Biological Services Program FWS/OBS-81 /37 March 1982 THE ECOLOGY OF BOTTOMLAND HARDWOOD SWAMPS OF THE SOUTHEAST: A Community Profile I 49.89 ~~:137 Fish and Wildlife Service 2 c. U.S. Department of the Interior The Biological Services Program was established within the U.S. Fish and Wildlife Service to supply scientific information and methodologies on key environmental issues that impact fish and wildlife resources and their supporting ecosystems. The mission of the program is as follows: • To strengthen the Fish and Wildlife Service in its role as a primary source of information on national fish and wild­ life resources, particularly in respect to environmental impact assessment. • To gather, analyze, and present information that will aid decisionmakers in the identification and resolution of problems associated with major changes in land and water use. • To provide better ecological information and evaluation for Department of the Interior development programs, such as those relating to energy development. Information developed by the Biological Services Program is intended for use in the planning and decisionmaking process to prevent or minimize the impact of development on fish and wildlife. Research activities and technical assistance services are based on an analysis of the issues, a determination of the decisionmakers involved and their information needs, and an evaluation of the state of the art to identify information gaps and to determine priorities. This is a strategy that will ensure that the products produced and disseminated are timely and useful. Projects have been initiated in the following areas: coal extraction and conversion; power plants; geothermal, mineral and oil shale develop­ ment; water resource analysis, including stream alterations and western water allocation; coastal ecosystems and Outer Continental Shelf develop­ ment; and systems inventory, including National Wetland Inventory, habitat classification and analysis, and information transfer. The Biological Services Program consists of the Office of Biological Services in Washington, D.C., which is responsible for overall planning and management; National Teams, which provide the Program's central scientific and technical expertise and arrange for contracting biological services studies with states, universities, consulting firms, and others; Regional Staffs, who provide a link to problems at the operating level;and staffs at certain Fish and Wildlife Service research facilities, who conduct in-house research studies. Cover design by Groham Golden FWS/OBS-81/37 March 1982 THE ECOLOGY OF BOTTOMLAND HARDWOOD SWAMPS OF THE SOUTHEAST: A COMMUNITY PROFILE by Charles H. Wharton Institute of Ecology University of Georgia Athens, Georgia 30602 and Wiley M. Kitchens Edward C. Pendleton U.S. Fish and Wildlife Service National Coastal Ecosystems Team 1010 Gause Boulevard Slidell, Louisiana 70458 Timothy W. Sipe Department of Biology Wabash College Crawfordsville, Indiana 47933 Performed for National Coastal Ecosystems Team Biological Services Program Fish and Wildlife Service U.S. Department of the Interior Washington, D.C. 20240 {esf\ArCh Library DelpBa~tme~t of the Interiot :.,Jo~· 6 ona 1olog1cal Survey ?8g~ern Science Center r f. a.iundome Boulevard ua ayette, Louisiana 70506-315' DISCLAIMER The findings in this report are not to be construed as an official U.S. Fish and Wildlife Service position unless so designated by other authorized documents. This report should be cited as follows: Wharton, C.H., W.M. Kitchens, E.C. Pendleton, and T.W. Sipe. 1982. The ecology of bottomland hardwood swamps of the Southeast: a community profile. U.S. Fish and Wildlife Service, Biological Services Program, Washington, D.C. FWS/OBS-81/37. 133 pp. PREFACE This report is one in a series of The information in this profile will corr.rnunity profiles whose objective is to be useful to environmental ~anagers and synthesize extant literature for specific planners, wetland ecologists, students, wetland habitats into definitive, yet and interested laymen concerned with the handy ecological references. To the fate and the ecological nature and value extent possible, the geographic scope of of these ecosystems. The format, style, this profile is focused on bottomland and level of presentation should make this hardwood swamps occupying the riverine report adaptable to a variety of uses, floodplains of the Southeast whose drain­ ranging fror.-: preparation of environmental age originates in the Appalachian Moun­ assessment reports to supplementary or tains/Piedmont or Coastal Plain (see study topical reading material for college wet­ area Figure 1). References are occasion­ land ecology courses. The descriptive ally made to studies outside this area, materials detailing the floristics of primarily for comparative purposes or to these swamps have been cross-referenced to .. highlight important points. The sections specific site locations and give the detailing the plant associations and soils report the utility of a field guide hand­ in the study area are derived from field book for the interested reader. i nves ti gati ons conducted specifically for this project. The senior author wrote the original manuscript and accepts the responsibility In order to explain the complexities for all statements, theories, and figures of the ecological relationships that are not credited otherwise. The co-authors operating in these bottomland hardwood extensively revised, reorganized the for­ ecosystems, this report details not only mat, and contributed parts of the manu­ the biology of floodplains but also the script, especially Chapters 3 and 4. geomorphological and hydrological compo­ nents and processes that are operating on Any questions or comments about or various scales. These factors, in concert requests for this publication should be with the biota, dictate both the ecologi­ directed to: cal structure and function of the bottom­ land hardwood ecosystems. We have utilized Information Transfer Specialist the ecol ogi cal zone concept developed by National Coastal Ecosystems Team the National Wetlands Technical Council to U.S. Fish and Wildlife Service organize and explain the structural com­ NASA/Slidell Computer Complex plexity of the flora and fauna. 1010 Gause Boulevard Slidell, LA 70458 ii i ~ I 1 CONTENTS PREFACE . iii FIGURES ... vi TABLES ... X ACKNOWLEDGMENTS Xii INTRODUCTION . 1 CHAPTER 1. MODERN AND PALEO-GEOMORPHOLOGY OF FLOODPLAINS 4 Introduction .......... 4 Origin and Dynamics of Floodplains 4 Features of Modern Floodplains 8 Paleo-Geomorphology 12 CHAPTER 2. HYDROLOGY. 16 Alluvial Rivers 16 Blackwater Rivers 17 Spring-fed Streams .. 17 Bog and Bog-fed Streams . 20 Flooding Duration and Frequency 20 CHAPTER 3. PHYSICOCHEMICAL ENVIRONMENT 21 Chemical Characteristics of Rivers .•••.... 21 Physicochemical Characteristics of Floodplain Soils 23 CHAPTER 4. FLORA OF BOTTOMLAND HARDWOOD COMMUNITIES 31 Introduction .......•....•.. 31 The Anaerobic Gradient ..•..•.....•. 31 Plant Responses to Anoxia-related Stresses ... 32 Plant Community Patterns in the Floodplain .........•.. 37 Disturbance and Succession in Bottomland Hardwood Plant Communities 76 Primary Productivity of Floodplain Forests 80 t CHAPTER 5. FAUNA OF BOTTOMLAND HARDWOOD ZONES 84 ~ Fauna of Zones II and III ..... 84 l Fauna of Zone IV ..•....... 90 Fauna of Zone V . • . 91 The Use of Bottomland Hardwood Zones by Fish . 92 Trophic Relationships ...... 95 ' Summary of Faunal Utilization .•..... 100 CHAPTER 6. COUPLING WITH OTHER SYSTEMS ...•....... 103 Natural Couplings with Headwater Tributaries and Estuaries 103 Coupling with River Deltas ........••••.. 104 Chemical Coupling with the Uplands ......... 104 Modifications of River and Floodplain ....... 105 Chemical Coupling with the Water Table and Atmosphere 107 Coupling Via Faunal Movements ..... 107 Su1T111ary . 107 REFERENCES ................ 109 APPENDIX: SOILS OF SOUTHEASTERN FLOODPLAINS 127 V FIGURES Number 1 Major river floodplains and their associated bottomland hardwood communities within the Carolinas, Georgia, and Florida ..... 2 2 Landsat image of the floodplain of the Oconee River, GA, showing how large alluvial rivers that drain the Piedmont form extensive tracts of bottomland hardwoods below the fall line 5 3 Point bar and meander formation in floodplains 6 4 Diagram of an idealized alluvial floodplain with various depositional environments ............... 9 5 A meander bend and cross section showing levee and ridge and swale topography so common on modern and relict surfaces 10 6 Aerial photomosaic of the lower Roanoke River indicating flood­ plain features characteristic of rivers approaching the coast. 11 7 Sea level changes between the Sangamon interglacial period and modern times . 13 8 Development of present-day relict and modern floodplain surfaces 14 9 Hydrographs of four types of southeastern floodplain rivers and streams . 17 10 Hydrographs of an alluvial river showing the possible effects of an increase in floodplain width on water levels, between upstream and downstream . 17 11 Two photos showing drydown and inundation of the floodplain in the Congaree Swamp Nati ona 1 Monument . 18 12 Relation of flood discharge of Oconee River (GA) to distance downstream . 19 13 Diagram of the water budget for Creeping Swamp (NC), July 1974- June 1975 ................... 19 14 Indication of where Tertiary limestones lie at or near the surface, often giving rise to spring-fed rivers and contributing heavily to the Suwannee-Santa Fe system . 19 vi FIGURES