National Wetlands Inventory MARCH 1984 Wetlands of the United States: Current Status and Recent Trends U.S. Department of the Interior Fish and Wildlife Service Photos on Cover By : Ackerknecht, Childers, Tiner, USFWS WETLANDS OF THE UNITED STATES : CURRENT STATUS AND RECENT TRENDS by Ralph W. Tiner, Jr. U .S. Fish and Wildlife Service Habitat Resources One Gateway Center Newton Corner, Massachusetts 02158 MARCH 1984 For sale by the Superintendent of Documents, U.S. Government Printing Office, Washington, D.C. 20402 Table of Contents Page Acknowledgements . i Table of Contents . ii List of Figures . iv List of Tables . vi Executive Summary . vii Introduction . 1 What Is A Wetland? . 2 The Fish and Wildlife Service's Definition . 2 References . 3 Major Wetland Types of the United States . 5 Estuarine Wetlands . 6 Estuarine Emergent Wetlands . 6 Estuarine Intertidal Flats . 6 Estuarine Scrub-Shrub Wetlands . 8 Palustrine Wetlands . 9 Palustrine Emergent Wetlands. 9 Palustrine Scrub-Shrub Wetlands . 11 Palustrine Forested Wetlands . 11 References . 11 Why Are Wetlands Important? . 13 Fish and Wildlife Values. 13 Fish and Shellfish Habitat . 13 Waterfowl and Other Bird Habitat . .. 14 Furbearer and Other Wildlife Habitat . 16 Environmental Quality Values . 18 Water Quality Improvement . 18 Aquatic Productivity . 19 Socio-Economic Values. 19 Flood and Storm Damage Protection . 21 Erosion Control . 23 Water Supply and Groundwater Recharge . 23 Harvest of Natural Products . 23 Recreation and Aesthetics . 24 Summary . .. 25 References . 26 Current Status and Trends of U.S. Wetlands. 28 Current Status . 28 Forces Changing Wetlands . 30 Recent National Wetland Trends . 30 Recent Gains . 31 Recent Losses . 31 Regional Historical Perspective . 32 Current Regional Development Pressures. 33 National Problem Areas . 35 Estuarine Wetlands of the U.S . Coastal Zone . 36 Louisiana's Coastal Marshes . 37 Chesapeake Bay's Submerged Aquatic Beds . 39 South Florida's Palustrine Wetlands . 40 Prairie Pothole Region's Emergent Wetlands. 42 Wetlands of Nebraska's Sandhills and Rainwater Basin . 46 Forested Wetlands of the Lower Mississippi Alluvial Plain . 48 North Carolina's Pocosins . 49 Western Riparian Wetlands . 50 Urban Wetlands . 51 References . 52 The Future of America's Wetlands. 54 Management Recommendations . 56 References . 57 Appendix A. Glossary of Common and Scientific Names of Wetland Plants . 58 List of Figures No. Page 1 Schematic diagram showing wetlands, deepwater habitats, and uplands on landscape . 2 2 The Fish and Wildlife Service's official wetland classification report . 3 3 Classification hierarchy of wetlands and deepwater habitats, showing systems, subsystems, and classes . 4 4 Diagram showing major wetland and deepwater habitat systems . 5 5 Examples of estuarine emergent wetlands . 7 6 Cross-section of a Northeastern salt marsh . 8 7 Examples of estuarine intertidal flats . 8 8 Mangrove-dominated estuarine scrub-shrub wetlands of Florida . 9 9 Examples of palustrine emergent wetlands . 10 10 Generalized vegetation zones of a pothole wetland in relationship to water regime . 10 11 Examples of palustrine scrub-shrub wetlands . 11 12 Examples of palustrine forested wetlands . 12 13 Wetland habitat utilization by several families of birds . 14 14 Migratory birds using wetlands . 15 15 Waterfowl habitat areas of major national concern . 16 16 Wetlands are important to many other wildlife species . 17 17 Aerial view of Tinicum Marsh near Philadelphia, Pennsylvania . 19 18 Relative productivity of wetland ecosystems in relation to others . 20 19 Simplified food pathways from estuarine wetland vegetation to commercial and recreational fishes . 20 20 Wetland value in reducing flood crests and flow rates after rainstorms . 21 21 Wetland drainage and filling increase the potential for damaging floods . 22 22 Estuarine-dependent fish, like salmon, provide the majority of the commercial fisheries in the United States . 24 23 Wetlands provide opportunities for recreational fishing . 25 24 Many Americans enjoy watching birds in and around wetlands . 25 25 Relative abundance of wetlands in the U .S. (1984) . 28 26 Extent of wetlands in the conterminous U.S . in the mid-1970's . 29 27 Original and remaining acreages.