

S S

S

S S S S S

S S S

S S S S

S

S S S S S S

S

S S S

S

S

S S

V W X

S

Y

413

Species

Scirpus validus Scleria baldwinii Scleria ciliata Scleria ciliata Scleria pauciflora Scleria reticularis Scleria triglomerata CYRILLACEAE Cyrilla racemiflora DENNSTAEDTIACEAE Pteridium aquilinum DIOSCOREACEAE Dioscorea villosa DROSERACEAE Drosera capillaris Drosera intermedia Drosera leucantha DRYOPTERIDACEAE Athyrium asplenioides Athyrium pycnocarpon Dryopteris ludoviciana Onoclea sensibilis Polystichum acrostichoides EBENACEAE Diospyros virginiana ELEAGNACEAE Elaeagnus pungens Elaeagnus umbellata EQUISETACEAE Equisetum arvense Equisetum hyemale ERICACEAE Chimaphila maculata Epigaea repens Gaylussacia dumosa Gaylussacia frondosa Kalmia angustifolia ssp. carolina Kalmia latifolia Leucothoe axillaris Leucothoe racemosa Lyonia ligustrina Lyonia lucida Lyonia mariana Monotropa hypopithys Oxydendrum arboreum Rhododendron arborescens

Common Name

Softstem bulrush, great bulrush Baldwin’s nut rush Hairy nut rush Smooth nut rush Papillose nut rush Netted nut rush Tall nut rush TITI Titi, cyrilla BRACKEN FERN Bracken fern, eastern bracken YAM Whorled wild yam SUNDEW Pink-flower sundew White-flower sundew, spoon-leaf sundew Dwarf sundew WOOD FERN Southern lady fern Narrow-leaved glade fern Southern shield fern Sensitive fern Christmas fern EBONY Common persimmon OLEASTER Autumn silverberry, eleagnus, thorny eleagnus Autumn olive, spring silverberry HORSETAIL Horsetail, field horsetail Tall scouring rush HEATH Spotted wintergreen, pipsissewa Trailing arbutus Huckleberry, southern dwarf huckleberry Dangleberry Southern sheepkill, Carolina wicky Mountain laurel Dog-hobble, coastal dog-hobble Fetter bush, coastal sweetbells, coastal fetterbush Maleberry Fetter bush Staggerbush Pinesap Sourwood, sorrel tree Sweet azalea, smooth white azalea O U C U C O R U C O U C O U U O

GH GH SW SW SW SW SW SW SW SW SW GH TW SW

O U U O U

GF GF GF GF GF

GF GF

U O O

AQ AQ AQ

A

O

VH

U U

A

SW SW

C

SW GF

TW

U R O C U R C

RA

GG GG GG GG GG GG GG

GF

S

C

S S

S

S S S

S

M S S S S

S S

S S S

M M

S

S

S

M M

S

S

S

S S S

S

M

M M

S

B

S S M O O M M M

S

M

M

S

S

A

S

S

S

S

D

S

S

S

S

F

S

M

S

S

M M

S

S

S S S

S

M

E

M

S

S

O

S

G H

M

I

J

S S S

S S

S

S S S

S

S

K

S

S S S S

S S S

S

S

S

M

S

S

S

M

O

S

S S

S

S

S

S S

S

S S S

S

S

S

S

S S S

M

S

S S S

M N O

M M M

L

M

S

S

O

P

S

S

S

Q

S

S

S S S S

S

S

S

S S

M M

S M S M

S S

S

S

S

O S M M

S

M

R

S

S

T

S

S

U

S

M

S

S

S S

S

V W X

M M

Y

414

Species

Rhododendron canescens Rhododendron flammeum Rhododendron nudiflorum Rhododendron viscosum Vaccinium arboreum Vaccinium atrococcum Vaccinium corymbosum ssp. formosum Vaccinium elliottii Vaccinium pallidum Vaccinium stamineum Vaccinium tenellum Vaccinium vacillans ERIOCAULACEAE Eriocaulon compressum Eriocaulon decangulare Lachnocaulon anceps EUPHORBIACEAE Acalypha gracilens Acalypha rhomboidea Cnidoscolus stimulosus Croton capitatus Croton elliottii Croton glandulosus Euphorbia chamaesyce Euphorbia corollata Euphorbia curtisii Euphorbia gracilior Euphorbia heterophylla Euphorbia ipecacuanhae Euphorbia maculata Euphorbia supina Phyllanthus carolinensis Sebastiania ligustrina Stillingia aquatica Stillingia sylvatica Tragia urens Tragia urticifolia FABACEAE Aeschynomene indica Amorpha fruiticosa Amorpha herbacea Amphicarpa bracteata Apios hypogaea Astragalus michauxii

Common Name

Southern pinxterbloom, piedmont azalea Oconee azalea, flame azalea Early wild azalea, election pink azalea Late azalea, swamp azalea Sparkleberry, farkleberry Black highbush blueberry Highbush blueberry Elliott’s blueberry, mayberry Southern low blueberry Whiteleaf deerberry, Florida deerberry Slender blueberry, small-cluster blueberry Early low blueberry PIPEWORT Pipewort Common ten-angled pipewort Bog-buttons, hatpins SPURGE Shortstalk copperleaf Rhombic copperleaf Tread softly, spurge nettle, finger-rot Woolly croton, hogwort, capitate croton Elliott’s croton, pondshore croton Doveweed, tooth-leaved croton, sand croton Prostrate spurge Tramps spurge White sandhill sprurge, Curtis’ spurge Maroon sandhills spurge Painted leaf poinsettia, fire-on-the-mountain Carolina ipecac Small eyebane Spotted spurge, milk purslane Carolina leaf-flower Sebastian bush Corkwood Queen’s delight Southeastern noseburn Nettleleaf noseburn LEGUME Southern joint-vetch Tall indigo bush, dull-leaf indigo bush Dwarf indigo bush Hog peanut Groundnut Sandhills milk vetch

C R C O A U A C C C O U O C O O C C O R U O C U U U C O A O U R C O U U U O U O R

GH GH GH GH GH GH GH GH GH GH GH GH GH GH GH GH GH GH SW SW GH GH GH GH SW SW VH GH GH

Growth Form SW SW SW SW SW SW SW SW SW SW SW SW

Relative Abundance M M

M

S

S

S S M

S

S

S S

M M

S

S S S S S S

S

S

S S S S

C

S

B

M

A

M

S

S M

M

D

S

S M

M

S S

S S

S

E

S

S S

S

M

S M

S

S

F

M

S

S S

S

G H

M

I

S

J

S

S

S

S

S

K

S S

S

L

O

S

S

M

S S S S

S S

S S

S

S

S

S S

S

S

S

S S S

S S

S

S

S

S

S

S S

O

P

S M M

S S

M

S S M M M S S S

O

S

M N O

Habitat Type

S S S

S

S

S

S

S

Q

S S

S

S S

S M M

S

S

M S S M S S M M

S S S M S

R

S

S S

S

T

S S

S

S

S

U

S

S S S

S

S

S

S

S

S

M S

S S S S

S S

S

S S

S

S S

S

V W X

Y

415

Species

Astragalus villosus Baptisia alba Baptisia australis Baptisia cinerea Baptisia lanceolata Baptisia microphylla Baptisia pendula Baptisia perfoliata Baptisia tinctoria Cassia fasciculata Cassia nictitans Cassia obtusifolia Cassia occidentalis Centrosema virginianum Cercis canadensis Clitoria mariana Crotalaria angulata Crotalaria lanceolata Crotalaria mucronata Crotalaria purshii Crotalaria sagittalis Crotalaria spectabilis Desmodium canescens Desmodium ciliare Desmodium fernaldii Desmodium glabellum Desmodium glutinosum Desmodium humifusum Desmodium laevigatum Desmodium lineatum Desmodium marilandicum Desmodium nudiflorum Desmodium nuthallii Desmodium paniculatum Desmodium rotundifolium Desmodium sessiliflorum Desmodium strictum Desmodium tenuifolium Desmodium tortuosum Desmodium viridiflorum Galactia macreei Galactia mollis Galactia regularis Galactia volubilis Gleditsia aquatica Gleditsia triacanthos

Common Name

Southern milk vetch, bearded milk vetch Narrow-pod white wild indigo Tall blue wild indigo Carolina wild indigo Lanceleaf wild indigo Little-leaf false indigo Thick-pod white wild indigo Dollar-leaf indigo, gopherweed, catbells Yellow false indigo, honesty weed, rattleweed Partridge pea, common partridge pea Wild sensitive plant Sicklepod, coffee weed Coffee senna Spurred butterfly pea Redbud Butterfly pea, false butterfly pea Low rattlebox Lanceleaf rattlebox Rattlebox Coastal plain rattlebox Common rattlebox Showy rattlebox Hoary tick trefoil Hairy tick trefoil Fernald’s tick trefoil Beggar-ticks Heartleaf tick trefoil, clusterleaf tick trefoil Creeping tick trefoil Tick trefoil, beggar-ticks Matted tick trefoil Tick trefoil, stick tights, beggar’s-lice Naked tick trefoil Tick-trefoil, beggar-ticks Panicled tick trefoil Dollar-leaf, round-leaf tick trefoil, Sessile-leaf tick trefoil Pineland tick trefoil, sandhill tick trefoil Slim-leaf tick trefoil, slippery-leaf tick trefoil Tick trefoil, stick tights, beggar’s-lice Velvet-leaf tick-clover Milkpea Milkpea Milkpea Milkpea Water locust Honey locust

GH GH GH GH GH GH GH GH GH GH GH GH GH GH SW VH GH GH GH GH GH GH GH GH GH GH GH GH GH GH GH GH GH GH GH GH GH GH GH GH GH GH GH GH TW TW

GF R U R U R U O U C A C O U O U C R U O O C A O O C O U C C O C C O C C O O C O U U R O O O U

RA

A

M

S

S S

S

B

C

D

S M

S S

E

S

F

G H

I

J

S

S

K

L

S

S

S S

S S

S S S S S S S S S

S S S

S S

S S

S S S S S

S S

S S S

S S

S

S

S S S

S

S

S

S

S S S S S M S S S S S

S

S

S

S

S

S

S

S

M N O

S

S

S

S

M

M

S S S

S S S S

S

P

S

S S

S S S

S S S S S

S S S S

S

S S

S

S

S S

S S

S S

Q

S

M

S S M

S S S S S M S S M

S

M

M

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S S

S S S

S

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S S S S S S S S S

S

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S S S

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S

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S S S

S S

S

S

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S

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S S S

S S S

S

S

S

S S S S S

S

S

S S

S

S

S

S

S

S S S S

S

S

S S S S

S S

V W X

S

Y

416

Species

Indigofera caroliniana Lespedeza angustifolia Lespedeza bicolor Lespedeza capitata Lespedeza cuneata Lespedeza hirta Lespedeza intermedia Lespedeza procumbens Lespedeza repens Lespedeza stipulacea Lespedeza striata Lespedeza stuevei Lespedeza thunbergii Lespedeza virginica Lupinus diffusus Lupinus perennis Lupinus villosus Medicago lupulina Melilotus alba Petalostemem pinnatum Phaseolus polystachios Pueraria lobata Rhynchosia difformis Rhynchosia reniformis Rhynchosia tomentosa Robinia hispida Robinia nana Robinia pseudo-acacia Sesbania exaltata Strophostyles umbellata Stylosanthes biflora Tephrosia florida Tephrosia hispidula Tephrosia spicata Tephrosia virginiana Trifolium arvense Trifolium campestre Trifolium dubium Trifolium incarnatum Trifolium repens Vicia angustifolia Vicia dasycarpa Vicia grandifolia Vicia hirsuta

Common Name

Carolina indigo Narrow-leaved lespedeza Bicolor lespedeza Bush clover Sericea lespedeza, Chinese lespedeza Hairy lespedeza Wand lespedeza Downy trailing lespedeza Smooth training lespedeza Korean clover, Korean lespedeza Japanese clover, common lespedeza Velvety lespedeza Robust red lespedeza Virginia lespedeza Sandhill lupine Smooth lady lupine, northern sundial lupine Pink sandhill lupine, hairy lupine Black medic, yellow trefoil White melilot, white sweet clover Summer farewell, eastern prairie clover Wild bean Kudzu Dollar-leaf Dollar-leaf, dollar-weed Dollar-leaf Bristly locust Dwarf bristly locust Black locust Sesban, coffee weed, indigo weed Perennial sand bean Pencil flower Florida goats-rue Goats-rue Goats-rue Virginia goats-rue Rabbit foot clover Low hop clover Low hop clover Crimson clover White clover Cow vetch, narrowleaf vetch Smooth vetch, winter vetch Bigleaf vetch Tiny vetch, hairy tare

Growth Form GH GH SW GH GH GH GH GH GH GH GH GH GH GH GH GH GH GH GH GH GH VW GH GH GH SW SW TW GH GH VH GH GH GH GH GH GH GH GH GH GH GH GH GH

U O C C A C C C C A A O U C O U O O O U U O C O O U O R O U O O O O C A O O U O O O U O

Relative Abundance S

A

B

C

D

E

M

S

F

M

G H

I

J S

K

L

S

S

S

S S

S S S

S S M

S

M M M S

S S

S S

S

S S S S S S

S

S S

S S M M

S S S S

S

S

S

S

S

S

S

M N O

Habitat Type

S

S

M

M M M

S

S S S

S

S

P

S S

S S S

S

S S

S S S S

S

Q

S S

S

S

S

S

S

M

S S

S S

M S M S M S M M M M

S M

S M M S

S

M

R

S

S

S

S

S

S

S

T

S

S

M

U

S S S S S S S S S

S

S

S

S

S S

S S

S S

S

S S S S S S S S S

S

S

S

S S S S

S S

S

S S S S

S S S

S

S

S S

S

S S

S S S S S S

S S S

V W X

S

S S

S S

S

S S

S

S

Y

417

Species

Vicia tetrasperma Vicia villosa Wisteria floribunda Wisteria frutescens Wisteria sinensis Zornia bracteata FAGACEAE Castanea alnifolia Castanea pumila Fagus grandifolia Quercus acutissima Quercus alba Quercus alba ssp. austrina Quercus coccinea Quercus durandii Quercus falcata Quercus falcata ssp. pagodaefolia Quercus incana Quercus laevis Quercus laurifolia Quercus laurifolia ssp. hemisphaerica Quercus lyrata Quercus marilandica Quercus michauxii Quercus nigra Quercus nuttallii Quercus palustrus Quercus phellos Quercus prinus Quercus rubra Quercus shumardii Quercus stellata Quercus stellata ssp. margaretta Quercus stellata ssp. similis Quercus velutina Quercus virginiana FUMARIACEAE Corydalis flavula Dicentra canadensis GELSEMIACEAE Gelsemium sempervirens GENTIANACEAE Bartonia paniculata Bartonia verna Gentiana alba Gentiana autumnalis

Common Name

Slender vetch, smooth tare, lentile vetch Hairy vetch, fodder’s vetch Japanese wisteria American wisteria Chinese wisteria Zornia BEECH Smooth chinquapin Eastern chinquapin American beech, white beech Sawtooth oak White oak Bluff oak Scarlet oak Durand oak Southern red oak Cherrybark oak, swamp red oak Bluejack oak Turkey oak Laurel oak, swamp laurel oak, Darlington oak Sand laurel oak Overcup oak Blackjack oak Swamp chestnut oak Water oak Nuttall’s oak Pin oak, swamp pin oak Willow oak Chestnut oak Northern red oak Shumard oak Post oak Sand post oak Swamp post oak Black oak Live oak FUMITORY Short-spurred corydalis Squirrel corn JESSAMINE Yellow jessamine, Carolina jessamine GENTIAN Screwstem bartonia, twining screwstem Spring bartonia, white bartonia Pale gentian Pinebarren gentian

O C U R A O U U O U C R U R A O C A C A O O C A U U C R R U C C U C U R R C R U R U

SW SW TW TW TW TW TW TW TW TW TW TW TW TW TW TW TW TW TW TW TW TW TW TW TW TW TW TW TW GH GH VW GH GH GH GH

RA

GH GH VW VW VW GH

GF

S

S

M

A

S S

S S

O M S S S

S S

S S

S O

S

S

S

M

D

M M M M

S

S

S S

F

S M

S

M M

S

S S M

S S

S S M S S

S

S

S S S

S S

S

S

E

M M M M

M

M

S

S

S

M S S

M S

S

S S

S

C

S

M

B

S

G H

I

J

S

S

K

S S

S

S

S

L

M

S S

S

S

S

S

M M

S

S S

S

S

S

S

S S S

S

S

S

S

M

M N O

M

M

S S

M

S

S

S S

M

S

P

S

S

O S

O

S

S

S

Q

M S

M S

S O S

S S M

S S

M S S

S

S

S

S S

S

S

S

S S S M S S M M S S M

S S S

S S

O S

O S S

S S S

R

S

S

S

S

S

S

M

S

T

S

S

M

S

S

S

S

U

S

S S

S S

S

S

S

S S S

V W X

S S

S

Y

418

Species

Gentiana catesbaei Sabatia angularis Sabatia calycina Sabatia campanulata Sabatia quadrangula GERANIACEAE Geranium carolinianum Geranium maculatum Geranium pusillum GINKGOACEAE Ginkgo biloba HAEMODORACEAE Lachnanthes caroliniana HALORAGAGEAE Myriophyllum brasiliense Myriophyllum heterophyllum Myriophyllum laxum Myriophyllum pinnatum Myriophyllum spicatum Proserpinaca palustris Proserpinaca pectinata HAMAMELIDACEAE Fothergilla gardenii Hamamelis virginiana Liquidambar styraciflua HEMEROCALLIDACEAE Hemerocallis fulva HYACINTHACEAE Ornithogalum umbellatum HYDRANGEACEAE Decumaria barbara Hydrangea arborescens ssp. arborescens Philadelphus inodorus HYDROCHARITACEAE Vallisneria americana HYDROPHYLLACEAE Hydrolea quadrivalvis Phacelia bipinnatifida Phacelia dubia HYPERICACEAE Ascyrum hypercoides Ascyrum stans Hypericum adpressum

Coastal plain gentian Common marsh pink, rose pink sabatia, Coastal rose pink Slender marsh pink Four-angle sabatia GERANIUM Cranesbill, Carolina cranesbill Wild geranium Small-flower cranesbill, European geranium GINKGO Ginkgo BLOODWORT Redroot, bloodwort MILFOIL Parrot feather Water milfoil, southern water milfoil Piedmont milfoil, loose water milfoil Alternate-leaf water milfoil Eurasian water milfoil Common mermaid weed Feathery mermaid weed WITCH HAZEL Coastal witch alder Common witch hazel Sweetgum, red gum DAYLILY Daylily, orange daylily HYACINTH Star-of-Bethlehem HYDRANGEA Climbing hydrangea, woodvamp Wild hydrangea Common mock orange WATERWEED Eel grass, tape grass, water celery WATERLEAF Hydrolea, waterpod Fernleaf phacelia, forest phacelia Appalachian phacelia ST.-JOHN’S-WORT St. Andrew’s cross St.-Peter’s-wort Creeping St.-John’s-wort, bog St.-John’s-wort

O O R O R A O U U O A O R U R U O R U A O U C U U A O U U C O U

GH GH GH GH GH GH GH GH TW GH AQ AQ AQ AQ AQ AQ AQ SW SW TW GH GH VW SW SW AQ AQ GH GH SW SW GH

Growth Form

Common Name

Relative Abundance S

M

M

M

A

C

D

S

S S O

S

S

S S S

M

S

S

M S M

S

S S M M M S

B

S

S

S S

M

S

S

S S

E

S

S

S

S

S

S

S S

F

O

S

S

S

S

S

S

G H

S

S

I

S

S

S

M

S

S

S S

M

S S

S

S

M

S

S

S S

S S

M N O S S

L

S

K

M M

S S S

J

Habitat Type P

S S

S

Q

S

S

S S

M S S

S S

S

S

M M S M S S

M S

S S M M

R

S

T

S S

S

S

M

U

S

S

S

S

S

S

M

S

S

S

S S

S

S

S

S

S

S

V W X

S

Y

419

Species

Hypericum canadense Hypericum cistifolium Hypericum denticulatum Hypericum drummondii Hypericum fasciculatum Hypericum gentianoides Hypericum lloydii Hypericum mutilum Hypericum myrtifolium Hypericum nudiflorum Hypericum punctatum Hypericum setosum Hypericum suffruticosum Hypericum tubulosum Hypericum virginicum Hypericum walteri HYPOXIDACEAE Hypoxis hirsuta ssp. hirsuta Hypoxis micrantha IRIDACEAE Belamcanda chinensis Gladiolus × gandovensis Iris verna Iris virginica Sisyrinchium albidum Sisyrinchium angustifolium Sisyrinchium arenicola Sisyrinchium atlanticum Sisyrinchium capillare Sisyrinchium mucronatum ISOETACEAE Isoetes engelmannii Isoetes hyemalis ITEACEAE Itea virginiana JUGLANDACEAE Carya aquatica Carya cordiformis Carya glabra Carya illinoisiensis Carya myristiciformis Carya ovalis Carya ovata Carya pallida Carya tomentosa

Common Name

Canada St.-John’s-wort St.-John’s-wort Coppery St.-John’s-wort Nits-and-lice, Drummond’s St.-John’s-wort Peelbark St.-John’s-wort Pineweed, orange grass Lloyd’s St.-John’s-wort Common dwarf St.-John’s-wort St.-John’s-wort St.-John’s-wort Spotted St.-John’s-wort St.-John’s-wort Pineland St.-John’s-wort Marsh St.-John’s-wort Marsh St.-John’s-wort Walter’s marsh St.-John’s-wort STAR GRASS Yellow star grass Yellow star-grass IRIS Blackberry lily Gladiolus Dwarf iris, vernal iris, sandhill iris Southern blue-flag iris Blue-eyed grass Blue-eyed grass Blue-eyed grass Atlantic blue-eyed grass Wiry blue-eyed grass Blue-eyed grass QUILLWORT Engelmann’s quillwort Winter quillwort SWEET-SPIRES Virginia willow, sweet-spires HICKORY Water hickory, bitter pecan Bitternut hickory Pignut hickory Pecan Nutmeg hickory Sweet pignut hickory, red hickory Shagbark hickory Sand hickory, pale hickory Mockernut hickory

U U O U U C C C R C O C R U O O U U U U R R U A C O U U U U C O U O U R U U C A

GH GH GH GH GH GH GH GH GH GH GH GH AQ AQ SW TW TW TW TW TW TW TW TW TW

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M M

M

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M

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T

S

S

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S

S

O

S

S

S

S

S

O

S

S

S

S

S

S

S

S

V W X

S

S

Y

420

Species

Juglans cinerea Juglans nigra JUNCACEAE Juncus acuminatus Juncus biflorus Juncus canadensis Juncus coriaceus Juncus debilis Juncus dichotomus Juncus effusus Juncus elliottii Juncus polycephalus Juncus repens Juncus scirpoides Juncus tenuis LAMIACEAE Callicarpa americana Glecoma hederacea Hedeoma pulegiodes Lamium amplexicaule Leonotus nepetaefolia Lycopus amplectans Lycopus rubellus ssp. rubellus Lycopus virginicus Macbridea caroliniana Mentha piperita Monarda punctata Nepeta cataria Prunella vulgaris Pycnanthemum flexuosum Pycnanthemum incanum Salvia azurea Salvia lyrata Salvia urticifolia Satureja georgiana Scutellaria elliptica Scutellaria integrifolia Scutellaria lateriflora Stachys floridana Trichostema dichotomium Trichostema setaceum LAURACEAE Lindera benzoin Lindera subcoriacea

Common Name

Butternut, white walnut Black walnut CORD GRASS Sharp fruited rush Rush Canada rush Rush Rush, weak rush, creeping rush Forked rush Soft rush Elliott’s rush Many-headed rush Rush Rush Path rush MINT Beautyberry Gill-over-ground, ground ivy American pennyroyal Henbit, dead-nettle Lions-ears Sessile-leaved water-horehound Stalked bugleweed Virginia bugleweed Carolina macbridea, Carolina bird-in-nest Mint Eastern horse mint Catnip, catmint Heal-all, American self-heal Savanna mountain mint Mountain mint Azure sage Lyre-leaved sage Nettle-leaved sage Georgia calamint Skullcap Skullcap Skullcap Florida betony, rattlesnake weed Common blue-curls Narrowleaf blue-curls LAUREL Spicebush Bog spicebush, odorless spicebush

R U U C U U C O A O U O O O C O C O U U U U R R C U O R R C U R R O U U U A U O R

AQ AQ AQ AQ AQ AQ AQ AQ AQ AQ GG GG SW GH GH GH GH GH GH GH GH GH GH GH GH GH GH GH GH GH SW GH GH GH GH GH GH SW SW

Growth Form TW TW

Relative Abundance

C

S

S

S

S

S

S

D

M S O M S M M

S

S

S

S

S

M M M

B

M M

A

S

S

S

M

S

E

S

S

S

S S M

S

S M S

S S

F

S

S S

S S

S S S S S S S S

G H

S S

I

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J

S

S

K

L

S S

S

S

S S

S S

S

M

S

S

S

S

S

M N O

Habitat Type

S

P

S S

S S

S S S

S

Q

S

M S

M

M S S S

S

S

M S

R

M

S

S

S S

M S

S

S

S

S

S

T

S

S

S S

U

S

S

S S

S

S S

S

S S

S

S

S

S

S

S

S

S S S

S S S S

S

V W X

M

Y

421

Species

Lindera melissaefolium Persea borbonea Persea borbonea ssp. palustrus Sassafras albidum LEMNACEAE Lemna perpusilla Spirodela polyrrhiza Wolffia papulifera Wolffiella floridana LENTIBULARIACEAE Pinguicula lutea Utricularia biflora Utricularia fibrosa Utricularia floridana Utricularia inflata Utricularia olivacea Utricularia purpurea Utricularia subulata LILIACEAE Allium ampeloprasum Allium canadense Allium cuthbertii Allium inodorum Allium sativum Allium vineale Colchicum autumnale Lilium catesbaei Lilium michauxii Medeola virginiana Polygonatum biflorum Smilacina racemosa Uvularia floridana Uvularia perfoliata Uvularia puberula Uvularia sessilifolia Yucca filamentosa LINACEAE Linium virginianum ssp. medium Linum striatum LOGANIACEAE Cynoctonum mitreola Polypremum procumbens LYCOPODIACEAE Lycopodium appressum

Common Name

Pondberry Red bay Swamp red bay Sassafras DUCKWEED Duckweed Greater duckweed Water-meal Mud-midgets BLADDERWORT Yellow butterwort Longspur creeping bladderwort Fibrous bladderwort Florida bladderwort Swollen bladderwort, inflated bladderwort Dwarf bladderwort, minute bladderwort Purple bladderwort Slender bladderwort, zigzag bladderwort LILY Wild leek Wild onion Striped garlic, Cuthbert’s onion False garlic Garlic Field garlic, field onion, wild onion Autumn crocus, meadow saffron Catesby’s lily, pine lily Carolina lily Indian cucumber root Solomon’s seal False Solomon’s seal Florida bellwort Perfolate bellwort Coastal bellwort Sessile bellwort Bear grass, curlyleaf yucca, spoonleaf yucca FLAX Northern yellow flax Ridgestem yellow flax LOGANIA Caribbean miterwort Polypremum CLUB MOSS Southern bog clubmoss

R C O A U U U O U O U R U R U U U O R U R C R U R U O U U U U U A U O U C O

AQ AQ AQ AQ AQ AQ AQ AQ AQ AQ AQ AQ GH GH GH GH GH GH GH GH GH GH GH GH GH GH GH GH SW GH GH GH GH GF

RA

SW TW TW TW

GF

B

S

S

M M

M

M

M

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C

M M S S

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S

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M M O O S

A

S

S

S

S

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S

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S

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M M

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M M S

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S

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S

S S

S

S

S

S S

S

S

S S

S

S

S

S

S S S S

S

S

V W X

Y

422

Species

Lycopodium carolinianum Lycopodium flabelliforme Lycopodium obscurum Lycopodium prostratum LYTHRACEAE Ammannia coccinea Decodon verticillatus Lagerstroemia indica Rotala ramosior MAGNOLIACEAE Liriodendron tulipifera Magnolia grandiflora Magnolia virginiana MALVACEAE Hibiscus moscheutos Hibiscus syriacus Sida rhombifolia MELANTHIACEAE Amianthium muscaetoxicum Chamaelirium luteum Melanthium virginicum Zigadenus densus MELASTOMATACEAE Rhexia alifanus Rhexia aristosa Rhexia cubensis Rhexia mariana Rhexia mariana ssp. purpurea Rhexia petoliata Rhexia virginiana MELIACEAE Melia azedarach MENISPERMACEAE Calycocarpum lyonii Cocculus carolinus Menispermum canadense MENYANTHACEAE Nymphoides aquatica Nymphoides cordata MIMOSACEAE Albizia julibrissin Schrankia microphylla ssp. angustata MOLLUGINACEAE Mollugo verticillata

Common Name

Slender bog clubmoss Southern running pine Common ground pine Prostate bog clubmoss LOOSESTRIFE Scarlet toothcup Water loosestrife, swamp loosestrife Crepe myrtle Toothcup MAGNOLIA Tulip poplar, yellow poplar Southern magnolia, bull bay Sweet bay MALLOW Eastern rose mallow Rose of Sharon, althaea Arrowleaf mallow, arrowleaf sida BUNCH FLOWER Fly-poison Devil’s-bit Virginia bunchflower Death camas, crow poison, black snakeroot MELASTOME Smooth meadow beauty Three-awned meadow beauty West Indies meadow beauty Pale meadow beauty Meadow beauty Short-stemmed meadow beauty Virginia meadow beauty MAHOGANY Chinaberry MOONSEED Moonseed, cupseed Coralbeads, Carolina moonseed Moonseed, common moonseed BUCKBEAN Big floating-heart, banana floating-heart Little floating-heart MIMOSA Silk tree, albizia Sensitive brier, eastern sensitive brier CARPETWEED Carpetweed

U O O O U O U O C U C O R C U R R U C R R A O O C U R U R U C U A O

GH SW SW GH TW TW TW SW SW GH GH GH GH GH GH GH GH GH GH GH GH TW VW VW VW AQ AQ TW GH GH

Growth Form GF GF GF GF

Relative Abundance

S M

M S

C

D

M

E

M

S S

S

M

S

S

F

S

S S S

S

M

M M

S

M M

O S M M M M S S M S

S O

B

S S S S M M M

O

S

S

S

S

A

S S

S

S

S

S

S

S

S M

G H

S

S S

S

S

I

S

S

K

S S S S S

S S

M

M M

J

S

S

L

S

S

S

S S S

M S

S S

S S S S

S

S S S S

S

S

M N O

Habitat Type

S

P

S

S

S

Q

S S

M S S

S M

S

R

S S

S S

S S

S M

S

S

S

S

S

T

S

S

S

S

S

U

S

S

S

S

S

S

S

S

S

S

S

S S

S

S S

S

V W X

S S

S

Y

423

Species

MORACEAE Maclura pomifera Morus rubra MYRICACEAE Myrica cerifera Myrica heterophylla NAIADACEAE Najas guadalupensis NARTHECIACEAE Aletris farinosa NELUMBONACEAE Nelumbo lutea NOLINACEAE Nolina georgiana NYMPHACEAE Nuphar luteum ssp. macrophyllum Nymphaea odorata NYSSACEAE Nyssa aquatica Nyssa sylvatica ssp. biflora Nyssa sylvatica ssp. sylvatica OLEACEAE Chionanthus virginicus Forestiera acuminata Forestiera segregata Fraxinus americana Fraxinus caroliniana Fraxinus pennsylvanica Jasminum nudiflorum Ligustrum japonicum Ligustrum sinense Ligustrum vulgare Osmanthus americanus ONOGRACEAE Gaura biennis Gaura filipes Ludwigia alternifolia Ludwigia arcuata Ludwigia decurrens Ludwigia glandulosa Ludwigia hirtella Ludwigia leptocarpa Ludwigia linearis Ludwigia palustrus Ludwigia pilosa Ludwigia spathulata

Common Name

MULBERRY Osage orange Red mulberry BAYBERRY Wax myrtle, southern bayberry Black bayberry, pocosin bayberry NAIAD Brushy pondweed, southern naiad ASPHODEL White stargrass, northern white colic root LOTUS Yellow lotus, American lotus lily, pond nuts BEARGRASS Sandhill lily, beargrass, Georgia lily WATER LILY Cow lily, spatterdock, yellow pond lily White water lily TUPELO Water tupelo, tupelo gum, cottom gum Swamp tupelo, swamp black gum, water gum Black gum, sour gum, pepperidge OLIVE Fringe tree, old-man’s beard Swamp forestiera, swamp privet Upland forestiera, southern privet White ash Carolina ash, pop ash Green ash Jasmine, winter jasmine Privet, Japanese privet Privet, Chinese privet Privet, common privet Devilwood, wild olive EVENING PRIMROSE Biennial gaura, northeastern gaura Threadstalk gaura Alternate-leaf seedbox Seedbox Wingstem water primrose Small-flowered seedbox Rafinesque’s seedbox Water-willow seedbox Narrowleaf seedbox Common water-purslane Hairy seedbox Spatulate seedbox, southern water-purslane C R O A A A C

GH AQ AQ TW TW TW

U U C R O O O O O O O R

U

GH AQ

GH GH GH GH GH GH GH GH GH GH GH GH

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AQ

U U R U C C U C A C U

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SW SW

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S S

M

S

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S

S

Y

S S S

S

S

S

S

M M

V W X

424

Species

Ludwigia sphaerocarpa Ludwigia suffruticosa Oenothera biennis Oenothera fruticosa Oenothera laciniata Oenothera speciosa Oenothera tetragona OPHIOGLOSSACEAE Botrychium biternatum Botrychium dissectum Botrychium lunariodes Botrychium virginianum Ophioglossum crotalophoroides Ophioglossum petiolatum Ophioglossum vulgatum ORCHIDACEAE Calopogon pulchellus Cypripedium acaule Goodyera pubescens Habenaria cillaris Habenaria clavellata Habenaria cristata Habenaria flava Habenaria lacera Habenaria repens Hexalectris spicata Isotria verticillata Listera australis Malaxis unifolia Spiranthes cernua Spiranthes gracilis Spiranthes grayi Spiranthes ovalis Spiranthes praecox Spiranthes vernalis Tipularia discolor OROBANCHACEAE Conopholis americana Epifagus virginiana OSMUNDACEAE Osmunda cinnamonea Osmunda regalis ssp. spectabilis OXALACEAE Oxalis corniculata

Common Name

Glove-fruited seedbox Shrubby seedbox Common evening primrose Southern sundrops Cut-leaved evening primrose Evening primrose, sundrops Northern sundrops ADDER’S-TONGUE FERN Southern grape fern, sparse-lobed grape fern Common grape fern, dissected grape fern Winter grape fern, prostrate grape fern Rattlesnake fern Bulbous adder’s-tongue fern Stalked adder’s-tongue fern Southern adder’s-tongue fern ORCHID Common grass pink Pink lady’s slipper, mocassin flower Rattlesnake plantain, downy rattlesnake orchid Yellow fringed orchid Small green wood orchid Crested fringed-orchid Southern rein orchid Green-fringe orchid Water-spider orchid Crested coral root, brunetta Large-whorled pogonia, large five-leaves Southern twayblade Green adder’s mouth Nodding ladies’ tresses Southern slender ladies’ tresses Little ladies’ tresses, little pearl-twist Oval ladies’ tresses Giant ladies’ tresses, grassy ladies’ tresses Spring ladies’ tresses Crane-fly orchid BROOMRAPE Squaw root, cancer root, squaw corn Beech drops ROYAL FERN Cinnamon fern Royal fern WOOD-SORREL Creeping yellow wood sorrel

R R C U U C R O U C C O O C R U U U O U U R R R U U R R U O U U U O U U O C C

GF GF GF GF GF GF GF GH GH GH GH GH GH GH GH GH GH GH GH GH GH GH GH GH GH GH GH GH GH GF GF GH

Growth Form GH GH GH GH GH GH GH

Relative Abundance S

S S S

S

S

S

F

S

G H

I

J

S

S

S S

S S S

M

S S S

S S S

S

O S

S S

S S

S S S M S M M M M S S M S M M

S S M S S S S

S

S

M S

S S

S

S

S

K

L

S

S S

S

S

S

S

S S

S

M S

M

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M N O

P

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S S

S

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S

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M

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S

S

S S

S

S S

S S S S

S

M

M

S S

S

M M

M S

S

S

E

S

M

D

S S

S

C

S S

B

M M S S M M O S S

S

S

S

A

Habitat Type

S

S

T

S

S

S

U

S

S

S

S

S

S

S

S

S S S S

S

S

S S

S

S

S

S

S

S

S S S

S

V W X

Y

425

Species

Oxalis florida ssp. dillenii Oxalis florida ssp. florida Oxalis rubra Oxalis stricta Oxalis violacea PAPAVERACEAE Eschscholzia californica Sanguinaria canadensis PASSIFLORACEAE Passiflora incarnata Passiflora lutea PENTHORACEAE Penthorum sedoides PHRYMACEAE Phryma leptostachya PHYTOLACCACEAE Phytolacca americana PINACEAE Pinus clausa Pinus echinata Pinus elliottii Pinus glabra Pinus palustrus Pinus serotina Pinus taeda Pinus virginiana PLANTAGINACEAE Plantago aristata Plantago hookeriana Plantago lanceolata Plantago virginica PLATANACEAE Platanus occidentalis POACEAE Agrostis hyemalis Agrostis perennans Agrostis stolonifera Aira elegans Amphicarpum muehlenbergium Andropogon elliottii Andropogon gerardii Andropogon scoparius Andropogon ternarius Andropogon virginicus Anthaenantia villosa Aristida beyrichiana

Common Name

Yellow wood sorrel Florida wood sorrel Red wood sorrel Yellow sorrel Violet wood sorrel POPPY California poppy Bloodroot PASSIONFLOWER May pop, purple passionflower Yellow passionflower DITCH-STONECROP Ditch-stonecrop, American penthorum LOPSEED American lopseed POKEWEED Pokeweed PINE Sand pine Shortleaf pine Slash pine Spruce pine Longleaf pine Pond pine, swamp pine Loblolly pine Virginia pine, scrub pine PLANTAIN Buckthorn plantain Wright’s plantain English plantain, ribgrass Virginia plantain PLANE-TREE Eastern sycamore GRASS Rough bent grass, fly-away grass Autumn bent grass, upland ben tgrass Redtop, black bent grass Elegant hair grass Goober-grass Big bluestem Turkey-foot bluestem Little bluestem Splitbeard bluestem Broomsedge, broomstraw Green silky-scale Wire grass, Carolina wire grass

A U U O U U U A O O O A U U A R A C A R O C A O C U O U U R U U A O A U U

GH GH VH VH GH GH GH TW TW TW TW TW TW TW TW GH GH GH GH TW GG GG GG GG GG GG GG GG GG GG GG GG

RA

GH GH GH GH GH

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V W X

M M S M M M S M M M S M

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S M S M M

S

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M S S S S M M M

S

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M M S M

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S

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O S O M

S S

S

S

O S S

M

M

S

M N O

S

M O S

L

S

S

O

O

O

S

S

Y

426

Species

Aristida condensata Aristida dichotoma Aristida lanosa Aristida longespica Aristida oligantha Aristida purpurascens Aristida tuberculosa Arundinaria gigantea Arundinaria tecta Arundo donax Avena sativa Bromus catharticus Bromus japonicus Cenchrus echinatus Cenchrus longispinus Cynodon dactylon Dactylis glomerata Danthonia compressa Danthonia sericea Danthonia spicata Digitaria filiformis Digitaria ischaemum Digitaria sanguinalis Echinochloa crus-galli Echinochloa walteri Eleusine indica Elymus villosus Elymus virginicus Eragostis capillaris Eragostis curvula Eragostis refracta Eragostis spectabilis Eremochloa ophiuroides Erianthus alopecuroides Erianthus giganteus Festuca elatior Festuca octoflora Festuca sciurea Glyceria canadensis Glyceria maxima Glyceria striata Gymnopogon ambiguus Gymnopogon brevifolius Holcus lanatus

Common Name

Piedmont three awn Fork-lip three awn Woolly three awn Slimspike three awn Few-flowered three awn, prairie three awn Arrowfeather, purple three awn Poverty grass, needlegrass River cane, switchcane, cane, giant cane Switchcane, cane Giant reed Oats Rescue grass Japanese chess Southern sandspur, bristly sandspur Northern sandspur, common sandspur Bermuda grass, scutch grass Orchard grass Slender oat grass, mountain oat grass Silky oat grass Poverty oat grass Slender crabgrass Smooth crabgrass, small crabgrass Crabgrass Barnyard grass Salt marsh cockspur grass Goosegrass, yardgrass Wild rye, velvet rye Virginia rye Lace grass Weeping love grass Coastal love grass Purple love grass Centipede grass Savanna plume grass Plume grass, giant plume grass Fescue, meadow fescue Southern six-weeks fescue Squirreltail fescue Rattlesnake manna grass American manna grass Fowl manna grass, nerved manna grass Eastern beard grass Pineland beard grass Velvet grass, soft grass, Yorkshire fog

Growth Form GG GG GG GG GG GG GG GG GG GG GG GG GG GG GG GG GG GG GG GG GG GG GG GG GG GG GG GG GG GG GG GG GG GG GG GG GG GG AQ AQ AQ GG GG GG

R U U C U O A U A C R R U U O A U U O C O C C U R O O U U O U U C U C U U U U U U U U O

Relative Abundance A

S S

B

M

S S

S O

C

S M

D

S

M

O

E

S M M

O

S

S

S

F

S S S

S

S

S

M

G H

I

J

S

M

K

L S

S

S S

S S

S

S S

M M

S S

S

S

S

M M

S S S M S S M

S M

S

S S

S

M N O

Habitat Type

S

S

S

S S

P

U

S

S

S S S S

S S

S

M

S

S S S

S S

S S S S

S S

S S S

S

S

S

S

S

S

S

S

S

S S S S

S S

S

S

S

S S S S

V W X

S S

S

T

S S

S

S S S

S S

S

S

M

M M

R

S S

S S

S

Q

S

S

S

S S S

Y

427

Species

Hydrochloa caroliniensis Leersia hexandra Leersia lenticularis Leersia oryzoides Leersia virginica Leptoloma cognatum Lolium multiflorum Manisuris rugosa Melica mutica Microstegium vinineum Muehlenbergia capillaris Muehlenbergia schreberi Muehlenbergia tenuflora Oplismenus setarius Panicum aciculare Panicum agrostoides Panicum anceps Panicum angustifolium Panicum boscii Panicum chamaelonche Panicum ciliatum Panicum columbianum Panicum commonsianum Panicum commutatum Panicum consanguineum Panicum curtifolium Panicum dichotomiflorum Panicum dichotomum Panicum fusiforme Panicum gymnocarpon Panicum hemitomon Panicum hians Panicum lanuginosum Panicum laxiflorum Panicum leucothrix Panicum longifolium Panicum meridionale Panicum nitidum Panicum oligosanthes Panicum polyanthes Panicum ravenelii Panicum scoparium Panicum sphaerocarpon Panicum tenue Panicum verrucosum Panicum villosissimum

Common Name

Southern water-grass Southern cutgrass Catchfly cutgrass Rice cutgrass White cutgrass Fall witchgrass, saltmeadow grass Rye-grass, Italian rye grass Wrinkled joint grass Melic grass, two-flower melic Sasa-grass Muhly grass, hair grass Muhly grass, nimblewill Muhly grass, common slender muhly grass Woods grass Needle witchgrass Redtop panic grass Beaked panic grass Narrowleaf witchgrass Bosc’s witchgrass Carpet witchgrass Dwarf witchgrass American witchgrass Low-stiff witchgrass, Common’s witchgrass Variable witchgrass Kunth’s witchgrass Short-leaved witch-grass Spreading panic grass, fall panic grass Forked witchgrass Spindle-fruited witchgrass Swamp phanopyrum, swamp panic grass Maidencane Gaping panic grass Woolly witchgrass Open-flower witchgrass Roughish witchgrass Long-leaved panic grass Matting witchgrass Shining witchgrass Few-flowered witchgrass Small-fruited witchgrass Ravenel’s witchgrass Velvet witchgrass Round-fruited witchgrass White-edged witchgrass Warty panic grass White-haired witchgrass

GG AQ GG GG GG GG GG GG GG GG GG GG GG GG GG GG GG GG GG GG GG GG GG GG GG GG GG GG GG AQ AQ GG GG GG GG GG GG GG GG GG GG GG GG GG GG GG

GF U O U U U U R R O R U C R R C C C C C U U U U C O R O O U U C O O O U O U U U U O C C O C O

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S

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S

S

S

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S

S S S S

V W X

S

S

Y

428

Species

Panicum virgatum Panicum wrightianum Paspalum bifidum Paspalum dilatatum Paspalum floridanum Paspalum laeve Paspalum notatum Paspalum praecox Paspalum setaceum Paspalum urvillei Phalaris caroliniana Phyllostachys aurea Poa annua Poa autumnalis Poa chapmaniana Poa pratensis Poa sylvestris Sacciolepis striata Setaria corrugata Setaria geniculata Setaria glauca Sorghastrum elliottii Sorghastrum nutans Sorghastrum secundum Sorghum halepense Sorghum vulgare Sphenopholis nitida Sphenopholis obtusata Sporobolus clandestinus Sporobolus junceus Sporobolus poirettii Sporobolus teretifolius Stipa avenacea Tridens flavus ssp. flavus Triplasis americana Triplasis purpurea Tripsacum dactyloides Triticum aestivum Uniola latifolia Uniola laxa Uniola sessiliflora Urochloa ramosa Zizianopsis milacea

Common Name

Switchgrass Wright’s witchgrass Pitchfork paspalum, pitchfork crown grass Dallis grass Florida paspalum Paspalum Bahia grass Early crown grass Paspalum Vasey grass Canary grass, maygrass Bamboo, golden bamboo Speargrass, annual bluegrass Autumn bluegrass Bluegrass Kentucky bluegrass, june grass Forest bluegrass Wet-grass Foxtail Knotroot bristlegrass, perennial foxtail grass Yellow foxtail grass Slender Indian grass Yellow Indian grass Lopsided Indian grass Johnson grass Sorghum, milo, broomcorn Shining wedgegrass Prairie wedgegrass Rough dropseed Piney-woods dropseed Smut grass, blackseed Wireleaf dropseed Needlegrass, black oat grass Tall redtop, purpletop tridens Southern sand grass Purple sand grass Eastern gamma grass Wheat, winter wheat, spring wheat River oats, inland sea oats Slender spikegrass Longleaf spikegrass Browntop millet, dixie signal grass Rice grass, Southern wild rice, water millet

Growth Form GG GG GG GG GG GG GG GG GG GG GG GG GG GG GG GG GG AQ GG GG GG GG GG GG GG GG GG GG GG GG GG GG GG GG GG GG GG GG GG GG GG GG AQ

C U O O U U A C O U R R U U U U R U U C O U O C O C U O U U O R C C O C R U O U U R R

Relative Abundance

B

C

D

E

M

S

S S

S

S S

M

S S S

M

S

M M

S

S S

S S

S

S

S

S

M M M M M M M M

A

S

S

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F

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S

S S

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S

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S

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S

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S

S

M N O

Habitat Type

S

S S S

P

S

S

S

R

O S

S

S

M

M

S M

S

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Q

S S S

S

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S S S

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S

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S S

S

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S

S

S

Y

S S S S

S

S

S

S

S M M S

S S

S S

S S

S

S S

S

S

V W X

429

Species

POLEMONIACEAE Phlox amoena Phlox carolina Phlox nivalis POLYGALACEAE Polygala cruciata Polygala curtissii Polygala cymosa Polygala incarnata Polygala lutea Polygala polygama Polygala ramosa POLYGONACEAE Brunnichia ovata Eriogonum tomentosum Polygonella americana Polygonella gracilis Polygonella polygama Polygonum hirsutum Polygonum hydropiperoides Polygonum lapathifolium Polygonum pensylvanicum Polygonum persicaria Polygonum punctatum Polygonum sagittatum Polygonum scandens Polygonum setaceum Rumex acetosella Rumex crispus Rumex hastatulus Tovara virginianicum POLYPODIACEAE Polypodium polypodioides PONTEDERIACEAE Pontederia cordata PORTULACACEAE Claytonia virginica Portulaca pilosa POTAMOGETONACEAE Potamogeton berchtoldii Potamogeton diversifolium Potamogeton epihydrus Potamogeton pulcher PRIMULACEAE Lysimachia lanceolata Lysimachia quadrifolia

Common Name

JACOB’S LADDER Hairy phlox Carolina phlox Trailing phlox, pineland phlox MILKWORT Southern drumheads Appalachian milkwort Tall pinebarren milkwort Pink milkwort, procession flower Orange milkwort, red-hot poker Bitter milkwort Short pinebarren milkwort SMARTWEED Ladies’ eardrops, red vine, buckwheat vine Dog-tongue, sandhill wild buckwheat Common joint-weed Wireweed October flower Hairy smartweed Water pepper Dockleaf smartweed, pale smartweed Common smartweed, Pennsylvania smartweed Lady’s thumb, heartsease Dotted smartweed Arrowleaf-tearthumb, scratch grass Climbing buckwheat Swamp smartweed Sheep sorrel, red dock, sourgrass Curly dock Wild dock, Engelmann’s sorrel Jumpseed POLYPLOIDY FERN Resurrection fern, little gray polypody PICKERELWEED Pickerelweed, heart-leaf pickerelweed PURSLANE Southern spring beauty Purslane, hairy purslane PONDWEED Slender pondweed Common snailseed pondweed Ribbonleaf pondweed Spotted pondweed PRIMROSE Lanceleaf loosestrife Whorled loosestrife, swamp loosestrife C C U C C O O A U U

GH GH AQ AQ AQ AQ GH GH

U C U U C U C U C C O O C O A C C O

VW GH GH GH GH VH VH VH VH VH VH VH VH VH GH GH GH VH GF

U U O O C O U

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AQ

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A

S

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B

S

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U

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S

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S S S

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S

S

S S S S

S

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V W X

Y

430

Species

PTERIDACEAE Adiantum capillus-veneris RANUNCULACEAE Actaea pachypoda Clematis crispa Clematis virginiana Delphinium ajacis Delphinium carolinianum Hepatica americana Ranunculus pusillus Thalictrum subrotundum Trautvetteria caroliniensis Xanthorhiza simplicissima RHAMNACEAE Berchemia scandens Ceanothus americanus Rhamnus caroliniana ROSACEAE Agrimonia incisa Agrimonia pubescens Amelanchier arborea Amelanchier arborea ssp. laevis Amelanchier oblongifolia Amelanchier spicata Crataegus aestivalis Crataegus crus-galli Crataegus flabellata Crataegus flava Crataegus marshallii Crataegus phaenopyrum Crataegus punctata Crataegus sphatulata Crataegus uniflora Crataegus viridis Duchesnea indica Fragaria virginiana Potentilla canadensis Potentilla recta Prunus americana Prunus angustifolia Prunus caroliniana Prunus persica Prunus serotina Prunus umbellata

Common Name

MAIDENHAIR FERN Southern maidenhair fern, venus-hair fern BUTTERCUP White baneberry, doll’s-eyes, white cohosh Leather flower, marsh clematis Virgin’s-bower, purple clematis Rocket larkspur, annual larkspur Carolina larkspur Round-lobed hepatica, liverleaf Spearwort, low spearwort Reclined meadow rue, slight meadow rue Carolina tassel rue, false bugbane Yellow-root BUCKTHORN Rattan vine, supplejack New Jersey tea Carolina buckthorn ROSE Pineland groovebur Soft agrimony, downy agrimony, soft groovebur Downy serviceberry Smooth serviceberry Oblong-leaf serviceberry Shadbush Eastern mayhaw Cockspur haw Fan haw Yellow haw Parsley haw, Marshall’s haw Swamp Washington haw Dotted haw Little hip haw One-flower haw, sand haw Green haw Indian strawberry Wild strawberry Cinquefoil, running five-fingers Cinquefoil, five-fingers American plum Chickasaw plum Carolina cherry, laurel cherry Peach Black cherry, Alabama black cherry Flatwoods plum, hog plum, black sloe U R U U O R R O R R U C U R R U O C R U U O O O C U O U C U C U C U U A C U A C

GH VW VW GH GH GH AQ GH GH SW VW SW TW GH GH SW SW SW SW SW SW SW SW SW SW SW SW SW SW GH GH GH GH SW SW TW SW TW SW

Growth Form GF

Relative Abundance S

A

S

S S S

M S

C

S

S

S

S

S

S

S

S

S

S

M

S S S

S

E

S

S

S

S

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M M

S

S

S

B

S

S

S

S S

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F

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G H

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S S S S

S

S

S S

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S S

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S

S

S

S

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S S

S

S

S

S

M N O

Habitat Type

S

S

M

P

S

S

S

S

S

S

S

Q

M S S

S S

S

S

S

S

S S S

S S M M

S M M

M M S

M M

S S S

S S S

S S M M S M S M M

S S S

M M

S

M

S

S

R

S

S S S

S

S S S S

T

S

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S

U

S

S S

S

S

S

S

S

S

S S S S S S S

S

S

S S

V W X

Y

431

Species

Pyrus angustifolia Pyrus coronaria Pyrus malus Rosa carolina Rosa laevigata Rosa palustris Rubus argutus Rubus betulifolius Rubus cuneifolius Rubus enslenii Rubus flagellaris Rubus hispidus Rubus pensylvanicus Rubus recurvicaulis Rubus trivialis Sorbus arbutifolia Spiraea tomentosa Waldsteinia lobata RUBIACEAE Cephalanthus occidentalis Diodia teres Diodia virginiana Galium aparine Galium circaezans Galium hispidulum Galium obtusum Galium pilosum Galium tinctorium Galium triflorum Galium uniflorum Houstonia longifolia Houstonia purperea Houstonia pusilla Mitchella repens Oldenlandia uniflora Richardia brasilliensis Richardia scabra Sherardia arvensis RUTACEAE Xanthoxylum americanum Xanthoxylum clava-herculis SALICACEAE Populus alba Populus deltoides Populus heterophylla Salix caroliniana

Common Name

Southern crabapple, narrowleaf crabapple Wild crabapple, American crabapple Apple Pasture rose Cherokee rose Swamp rose Southern blackberry, highbush blackberry Swamp blackberry Sand blackberry Southern dewberry Northern dewberry Swamp dewberry Pennsylvania blackberry Recurved blackberry Creeping dewberry, southern dewberry Red chokeberry Meadowsweet, hardhack, steeplebush Barren strawberry MADDER Buttonbush Diodia, rough buttonweed Diodia, smooth buttonweed Cleavers Southern forest bedstraw Pineland bedstraw Bluntleaf bedstraw Old-field bedstraw Southern three-lobed bedstraw Sweet-scented bedstraw One-flower bedstraw Eastern longleaf bluet Summer bluet Tiny bluet Partridgeberry Oldenlandia Richardia Richardia Field madder CITRUS Toothache tree, devil’s walking-stick Southern prickly ash, Hercules’-club WILLOW White poplar, silvery poplar Eastern cottonwood Swamp cottonwood Crack willow, coastal plain willow

C U U U U U U U A C O C C U A C R R C C C U C O O C O O U U R U C U A C O R U R U U O

SW GH GH GH GH GH GH GH GH GH GH GH GH GH GH GH GH GH GH SW SW TW TW TW TW

RA

SW SW SW SW SW SW SW SW SW SW SW SW SW SW SW SW SW GH

GF

M

A

S

S

S

S

S

B

M S S

S

S

S

S

M

S

S

M

C

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S

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M

S

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S

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S

S

S S S

S

S

S S

S

S

S

S

S S

S

S S S

S S

S S S S

S

S S S S S

V W X

S S

Y

432

Species

Salix humilis Salix nigra SANTALACEAE Nestronia umbellata SAPINDACEAE Aesculus pavia SAPOTACEAE Bumelia lanuginosa SARRACENIACEAE Sarracenia minor Sarracenia rubra SAURURACEAE Saururus cernuus SAXIFRAGACEAE Heuchera americana Parnassia caroliniana Saxifragia virginiensis SCROPHULARIACEAE Agalinis aphylla Agalinis decemloba Agalinis fasciculata Agalinis linifolia Agalinis setacea Amphianthus pusillus Aureolaria pectinata Aureolaria pedicularia Aureolaria virginica Bacopa caroliniana Bacopa monnieri Buchnera floridana Chelone glabra Gratiola pilosa Gratiola ramosa Gratiola virginiana Linaria canadensis Linaria vulgaris Lindernia anagallidea Lindernia monticola Mecardonia acuminata Micranthemum umbrosum Paulownia tomentosa Penstemon australis Penstemon laevigatus Seymeria cassiodes

Common Name

Tall prairie willow, dwarf pussy willow Black willow SANDALWOOD Indian olive, nestronia SOAPBERRY Red buckeye BUCKTHORN Woolly bumelia, gum bumelia PITCHER PLANT Hooded pitcher plant Sweet pitcher plant LIZARD’S TAIL Lizard’s tail, water dragon SAXIFRAGE American alumroot Carolina grass-of-parnassus Early saxifrage SNAPDRAGON Scale-leaf foxglove Gerardia Beach foxglove Smooth foxglove, flax-leaf foxglove Gerardia Pool-sprite Hairy false foxglove, southern oak-leach Appalachian annual oak-leach Downy false foxglove, Virginia oak-leach Carolina water hyssop, blue water hyssop Smooth water hyssop Florida bluehearts White turtle-head Hedge hyssop Hedge-hyssop Hedge hyssop Blue toadflax Butter-and-eggs, wild snapdragon False pimpernel, cooper-rider Flatrock pimpernel, riverbank pimpernel Mecardonia Shade mudflower Princess tree Sandhill beardtongue Southern beardtongue Senna seymeria

U C R C R R R C U R R U R U U U R C U O R U U U C O O C U O R O U U U O O

SW SW TW GH GH GH GH GH GH GH GH GH GH GH AQ GH GH GH AQ AQ GH GH GH GH GH GH GH GH GH GH AQ TW GH OH GH

Growth Form SW TW

Relative Abundance

B

M

S

S

S

S

M M

A

S

S

S

S

M

S

S

S

C

S

O

M

S

D

S

S

S

M

S

S

S

M

S S

F

S

S

S

O

S

E

S S

S

S

S

S S S

S S

S

S

G H

S

S S

S

I

S

J

S S

S

S S

S

S

S

K

S

S

L

S S S

S

S S

S

S S

S

S

S

S

S

S

M

S

S

S S

S

M

S

S

M M

M N O

Habitat Type

S

S

S

S

S

P

S

S

S

S

Q

S

S

S

M

S

M S S M S S

S S S

S

M M

S

R

S

T

M

U

S

S S S

S

S

S

S

S

S

S

S

S

S

S S

S

S

V W X

M

Y

433

Species

Verbascum virgatum Veronica arvensis Veronica peregrina SELAGINELLACEAE Selaginella apoda SIMAROUBACEAE Ailanthus altissima SMILACACEAE Smilax bona-nox Smilax ecirrata ssp. hugeri Smilax glauca Smilax hispida Smilax laurifolia Smilax pulverulenta Smilax pumila Smilax rotundifolia Smilax smallii Smilax walteri SOLONACEAE Lycium barbarum Physalis angulata Physalis heterophylla Physalis virginiana Solanum carolinense Solanum americanum STRYCHNACEAE Spigelia marilandica STYRACACEAE Halesia caroliniana Halesia parviflora Styrax americana Styrax grandifolia SYMPLOCACEAE Symplocus tinctoria THEACEAE Gordonia lasianthus Stewartia malachodendron THELYPTERIDACEAE Thelypteris hexagonoptera Thelypteris palustris TILIACEAE Tilia caroliniana TOFIELDIACEAE Tofieldia glabra Tofieldia racemosa

Common Name

Mullein Corn speedwell, wall speedwell Common purslane speedwell SPIKE MOSS Meadow spike moss PARADISE TREE Tree-of-heaven GREENBRIER Catbrier, tramp’s-trouble, bullbrier Huger’s carrion flower Saw-brier, glaucous greenbrier Bristly greenbrier, hellfetter, China-root Bamboo vine, laurel-leaf greenbrier Carrion flower Sarsaparilla vine, dwarf smilax Common greenbrier, horsebrier Jackson-brier, sweet-scented smilax Coral greenbrier, redberry greenbrier NIGHTSHADE Common matrimony vine Smooth ground cherry Clammy ground cherry Virginia ground cherry Horse nettle, bull nettle American Nightshade INDIAN PINK Indian pink, pinkroot, wormgrass STORAX Common silverbell Little silverbell, four-winged silverbell American snowbell Bigleaf snowbell SWEETLEAF Sweetleaf TEA Loblolly bay Silky camelia, Virginia stewartia MARSH FERN Broad beech fern Marsh fern BASSWOOD Carolina basswood FALSE ASPHODEL Carolina bog asphodel, white asphodel Coastal bog asphodel

R C O O U A R O O O O R C U U U O U C C C U R R O U C U U R O U U U

GF TW VW SW VW VW VW SW SW VW VW VW VH GH GH GH GH GH GH SW SW SW SW SW TW SW GF GF TW GH GH

RA

GH GH GH

GF

S

S

S

S M S S M S

B

S S

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S

S

S

S

M M

O

S

A

S

D

S

E

F

S

M S

S

S

S S S S

S

S

S

S

S

S S S S

S

S

S

M

S S S S S S S S M M S M S S S M S S M

S

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G H

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K

S

S

S S

S

S

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M M

S S

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S

S

S

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M N O

S

L

S

S

P

S

S

S

Q

S

S

S

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S S M S

S

S

S S S

S S S S

S

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S

S

S S S

S

S S S

S S S S

M

S

S

S

S

S

T

S

S

S

S

M

U

S S

S

S

S

S

S S

S

S

S

S

S

S S

S S

S S S

S

S

S

S

S S

V W X

Y

434

Species

TRILLIACEAE Trillium cuneatum Trillium pusillum Trillium viride TURNERACEAE Piriqueta caroliniana TYPHACEAE Sparganium americanum Typha angustifolia Typha domingensis Typha latifolia ULMACEAE Planera aquatica Ulmus alata Ulmus americana Ulmus rubra UTRICACEAE Boehmeria cylindrica Laportea canadensis Pilea pumila Utrica dioica VERBENACEAE Lantana camara Phryma leptostachya Verbena brasiliensis Verbena carnea VIOLACEAE Viola affinis Viola arvensis Viola brittoniana Viola eriocarpa Viola lanceolata Viola palmata Viola papilionacea Viola pedata Viola primulifolia Viola rafinequii Viola septemloba Viola tricolor Viola triparata Viola villosa Viola walteri VISCACEAE Phorodendron serotinum

Common Name

TRILLIUM Little sweet Betsy, purple toadshade Least trillium, Carolina trillium Mottled trillium TURNERA Piriqueta CATTAIL Bur reed Narrowleaf cattail Southern cattail Common cattail ELM Water elm, plane-tree, planer tree Winged elm American elm Slippery elm NETTLE False nettle Wood nettle Clearweed, greenfruit clearweed, coolwort European stinging nettle, great nettle VERBENA Common lantana American lopseed Vervain Carolina vervain VIOLET Violet Field pansy Violet Hairy yellow violet, downy yellow violet Lanceleaf white violet, lanceleaf violet Wood violet, purple wood violet Confederate violet, common blue violet Bird’s-foot violet Yellow forest violet Wild pansy Hairy blue violet Johnny-jump-up Three-parted yellow violet Southern woolly violet Walter’s violet, prostrate blue violet MISTLETOE American mistletoe U R U U O R O A O C C U O O U U R R C U O U U O U R U C O C U U U U R A

GH AQ AQ AQ AQ TW TW TW TW GH GH GH GH VW GH GH GH GH GH GH GH GH GH GH GH GH GH GH GH GH GH GH TH

Growth Form GH GH GH

Relative Abundance M

A

C

S

S S

S

S S S S S

S

S

S

S S S

S M S M

S

S

S

S S S

S S M M

B

S

S M M

S

D

S

S

S

S

S

S S S

S S S S

M

S

E

S

S

S S

S

M M

F

S

S

S S S S

G H

S

S S

I

J

S

S

K

S

S

L

S

S

S S

M

S

S

S

M N O

Habitat Type

S

S

P

S

S

S

S

Q

S

S S S

S

S

S S S S

S

S

S

S

S

S S S

S

S

S S S

S S M M S M

M M S S M

R

T

S

U

S

S

S

S

S

S

S

S

S

S

S

S

S

S

V W X

Y

435

Species

VITACEAE Ampelopsis arborea Parthenocissus quinquefolia Vitis aestivalis Vitis baileyana Vitis riparia Vitis rotundifolia Vitis vulpina XYRIDACEAE Xyris ambigua Xyris baldwiniana Xyris caroliniana Xyris difformis Xyris fimbriata Xyris jupicai Xyris platylepis

Common Name

GRAPE Pepper vine, cissus Virginia creeper Summer grape, pigeon grape Possum grape Riverside grape Muscadine grape Frost grape, winter grape, chicken grape YELLOW-EYED GRASS Yellow-eyed grass Baldwin’s yellow-eyed grass Pineland yellow-eyed grass Southern yellow-eyed grass Giant yellow-eyed grass Yellow-eyed grass Yellow-eyed grass A A C R U A O C U O A O O C

GH GH GH GH GH GH GH

RA

VW VW VW VW VW VW VW

GF

S

M

S

A

C

M M S S S S S M S S S S S M

B

S

D

M S S S S S S

E

S S S S

K

L

S S

S

S

S

S

S

S

S S

M N O

M

J

S

I

S

S

G H

S S S

F

M

P

S

Q

S S S S S S

R

M S S S S S S

S

S

S

T

S

S

U

S

S

S

S S

S

S

S

S S

S

S

V W X

Y

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List of Reviewers Gary Achtemeier, USFS Southern Research Station Buddy Baker, South Carolina Department of Natural Resources Judy Barnes, South Carolina Department of Natural Resources Chris Barton, USFS Southern Research Station Darold Batzer, University of Georgia Steve Bennett, South Carolina Department of Natural Resources Lehr Brisbin, Savannah River Ecology Laboratory Mark Brooks, Savannah River Archeological Research Program Mike Caudell, South Carolina Department of Natural Resources Alex Clark, USFS Southern Research Station Mark Coleman, USFS Southern Research Station Beverly Collins, Savannah River Ecology Laboratory Dan Connelly, National Audubon Society Jim Cook, Savannah River National Laboratory Malcom Coulter, IUCN, BirdLife International, Wetlands International Bob Crais, USFS–Savannah River Don Dagnan, USFS–Savannah River Adrienne DeBiase, Savannah River Ecology Laboratory Barny Dunning, Purdue University Mark Ford, USFS Northeast Research Station David Guynn, Clemson University Paul Hamel, USFS Southern Research Station Jim Hanula, USFS Southern Research Station Dean Harrigal, South Carolina Department of Natural Resources Tim Harrington, University of Georgia Gary Hepp, Auburn University Don Imm, USFS–Savannah River

Patrick Jackson, U.S. Department of Energy Bill Jarvis, USFS–Savannah River Bob Jones, Virginia Polytechnic Institute Randy Kolka, USFS North Central Research Station Charles Kwit, University of Florida Harry LeGrand, North Carolina Department of Natural Resources Beth LeMaster, USFS–Francis Marion and Sumter National Forests Bill Littrell, Westinghouse Savannah River Company Steve Lohr, Shaw Air Force Base Bart Marcy, Westinghouse Savannah River Company Jack Mayer, Westinghouse Savannah River Company J. Vaun McArthur, Savannah River Ecology Laboratory Alex Menzel, West Virginia University Karl Miller, University of Georgia Joe Mitchell, University of Richmond Chris Moorman, North Carolina State University Allen Nicholas, USFS–Savannah River Vernon Osteen, Westinghouse Savannah River Company Mike Paller, Savannah River National Laboratory Perran Ross, University of Florida Kevin Russell, Willamette Industries, Inc. Sarah Schweitzer, University of Georgia Gary Sick, USFS–Savannah River Ronald Susott, USFS Rocky Mountain Research Station John Sweeney, Clemson University John Taylor, USFS Southern Region State and Private Forestry Carl Trettin, USFS Southern Research Station Jeff Walters, Virginia Polytechnic Institute Julie Weston, Savannah River Ecology Laboratory

About the Authors CHRISTOPHER D. BARTON is assistant professor of forest hydrology and watershed management at the University of Kentucky. He was formerly a soil scientist with the U.S. Forest Service Southern Research Station’s Center for Forested Wetlands Research, where he was stationed at the Savannah River Site. BRUCE A. BAYLE is air resource program manager with the U.S. Forest Service in Atlanta, Georgia. JOHN I. BLAKE is assistant manager for research at the U.S. Forest Service–Savannah River. RONALD T. BONAR (retired) is a former assistant manager for timber at the U.S. Forest Service–Savannah River. I. LEHR BRISBIN, JR. is senior research ecologist with the University of Georgia’s Savannah River Ecology Laboratory and adjunct associate professor of ecology and pharmaceutical and biomedical sciences at the University of Georgia. A. LAWRENCE BRYAN, JR., is research coordinator with the University of Georgia’s Savannah River Ecology Laboratory. KURT A. BUHLMANN is visiting research ecologist at the University of Georgia’s Savannah River Ecology Laboratory. WILLIAM D. CARLISLE is a wildlife biologist with the Kentucky Department of Natural Resources. He was formerly a graduate research assistant in the Department of Forest Resources, Clemson University, where he conducted his thesis research on the Savannah River Site. MICHAEL B. CAUDELL is a wildlife management biologist with the South Carolina Department of Natural Resources at the Savannah River Site. BRENT J. DANIELSON is an associate professor in the Department of Ecology, Evolution, and Organismal Biology, Iowa State University. He was formerly a graduate research assistant in the University of Georgia’s Institute of Ecology, where he conducted his doctoral research on the Savannah River Site. MILES DENHAM is a fellow scientist with the Savannah River National Laboratory on the Savannah River Site. J. WHITFIELD GIBBONS is professor of ecology at the University of Georgia and former head of the Environmental Outreach and Education program at the Savannah River Ecology Laboratory. JUDITH L. GREENE is a research coordinator with the University of Georgia’s Savannah River Ecology Laboratory. NICK M. HADDAD is an assistant professor at North Carolina State University. He was formerly a graduate research assistant in the University of Georgia’s Institute of Ecology, where he conducted his doctoral research on the Savannah River Site. CHARLES H. HUNTER, JR., is senior meteorologist with the Savannah River National Laboratory on the Savannah River Site. DONALD W. IMM is a botanist with the U.S. Forest Service–Savannah River. WILLIAM L. JARVIS (retired) is a former wildlife biologist with the U.S. Forest Service– Savannah River.

468

About the Authors

PAUL E. JOHNS (retired) is a former research coordinator with the University of Georgia’s Savannah River Ecology Laboratory. PETER A. JOHNSTON is a biological science technician with the red-cockaded woodpecker management program of the U.S. Forest Service–Savannah River. CLIFF G. JONES is a hydrologist with the U.S. Forest Service–Savannah River. ROBERT A. KENNAMER is a research coordinator with the University of Georgia’s Savannah River Ecology Laboratory. JOHN C. KILGO is a research wildlife biologist with the U.S. Forest Service Southern Research Station’s Center for Forested Wetlands Research. He is stationed at the Savannah River Site. RANDALL K. KOLKA is a project leader and research soil scientist with the Ecology and Management of Riparian and Aquatic Ecosystems Unit of the U.S. Forest Service North Central Research Station. He was formerly a research soil scientist with the Center for Forested Wetlands Research Unit of the U.S. Forest Service Southern Research Station, where he was stationed at the Savannah River Site. YALE LEIDEN is an educator in Tifton, Georgia. Formerly he was an ecological researcher with the University of Georgia’s Savannah River Ecology Laboratory. SUSAN C. LOEB is project leader with the Threatened and Endangered Species Unit of the U.S. Forest Service Southern Research Station. She is stationed at Clemson University. BARTON C. MARCY, JR., is senior fellow scientist with the Westinghouse Savannah River Company’s Environmental Services Section at the Savannah River Site. JOHN J. MAYER is a fellow scientist with the Westinghouse Savannah River Company’s Environmental Services Section at the Savannah River Site. BOBBY MCGEE is a resource conservationist with the USDA Natural Resources Conservation Service at the Savannah River Site. KENNETH W. MCLEOD is an associate research ecologist with the Savannah River Ecology Laboratory. TONY M. MILLS is education coordinator with the University of Georgia’s Savannah River Ecology Laboratory. WILLIAM F. MOORE is instructor of wildlife technology at Abraham Baldwin Agricultural College. He was formerly a graduate research assistant in the Department of Forest Resources, Clemson University, where he conducted his doctoral research on the Savannah River Site. ERIC A. NELSON is a principal scientist with the Savannah River National Laboratory at the Savannah River Site. SEAN POPPY is education program specialist with the University of Georgia’s Savannah River Ecology Laboratory. TRAVIS J. RYAN is an assistant professor in the Department of Biological Sciences, Butler University, in Indianapolis, Indiana. He was a graduate research fellow at the Savannah River Ecology Laboratory. DAVID E. SCOTT is a research coordinator and photographer at the University of Georgia’s Savannah River Ecology Laboratory. DANIEL J. SHEA is fire planner with the U.S. Forest Service–Savannah River. GARY SICK (retired) is former assistant manager for natural resources at the U.S. Forest Service–Savannah River. BARBARA E. TAYLOR is an associate ecologist at the University of Georgia’s Savannah River Ecology Laboratory and adjunct member of the Faculty of Ecology at the University of Georgia. TRACEY D. TUBERVILLE is a research coordinator and Ph.D. student at the University of Georgia’s Savannah River Ecology Laboratory. DAVID L. WHITE is a plant ecologist with the Threatened and Endangered Species Unit of the U.S. Forest Service Southern Research Station, located in Clemson, South Carolina. LYNN D. WIKE is a principal scientist in applied ecology with the Savannah River National Laboratory at the Savannah River Site. CHRISTOPHER T. WINNE is a graduate research fellow pursuing a Ph.D. at the University of Georgia’s Savannah River Ecology Laboratory.

Index Italicized page numbers refer to figures and tables. Abandoned farmland, 2, 9, 11, 31, 127, 332 Abandoned home sites, 66, 70, 131, 136 Acidity, 28–29, 47, 150, 169, 267–66, 279 Agriculture, 6, 8–12, 18, 31; amphibians/reptiles and, 204, 218–19; bird habitat and, 239, 344; endangered species and, 280, 301, 303, 392; old-field pine and, 107, 127–29 Aiken Plateau, 3, 4–5, 31–34, 132, 137 Ailey soils, 36 Air quality, 28–30, 82–84, 83–84, 309 Alkalinity, 48, 49, 267 American alligator, 21, 85, 223, 285–89, 379 American kestrel, 316 American nailwort, 277, 278, 280 American shad, 338–39 American swallow-tailed kite, 315–16 American woodcock, 341, 342, 343, 344 Amphibians, 85, 203–23, 205–09, 210, 214, 216; as endangered species, 285–89, 286, 318–20, 392 Anadromous species, 192, 196, 282 Annelids, 161, 164, 166 Annosum root rot, 69, 73 Anthropogenic disturbance, 26, 31, 39, 41, 55, 67, 84; amphibians/reptiles and, 209, 213, 218–20; endangered species and, 291–93, 297–98; nongame birds and, 291–93, 297–98. See also Nuclear facilities Aquatic invertebrates, 90, 161–73, 162–63, 165–66, 172–73; as sensitive animals, 320–22 Aquifers, 30, 33, 42, 44–45, 50, 55, 60 Area-sensitive species, 236–37, 236, 317 Artificial cavities, 307–8, 307, 311, 392 Ashes, 87, 90, 92, 142–43, 147–50, 155 Asiatic clam, 174–75 Atlantic sturgeon, 320 Atmospheric stability, 25–26

Atomic Energy Commission (AEC), 2, 10, 12, 60, 127, 330 Avian savanna community, 72 Avian Vacuolar Myelinopathy (AVM), 298, 300–01, 357–58 Bachman’s sparrow, 99, 318 Bald cypress, 89–90, 92, 97, 141–43, 145, 149–50, 155, 329 Bald eagle, 295–301, 296, 299; Avian Vacuolar Myelinopathy (AVM), 298, 300–01, 357–58 Bald Eagle Protection Act (1940), 295 Baldwin’s nut rush, 277, 279 Banding, 357, 359, 366 Bark beetle attacks, 26 Barnwell Group, 33 Bats, 161, 253, 256, 259–60, 260, 313–15 Bayhead community, 152, 153 Beaver, 7, 85, 367–68, 369 Beaver Dam Creek, 43, 46, 47–48, 48–49, 53; endangered species and, 288, 291, 292; fishes in, 192–94; nongame birds and, 231, 291, 292 Beaver ponds, 43, 94, 145, 168, 231, 352 Beech, 137, 139–40, 149, 151 Beech bluff community, 137, 138–39 Benthic habitat, 161, 163–64, 173, 357 Benthic insectivorous species, 188, 192 Biological legacy, 219–20 Birdsville wood stork colony, 290–91, 294 Black bear, 7, 315 Blackwater streams, 30, 47–48, 50, 143, 150, 174, 278–79 Blanton-Lakeland Association, 36 Blanton soils, 36, 268 Bobcat, 85, 366, 370, 373, 379, 384 Bodiford Mill Creek, 52 Bog spicebush, 277, 279–80 Boll weevil, 9, 43 Borax treatments, 69, 73 Borrow pits, 41

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Index

Bottomland hardwood forest, 37, 43, 51, 53, 56, 149–50; commercial harvesting of, 329; ecological restoration and, 87, 90; fishes and, 185; nongame birds and, 232–33, 234, 235–37, 236; nongame mammals and, 259–60; silviculture and, 64, 66 Bottomlands, 4, 24, 37; ecological restoration of, 89–93; vegetation types in, 141–54, 144, 146–47, 152 Boykin’s lobelia, 277, 279 Branchiopods, 170 Brandywine Terrace, 3, 32–34 Brood parasitism, 235 Brook floater, 320 Brother spike mussel, 320–21 Brown-spot disease, 63–64, 78, 79 Buffer capacity, 28–29, 47, 74 Buffer zones, 13, 39, 85, 97, 221 Burma Road population of coneflower, 266–70, 271 Burning. See Fire Butterflies, 173, 175–82, 176, 182 Buttonbush, 125, 142, 155 Buttonbush swamp community, 144, 145 Caddisflies, 167–68 Calcic slope community, 137, 138–39 Calcic soils, 277 Calcium, 28–29, 48, 49, 137, 267 Canby’s bulrush, 277, 279 Canebrakes, 4, 75, 155, 317 Canopy-nesting species, 227, 229–31 Carbon (CO2), 38–39, 48, 49, 53, 92, 154, 393 Carbon sequestration, 400 Carolina bay rim community, 134, 135 Carolina bays, 18, 74, 120–27, 123–24, 126, 135; amphibians/reptiles and, 215–16, 216, 219, 221, 289, 318–19; aquatic invertebrates in, 169–70; butterflies and, 183; ecological restoration of, 88, 93–98, 94–96, 98, 392; endangered species and, 279–80, 286, 289–94, 313, 318–19; fishes in, 201, 201; nongame birds and, 231, 290–94; nongame mammals and, 263, 313; physical environment and, 37–38, 43–44, 53–55, 55, 56, 56; waterfowl and, 350 Carolina birds-in-nest, 277, 279 Carolina larkspur, 276, 278 Castor Creek, 50 Cation exchange capacity (CEC), 29, 31, 36, 38–39, 267–68, 273 Cattle, 6–7, 84 Cavity-nesting species, 70, 73, 229, 230, 301–312, 316, 348, 351, 355 Cavity restrictors, 311 Cedar Creek, 167–68

Cenozoic geologic formations, 33 Cesium-137. See Radiocesium (137Cs) Chapman’s sedge, 276, 278 Chastain soils, 35 Chastain-Tawcaw-Shellbluff Association, 35 Chemical site preparation. See Herbicides Chemical variables, 38, 43, 45, 47–48, 49, 150 Chew Mill Pond wood stork colony, 290 Chironomids, 167, 169–70 Christmas Bird Count, 235, 239, 316–17, 341–42, 342, 343 CISC (Continuous Inventory of Stand Conditions), 110–11, 111, 112 Cladocerans, 169–70, 171, 174 Clay soils, 4, 33–38, 55, 267, 278 Clean Air Act, 28–29, 64 Clean Water Act, 64 Clear-cutting: amphibians/reptiles and, 218, 221; bird habitat and, 235, 237–38, 237–38, 343; ecological restoration and, 87, 99; mammal habitat and, 259, 263; silviculture and, 59, 64, 66, 69–70, 74, 330, 336 Clemson University, 256, 376 Climate, 20–30; atmospheric stability, inversions, and fog, 25–26; evapotranspiration and soil water deficits, 24–25; lightning, wind, and disturbance, 26–v28, 27; precipitation, 21–23, 22–23; temperature and humidity, 23–24, 24 Clinchfield Formation, 33 Coal-fired power plants, 28, 53 Coleopterans, 168 Commercial fishing, 338–39 Commercial timber harvesting, 64, 69–70, 74–75, 328–38; inventories, 330, 331–32, 331; land-use history, 329–31; measurements, 329; minor products, 337–38; revenues, 332–37, 331–34 Common ground dove, 316 Common snipe, 341–42, 342 Competition: ecological restoration and, 87, 89, 92; endangered species and, 267, 272–74, 281; silviculture and, 59, 66–67, 72 Congaree Formation, 33, 327 Conservation, 70, 174–75, 174–75; status of mammals, 254–55 Construction sites, 64, 74, 85, 171, 300 Contamination, 14–16, 18; amphibians/reptiles and, 289; ecological restoration and, 85, 95, 393; endangered species and, 289, 297, 301; fishes and, 198; physical environment and, 45, 47–48, 49, 50–51, 53–54; small game species and, 345; waterfowl and, 355, 359; white-tailed deer and, 388–89 Cooling water systems, 2, 43, 47, 51–54, 51; aquatic invertebrates and, 171–72; endan-

Index gered species and, 285, 288, 291, 297; fishes and, 187, 192, 195, 199, 285, 340; waterfowl and, 356–57 Copepods, 169–70, 174 Corridors, 39, 87, 89, 90, 92, 131, 263 Cove hardwoods community, 138–39, 139–40 Coyote, 364, 368–69, 379, 384 Crackerneck Wildlife Management Area and Ecological Reserve, 17, 74, 158, 168, 305; fishing and, 338; hunting and, 341–42, 344, 344–47, 360–62, 368 Craig’s Pond, 219, 239, 291 Cretaceous deposits, 328 Crouch Branch, 44–45, 50 Crustaceans, 164, 165, 169–70 CSRA (Central Savannah River Area), 3, 5–6, 8–9 Cutover forests, 2, 11, 11, 60, 64, 329, 331 Cypress-knee sedge, 276, 279 Cypress-tupelo swamp habitats, 4, 18, 31, 89, 91, 97, 228, 230–31, 279. See also Bald cypress; Swamp tupelo Dams, 43, 52–54, 64, 198, 200, 286–87, 292, 298 Davis Branch, 52 Decapod crustaceans, 168 Deeply flooded river swamp community, 142–43, 144 Deeply flooded slough community, 143, 144 Deer Management Plan, 385–86 Deltas, 37, 50–52; ecological restoration and, 89–90, 90, 91–92; endangered species and, 288, 291–92, 292; nongame birds and, 231, 291–92, 292 Depression wetlands, 9, 35, 120–27, 201, 201, 231, 279 Dick’s Pond, 169 Dipterans, 168–69 Discharge for streams, 47–48, 48, 56 Disturbance, 26–28, 27, 31, 37, 56; amphibians/reptiles and, 215, 222; endangered species and, 267, 272–73, 278–81; plant communities and, 108–10; silviculture and, 67, 70. See also Anthropogenic disturbance Dothan soils, 36, 40 Drainages, 43–44, 52, 55–56; bottomlands and, 141; Carolina bays and, 94, 94–96, 97, 120; pine savannas and, 119; sensitive plants and, 279; upland hardwood/pinehardwood forests and, 132 Drawdowns, 279, 287, 292–93, 298, 345, 357, 358 Dredging, 43, 52 Drought, 5, 21, 24–25, 30, 76, 109, 120; endangered species and, 267, 272, 292–93;

471

fishes and, 187; nongame birds and, 219, 222, 292–93 Drowned horned rush, 277, 279 Dry Bay, 218 Dry Branch Formation, 33 Dry-mesic exposed slope community, 138–39, 140–41 Dry-mesic pine-evergreen hardwood forest community, 134, 136 Dry pine-oak woodland communities, 133, 134, 135 Durand oak, 277, 279 Dutchman’s pipe, 276, 279 Dwarf bladderwort, 277, 279 Eagle Bay bald eagle nest, 295, 298–300, 299 Eastern coral snake, 320 Eastern cottontail, 341, 344, 346 Eastern spotted skunk, 366, 372 Eastern woodrat, 315 Ecological restoration, 78, 84–102, 86, 88, 391–96; amphibians/reptiles and, 223, 392; aquatic invertebrates and, 171–72; of bottomlands and riparian zones: Pen Branch, 89–93, 391–92; of Carolina bays, 93–98, 392; commercial harvesting and, 328; of hardwoods, 85–89; of savannas, 99–102, 100–101, 129, 184; silviculture and, 70, 72–73; of soils, 37, 39–41 Economic resources. See Harvestable natural resources Edisto Experiment Station (Blackville, S.C.), 25 Electrofishing, 192, 194, 196–97, 200, 339 Elevation, 31–33, 32 Ellenton Bay, 55, 214, 218–20, 376 Elliott’s croton, 276, 279–80 Endangered species, 77, 174, 202, 239, 253, 264–322; American alligator, 285–89; bald eagle, 295–301; red-cockaded woodpecker, 17, 301–312; sensitive animals, 312–22; sensitive plants, 275–82, 276–77, 278; shortnose sturgeon, 282–85, 284; Smooth purple coneflower, 266–74; wood stork, 289–94 Endangered Species Act (1973), 64, 285, 294–95, 312 Endangered Species Preservation Act (1966), 295 Entrainment, 202–03, 284 Eocene deposits, 33–34, 327 Eolian deposits, 34 Ephemeral habitat, 53, 238, 290–91, 294 Erosion, 9, 31, 39, 41, 60, 89, 127 Evapotranspiration (ET), 24–25, 47, 55, 120–21, 132, 291 Exotic species, 84 Extinction, 7–8 Extirpation, 219, 253, 380, 395

472

Index

Farming, 6–9, 31, 43–44, 55, 75, 84. See also Agriculture Featured species, 66, 69 Federal Register, 275 Feldspar, 327–28, 327 Feline panleukopenia, 373 Feral hogs, 374–76 Fertilization, 9, 30–31, 39, 41; endangered species and, 268, 272–73; silviculture and, 59, 69, 73; upland pine forest and, 127 Fire, 4, 6, 10, 64, 75–76, 110, 395; amphibians/reptiles and, 220–22; bald eagle and, 300; bird habitat and, 124, 233; Carolina bays and, 121–22; marshes and, 154–55; pine savannas and, 17, 26, 81, 99–102, 115–16; red-cockaded woodpecker and, 301, 303, 308–09, 309; sensitive plants and, 278, 280–81; smooth purple coneflower and, 267, 270, 271, 272–74; upland pine forest and, 128. See also Prescribed fire management; Wildfires Fire ants, 223, 345 Fisheries, 338–40 Fishes, 184–203, 185–86, 189–90, 193, 199, 201; as endangered species, 282–85; as sensitive animals, 320 Fishing, 17, 197, 338–40, 340 Flooded low flats community, 146–47, 148, 150 Flooding, 26, 37, 44, 47, 56, 89, 108–09, 393; bottomlands and, 147–50; Carolina bays and, 121–23, 125–26; fishes and, 187; nongame birds and, 230–31; sensitive plants and, 279; swamps and, 141–42, 142, 143 Floodplains, 4, 5; aquatic invertebrates and, 167–68; ecological restoration and, 89–90, 92; endangered species and, 278–79, 313; physical environment and, 31, 33, 35, 37, 42–43, 50–52, 56; vegetation types on, 141–54, 144, 146–47, 152 Florida bladderwort, 277, 279 Florida green water snake, 319 Flow rates, 47, 50–51, 51, 52 Flying squirrel control, 305, 311–12, 312 Fog, 25–26 Foraging, 14; endangered species and, 289–91, 293–95, 297, 300, 313; nongame birds and, 231–32, 235–36, 289–91, 293–95, 297, 300; nongame mammals and, 259, 260, 313; wild turkey and, 365 Forested Carolina bay, 122–25, 123 Forest-edge species, 232–33 Forested stream pond community, 144, 145 Forest-interior species, 238–39 Forest management, 18, 57–102; bird habitat, 226–27, 229, 232–34, 237–38, 237–38, 291, 392; commercial harvesting

and, 328–29; ecological restoration, 84–102, 391–96; prescribed fire management, 75–84; silviculture and timber harvesting, 59–75; soils and geology, 30, 33, 39–41. See also Natural resource management; Prescribed fire management Forest-nesting birds, 232, 236 Fourmile Branch, 43, 46, 47–52, 48–49, 51; amphibians/reptiles and, 286; endangered species and, 288, 291, 292; fishes in, 187, 190, 192, 193, 194–95; nongame birds and, 231, 291, 292 Fox squirrel, 70, 341, 344, 347 Francis Marion National Forest (S.C.), 305, 310 Fuel loading, 75, 77–79, 80, 81, 99 Fuquay-Blanton-Dothan Association, 36 Fuquay soils, 36, 40 Furbearers, 341, 346–347, 366–73 Furbearer Scent Station Survey, 366, 373 Furrowing, 60, 62–63, 67 Fusiform rust stem canker, 69 Gannts Mill Creek, 52 Genetics, 282, 289, 305 Geology. See Soils and geology Georgia Department of Natural Resources (GDNR), 339 Georgia Wildlife Resource Division, 202 Gopher frog, 318–19 Gopher tortoise, 21, 99, 319 Gravel, 33–34, 39, 41, 327–28 Gray fox, 366, 370–71, 370 Gray squirrel, 341, 344, 347 Grazing, 6–7, 257, 280 Great Indian plantain, 276, 278 Green-fringe orchid, 274, 279–80 Groundwater, 34, 42, 44–45, 50–51, 53–56, 120, 190 Habitat: for amphibians and reptiles, 213–15, 283; for aquatic invertebrates, 162–63, 165–66, 167–71; for endangered species, 290–91, 290, 295–97, 296; for fishes, 192–203, 193, 199, 201; for nongame birds, 225–38, 228, 230, 234, 236, 240–52, 290–91, 290, 295–97, 296; for nongame mammals, 257–60, 257–58, 260; for wild turkey, 364–65 Habitat management areas (HMA), 305, 305 Hairy milkpea, 275, 276 Hardwood forests, 4, 5; butterflies and, 183; ecological restoration of, 85–89, 88, 99; nongame birds and, 228, 229–30, 233; prescribed fire management and, 76, 81; sensitive plants and, 279; silviculture and, 59, 62, 66–70, 72–74, 331; upland forests of, 131–41; wild turkey and, 364–65

Index Harvestable natural resources, 323–89; commercial forest products, 328–38, 320; fisheries, 338–40; furbearers, 366–73; minerals, 325–28, 327; small game, 341–48, 342, 344; waterfowl, 347–59, 349–50, 351, 354, 358–59; white-tailed deer, 380–89, 389; wild hog, 374–79, 375, 377; wild turkey, 359–66, 361 Harvesting practices, 8, 64, 69–70, 71, 74–75; ecological restoration and, 87, 95, 96, 97, 99 Headwater species, 188 Heavy metals, 48, 50–51, 53–54 Heavy minerals, 328 Henslow’s sparrow, 317–18 Herbaceous Carolina bay, 125–27, 126 Herbicides, 81, 128, 157; ecological restoration and, 87, 90–91; endangered species and, 268, 272–74, 281, 309; nongame birds and, 233; silviculture and, 60, 64, 67–68, 71–73 Herbivory, 92, 106 Heronries, 231 Herpetofauna, 203–23, 285–89 High terrace community, 148–49, 150–51 Hogs, 7, 10, 60, 84, 251, 374–79 Holocene deposits, 34–35 Home range, 365–66 Hooded mergansers, 351, 355 Hoopnetting, 195, 194 Hornsville soils, 35 Huber Formation, 33, 327 Humidity, 23–24, 24 Hunting, 5–6, 17; for deer, 376, 377, 379–84, 383, 388–89; endangered species and, 285–86, 295, 300; for small game, 341–42, 344–46; for waterfowl, 348, 353, 357; for wild hog, 374, 376, 377, 378–79; for wild turkey, 359–62 Hurricanes, 26–27, 27, 121, 222, 305 Hydras, 164, 166 Hydric soils, 37 Hydroperiods, 37, 44, 55–56, 56; amphibians/ reptiles and, 215, 217–18; aquatic invertebrates and, 169–70; ecological restoration and, 97; nongame birds and, 231 Ice glazing, 26–27, 27, 28, 66, 69 Ichthyoplankton, 192, 194, 196–97, 202 Ilmenite, 327, 328 Impoundments, 43, 53–54, 85; aquatic invertebrates in, 168–69, 171–73; endangered species and, 286, 292, 294; fishes in, 197–200, 282 Incised groovebur, 274, 278 Indian Grave Branch, 51, 195, 313 Indian olive, 277, 278, 280 Industrial operations. See Nuclear facilities Insects, 73, 161–64, 162–63, 170

473

International leather trade, 286 Invasive species, 14, 174–75, 223, 345 Inversions, 25–26, 82 Invertebrates. See Aquatic invertebrates Iron concentrations, 36, 45 Isopods, 170–71 Jacobson’s Landing wood stork colony, 290 Joyce Branch, 54 Kaolin, 33, 38, 47, 133, 326–27, 327 Kathwood foraging ponds, 294 Kleptoparasitism, 311 Kudzu, 84 Lacey Act, 285 Lakeland soils, 36 Lakes, 197–200, 286. See also Impoundments Lanceleaf wild indigo, 276, 278, 280 Land management, 107–8, 390–93. See also Forest management; Prescribed fire management Landscape structure: amphibians/reptiles and, 218; nongame birds and, 235–38, 236–38, 239; nongame mammals and, 262–63, 262; silviculture and, 70 Land Use Baseline Report, 16 Land-use history, 2–12, 38, 43–44, 59; amphibians/reptiles and, 218–20; preEuropean settlement, 3–6, 5; settlement to 1865, 6–8; commercial harvesting and, 329–31; years 1865 to 1950, 8–10; years 1951 to 2001, 10–12, 78; prior to 1951, 31, 43–44; current, 12–18; nongame mammals and, 259 Land Use Plan, 66 Large stream swamp community, 143, 144 Late Cretaceous sediments, 44 Least trillium, 277, 278 Lentic habitats, 167, 170 Lightning, 6, 26–28, 75–76, 110, 303 Lime, 31, 41, 64 Little brown bat, 314 Little bur-head, 276, 279–80 Littoral habitat, 161, 163–64, 169, 174, 200, 298 L Lake, 43, 47, 52–54, 196–98, 288, 295, 297, 300–01, 357, 358, 368 Loamy floodplains community, 146–47, 148 Loamy soils, 35–38, 62, 117, 131, 215, 279 Loamy terrace community, 146–47, 149 Loblolly pine, 21, 30; bottomlands and, 148, 151, 153–54; Carolina bays and, 122, 125; commercial harvesting of, 328; marshes and, 155; silviculture and, 61, 62, 67–70, 73–76, 224. See also Pine savannas; Upland pine forest; Upland pinehardwood forest

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Index

Loggerhead shrike, 316–17 Logging, 8–10, 18, 39, 43, 66, 71–72, 174, 301, 303, 330. See also Commercial timber harvesting Longleaf pine, 4, 4, 7, 9–10, 21, 26; bottomlands and, 154; Carolina bays and, 122; commercial harvesting of, 326–27; ecological restoration of, 84–85, 99; prescribed fire management and, 78, 81; sandhill woodlands and, 120; silviculture and, 60–64, 61–63, 66–75, 226. See also Pine savannas; Upland pine forest; Upland pine-hardwood forest Long Range Comprehensive Plan (SRS), 15–16, 396–97 Long-tailed weasel, 366, 371 Lost Lake, 95, 391 Lotic habitats, 167 Lower Three Runs, 18, 43, 46, 48, 48, 52–54; amphibians/reptiles and, 286, 288; beaver and, 368; commercial harvesting and, 330; endangered species and, 288, 299, 321; fishes in, 192, 196–99 Lucy soils, 37 Macrophytes, 50, 169, 195, 286, 293, 298, 357 Magnesium, 28–29, 137, 267 Mammals. See Nongame mammals Marshes, 154–57, 183, 279–80, 286 Marsh rabbit, 341, 347 Mast production, 7, 70, 74, 364–65, 378–80 Mature dry-mesic pine-oak woodland community, 134, 135 McBean Formation, 33 McQueen Branch, 44–45, 50 Meadows. See Upland meadows Mechanical cutting, 68, 87, 307 Mechanical planting, 67–68, 71–72 Mechanical site preparation, 39, 66–67, 71–72, 220, 233 Mercury, 43, 53–54, 198, 289, 297, 301, 355, 359 Mesic habitats, 56, 87, 117, 119, 131, 133, 211, 229 Mesic pine bottom community, 151, 152 Mesic pine-hardwood forest community, 134, 135–36, 259–60 Mesic slope community, 138–39, 140 Mesozoic geologic formations, 33 Meyers Branch, 18, 43–44, 48, 49, 52–53; aquatic invertebrates in, 171; fishes in, 188, 193 Microcrustaceans, 164, 170 Mid-successional mesic pine-hardwoods community, 134, 136 Migratory habits: endangered species and, 282, 295, 297; nongame birds and, 224–25, 235, 238; small game species

and, 341, 343; waterfowl and, 348, 356–57 Mill Creek, 52, 188, 321 Mill Creek elliptio, 321 Minerals, 325–28, 327 Mink, 366, 371–72 Miocene deposits, 34 Mitigation banking program, 89, 97 Mitigation effort, 39, 89, 91 Mobile aviary, 310 Moist clay terrace community, 146–47, 149 Moist mixed forest community, 138–39, 140 Moist slope bottom community, 137, 138–39, 139 Moist stream bottoms, 151, 152 Mollusks, 161, 164, 166, 357 Monazite, 327, 328 Monitoring programs, 14, 18, 397; for air quality, 29–30, 82–84, 84; for butterflies, 173; commercial harvesting and, 328–29; disturbance and, 391–92; for endangered species, 266, 269, 281, 298, 300, 303, 312; for fishes, 297; for nongame birds, 231, 239; for waterfowl, 353; for white-tailed deer, 389; for wild turkey, 361–62, 366 Mosquito control, 43 Mourning dove, 341, 342, 343–44, 344, 345 Museum of Natural History (Univ. of Ga.), 312 Muskrat, 366, 368 Mussels, 320–22 NAAQS (National Ambient Air Quality Standards), 28 National Audubon Society, 294, 341 National Environmental Research Park, 59, 64, 204, 397–99 National Marine Fisheries Service, 282–83, 285 Native Americans, 6–7, 75, 110 Native species, 21, 26, 38, 41, 72, 75, 84–85, 95 Natural disturbance. See Disturbance Natural regeneration, 61, 64, 72, 74, 87 Natural resource management, 16–18; amphibians and reptiles, 204, 221; bald eagle, 296, 298–300, 299; butterflies, 184; redcockaded woodpecker, 303, 304, 305–12, 305, 307–10, 312; sensitive plants, 280–82; smooth purple coneflower, 266, 268, 272–74; white-tailed deer, 385–86; wood stork, 291. See also Forest management; Prescribed fire management Natural Resource Management Plan, 16, 70 The Nature Conservancy, 101, 275, 312 Nearctic migrants, 224–25 Neotropical migrants, 224–25, 238 Nest boxes, 351–54, 351, 354 Nesting: endangered species and, 290, 295, 296, 298–301, 299, 305, 316; nongame

Index birds and, 226–35, 228; waterfowl and, 351–55, 351, 354; wild turkey and, 361–65 New Savannah River Lock and Dam area, 339, 340 Nitrates (NO3), 28–29, 51 Nitrogen, 28, 31, 38, 143, 267, 273 Nitrogen oxides (NOx), 28–29 “No net loss” wetlands policy, 89 Nongame birds, 223–52, 228, 230, 234, 236, 240–52; endangered species and, 289–312; as sensitive animals, 315–16 Nongame mammals, 253–63, 254–55, 257–58, 260–62; as sensitive animals, 313–15 Northern bobwhite, 69–70, 99, 339, 342, 344, 345–46 North-facing slope community, 138–39, 140 Notched rainbow mussel, 322 Nuclear facilities, 2, 12–18; aquatic invertebrates and, 171–72; ecological restoration and, 85, 89, 90, 391–93; endangered species and, 284, 287–89, 291–92, 294, 297; fishes and, 187, 190, 192, 193, 195–96, 198–99, 203, 284, 340; nongame birds and, 231–33, 291–92, 294, 297; physical environment and, 41, 45, 47, 50–51, 51, 52–54; prescribed fire management and, 76, 79; vegetation types and, 157–61; waterfowl and, 356–57; watershed degradation and, 39, 47; whitetailed deer and, 388–89. See also Industrial operations Nutrient cycling, 92, 106–7 Nutrient loading, 52, 198–99 Nutrient status, 31, 38–39, 45, 47, 92, 127–28 Oak ridge community, 133, 134 Oconee azalea, 277, 278, 280 Odonates, 169–70 Old-field habitat, 227, 233–35, 239, 253, 259, 273, 373 Old-field pine, 27, 127, 302, 331; ecological restoration and, 85, 87, 88, 102, 395; silviculture and, 61–63, 61, 63, 72–73 Old-field vegetation, 38, 60, 157–61, 158 Old-home sites, 66, 70, 131, 136 Oligochaete worms, 170 Open-pan evaporation, 24–25, 25 Orangeburg Association, 36 Orangeburg soils, 36 Oxbow lakes, 168 Oxygen (02), 48, 49 Ozone (03), 28–30 Painted bunting, 317 Paleocene deposits, 33 Paleozoic geologic formations, 33

475

Parasitism, 235, 311, 355 PARC (Partners in Amphibian and Reptile Conservation), 204 Par Pond, 43, 47, 52–54, 64; amphibians/reptiles and, 216, 219, 223, 285–89, 286; aquatic invertebrates in, 171; beaver and, 368; endangered species and, 285–89, 286, 291–93, 295, 297–301; fishes in, 196–200, 199; nongame birds and, 232, 291–93, 295, 297–99, 301; small game species and, 344–45; waterfowl and, 356–57, 358, 359 Particulate matter (PM), 28, 82–84, 84 Partners In Flight, 316–17 Patterson Branch, 52 Peat Bay, 291 Pen Branch: amphibians/reptiles and, 213; aquatic invertebrates in, 171, 321; ecological restoration of, 18, 73, 89–93, 90–93, 391–92; endangered species and, 292, 292, 295, 297–300, 299, 301, 313, 321; fishes in, 187–88, 190, 192, 193, 194–95; nongame birds and, 231, 233, 239, 292, 292, 295, 297–300, 299, 301; physical environment of, 43, 46, 47–48, 48–49, 51, 51, 52 Pesticides, 9, 43, 59, 63, 295 pH levels, 28–29, 31, 38–39, 45, 48, 49, 50, 55, 137 Phosphates, 31, 273 Phosphorus, 38–39, 48, 49, 53, 137 Pickney soils, 37 Pine: butterflies and, 181–82; endangered species and, 268, 302–03, 305, 316, 318– 19; nongame birds and, 226–27, 228, 229, 232–33, 235–37, 302–03, 316, 318; nongame mammals and, 261; silviculture and, 59, 63–64, 66–67, 69–70, 73–74. See also Loblolly pine; Longleaf pine; Slash pine Pine forest. See Upland pine forest Pine-hardwood bottom community, 152, 320 Pine-oak ridge community, 133, 134 Pine savannas, 3, 4, 107–08, 115–19, 115, 118; butterflies and, 183–84; endangered species and, 275, 278, 280, 301; upland pine forest and, 128–29 Pine seep community, 152, 154 Pine snake, 319–20 Pine straw, 328, 337–38, 337 Piscivorous fish, 188 Planktonic habitat, 161, 164, 166, 169, 174–75 Plant communities, 106–61; disturbance and, 108–10; land management and, 107–08; resource conditions and, 107; SRS vegetation classifications, 110–13, 111; SRS vegetation types, 113–61, 114

476

Index

Planting, 30, 59, 61, 61, 62, 62, 63, 67–68, 72–73, 77–78; ecological restoration and, 90, 92 Pleistocene coastal terraces, 31–32 Plinthite, 36 Pliocene deposits, 34 Pondberry, 276, 279 Pond cypress, 122, 125 Pond pine, 122, 125, 154 Ponds, 43–44, 47, 52–54; amphibians/reptiles and, 219, 286, 288–89, 318; aquatic invertebrates and, 169–72; endangered species and, 279–80, 286, 288–89, 294, 297, 318; fishes and, 197–200; nongame birds and, 231–32, 294, 297. See also Impoundments Poplar Branch, 54 Post-planting treatments, 63–64, 68–69, 71, 71, 72–73 Precipitation, 21–23, 22–23, 50, 55, 77, 120–21 Predation, 7; amphibians/reptiles and, 215, 316; aquatic invertebrates and, 163, 170; ecological restoration and, 395; endangered species and, 287, 290, 293, 297, 302, 308, 311, 318; fishes and, 188, 191–92; nongame mammals and, 253; plant communities and, 106; small game species and, 345; white-tailed deer and, 384; wild hog and, 379; wild turkey and, 361–62, 363, 364, 368, 373 Pre-European settlement vegetation, 3–6, 5, 75, 86, 99, 112, 226, 391, 394–96 Prescribed fire management, 75–84; air quality impacts, 82–84, 83–84; amphibians/reptiles and, 217; characteristics of at SRS, 78–81, 79–80; commercial harvesting and, 326; ecological restoration and, 85, 87, 90–91, 96, 97, 99, 101, 395; endangered species and, 300, 303, 308–09, 309; nongame birds and, 227, 300, 303, 308– 09, 309; physical environment and, 17, 25, 30, 39; silviculture and, 61, 64, 66–67, 70–71, 73; wild turkey and, 364–65 Prescription planting, 61–63 Priestly-Taylor method, 25 Public values, 59 Pulp markets, 60, 64, 73 Pulpwood harvests, 10, 64, 69, 329 Pumping, 47, 52–54, 89 Quail, 345–46 Quartz, 33, 325, 328 Rabies, 371 Raccoon, 7, 161, 290, 364, 366, 367, 371 Radiation, 15, 18, 82, 388–89

Radiocesium (137Cs), 289, 297, 301, 344–45, 355, 359, 388–89 Radionuclides, 45, 51, 53–54, 393 Radon gas, 82 Rafinesque’s big-eared bat, 314 Railroads, 8, 10, 13, 43, 76, 78, 155, 234, 345 Rainfall, 21–23, 22, 26, 29–30, 55, 77, 121, 290–91, 294 Raptors, 73, 239, 345 Rare species, 183–84, 198, 204, 222, 275, 341, 343, 392. See also Sensitive animals; Sensitive plants Rayed pink fatmucket mussel, 321 Recruitment stands, 307–09 Red-cockaded woodpecker, 17, 26, 301–12; current status, 305; ecological restoration and, 85, 87, 88, 99, 391; management of, 305–12, 305, 307–10, 312, 392, 397; population history on SRS, 303–04, 304; prescribed fire management and, 78, 79, 81; silviculture and, 66, 69–70, 72–74; SRS vegetation classifications and, 112 Red fox, 364, 369–70, 370 Red-sore disease, 199 Reedy Branch, 188 Reforestation, 2, 11–12, 60, 69, 89, 360, 391, 394 Regeneration, 61, 64, 67–68, 72–75, 87, 391 Reintroduction, 266, 281, 319, 360 Rembert-Hornsville Association, 35 Rembert soils, 35 Reptiles, 85, 95, 161, 201–21, 205–09, 210; as endangered species, 318–20, 392; historical trends and future of, 222–23; landscape features for, 211; species distribution of, 211–22, 212–13 Restoration projects. See Ecological restoration Rich streamhead slope community, 137, 138–39 Rights-of-way, 234–35, 259, 268, 269, 270, 272–73, 317–18, 344, 365 Riparian zones, 42, 50–52, 51, 56, 89–93, 150, 183 Risher Pond, 214–15 Riverbank community, 146–47, 147–48 River bottoms, 145–50, 146–47 River levee community, 146–47, 148 River otter, 366, 373 Road 9 population of coneflower, 268, 272 Roadkills, 363, 367, 369, 381, 386–88, 387 Roads, 30, 39, 43, 75, 216, 234–35, 263, 272–73, 279 Robust redhorse, 202 Rose coreopsis, 276, 279 Rotation age, 64, 69–70, 72, 74–75, 305; bird habitat and, 223, 229, 232; small game species and, 347

Index Rotifers, 161, 164, 166, 166, 169, 174 Ruderal forest community, 131, 134, 136 Runoff, 30–31, 39, 41, 47, 50, 53, 55–56 Salkehatchie River, 39, 41 Sand-burrowing mayfly, 322 Sand floodplains community, 146–47, 148 Sandhill lily, 277, 278, 280 Sandhills, 2, 31, 45, 47, 60, 120, 150, 215 Sandhills milkpea, 276, 278 Sandhill woodlands, 116–20, 118, 129 Sandy soils, 31–32, 34–38, 324–26 Santee National Wildlife Refuge (Clarendon County, S.C.), 29 Savannah lilliput, 321 Savannah River, 41–44, 47, 50, 52–54, 56; aquatic invertebrates in, 167–68, 171–73, 320–21; endangered species and, 283, 284, 285, 289–91, 297, 313, 315, 320–21; fishes in, 190, 192, 196, 198–99, 201–203, 283, 284, 285; nongame birds and, 239, 290–91, 297; waterfowl and, 357 Savannah River Ecology Laboratory (SREL), 184, 203, 219, 234, 253, 256, 319, 366, 399 Savannah River National Laboratory, 399 Savannah River swamp, 18, 141–42; beaver and, 368; ecological restoration and, 87, 89; endangered species and, 288, 292–93, 297, 314–16; fishes in, 195; small game species in, 347; waterfowl and, 352; white-tailed deer and, 380 Savanna restoration, 17, 73–74, 76, 85, 88, 99–102, 100–01, 391 Sawtimber harvests, 10, 64, 69, 74, 329 Seasonal habitat shifts, 224–25, 235, 256 Sediment deposition, 31, 33, 43, 51–54, 89 Seeding, 30, 41, 61–62, 62, 63, 67–68, 72–73, 77, 85 Seeps, 152, 154, 278 Sensitive animals, 234, 312–22; amphibians and reptiles, 318–20; birds, 315–16; fishes, 320; invertebrates, 320–22; mammals, 313–15 Sensitive plants, 275–82, 276–77, 278; air quality and, 30; industrial operations and, 17–18; management of, 280–82; silviculture and, 70; status and locations on SRS, 279–80 Set-aside areas, 18, 229 Set-Aside Program (DOE), 17–18, 281 Shallowly flooded swamp community, 143, 144 Shear-and-rake, 66–67, 71 Shellbluff soils, 35 Shelterwood cut, 74 Shortleaf pine, 21, 117, 133, 154 Shortnose sturgeon, 282–85, 284

477

Shrub-nesting birds, 227, 229, 232, 317 Shumard oak, 137, 139, 148 Silverbells, 276, 278 Silviculture, 18, 59–75, 65, 71; ecological restoration and, 85, 92; years 1952 to 1971, 60–64; years 1972 to 1988, 64–70; years 1989 to 2004, 70–75 Site preparation, 59–61, 66–67, 71–72, 71, 78–79, 85, 87; bird habitat and, 230–31; ecological restoration and, 90–91 Skinface Pond, 338 Slash pine, 20–21, 61–62, 62, 64, 66, 69, 73–74, 85, 328–29, 331. See also Upland pine forest Slender arrowhead, 277, 279–80 Slopes, 32, 35–37; pine savannas and, 117, 119; sensitive plants and, 278–79; upland hardwood/pine-hardwood forests and, 131–33, 136–41 Small Furbearer Survey, 366–67, 367, 370, 372–73 Small game, 7, 77, 341–47, 342, 344 Small stream bottom community, 152, 153 Small stream swamp community, 143, 144, 145 Smoke dispersion, 25–26, 78–79, 82, 83, 305 Smooth purple coneflower, 266–74, 269–71, 276 Snag creation, 59, 72–73 Snags, 229, 232–33, 261 Snakes, 99, 204, 212–13, 319–20, 364 Soil Associations, 35–37 Soils and geology, 30–41; characteristics of, 37–39, 40; general physiography and, 31–35; land-use history, 31; restoration and watershed maintenance, 39–41; Soil Associations, 35–37; vegetation types and, 132–33, 150–51, 153–54 Soil water deficits, 24–25 Solid Waste Disposal Facility, 50 South Carolina Department of Natural Resources, 17, 74, 251, 273, 310–11, 315, 338, 360, 366, 379 Southeastern myotis, 313 Southern hognose snake, 319 Southern pine beetle attacks, 73 Southern red oak, 72, 133, 136–37, 140, 148–49, 151, 153 Southern swamp privet, 276, 279 Spatulate seedbox, 277, 279 Spawning, 191–92, 194, 196, 202–203, 282–84, 284, 339 Species abundance: butterflies, 175; fishes, 191–92, 194–95, 198–200, 202; nongame birds, 227, 230, 232–33, 234, 237–39; nongame mammals, 257

478

Index

Species diversity: butterflies, 173; ecological restoration and, 92, 93; fishes, 50, 195; nongame birds, 227, 232–33, 234; nongame mammals, 262, 262; silviculture and, 59, 70 Species richness: aquatic invertebrates, 168; ecological restoration and, 92, 93, 99; fishes, 188, 194–95; nongame birds, 232–33, 234, 236–37, 236–37; nongame mammals, 262, 262 Sport fishing, 339–40, 340 SQEDs (squirrel excluder devices), 311 Squirrels, 7, 70, 305, 311–12, 312, 341, 347 Stand structure, 59, 74–75 Star-nosed mole, 314 Steel Creek, 46, 48, 48–49, 51, 52–53; amphibians/reptiles and, 214–16, 288; endangered species and, 288, 291, 292, 294; fishes in, 187, 190, 192, 195–96, 198; nongame birds and, 231, 233, 291, 292, 294 Stem injection, 60, 64, 67–68, 71, 99 Storm-damaged stands, 64, 69, 73 Storm water runoff, 39, 41, 50 Stream bank swamp community, 144, 145 Stream bottoms, 150–54, 152, 278 Stream channels, 32, 43, 155–56, 168, 288, 393 Stream corridors, 87, 89, 90, 92, 131 Stream order, 188–90, 189–90, 192, 197 Stream pocosins community, 152, 154, 277 Streams, 42–43, 45–53, 74; aquatic invertebrates in, 167–68; chemistry of, 47–48, 49; fishes in, 187–90, 189–90, 192–97; hydrology of, 45–47, 46; major, 48–53; sensitive plants and, 278–79 Streamsides, 154–57 Stream structure, 90, 197 Striped bass, 339 Striped garlic, 276, 278 Striped skunk, 366, 367, 372 Strom Thurmond Reservoir, 44, 292, 395 Suburban birds, 236, 239 Succession: bird habitat and, 226–27, 232–35, 234, 240–52, 294; bottomlands/floodplains and, 50, 56, 148; ecological restoration and, 85, 89, 92, 97; mammal habitat and, 257, 259, 263; silviculture and, 70, 72, 108; soils and, 38; upland hardwood/pine-hardwood forests and, 133–34 Sugarberry, 143, 147–49 Sulfates (SO4), 28–29, 48, 49, 53, 82 Sulfur dioxide (SO2), 28–29 Sunderland Terrace, 3, 32–33, 35 Surface runoff, 30–31, 39, 41, 50–51, 54 Surface water, 53–56 Sustainable natural resource objectives, 59, 70

Swainson’s warbler, 317 Swamp rabbit, 315, 341 Swamps, 4, 8, 10, 18, 24, 42–44; amphibians/reptiles and, 215; endangered species and, 290; silviculture in, 87, 89; vegetation types in, 141–45, 142 Swamp tupelo, 125–26, 143, 145, 153–54, 279 Sweet pitcher plant, 277, 279 Tailwater pools, 196–97 Tawcaw soils, 35 Temperatures, 21, 23–24, 24, 52–53, 89; of impoundments, 197–99; of ponds, 286–89; of streams, 47, 49, 50–51, 51, 52–54, 171–72, 185, 190–91, 195, 291 Tennessee Road population of coneflower, 268, 272 Terrace slope community, 137, 138–39 Tertiary formations, 33, 42, 44 Thermal effluents, 2, 50, 52–54, 56; aquatic invertebrates and, 168, 171; ecological restoration and, 85, 89, 91, 341–92; endangered species and, 284, 287; fishes and, 193, 195, 284; streamsides/marshes and, 155 Thinning: ecological restoration and, 91, 99, 101; endangered species and, 270, 271, 272, 274, 278; nongame birds and, 227, 233; silviculture and, 59, 64, 68–70, 72–74, 332, 336; wild turkey habitat and, 365 Threatened species, 17, 70, 174, 253. See also Endangered species Three-awned meadow-beauty, 277, 279 Tiger salamander, 318 Timber Management Plan (DOE), 67 Tinker Creek, 43, 46, 48, 48, 50, 188, 233, 321 Tobacco Road Sand, 33–34 Tornadoes, 26–27, 27, 71 Translocation, 309–10, 310, 360, 373, 392 Transport properties, 30–31, 39 Trichopterans, 168 Troup-Pickney-Lucy Association, 37 Troup soils, 37, 40, 268 Turbellarian worms, 164, 166 Turpentining, 8–9 University of Georgia, 151, 256, 314 Upland hardwood forest, 87, 108, 131–41, 131, 138–39, 228, 229, 259–60 Upland meadows, 157–61, 279–80 Upland pine forest, 127–31, 128, 130, 259–58, 279 Upland pine-hardwood forest, 131–41, 134, 138–39, 212 Uplands, 31, 34, 36–39, 40

Index Upper Coastal Plain, 2, 8, 31, 47, 150, 167, 204, 235 Upper Cretaceous sedimentary deposits, 42 Upper-terrace streams, 188–89, 191 Upper Three Runs, 10, 18, 33, 43–44, 46, 48, 48–49, 50, 52; amphibians/reptiles and, 213, 288; aquatic invertebrates in, 168, 174, 321–22; beaver and, 368; commercial harvesting and, 330; coyote and, 369; endangered species and, 288, 313, 321–22; fishes in, 190, 192, 193; nongame birds and, 231; small game species and, 347; wild hog and, 376 U.S. Department of Energy (DOE), 2, 12, 16–17, 59, 64, 99, 294, 338, 393–94, 399–400 U.S. Environmental Protection Agency (EPA), 28, 345, 389 U.S. Fish and Wildlife Service, 174, 285, 294–95, 356 U.S. Forest Service, 10–11, 30, 59, 110, 203, 219, 256, 275, 303, 315–16, 319, 338, 376, 399 Vaucluse-Ailey Association, 36 Vaucluse soils, 36, 45, 268 Vegetation classifications, 110–13, 111 Vegetation types, 113–61, 114; bottomlands, 141–54, 144, 146–47, 152; Carolina bays and wetland depressions, 120–27, 123–24, 126 (see also Carolina bays); floodplains, 141–54, 144, 146–47, 152; industrial areas, 157–61; marshes, 154–57; for nongame birds, 224–30, 240–52; for nongame mammals, 257; old fields, 159–63; pine savannas, 115–19, 118; sandhill woodlands, 116–20, 118; streamsides, 154–57; upland hardwood forest, 131–41, 131, 138–39; upland meadows, 157–61; upland pine forest, 127–31, 128, 130; upland pine-hardwood forest, 131–41, 134, 138–39 Virginia opossum, 366–67, 367 Volatile organic compounds (VOC), 29 Wagram soils, 268 Waterfowl, 91, 347–59, 349–50, 354, 358–59 Water quality, 30, 51, 54 Water resources, 41–56, 42 Watersheds, 37, 39–42, 47–53 Water tupelo, 90, 92, 141–43, 145, 149–50

479

West Indies meadow-beauty, 277, 280 Westinghouse Savannah River Company, 203–04, 256 Wetland depressions, 9, 35, 120–27, 201, 201, 231, 279 Wetlands, 17–18; amphibians/reptiles and, 215–21, 286, 288–89; aquatic invertebrates in, 169–70; ecological restoration and, 89–91, 91, 92, 95, 97–98, 392; endangered species and, 286, 288–95; fishes in, 201, 201; mink and, 372; muskrat and, 368; physical environment and, 24, 30–31, 37–38, 41–44, 42, 53, 56; vegetation types in, 150; waterfowl and, 351–53, 355–56 Wetlands Assessment, 64 Wet loamy flats community, 146–47, 148–49 Wet mixed forest community, 152, 153 Wet streamhead community, 152, 154 White-tailed deer, 7, 60, 78, 84–85, 221–22, 253, 380–89, 383, 387 Wicomico Terrace, 3, 32–33, 35 Wildfires, 10, 76–77, 77, 81, 84, 110, 395 Wild hog, 253, 374–79, 375, 377 Wildlife, 13–14; ecological restoration and, 85 (see also names of endangered species); prescribed fire management and, 78; silviculture and, 59, 66, 69–70, 72, 75; upland hardwood/pine-hardwood forests and, 132 Wild turkey, 7, 69–70, 78–79, 84–85, 359–66, 361–63, 379 Willow oak flats community, 146–47, 148–49 Wind, 26–28, 27, 31, 109–10, 132, 222, 300 Winter waterfowl, 356–59, 358–59 Wood ducks, 348–55, 351, 354 Wood stork, 289–94, 290, 292–93 Woody debris, 51, 191, 197, 222, 232–33, 259, 261, 261, 393 Woody vegetation, 52, 60, 63, 66–67, 79, 81, 259 Xeric habitats, 75, 120, 211, 229, 278 Yellow lamp mussel, 321 Yellow lance, 321 Yellow pines, 10, 127 Yellow poplar, 64, 230, 328 Zooplankton, 198

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