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 76 T5P \t\ Photos on Cover By: Ackerknecht, Childers, Tiner, USFWS /o^^ WETLANDS OF THE UNITED STATES; CURRENT STATUS AND RECENT TRENDS by ir ID" Si ! CD ; r^ ■ r- ' tr ■ □ i □ E □ • <-^ ± a s m I □ = a Ralph W. Tiner, Jr. U.S. Fish and Wildlife Service Habitat Resources One Gateway Center Newton Comer, Massachusetts 02158 MARCH 1984 0 I P(ir sale by the Superintendent of Docimients. U.S. Government Printing Office. Wasliington. D.C. 20402 Acknowledgements Many people have contributed to this report. The entire Service Directorate has reviewed the draft manuscript. Particular thanks are extended to the following individuals for their assistance in providing information and comments: David Almand (AP-WO). Ralph An- drews (HR-R5), Richard Bishop (Iowa Conservation Commission), Joe Carroll (HR-R4), Tony Davis (HR-R5), Clifford Day (HR-R5), Richard Eichhom (RE-WO), Chuck Elliott (HR-R6). Ron Erickson (HR-R3). David Fruge (HR-R4). Warren Hagenbuck (HR-R2). Jon Hall (HR-R7), Ben Harrison (HR-Rl), John Hefner (HR-R4), Ken Huntington (HR- R6), William Krohn (DBS-WO), William Mangun (AP-WO). Phil Morgan (FR-R4), Chuck Mullins (HR-R2), Bob Noffsinger (HR-R4), John Organ (WR-R5), Dennis Peters (HR-Rl), Richard Pospahala (MBM-L), Mark Schaffer (MBM-WO), Robert Smith (MBM-WO), Ronald Reynolds (MBM-L), Edwin Verburg (AP-WO), Larry Vinzant (HR- R4), Rolf Wallenstrom (DAHR) and Bill Zinni (HR-R5). Art work was prepared by Sonya Harris (NWI-WO). Manuscript typing and proofreading were done by Lois Cohen, Mar- guerite Donnelly. Alicia Marotta, Lynne Ricci (HR-R5), Suzanne Melancon (HR-WO), and Connie Walker (HR-WO). Special credit is due to Bill Wilen. National Coordinator, Wetlands Inventory, for his advice, criticism, and support during the entire scope of this report's preparation. 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 Falustrine 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 ni 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 1 1 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 of wetlands in the conterminous US 29 28 Net losses and gains in wetlands of the conterminous U.S. between the mid- 50's and mid-70's 31 IV 29 Causes of recent wetland losses (mid-1950's to mid-1970's) in the conterminous U.S.; losses to agriculture are highlighted 32 30 Historical losses of wetlands in Iowa and California 33 31 Rates of coastal wetland loss in the conterminous U.S 36 32 Filling of estuarine wetlands for residential housing in Long Island, New York, and other coastal areas was particularly heavy in the 1950's and 1960"s 37 i3 The status of wetland filling and diking in San Francisco Bay prior to the mid- I960's 36 34 Louisiana's coastal marshes are being permanently flooded by Gulf of Mexico waters at an accelerating rate 38 35 Chesapeake Bay and its major tributaries 39 36 Chesapeake Bay is one of the more important wintering areas for canvasbacks in North America 39 37 Channelization of the Kissimmee River directly destroyed many wetlands and facilitated drainage of more than 100,000 acres of wetlands 40 38 Present extent of wetlands in the Florida Everglades; former wetlands are also shown 41 39 Prairie pothole wetlands are the Nation's most valuable waterfowl production areas 42 40 Original extent and distribution of Minnesota's wetlands 44 41 Present extent and distribution of Minnesota's wetlands 45 42 Prairie pothole wetlands continue to be drained for agriculture 46 43 Sandhill cranes on a Platte River roost at sunrise 47 44 Actual and projected losses in bottomland forested wetlands of the Lower Mississippi Alluvial Plain 48 45 Bottomland wetlands are being channelized, clearcut and converted to agricultural uses in many areas of the Southeast 49 46 Most of the Nation's pocosin wetlands occur along the coastal plain of North Carolina 49 47 Comparison of the extent of natural or only slightly modified pocosins in North Carolina, (a) early I950's and (b) 1980 50 48 Riparian wetlands along rivers and lakes are important to many forms of wildlife in the West 51 49 Establishing waterfowl production areas is one way that the Service protects important waterfowl breeding habitat 55 50 Current status of state wetland protection efforts 56 List of Tables No. Page 1 List of major wetland values 13 2 Major causes of wetland loss and degradation 30 3 Examples of wetland losses in various states 34 4 Examples of recent wetland loss rates 35 VI Executive Summary This report identifies the current status of U.S. wetlands and major areas where wetlands are in greatest jeopardy from the national standpoint. It also presents e.xisting regional and national information on wetland trends. The report is divided into six chapters: (1) Introduction. (2) What Is a Wetland?, (3) Major Wetland Types of the United States, (4) Why Are Wetlands Important?. (5) Current Status and Trends of U.S. Wetlands, and (6) The Future of America's Wetlands. Wetlands include the variety of marshes, swamps and bogs that occur throughout the country. They range from red maple swamps and black spruce bogs in the northern states to salt marshes along the coasts to bottomland hardwood forests in the southern statfes to prairie potholes in the Midwest to playa lakes and riparian wetlands in the western states to the wet tundra of Alaska. The Fish and Wildlife Service has developed a scientifically sound wetland definition and classification system to inventory the Nation's wetlands. The bulk of America's wetlands fall into two ecological systems: (I) Estuarine System and (2) Palustrine System. The Estuarine System includes salt and brackish tidal marshes, mangrove swamps and intertidal fiats, while the Palustrine System encompasses the vast majority of the country's inland marshes, bogs, and swamps. Wetlands produce many benefits for society besides providing homes for many fish and wildlife species. Some of the more important public values of wetlands include flood control, v/ater quality maintenance, erosion control, timber and other natural products for man's use, and recreation. Approximately 215 million acres of wetlands existed in the conterminous U.S (i.e., lower 48 states) at the time of the Nation's settlement. In the mid-1970's, only 99 million acres remained, leaving just 46% of the original wetland acreage. The U.S. wetland resource for the lower 48 states encompassed 93.7 million acres of palustrine wetlands and 5.2 million acres of estuarine wetlands. Wetlands now cover about 5% of the land surface of the lower 48 states. The total wetland acreage for the lower 48 states amounts to an area roughly the size of California. Between the mid-I950's and the mid-I970's, about 1 1 million acres of wetland were lost, while 2 million acres of new wetland were created. Thus, in that 20-year interval, a net loss of 9 million acres of wetland occurred. This acreage equates to an area about twice the size of New Jersey. Annual wetland losses averaged 458.000 acres; 440,000 acres of palustrine losses and 18,000 acres of estuarine wetland losses. This annual loss equals an area about half the size of Rhode Island. Agricultural development was responsible for 87% of recent national wetland losses. Urban development and other development caused only 8% and 5% of the losses, respectively. The most extensive wetland losses occurred in Louisiana, Mississippi, Arkansas, North Carolina, North Dakota, South Dakota. Nebraska. Florida and Texas. Greatest losses of forested wetlands took place in the lower Mississippi Valley with the conversion of bottomland hardwood forests to farmland. Shrub wetlands were hardest hit in North Carolina where pocosin wetlands are being converted to cropland or pine plantations or mined for peat. Inland marsh drainage for agriculture was most significant in the Prairie Pothole Region of the Dakotas and Minnesota. Nebraska's Sandhills and Rainwater Basin and Florida's Everglades. Between the mid-1950's and mid-1970's, estuarine wetland losses were heaviest in the Gulf states, i.e., Louisiana, Florida, and Texas. Most of Louisiana's coastal marsh losses were attributed to submergence by coastal waters. In other areas, urban development was the major direct man- induced cause of coastal wetland loss. Dredge and fill residential development in coastal areas was most significant in Florida, Texas, New Jersey. New York, and California. The future of the Nation's wetlands depends on the actions of public agencies, private industry, and private groups and individuals. Recent population and agricultural trends point to increased pressure for converting wetlands to other uses, especially cropland. Increased wetland protection efforts by all levels of government and by private parties are needed to halt or slow wetland losses and to enhance the quality of the remaining wetlands. Major protection options are outlined in the report. Vll INTRODUCTION 1 The Fish and Wildlife Service has always recognized the importance of wetlands to waterfowl, other migratory birds and wildlife. Its responsibility for protecting these habitats comes largely from international treaties between the United States and other countries concerning migra- tory birds and from the Fish and Wildlife Coordination Act. Con.sequently. the Service has been active in pro- tecting these resources through various programs. The National Wildlife Refuge System was established to pre- serve and enhance migratory bird habitat in strategic loca- tions across the country. More than 12 million ducks breed annually in U.S. wetlands and millions more over- winter here. Waterfowl banded in North Dakota have been recovered in 46 states, 10 Canadian provinces and territories, and 23 other countries. Since the 1950's, the Service has been particularly concerned about wetland losses and their impact on fish and wildlife populations. In 1954, the Service conducted the first nationwide wetlands inventory which focused on wetlands important to waterfowl. This survey was per- formed to provide information for considering fish and wildlife impacts in land-use decisions. The results of this inventory were published in a well-known Service report entitled "Wetlands of the United States," commonly re- ferred to as Circular 39 (Shaw and Fredine 1956). Since that survey, wetlands have continued to change due to both natural processes and human activities. The conversion of wetlands for agriculture, residential and industrial developments and other uses has accelerated. During the 1960"s, the general public in many states became more aware of wetland values and concerned about wetland losses. They began to realize that wetlands provided significant public benefits besides fish and wild- life habitat, especially flood protection and water quality maintenance. Prior to this time, wetlands were regarded by most people as wastelands, whose best use could only be attained through alteration, e.g., draining for agricul- ture, dredging and filling for industrial and housing de- velopments and filling with sanitary landfill. Scientific studies demonstrating wetland values, especially for coastal marshes, were instrumental in increasing public awareness of wetland benefits and stimulating concern for wetland protection. Consequently, several states passed laws to protect coastal wetlands, including Massa- chusetts (1963), Rhode Island (1965), Connecticut (1969), New Jersey (1970), Maryland (1970), Georgia (1970) and New York (1972). Several of these states subsequently adopted inland wetland protection legisla- tion; Massachusetts, Rhode Island, Connecticut and New York. Most states with coastal wetlands followed the lead of these northeastern states and passed laws to protect these wetlands. During the early 1970"s, the Federal gov- ernment also assumed greater responsibility for wetlands through Section 404 of the Federal Water Pollution Con- trol Act (later amended as the Clean Water Act of 1977). Federal permits are now required for many types of con- struction in many wetlands, yet most agricultural and silvicultural activities are exempt. With increased public interest in wetlands and strengthened government regulation, the Service consid- ered how it could contribute to this resource management effort, since it has prime Federal responsibility for protec- tion and management of the Nation's fish and wildlife and their habitat. The Service recognized the need for sound ecological information to make decisions regarding poli- cy, planning, and management of the country's wetland resources. In 1974, the National Wetlands Inventory Pro- ject (NWI) was established. The NWI aims to generate scientific infomiation on the characteristics and extent of the Nation's wetlands. The purpose of this information is to foster wise use of U.S. wetlands and to provide data for making quick and accurate resource decisions. Two very different kinds of information are needed: ( 1 ) detailed maps and (2) status and trends reports. First, detailed wetland maps for geographic areas of critical concern are needed for impact assessment of site-specific projects. These maps serve a purpose similar to the Soil Conservation Service's soil survey maps, the National Oceanic and Atmospheric Administration's coastal geo- detic survey maps, and the Geological Survey's topo- graphic maps. Detailed wetland maps are used by local, state and Federal agencies as well as by private industry and organizations for many purposes, including compre- hensive resource management plans, environmental im- pact assessments, permit reviews, facility and corridor siting, oil spill contingency plans, natural resource inven- tories, wildlife surveys and other uses. Wetland maps have been produced for Hawaii, 30% of the lower 48 states and 6% of Alaska. Present plans are to complete wetland mapping for at least 55% of the conterminous U.S. and 16% of Alaska by 1988. Secondly, national estimates of the current status and trends (i.e., losses and gains) of wetlands are needed in order to provide im- proved information for reviewing the effectiveness of existing Federal programs and policies, for identifying national or regional problems and for general public awareness. A technical report of these trends has been recently published (Frayer, et al. 1983). The purpose of this report is to inform government agencies, private industry and organizations, the scienti- fic community, and the general public about the current status and historical trends of U.S. wetlands. It also iden- tifies key regions where wetlands remain in greatest jeop- ardy and presents management recommendations for improving wetland protection. The Service's study of recent wetland gains and losses provides the national perspective for this report and targets current problem areas. Other studies address regional and historical wet- land changes. These sources provide the necessary docu- mentation for presenting a complete picture of trends in America's wetlands and the basis for identifying future problems. While focusing on wetland trends, the report begins with discussions of the concept of wetland, major types of U. S. wetlands and wetland values. This back- ground is essential for understanding the significance of what is happening to the Nation's wetlands. Appendix A provides a glossary of common and scientific names of plants referred to in this report. WHAT IS A WETLAND? All of us are familiar with marshes and swamps either through our own observations or readings. The term "wetland." however, may be relatively new to many peo- ple. Essentially, wetlands include the wide variety of marshes, swamps and bogs that occur throughout the country. They range from red maple swamps and black spruce bogs in the northern states to salt marshes along the coasts to bottomland hardwood forests in the southern states to prairie potholes in the Midwest to playa lakes and cottonwood-willow riparian wetlands in the western states to the wet tundra of Alaska. Wetlands usually lie in depressions or along rivers, lakes, and coastal waters where they are subject to period- ic flooding. Some, however, occur on slopes where they are associated with groundwater seeps. Conceptually, wetlands lie between well-drained upland and permanent- ly flooded deep waters of lakes, rivers and coastal embay- ments (Figure 1). Recognizing this, one must determine where along this natural wetness continuum wetland ends and upland begins. Many wetlands form in distinct de- pressions or basins that can be readily observed. Howev- er, the wetland-upland boundary is not always that easy to identify. Wetlands may occur in almost imperceptibly shallow depressions and cover vast acreages. In the Prai- rie Pothole Region, wetland boundaries change over time due to varying rainfall patterns. In these situations, only a skilled wetland ecologist or other specialist can identify the wetland boundary with precision. Wetlands were historically defined by scientists work- ing in specialized fields, such as botany or hydrology. A botanical definition would focus on the plants adapted to flooding and/or saturated soil conditions, while a hy- drologist's definition would emphasize the position of the water table relative to the ground surface over time. A more complete definition of wetland involves a multi- disciplinary approach. The Service has taken this ap- proach in developing its wetland definition and classifica- tion system. The Fish and Wildhfe Service's Definition of Wetlands Prior to conducting an inventory of the Nation's wet- lands, the Service had to first define what a wetland is and where along the soil moisture gradient to draw the line between wetland and upland. To do this, the Service enlisted the help of the Nation's leading wetland scien- tists and selected four of them to develop a new wetlands classification system (Figure 2). The authors represented several disciplines including waterfowl biology, hydrol- ogy, wetland ecology and marine biology. UPLAND UPLAND ...^fiifS-. Water table V Depressional Wetland — V — V — V — Overflow Deepwater Overflow Wetland Habitat Wetland Water table Stream Groundwater Discharge Seepage Wetland on Slope Fig. 1. Schematic diagram showing wetlands, deepwater habitats, and uplands on landscape. Note differences in wetlands due to hydrology and topographic location. Biological Services Prograii Classification of Wetlands and Deepwater Habitats of the United States Fish and Wildlife Service U.S. Department of ttie Interior Fig. 2. The Fish and Wildhfe Service's official wetland classification report . In developing an ecologically sound definition of wet- land, it was acknowledged that "there is no single, cor- rect, indisputable, ecologically sound definition for wetlands, primarily because of the diversity of wetlands and because the demarcation between dry and wet envi- ronments lies along a continuum" (Cowardin. et al. 1979). Previous wetland definitions grew out of different needs for defining wetlands among various disciplines, e.g., wetland regulators, waterfowl managers, hydrolo- gists, flood control engineers and water quality experts. The Service needed a definition that would allow accurate identification and delineation of the Nation's wetlands for resource management purposes. The Service specifically defines wetlands as follows: "Wetlands are lands transitional between terrestrial and aquatic systems where the water table is usually at or near the surface or the land is covered by shallow water. For purposes of this classification wetlands must have one or more of the following three attributes: 1) at least periodically, the land supports predominantly hydrophytes; 2) the sub- strate is predominantly undrained hydric soil; and 3) the substrate is nonsoil and is saturated with water or covered by shallow water at some time during the growing season of each year." (Cowardin, et al. 1979). In defining wetland from an ecological standpoint, the Service emphasizes three key attributes of wetland: I) hydrology — the degree of flooding or soil saturation, 2) wetland vegetation (hydrophytes), and 3) hydric soils. All areas considered wetland must have enough water at some time during the growing season to stress plants and animals not adapted for life in water or saturated soils. Most wetlands also have hydrophytes and hydric soils present. The Service is preparing a list of hydrophytes and the Soil Conservation Service is developing a list of hydric soils to help further define wetland. It is interesting to note that a similar approach to wet- land definition was recently used in a Federal court case in Louisiana to make a legal wetland determination (Scott 1979). In his ruling, the judge decided that the area in dispute constituted wetland according to Section 404 of the Clean Water Act because: 1) records showed that virtually all of the tract was flooded every other year (hydrology criterion), 2) the soil types were classified as wetland soils, with two exceptions where information was inadequate (hydric soil criterion), and 3) vegetation capable of surviving and reproducing in wetlands pre- dominated the site (hydrophyte criterion). Thus, the ratio- nale for using these three key attributes now has legal precedent. Particular attention should be paid to the reference to flooding or soil saturation during the growing season in the Service's definition. When soils are covered by water or saturated to the surface, free oxygen is usually not available to plant roots. Most plant roots must have ac- cess to free oxygen for respiration and growth; flooding during the growing season presents problems for the growth and survival of most plants. In a wetland situa- tion, plants must be adapted to cope with these stressful conditions. If flooding occurs only in winter when the plants are donnant, there is little or no effect on them. It is important to note that the Service does not include permanently flooded deepwater areas as wetland. In- stead, these waterbodies (generally deeper than six feet) are defined as deepwater habitats, since water and not air is the principal medium in which dominant organisms must live. In summary, the Service has developed a scientifically sound definition of wetland based on the degree of flood- ing or soil saturation and the presence of wetland plants and/or hydric soils. It is the product of four years of field testing and review by the scientific community. Conse- quently, the Service's concept of wetland is being widely accepted as the national and international standard for identifying wetland. References Cowardin, L.M.. V. Carter, F C. Goiet, and E.T. LaRoe. 1979. Classi- fication of Wetlands and Deepwater Habitats of the United States. U.S. Fish and Wildlife Service. FWS/OBS-79/31. 103 pp. Scott, N.S. 1979. Opinion. Civil Action No. 78-1428. The Avoyelles Sportsmen's League. Inc.. et. al. v. Clifford L. Alexander, et. al. U.S. District Court. Western District of Louisiana, Alexandria Divi- sion. 20 pp. System Subsystem I — Marine - — Estuarine- E- < 3 < X a a E- < S a. W" K) D Q Z < Q Z < J E- U - Subtidal - -Intertidal ■ - Subtidal - -Intertidal- - Riverine - - Tidal - -Lower Perennial - -Upper Perennial - -Intermittent - — Lacustrine - -Limnetic ■ -Littoral- L Palustrine- Class -Rock Bottom -Unconsolidated Bottom -Aquatic Bed -Reef -Aquatic Bed -Reef -Rocky Shore — Unconsolidated Shore -Rock Bottom -Unconsolidated Bottom -Aquatic Bed -Reef — Aquatic Bed -Reef — Streambed — Rocky Shore -Unconsolidated Shore -Emergent Wetland — Scrub-Shrub Wetland — Forested Wetland — Rock Bottom — Unconsolidated Bottom — Aquatic Bed — Rocky Shore — Unconsolidated Shore — Emergent Wetland — Rock Bottom — Unconsolidated Bottom — Aquatic Bed — Rocky Shore — Unconsolidated Shore — Emergent Wetland — Rock Bottom — Unconsolidated Bottom — Aquatic Bed — Rocky Shore — Unconsolidated Shore -Streambed -Rock Bottom -Unconsolidated Bottom -Aquatic Bed -Rock Bottom -Unconsolidated Bottom -Aquatic Bed - Rocky Shore - Unconsohdated Shore - Emergent Wetland -Rock Bottom - Unconsolidated Bottom -Aquatic Bed -Unconsolidated Shore -Moss-Lichen Wetland -Emergent Wetland -Scrub-Shrub Wetland - Forested Wetland Fig. 3. Classification hierarchy of wetlands and deepwater habitats, showing systems, subsystems, and classes. The Palustrine System does not include deepwater habitats (Cowardin. et al. 1979). MAJOR WETLAND TYPES OF THE UNITED STATES Wetlands occur in every state of the country and due to regional differences in climate, vegetation, soil and hy- drologic conditions, they exist in a variety of sizes, shapes and types. Although more abundant in other areas, wetlands even exist in deserts. The Service's classification system (Cowardin. et al. 1979) groups wetlands according to ecologically similar characteristics. It first divides wetlands and deepwater habitats into five ecological systems: (1) Marine, (2) Estuarine, (3) Riverine, (4) Lacustrine, and (5) Palus- trine (Figure 3). The Marine System generally consists of the open ocean and its associated coastline (Figure 4). It is mostly a deepwater habitat system, with marine wetlands limited to intertidal areas like beaches, rocky shores and some coral reefs. The Estuarine System includes coastal wetlands like salt and brackish tidal marshes, mangrove swamps, and intertidal flats, as well as deepwater bays, sounds and coastal rivers. The Riverine System is limited to freshwater river and stream channels and is mainly a deepwater habitat system. The Lacustrine System is also a deepwater dominated system, but includes standing wa- terbodies like lakes, reservoirs and deep ponds. The Palustrine System encompasses the vast majority of the country's inland marshes, bogs and swamps and does not include any deepwater habitat. Characteristics of the ma- jor wetland types in the U.S. are described in the follow- ing sections. The discussion focuses on estuarine and palustrine wetlands because they are the most abundant types. MARINE SYSTEM (OCEAN) LEGEND System boundary Estuarine System Riverine System \\ Lacustrine System Palustrine System Rocky shore Intertidal beach Tidal flat Aquatic bed ^3 Emergent wetland f\^ Forested wetland Fig. 4. Diagram showing major wetland and deepwater habitat systems. Estuarine Wetlands Estuarine wetlands are found along the U.S. coastline and are associated with estuaries or brackish tidal waters. They are represented by three major types: ( 1 ) emergent wetland, (2) intertidal flat, and (3) scrub-shrub wetland. Other coastal wetlands include intertidal coral and mol- lusk reefs, rocky shores, and beaches. Estuarine Emergent Wetlands Estuarine emergent wetlands are dominated by grass or grass-like plants (Figure 5). They are commonly called "salt marshes" and "brackish tidal marshes". Salt marshes characteristically lie behind barrier is- lands and beaches along all coasts in relatively high salin- ity waters. They are best represented along the Alaskan, Atlantic and Gulf coasts. Salt marshes are flooded by tides for varying periods depending on elevation and tidal amplitude. Two distinct zones can be observed based on differences in frequency and duration of flooding and associated vegetation: ( 1 ) regularly flooded marsh and (2) irregularly flooded marsh (Figure 6). The regularly flooded marsh is flooded and exposed at least once daily by the tides. In New England, this marsh is generally limited to tidal creek banks, while in the Southeast, it is the dominant coastal wetland type covering vast acre- ages. Along the Atlantic and Gulf coasts, smooth cord- grass dominates the regularly flooded marsh, while on the West coast, California cordgrass prevails. These grasses are among the most productive marsh plants. Lying above the regularly flooded zone, the irregularly flooded marsh is exposed to air for long periods and flooded only at irregular intervals, usually monthly during spring and storm tides. Vegetation in this zone is more varied, in- cluding salt hay cordgrass, spikegrass, black grass, alka- ligrass, Baltic rush, black needlerush, glassworts, saltworts, sea ox-eye, high-tide bush, reed, bulrushes, asters and switchgrass. On the West coast, Lyngbye's sedge, hairgrass and jaumea are other important species. Salt marshes along the Beaufort Sea in Alaska are domi- nated by alkaligrass and sedges. Moving upstream in coastal rivers where seawater is diluted by freshwater, the brackish tidal marshes can b = found. Salinity here fluctuates greatly with the tides, river flow and the seasons. Nearest the salt marshes, black needlerush dominates brackish marshes along the South Atlantic and Gulf coasts, while big cordgrass, narrow- leaved cattail and bulrushes are important in more north- em areas. As the upstream limit of salt water influence is approached, a highly diverse assemblage of emergent plants characterizes these marshes, including big cord- grass, narrow-leaved cattail, pickerelweed, wild rice, gi- ant cutgrass, marsh mallow, arrowheads, smartweeds, sedges, bulrushes, beggar" s-ticks and reed. Most of these plants, however, reach their maximum abundance in the Nation's inland wetlands. Estuarine Intertidal Flats Intertidal flats often lie seaward of tidal marshes and mangroves, at river mouths or along rocky coasts. They also occur as barren areas within the hieh marsh in high ^^^'^i!"^;-..-.;^' Burr Cowardin et al. JtiatHskmm, ChiWers Cowardin el a Cowardin el al Fig. 5. Examples of estuarine emergent wetlands, (a) mixed plant community of iiregularly flooded marsh, (b) reed-salt hay cordgrass marsh, (c) regularly flooded cordgrass marsh, (d) black needlerush marsh, (e) Lyngbye's sedge marsh and (f) Alaskan irregularly flooded marsh. UPLAND Spring or Storm Tide Daily Higli Tide switchgrass high-tide bush black grass salt hay cordgrass spikegrass salt marsh aster smooth cordgrass glasswort (ta" 'o'"'") smooth cordgrass (short form) V IRREGULARLY FLOODED MARSH Fig. 6. Cross-sectional diagram of a Northeastern salt marsh. REGULARLY FLOODED MARSH V INTERTIDAL FLAT ESTUARINE OPEN WATER (BAY) salinity areas. Tidal flats appear at low tide largely as unvegetated expanses of mud or sand, although micro- scopic plants like diatoms, bluegreen algae and dinofla- gellates may be extremely abundant (Figure 7). On occasion, macroscopic algae like sea lettuce may locally dominate these flats. These wetlands are particularly ex- tensive in areas with high tidal ranges such as Alaska and Maine. Estuarine Scrub-Shrub Wetlands Estuarine scrub-shrub wetlands are characterized by salt-tolerant woody vegetation less than 20 feet in height. Common estuarine shrubs along the Atlantic and Gulf coasts are high-tide bush and sea myrtle. Estuarine shrub wetlands are perhaps best represented by mangrove swamps, which have a limited distribution in the U.S. ,^-. Cowardin et al Cowardin et al Fig. 7. Examples of estuarine intertida! flats, (a) Alaska and (b) Virginia. Fig. 8. Mangrove-dominated estuarine scrub-shrub wetlands of Florida, (a) aerial view and (b) close-up of red mangroves. (Figure 8). Mangroves are generally found south of the 30° N Latitude and reach their maximum abundance in Florida, Puerto Rico, and the Virgin Islands. These wet- lands are dominated by tall shrub forms of two man- groves: (1) red mangrove and (2) black mangrove. Red mangroves dominate the regularly flooded zone, while black mangroves characterize higher irregularly flooded areas. Salt marshes of smooth cordgrass, black needle- rush, spikegrass, and saltwort may be closely associated with Florida's mangrove swamps. Palustrine Wetlands Palustrine wetlands occur in the interior of the country and largely consist of freshwater wetlands, although in- land salt and brackish marshes exist in arid and semiarid areas. Palustrine wetlands are represented by three major types: ( 1 ) emergent wetland, (2) scrub-shrub wetland and (3) forested wetland. Shallow open waterbodies such as ponds and playa lakes (less than 6.6 feet deep) are also considered wetland by the Service. depending on the region of the country and individual characteristics. Emergent wetlands may be flooded for variable periods from as little as a couple of weeks early in the growing season to permanently flooded throughout the year. Some palustrine marshes are flooded by fresh tidal waters, mainly along the Atlantic, Gulf, and Alas- kan coasts. Differences in local hydrology affect the wet- ness of a given marsh and the corresponding vegetative community. This is particularly evident in the Prairie Pothole Region. Here wetland vegetation growing in gla- cial depressions often creates a distinct zonal pattern re- lated to differences in water regime (Figure 10). Emergent wetlands occur in a variety of situations, in- cluding along the margins of rivers and lakes, in upland depressions, in seepage areas on gentle slopes and in saturated permafrost areas of Alaska. Common marsh plants include cattails, wild rice, sedges, rushes, bul- rushes, spikerushes, rice cutgrass, maidencane, reed, arrowheads, pickerel weed, smartweeds, and burreeds. Palustrine Emergent Wetlands Palustrine emergent wetlands are dominated by herba- ceous vegetation including certain grasses, cattails, rushes and sedges (Figure 9). These wetlands are com- monly referred to by a variety of terms, including "marsh", "wet meadow", "fen", and "inland salt marsh". 10 ZInni ■»" ' .rf*» ^Jtrf'^'-W -.'^.' NWI Cowardin et al Fig. 9. Examples of palustrine emergent wetlands, (a) Northeastern sedge meadow, (b) cattail marsh, (c) prairie pothole wetland, and (d) Western sedge meadow. LEGEND Water Regime Examples of Common Plants r|3 Permanently Flooded western widgeongrass, pondweed, muskgrass rn] Semipermanently Flooded slender bulrusti, cattail, hardstem bulrush [^ Seasonally Flooded burreed. smartweed. whitetop, spikerush [7^ Temporarily Flooded false aster, bluegrass, prairie cordgrass. saltgrass Fig. 10. Generalized vegetation zones of a pothole wetland in relationship to water regime (from Stewart and Kantrud 1972). II Cowardin et al. Fig. 11. Examples of palustrine scrub-shrub wetlands, (a) Northern leatherleaf bog and (b) pocosin. Palustrine Scrub-Shrub Wetlands Freshwater wetlands dominated by woody vegetation less than 20 feet tall represent palustrine scrub-shrub wet- lands (Figure 11). Although not as abundant as palustrine emergent and forested wetlands, they occur widely throughout the Nation. These shrub-dominated wetlands are commonly called "bog", "pocosin". "shrub-carr", or "shrub swamp" in different parts of the country. Northern and southern peat bogs are particularly inter- esting types of scrub-shrub wetlands. Both types are rare- ly flooded and are generally characterized by a saturated organic soil with the water table at or near the surface for most of the year. Northern bogs are prevalent in isolated depressions, along river courses and along the margins of lakes in states like Alaska, Maine, Michigan, Minnesota, New York and Wisconsin. Typical northern bog plants include leatherleaf, sweet gale, cotton grass, peat moss, bog rosemary. Labrador tea, cranberry, bog laurel, and sedges as well as stunted trees of black spruce, larch, lodgepole pine, and balsam fir. Southern bogs occur along the southeastern Coastal Plain and are locally called "pocosins." They are found on broad flat plateaus usually apart from large streams. Pocosins are dominated by evergreen shrubs of pond pine, sweet bay, inkberry, fet- terbush and titi. Other important scrub-shrub wetlands in the U.S. are characterized by buttonbush. alders, wil- lows, dogwoods and saplings of tree species like red maple and Cottonwood. Palustrine Forested Wetlands Forested wetlands dominated by trees taller than 20 feet occur mostly in the eastern half of the United States and Alaska (Figure 12). In the East, they are the most abundant wetland type. They include such diverse types as black spruce bogs, cedar swamps, red maple swamps, and bottomland hardwood forests. In the Prairie Pothole Region of the Dakotas, forested wetlands are relatively uncommon. As in other inland wetlands, flooding is ex- tremely variable depending on regional climate, topo- graphic position and local hydrology. In the North, important trees of the wetter swamps are red maple, ashes, northern white cedar, black spruce and larch. Bald cypress, water tupelo. red maple, black gum. Atlantic white cedar, overcup oak, and black willow are common in southern wet swamps. In the Northwest, western hem- lock, red alder and willows are important species. Drier swamps, those flooded only briefly during the growing season, are characterized by silver maple, pin oak, syca- more and beech in the North and by sweet gum, loblolly pine, slash pine, tulip poplar, beech, black walnut, syca- more, water hickory, pignut hickory and various oaks (e.g., water, laurel, and willow) in the South. Cotton- wood, box elder, willows, green ash and elms dominate riparian wetlands along western streams. Black spruce, larch, lodgepole pine and balsam poplar are the major forested wetland species in Alaska. References Cowardin. L.M., V. Carter, F.C. Golet. and E.T. LaRoe. 1979. Classi- fication of Wetlands and Deepwater Habitats of the United States. U.S. Fish and Wildlife Service. FWS/OBS-79/31. 103 pp. Hofstetter, R.H. 1983. Wetlands in the United States. In: A. J. P. Gore (editor). Mires: Swamp, Bog. Fen and Moor. Elsevier Scientific Publishing Co.. Amsterdam, pp. 201-244. MacDonald. K.B. 1977. Plant and animal communities of Pacific North American salt marshes. In: V.J, Chapman (editor). Wet Coastal Ecosystems. El.sevier Scientific Publishing Co.. Amsterdam, pp. 167-191. Reimold, R.J. 1977. Mangals and salt marshes of eastern United States. In: V.J. Chapman (editor). Wet Coastal Ecosystems. Elsevier Scien- tific Publishing Co., Amsterdam, pp. 157-166. Shaw, S.P. and C.G. Fredine. 1956. Wetlands of the United States. Their Extent and Their Value lo Waterfowl and Other Wildlife. U.S. Fish and Wildlife Service. Circular 39. 67 pp. Stewart, R.E. and H. A. Kantrud. 1972. Vegetationof Prairie Potholes, North Dakota, in Relation to Quality of Water and Other Environ- mental Factors. U.S. Geol. Survey. Prof. Paper 585-D. 36 pp. 12 Hi ■■ Mh^^ Tiner Cowardin et al. :m^y,^^^ USFWS Fig. 12. Examples of palustrine forested wetlands, (a) red maple swamp, (b) Atlantic white cedar swamp, (c) bald cypress swamp, (d) bot- tomland hardwood swamp, (e) riparian forested wetland, and (0 Alaskan forested wetland mixed with scrub-shrub wetland. 13 WHY ARE WETLANDS IMPORTANT? Although often used by many people for hunting, trap- ping and fishing, wetlands were largely considered wastelands whose best use could only be attained through "reclamation projects." such as drainage for agriculture and tilling for industrial or residential development. Much to the contrary, wetlands in their natural state pro- vide a wealth of values to society (Table 1). Wetland benefits can be divided into three basic categories: ( 1 ) fish and wildlife values, (2) environmental quality values and (3) socio-economic values. The following discussion em- phasizes the more important values. For an indepth ex- amination of wetland value, the reader is referred to "Wetland Functions and Values: The State of Our Under- standing" (Greeson, et al. 1979). In addition, the Service has created a wetland values database which records ab- stracts of over 2000 articles (Stuber 1983). Table 1. List of major wetland values. FISH AND WILDLIFE VALUES • Fish and Shellfish Habitat • Waterfowl and Other Bird Habitat • Furbearer and Other Wildlife Habitat ENVIRONMENTAL QUALITY VALUES • Water Quality Maintenance • Pollution Filter • Sediment Removal • Oxygen Production • Nutrient Recycling • Chemical and Nutrient Absorption • Aquatic Productivity • Microclimate Regulator • World Climate (Ozone layer) SOCIO-ECONOMIC VALUES • Flood Control • Wave Damage Protection • Erosion Control • Groundwater Recharge and Water Supply • Timber and Other Natural Products • Energy Source (Peat) • Livestock Grazing • Fishing and Shellfishing • Hunting and Trapping • Recreation • Aesthetics • Education and Scientific Research Fish and Wildlife Values The variety of wetlands across the country create habi- tats for many forms of fish and wildlife. Some animals spend their entire lives in wetlands, while others use wetlands primarily for reproduction and nursery grounds. Numerous fish and wildlife frequent marshes and swamps for feeding or feed on organisms produced in wetlands, whereas many animals visit wetlands for drinking water. Wetlands are also crucial for survival of numerous endan- gered animals. Fish and Shellfish Habitat Both inland and coastal wetlands are essential to main- taining important fish populations. Estuarine wetlands are also important producers of shrimp, crabs, oysters and clams for man's consumption. Approximately two-thirds of the major U.S. commer- cial fishes depend on estuaries and salt marshes for nurs- ery or spawning grounds (McHugh 1966). Among the more familiar wetland-dependent fishes are menhaden, bluefish, fluke, sea trout, spot, mullet, croaker, striped bass, and drum. Coastal marshes along the Atlantic and Gulf coasts are most important in this regard. In the Pacific Northwest, coastal wetlands along spawning streams are vital to many salmon species (Merrell and Koski 1979). Coastal wetlands are also essential for important shell- fish like shrimp, blue crabs, oysters and clams. These areas serve as the primary nursery grounds for penaeid shrimp, whose young grow rapidly and reach adulthood here. Scientific studies have recently demonstrated a di- rect correlation between the amount of coastal marsh and shrimp production (Turner 1977). Freshwater fishes also find wetlands important for sur- vival. In fact, most freshwater fishes can be considered wetland-dependent because: (I) many species feed in wetlands or upon wetland-produced food, (2) many fishes use wetlands as nursery grounds and (3) almost all impor- tant recreational fishes spawn in the aquatic portions of wetlands (Peters, et al. 1979). Marshes along Lake Michigan, for example, are spawning grounds for north- em pike, yellow perch, carp, smallmouth bass, large- mouth bass, bluegill. bullhead and other fishes, including minnows (Jaworski and Raphael 1978). Prized gamefish — muskies and walleyes — may spawn in flooded marshes as well as feed there. Bottomland hardwood forests of the South serve as nursery and feeding grounds for young warmouth and largemouth bass, while adult 14 WRENS PLOVERS TERNS ICTERIDS — SHORT-BILL - LONG-BILL- BLACK -FORSTERS- RUDDY ■REDHEAD AMERICAN ' KING R.- - SORA — — VIRGINIA- • LEAST ■ COOT GALLINULE BOBOLINK tUEADOWLARK u,^^ REDWING YELLOWHEAD UPLAND GRASSES LOWLAND GRASSES SEDGE CATTAIL HARDSTEM MINK MUSKRAT MUSKRAT Fig. 13. Wetland habitat utilization by several families of birds (from Weller and Spatcher 1965). bass feed and spawn in these wetlands. River swamps in Georgia produce 1 ,300 pounds of fish per acre (Wharton 1970). The bottomlands of the Altamaha River in Geor- gia are used for spawning by hickory shad and blueback herring (Wharton and Kitchens 1982). Southern bottom- land forested wetlands are also the home of the edible red swamp crayfish ("crawdads"") which burrow down to the water table when flooding waters recede (Patrick, et al. 1981 ). Wetland vegetation along western rivers is impor- tant to fishes in many ways, including providing cover, shade for water temperature regulation, and food for aquatic insects which are eaten by fishes. Waterfowl and Other Bird Habitat In addition to providing year-round habitats for resi- dent birds, wetlands are especially important as breeding grounds, overwintering areas and feeding grounds for migratory waterfowl and numerous other birds (Figure 13). Both coastal and inland wetlands serve these valu- able functions. Salt marshes along the Atlantic coast are used for nest- ing by birds such as black ducks, laughing gulls, Forster's terns, sharp-tailed sparrows, clapper rails, blue-winged teals, willets, marsh hawks, and seaside sparrows. Wad- ing birds like herons and egrets also feed and nest in coastal wetlands. Northeastern salt marshes are prime wintering grounds for black ducks in the Atlantic Fly way . Atlantic coastal marshes are also important feeding and stopover areas for migrating snow geese, peregrine fal- cons, shorebirds. wading birds and others. Intertidal mudflats along all coasts are principal feeding grounds for migratory shorebirds (e.g.. oystercatchers, plovers and knots), while swallows and chimney swifts can often be seen feeding on flying insects over the marshes. As one moves upstream into the fresh coastal marshes, other birds can be observed nesting including redwinged blackbirds, long-billed marsh wrens, least bitterns and clapper rails. Nesting birds of freshwater tidal marshes in New Jersey, for example, include these four birds, plus American goldfinch, swamp sparrow. Indigo bunting, common yellowthroat, yellow warbler, Traill's fly- catcher, wood duck, green heron, and common gallinule (Hawkins and Leek 1977). Many of these birds utilize non-tidal wetlands as well for nesting. The Nation's inland wetlands are most noted for water- fowl production, although they also serve as important nesting, feeding and resting areas for other migrating birds (Figures 14 and 15). The Prairie Pothole Region of the Dakotas is the principal breeding area for waterfowl in the United States. Pothole nesters include 15 species, with mallard, pintail and blue-winged teal most abundant (Smith, et al. 1964). Many of these nesters use different types of wetlands for mating and for rearing young. Indi- vidual mallard hens may use more than 20 different wet- lands during the nesting season (Dwyer, et al. 1979). Besides waterfowl . other birds also nest in these wetlands such as redwinged blackbirds. Brewer's blackbirds, king- birds, killdeer, spotted sandpipers, sparrows, Wilson's phalaropes and black terns (Johnsgard 1956). Pothole and other inland emergent wetlands also provide important 15 Krey Fig. 14. Migratory birds using wetlands, (a) American avocet turning her eggs, (b) red-necked grebe on nest, (c) snowy egret on nest, and (d) pintails feeding. winter cover and nesting habitat for ring-necked plieas- ant. In fact, the pheasant population in east-central Wis- consin is directly related to the amount and distribution of wetlands available (Gates and Hale 1974). Playa lake wetlands in the Texas Panhandle are important nesting habitats for pheasants, mourning doves, redwinged blackbirds, and others (Guthery 1981), Bottomland forested wetlands of the South are primary wintering grounds for North American waterfowl as well as important breeding areas for wood ducks, herons, egrets and white ibises. Wild turkeys even nest in bottom- land hardwood forests. Other common bird inhabitants include barred owls, downy and red-bellied woodpeck- ers, cardinals, pine warblers, wood peewees, yellow- throats and wood thrushes (Wharton and Kitchens 1982). In the Northeast, red maple swamps are among the most abundant wetland types. A study of breeding birds in eight western Massachusetts swamps revealed a total of 46 breeding species (Swift 1980). Most common breeders include yellowthroat, veery, Canada warbler, ovenbird, northern waterthrush and gray catbird. The wood duck is another important resident of forested wet- lands, primarily in the eastern half of the U.S., where it nests in cavities of dead trees or in man-made nesting boxes. In the West, riparian forested wetlands along rivers are valuable bird nesting and migration stopover areas. Wauer (1977) found 94 avian species nesting in riparian vegetation of the Rio Grande, including mourning doves. 16 ..^- -^ .OS^ A Priority Area Name Frame Potholes and Parklands 2 Central Valley ot" California 3 > ukon-Kusl^ol\wim Delta 4 Middle-Upper Atlantic Coast ? Lower Mississippi River Delia and Red Ri\cr Basin 6 Izembek Lagoon 7 Upper Mississippi River and Norrhern Lakes H Northern Great Plains 4 Yukon Flats lU Intermountain West (Great Basinl I I Teshelpuk Lake Middle-Lipper Paeihe Coasl Klamath Basin L!pper Alaska Peninsula Copper River Delta West-Central Gult Coast Upper Cook Inlel San Francisco Bay Nt United States - SE Canada Sandhills and Rainwater Basin Playa Lakes Fig. 15. Waterfowl habitat areas of major national concern (from U.S. Fish and Wildlife Service 1984). verdins, northern orioles and brown-headed cowbirds. These riparian wetlands were very important to migrating birds in the spring and fail. In Arizona, the yellow-billed cuckoo and blue-throated hummingbird are restricted to cottonwood-willow forested wetlands (Brown, et al. 1977). Riparian wetlands may be more important to mi- grating birds in arid regions than in more humid areas. The availability of food, water, cover, and suitable north- south routing strongly influence migrants (Wauer 1977). Alaskan and other tundra wetlands are prime breeding grounds for most shorebirds such as sandpipers, plovers and their relatives. Nearly the entire Pacific Flyway pop- ulations of the cackling Canada goose and the white- fronted goose nest in Alaska's Yukon-Kuskokwim Delta. Alaska is also the most important production area for pintail in the U.S. (U.S. Fish and Wildlife Service 1984). During droughts in the Prairie Pothole Region, Alaska's wetlands are heavily used by North American waterfowl for nesting. Hawaii's wetlands are especially important to endan- gered birds. The Hawaiian stilt, Hawaiian coot, Hawaiian gallinule, and Hawaiian duck depend on wetlands for survival. Wetlands are, therefore, crucial for the existence of many birds, ranging from waterfowl and shorebirds to songbirds. Some spend their entire lives in wetland envi- ronments, while others primarily use wetlands for nest- ing, feeding or resting. Furbearer and Other Wildlife Habitat If a fur trapper is asked about the value of wetlands, he is likely to reply that they produce furbearers, like musk- rats, beavers and nutria. Muskrats are the most wide ranging of the three, inhabitating both coastal and inland marshes throughout the country. By contrast, beavers tend to be restricted to inland wetlands, with nutria limit- 17 Goeke C D Fig. 16. Wetlands are important to many other wildlife, (a) beaver, (b) caribou, (c) alligator, and (d) spring peeper. USFWS ed to coastal wetlands of the South. Other wetland-utiliz- ing furbearers include otter, mink, raccoon, skunk and weasels. Other mammals also frequent wetlands, such as marsh and swamp rabbits, numerous mice, hog lemmings and shrews. Larger mammals may also be observed. Black bears find refuge and food in forested and shrub wetlands of northeastern Pennsylvania and western Mas- sachusetts, for example. In northern states, white-tailed deer depend on white cedar and other evergreen swamps for winter shelter and food. By contrast, the extensive wetlands of Alaska's North Slope are used as summer range and calving areas by caribou. Other forms of wildlife make their homes in wetlands (Figure 16). Turtles, reptiles, and amphibians are impor- tant residents. Turtles are most common in freshwater marshes and ponds. The more important ones are the painted, spotted, Blanding's, map, mud, pond, musk and snapping turtles (Clark 1979). The endangered Plymouth red-bellied turtle and bog turtle are also wetland-depen- dent (Williams and Dodd 1979). Along the coast, the diamond-backed terrapin is a common inhabitant of salt marshes, while young loggerhead turtles spend some time in estuaries after hatching before going out to sea. The largest reptiles occurring in the United States — the American alligator and the American crocodile — live in wetlands. The crocodile, an endangered species, is now only found in mangroves and coastal waters of Flor- ida Bay, while the alligator occurs from Florida north to North Carolina and west to Texas. The alligator lives in both brackish and freshwater wetlands, but is most abun- dant in the latter. Alligators create "gator holes" in the Everglades, which persist through the dry season. Fishes and invertebrates concentrate in these holes which make them easy prey for birds and other animals. Gator holes with their abundance of food are important to the breed- ing success of birds like the wood ibis (Williams and Dodd 1979). Many snakes inhabit wetlands, with water snakes be- ing most abundant throughout the U.S. (Clark 1979). Other important wetland snakes include cottonmouth 18 moccasin, garter, queen, mud and swamp snakes. In bot- tomland wetlands of the South, copperheads and cane- brake rattlesnakes can be found as well as northern brown, garter, rough green and rat snakes (Wharton and Kitchens 1982). The San Francisco garter snake, an en- dangered species, also requires wetlands for survival (Williams and Dodd 1979). Nearly all of the approximately 190 species of amphib- ians in North America are wetland-dependent, at least for breeding (Clark 1979). Every freshwater wetland in the U.S., except in the Arctic tundra, probably has some frogs. Common frogs include the bull, green, leopard, mink, pickerel, wood and chorus frogs and spring peep- ers. Many salamanders use temporary ponds or wetlands for breeding, although they spend most of the year in uplands. Numbers of amphibians, even in small wet- lands, can be astonishing. For example, 1,600 salaman- ders and 3,800 frogs and toads were found in a small gum pond (less than 100 feet wide) in Georgia (Wharton 1978). Environmental Quality Values Besides providing homes for fish and wildlife, wet- lands play a less conspicuous but nonetheless important role in maintaining high environmental quality, especial- ly in aquatic habitats. They do this in a number of ways, including purifying natural waters by removing nutrients, chemical and organic pollutants, and sediment and pro- ducing food which supports aquatic life. Water Quality Improvement Wetlands help maintain good water quality or improve degraded waters in several ways; ( I ) removing nutrients. (2) processing chemical and organic wastes, and (3) re- ducing sediment loads of water. Wetlands are particularly good water filters because of their location between land and water. Thus, they can both intercept runoff from land before it reaches the water and help filter nutrients, wastes and sediment from flooding waters. Clean waters are important to man as well as to aquatic life. First, wetlands remove nutrients, especially nitrogen and phosphorus, from flooding waters for plant growth and help prevent eutrophication or overenrichment of nat- ural waters. It is, however, possible to overload a wetland and thereby reduce its ability to perform this function. Every wetland has a limited capacity to absorb nutrients and individual wetlands differ in their ability to do so. Wetlands have been shown to be excellent removers of waste products from water. In fact, certain wetland plants are so efficient at this task that some artificial waste treatment systems are using the.se plants. For example, the Max Planck Institute of Germany has a patent to create such systems, where a bulrush is the primary waste removal agent (Sloey, et al. 1978). Numerous scientists have proposed that certain types of wetlands be used to process domestic wastes. Some wetlands are already used for this purpose. The Brillion Marsh in Wisconsin has received domestic sewage since 1923. This cattail marsh on the average removed 80% of biological oxygen demand, 86% of coliform bacteria, 51% of nitrates, 40% of chemical oxygen demand, 44% of turbidity, 29% suspended solids and 13% of total phos- phorus. After passing through Brillion Marsh, there was a significant improvement in water quality (Boto and Pat- rick 1979). Perhaps the best example of the importance of wet- lands for water quality improvement is Tinicum Marsh (Grant and Patrick 1970). Tinicum Marsh is a 512-acre freshwater tidal marsh lying just south of Philadelphia, Pennsylvania (Figure 17). Three sewage treatment plants discharge treated sewage into marsh waters. On a daily basis, it was shown that this marsh removes from flood- ing waters; 7.7 tons of biological oxygen demand, 4.9 tons of phosphorus, 4.3 tons of ammonia, and 138 pounds of nitrate. In addition, Tinicum Marsh adds 20 tons of oxygen to the water each day. Swamps also have the capacity for removing water pollutants. Bottomland forested wetlands along the Al- covy River in Georgia filter impurities from flooding waters. Human and chicken wastes grossly pollute the river upstream, but after passing through less than 3 miles of swamp, the river's water quality is significantly im- proved. The value of the 2,300-acre Alcovy River Swamp for water pollution control was estimated at $1 million per year (Wharton 1970). Wetlands play a valuable role in reducing turbidity of flooding waters. This is especially important for aquatic life and for reducing siltation of ports, harbors, rivers and reservoirs. Removal of sediment load is also valuable because sediments often transport absorbed nutrients, pesticides, heavy metals and other toxins which pollute our Nation's waters (Boto and Patrick 1979). Depres- sional wetlands should retain all of the sediment entering them (Novitski 1978). In Wisconsin, watersheds with 40% coverage by lakes and wetlands had 90% less sedi- ment in water than watersheds with no lakes or wetlands (Hindall 1975). Creekbanksof salt marshes typically sup- port more productive vegetation than the marsh interior. Deposition of silt is accentuated at the water-marsh inter- face, where vegetation slows the velocity of water caus- ing sediment to drop out of solution. In addition to improving water quality, this process adds nutrients to the creekside marsh which leads to higher plant productivity (DeLaune. et al. 1978). The U.S. Army Corps of Engineers has investigated the use of marsh vegetation to lower turbidity of dredged disposal runoff and to remove contaminants. In a 50-acre impoundment near Georgetown, South Carolina, after passing through about 2,000 feet of marsh vegetation, the effluent turbidity was similar to that of the adjacent river 19 Fig. 17. Aerial view of Tinicum Marsh near Philadelphia, Pennsylvania. This marsh is particularly valuable for improving water quality in an urban environment. (Lee, et al. 1976). Wetlands have also been proven to be good filters of nutrients and heavy metal loads in dredged material disposal effluents (Windom 1977). Aquatic Productivity Wetlands are among the most productive ecosystems in the world and they may be the highest, rivaling our best cornfields (Figure 18). Wetland plants are particularly efficient converters of solar energy. Through photosyn- thesis, plants convert sunlight into plant material or bio- mass and produce oxygen as a by-product. This biomass serves as food for a multitude of animals, both aquatic and terrestrial. For example, many waterfowl depend neavily on seeds of marsh plants, while muskrat eat cat- tail tubers and young shoots. Moose, caribou, black bears and brown bears graze on marsh plants in Alaska (Crow and Macdonald 1979). Although direct grazing of wetland plants is generally limited, their major food value is reached upon death when plants fragment to form detritus. This detritus fonns the base of an aquatic food web which supports higher consumers, like commercial fishes (Figure 19). This relationship is especially well-documented for coast- al areas. Animals, like shrimp, snails, clams, worms, killifish and mullet, eat detritus or graze upon the bacte- ria, fungi, diatoms and protozoa growing on its surfaces (Crow and Macdonald 1979; de la Cruz 1979). Many of these animals are the primary food for commercial and recreational fishes. Salmon are linked with wetlands and detritus. Juvenile salmon in Puget Sound, Washington, feed mainly on salt marsh midge larvae, which subsist on detritus (Crow and Macdonald 1979). Detritus from wet- land vegetation along western rivers feeds aquatic insects important to the diet of resident fishes. Thus, wetlands can be regarded as the farmlands of the aquatic environ- ment where great volumes of food are produced annually. The majority of non-marine aquatic animals depend, ei- ther directly or indirectly, on this food source. Socio-Economic Values The more tangible benefits of wetlands to mankind may be considered socio-economic values and they in- clude flood and storm damage protection, erosion con- trol, water supply and groundwater recharge, harvest of natural products, livestock grazing and recreation. Since these values provide either dollar savings or financial profit, they are more easily understood by most people. 20 2500 2000 • 1500 - 1000 - 500 FRESHWATER WETLAND WARM TEMPERATE MIXED FOREST CULTIVATED LAND GRASSLAND NET PRIMARY PRODUCTIVITY OF SELECTED ECOSYSTEMS [g/m2/year] ADAPTED FROM LIETH (1975) AND TEAL AND TEAL (1969) Fig. 18. Relative productivity of wetland ecosystems in relation to others (from Newton 1981). Fig. 19. Simplified food pathways from estuarine wetland vegetation to commercial and recreational fishes. 21 Flood and Storm Damage Protection In their natural condition, most wetlands serve to tem- porarily store flood waters, thereby protecting down- stream property owners from flood damage. After all, such flooding has been the driving force in creating these wetlands. This flood storage function also helps to slow the velocity of water and lower wave heights, which reduces the water's erosive potential. Rather than having all flood waters flowing rapidly downstream and destroy- ing private property and crops, wetlands slow the flow of water, store it for some time and slowly release stored waters downstream (Figure 20). In this way, flood peaks of tributary streams are desynchronized and flood waters do not all reach the mainstem river at the same time. This function becomes increasingly important in urban areas, where development has increased the rate and volume of surface water runoff and the potential for flood damage. In 1975, 107 people were killed by flood waters and potential property damage for the year was estimated to be $3.4 billion (U.S. Water Resources Council 1978). Almost half of all flood damage is suffered by agriculture as crops and livestock are destroyed and productive land is covered by water or lost to erosion. Approximately 1 34 million acres of the conterminous United States have severe flooding problems. Of this, 2.8 million acres are urban land and 92.8 million acres are agricultural land (U.S. Water Resources Council 1977). Many of these flooded farmlands are wetlands or previously drained wetlands. Although regulations required by the Federal Insurance Administration may help reduce flood losses from urban land, agricultural losses are expected to remain at present levels or increase as more wetlands are put into crop production. Protection of wetlands is, therefore, an im- portant means of minimizing flood damages in the future. The U.S. Army Corps of Engineers has recognized the value of wetlands for flood storage in Massachusetts. In the early 1970's, the New England Division considered various alternatives to providing flood protection in the lower Charles River watershed near Boston, including: (1) 55,000 acre-foot reservoir, (2) extensive walls and dikes, and (3) perpetual protection of 8,500 acres of wet- lands (U.S. Army Corps of Engineers 1976). If 40% of the Charles River wetlands were destroyed, flood dam- ages would increase by at least $3 million annually. Loss of all basin wetlands would cause an average annual flood damage cost of $17 million (Thibodeau and Ostro 1981 ). The Corps concluded that wetlands protection — "Natu- ral Valley Storage" — was the least-cost solution to flooding problems. In 1983, they completed wetland ac- quisition in the Charles River basin. i Ul I- < O I'i'I'I'I'I'i'l'' 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 I 1 II II l' i,l,l,l| I I f^ i ill' I I I I •^ Higher flood and higher flows Lower flood crest and lower flows WETLANDS NO WETLANDS I g m X Q O O TIME Fig. 20. Wetland value in reducing flood crests and flow rates after rainstorms (adapted from Kusler 1983). 22 Fig. 21. Wetland drainage and filling increase the potential for damaging floods. This flood storage value of wetlands has also been reported for other areas. In eastern Pennsylvania, the 1955 floods washed out all but two bridges along one stream; the remaining bridges lay immediately down- stream of the Cranberry Bog (Goodwin and Niering 1975). A Wisconsin study projected that floods may be lowered as much as 80% in watersheds with many wet- lands compared with similar basins with little or no wet- lands (Novitski 1978). Pothole wetlands in the Devils Lake basin of North Dakota store nearly 75% of the total ninoff (Ludden. et al. 1983). Recent studies at National Wildlife Refuges in North Dakota and Minnesota have demonstrated the role of wetlands in reducing streamflow. Inflow into the Agassiz National Wildlife Refuge and the Thief River Wildlife Management Area was 5.000 cubic feet per second (cfs). while outflow was only 1.400 cfs. Storage capacity of those areas reduced flood peaks at Crookston, Minnesota, by 1 .5 feet and at Grand Forks. North Dakota, by 0.5 feet (Bemot 1979). Drainage of wetlands was the most impor- tant land-use practice causing flood problems in a North Dakota watershed (Malcolm 1978; Malcolm 1979). Even northern peat bogs reduce peak rates of streamflow from snow melt and heavy summer rains (Verry and Boelter 1979). Destruction of wetlands through floodplain devel- opment and drainage has been partly responsible for re- cent major flood disasters throughout the country (Figure 21). Besides reducing flood levels and potential damage, wetlands may buffer the land from storm wave damage. Mangrove swamps are so effective in this regard that the Federal Insurance Administration's regulations state that 23 insured communities shall prohibit mangrove destruction or lose Federal flood insurance. Extensive mangrove stands protect many coastal communities in Florida. Past destruction of these wetlands for resort housing develop- ments has increased the potential for disaster. Other coastal wetlands and forested wetlands along lakes and large rivers may function similarly. Erosion Control Located between watercourses and uplands, wetlands help protect uplands from erosion. Wetland vegetation can reduce shoreline erosion in several ways, including: { I ) increasing durability of the sediment through binding with its roots, (2) dampening waves through friction and (3) reducing current velocity through friction (Dean 1979). This process also helps reduce turbidity and there- by improves water quality. Obviously, trees are good stabilizers of river banks. Their roots bind the soil making it more resistant to ero- sion, while their trunks and branches slow the flow of flooding waters and dampen wave heights. The banks of some rivers have not been eroded for 100 to 200 years due to the presence of trees (Leopold and Wolman 1957; Wolman and Leopold 1957; Sigafoos 1964). Among the grass or grass-like plants, bulrushes and reed have been regarded as the best at withstanding wave and current action (Kadlec and Wentz 1974; Seibert 1968). While most wetland plants need calm or sheltered water for establishment, they will effectively control erosion once established (Kadlec and Wentz 1974; Garbisch 1977). Wetland vegetation has been successfully planted to reduce erosion along U.S. waters. Willows, alders, ashes, cottonwoods, poplars, maples and elms are par- ticularly good stabilizers (Allen 1979). Successful emer- gent plants include reed canary grass, reed, cattail, and bulrushes in freshwater areas (Hoffman 1977). Along the Atlantic and Gulf coasts, smooth cordgrass and man- groves have been quite effective (Woodhouse, et al. 1976; Lewis and Thomas 1974). Water Supply and Groundwater Recharge Most wetlands are areas of groundwater discharge and some may provide sufficient quantities of water for public use. In Massachusetts, 40% to 50% of wetlands may be valuable potential sources of drinking water. At least 60 municipalities in the state have public wells in or very near wetlands (Motts and Heeley 1973). Urban develop- ment of wetlands and subsequent groundwater withdraw- als have caused saltwater intrusion into aquifers in many coastal areas. Prairie pothole wetlands store water which is important for wildlife and may be used for irrigation and livestock watering by farmers during droughts (Leitch 1981). These situations may hold true for many other states and wetland protection could be instrumental in solving current and future water supply problems. There is considerable debate over the role of wetlands in groundwater recharge. Recharge potential of wetlands varies according to numerous factors, including wetland type, geographic location, season, soil type, water table location and precipitation. Depressional wetlands like cy- press domes in Florida and prairie potholes in the Dakotas may contribute to groundwater recharge (Odum, et al. 1975; Stewart and Kantrud 1972; Winte'r and Carr 1980). Floodplain wetlands also may do this through overbank water storage (Mundorff 1950; Klopatek 1978). Marshes and swamps along the Ipswich River in Massachusetts occasionally operate as recharge areas (U.S. Department of the Interior 1962). Harvest of Natural Products A variety of natural products are produced by wet- lands, including timber, tish and shellfish, wildlife, peat, cranberries, blueberries, and wild rice. Wetland grasses are hayed in many places for winter livestock feed. Dur- ing other seasons, livestock graze directly in wetlands across the country. These and other products are harvest- ed by man for his use and provide a livelihood for many people. In the 49 continental states, an estimated 82 million acres of commercial forested wetlands exist (Johnson 1979). These forests provide timber for such uses as homes, furniture, newspapers and firewood. Most of these forests lie east of the Rockies, where trees like oak, gum, cypress, elm, ash and cottonwood are most impor- tant. The standing value of southern wetland forests alone is $8 billion. These southern forests have been harvested for over 200 years without noticeable degradation, thus they can be expected to produce timber for many years to come, unless converted to other uses. Conversion of bot- tomland forests in the Mississippi Delta to agricultural fields (e.g., soybeans) has reduced these wetlands by 75% (Giulio 1978; MacDonald, et al. 1979; Frederickson 1979). Wetlands also produce fish and wildlife for man's use. Commercial fishermen and trappers make a living from these resources (Figure 22). From 1956 to 1975, about 60% of the U.S. commercial landings were fishes and shellfishes that depend on wetlands (Peters, et al. 1979). Major commercial species associated with wetlands are menhaden, salmon, shrimp, blue crab and alewife from coastal waters and catfish, carp and buffalo from inland areas. Furs from beaver, muskrat, mink, nutria, and otter yielded roughly $35.5 million in 1976 (Demms and Purs- ley 1978). Louisiana is the largest fur-producing state and nearly all furs come from wetland animals. Freshwater wetlands provide a greater value of fur harvest per acre than estuarine wetlands (Chabreck 1979). 24 Fig.22. Estuarine-dependent fishes, like salmon, provide the majority of the commercial fisheries landings m the United States. Many wetlands produce peat which is used mainly for horticulture and agriculture in the United States. Over 52 million acres of peat deposits exist in the country. Five states account for more than 75% of the peat production: Michigan, Florida. Illinois, Indiana and New York (Car- penter and Farmer 1981). That is particularly interesting, since our largest peat reserves are in Alaska and Minneso- ta (Famham 1979). For centuries, peat has been used as a major fuel source in Europe. Recent shortages in other fuels, particularly oil and gas, have increased attention to wetlands as potential fuel sources. Unfortunately, peat mining destroys wetlands and most of their associated values. Recreation and Aesthetics Many recreational activities take place in and around wetlands. Hunting and fishing are popular sports. Water- fowl hunting is a major activity in wetlands, but big game hunting is also important locally. In 1980, 5.3 million people spent $638 million on hunting waterfowl and other migratory birds (U.S. Department of the Interior and Department of Commerce 1982). Saltwater recreational fishing has increased dramatically over the past 20 years, with half of this catch represented by wetland-associated species. Moreover, nearly all freshwater fishing is depen- dent on wetlands (Figure 23). In 1975 alone, sportfisher- men spent $13.1 billion to catch wetland-dependent fishes (Peters, et al. 1979). Other recreation in wetlands is largely non-consump- tive and involves activities like hiking, nature observation and photography, swimming, boating, and ice-skating. Many people simply enjoy the beauty and sounds of na- ture and spend their leisure time walking or boating in or near wetlands observing plant and animal life. The aes- thetic value of wetlands is extremely difficult to evaluate or place a dollar value upon. Nonetheless, it is a very important one because in 1980 alone. 28.8 million people (17% of the U.S. population) took special trips to ob- serve, photograph or feed wildlife (Figure 24). More- over, about 47% of all Americans showed an active interest in wildlife around their homes (U.S. Department of the Interior and Department of Commerce 1982). 25 Summary Marshes, swamps and other wetlands are an asset to society in their natural state. They provide numerous products for man's use and consumption, protect private property and provide recreational and aesthetic apprecia- tion opportunities. Destruction or alteration of wetlands eliminates or minimizes these values. Drainage of wet- lands, for example, eliminates all the beneficial effects of the marsh on water quality and directly contributes to flooding problems (Lee, et al. 1975). While the wetland landowner can derive financial profit from some of the values mentioned, the general public receives the vast majority of wetland benefits through flood and storm damage control, erosion control, water quality improve- ment and fish and wildlife resources. It is. therefore, in the public's best interest to protect wetlands to preserve these values for themselves and future generations. USFWS Fig. 23. Wetlands provide opportunities for recreational fishing. Marshall Fig. 24. Many Americans enjoy watching birds in and around wetlands. 26 References Allen, H H. 1979. Role of wetland plants in erosion control of npanan shorelines. In: P.E. Greeson, el al. Wetland Functions and Values: The State of Our Understanding. Amer, Water Resources Assoc, pp. 403-414. Bellrose, F.C. 1976. Ducks, Geese and Swans of North Amenca. Stackpole Books, Hamsburg, Pennsylvania. 544 pp. Bemot, C. 1979. Water Bank: Keeping Wetlands Wet. The Minnesota Volunteer 42(246):4. Boto, K.G. and W.H. Patrick. Jr. 1979. Role of wetlands in the removal of suspended sediments. In: P.E. Greeson, et al. Wetland Functions and Values: The State of Our Understanding. Amer. Water Re- sources Assoc, pp. 479-489. Brown, D.E.. C.H. Lowe, and J.F. Hausler. 1977. Southwestern ripar- ian communities: their biotic importance and management in An- zona. In: R R Johnson and DA. Jones (editors). Importance. Preservation and Management of Ripanan Habitat. A Symposium. USD. A. Forest Service. General Tech. Rept. RM-43. pp 201- 211. Carpenter, J.M. and G.T. Farmer. 1981. Peat Mining: An Initial As- sessment of Wetland Impacts and Measures to Mitigate Adverse Effects. EPA. Report. Washington. DC 61 pp Carter. V.. M.S Bedinger, R.P. Novitski and WO. Wilen. 1979. Water resources and wetlands. In: P.E. Greeson, et al. Wetland Functions and Values: The State of Our Understanding. Amer. Water Resources Assoc, pp. 344-376. Chabreck, R.H. 1979. Wildlife harvest in wetlands of the United States. In: P.E. Greeson. et al. Wetland Functions and Values: The State of Our Understanding. Amer. Water Resources Assoc, pp. 618-631. Clark, J.E. 1979. Fresh water wetlands: habitats for aquatic inverte- brates, amphibians, reptiles, and lish. In: P.E. Greeson, et al. Wet- land Functions and Values: The State of Our Understanding. Amer. Water Resources Assoc, pp. 330-343. Crow. J.H. and KB. MacDonald. 1979. Wetland values: secondary production. In: P.E. Greeson, el al. Wetland Functions and Values: The State of Our Understanding. Amer. Water Resources .'\ssoc. pp. 146-161. de la Cruz. A. A. 1979. Production and transport of detritus in wetlands. In: P.E. Greeson, et al. Wetland Functions and Values: The State of Our Understanding. Amer. Water Resources Assoc, pp. 162-174. Dean, R.G. 1979. Effects of vegetation on shoreline erosional pro- cesses. In: P.E. Greeson, et al. Wetland Functions and Values: The State of Our Understanding. Amer Water Resources Assoc, pp. 415-426. DeLaune, R.D., W.H. Patnck, Jr. and R J Buresk. 1978. Sedimenta- tion rates determined by l37Cs dating in a rapidly accreting salt marsh. Nature 275: 532-533. Demms, E.F., Jr. and D. Pursley (editors). 1978. North American Furbearers: Their Management. Research and Harvest Status in 1976. International Assoc, of Fish and Wildlife Agencies. 157 pp. Dwyer, T.J., G. Krapu and D. Janke. 1979. Use of prairie pothole habitat by breeding mallards. J. Wildl. Manage. 43(2): 527-531. Famham, R.S. 1979. Wetlands as energy sources. In: P.E. Greeson, et al. Wetland Functions and Values: The State of Our Understanding. Amer. Water Resources Assoc, pp. 661-672. Frederickson, L.H. 1979. Lowland hardwood wetlands: current status and habitat values for wildlife In: P.E. Greeson, et al. Wetland Functions and Values: The State of Our Understanding. Amer. Water Resources Assoc, pp. 296-306. Gates, J.M. and J.B. Hale. 1974. Seasonal Movement, Winter Habitat Use and Population Dislnbution of an East-Central Wisconsin Pheasant Population. Wise. Dept. Nat. Resources. Tech. Bull. No. 76. 56 pp. Garbisch, E.W.. Jr. 1977. Marsh development for soil erosion. In: Proc. of the Workshop on the Role of Vegetation in Stabilization of the Great Lakes Shoreline. Great Lakes Basin Commission, Ann Arbor. Michigan, pp. 77-94. Giulio, R.T.D. 1978. Wood Duck (Ai.\ sponsa) Brood Usage of Agri- cultural Fields and Wetlands in Concordia Pansh. Louisiana. M.S. Thesis. Louisiana State University, Baton Rouge. 137 pp. Good, RE.. D.F. Whigham and R.L. Simpson. 1978. Freshwater Wetlands. Ecological Processes and Management Potential. Aca- demic Press, New York. 378 pp. Goodwin, R.H. and W.A. Nienng. 1975. Inland Wetlands of the Unit- ed States. Evaluated as Potential Registered Natural Landmarks. National Park Service, Nat. Hist. Theme Studies. No. 2. 550 pp. Grant, R.R., Jr., and R. Patnck. 1970. Tinicum Marsh as a water punher. In: Two Studies of Tinicum Marsh. The Conservation Foundation, pp. 105-123. Greeson, P.B., JR. Clark and J.E. Clark (editors). 1979. Wetland Functions and Values: The State of Our Understanding. Proc. of the National Symposium on Wetlands. November 7-10, 1978. Amer. Water Resources Assoc, Minneapolis, Minnesota. 674 pp. Guthery, F.S. 1981. Playa basins and resident wildlife in the Texas Panhandle. In: Playa Lakes Symposium Proceedings. December 4- 5. 1979. Ariinglon, Texas.' U.S. Fish and Wildlife Service. FWS/OBS-81/07. pp. 47-51. Hawkins, P. and C.F. Leek. 1977. Breeding bird communities in a tidal freshwater marsh. Bull. N.J. Acad. Sci. 22(1): 12-17. Hindall, S.M. 1975. Measurements and Prediction of Sediment Yields in Wisconsin Streams. U.S. Geological Survey Water-Resources Investigations 54-75. 27 pp. Hoffman, G.R. 1977. Artificial establishment of vegetation and effects of fertilizer along shorelines of Lake Oahe and Sakakawea mainstem Missouri River reservoirs. In: Proc. Workshop on the Role of Vege- tation in Stabilization of the Great Lakes Shoreline. Great Lakes Basin Commission, Ann Arbor, Michigan, pp. 95-109. Jaworski, E. and C.N. Raphael. 1978. Fish, Wildlife, and Recreational Values of Michigan's Coastal Wetlands. Michigan Dept. Nat. Re- sources report. 209 pp. Johnsgard, P. A. 1956. Effects of water fluctuation and vegetation change on bird populations, particularly waterfowl. Ecology 37(4): 689-701. Johnson, R.L. 1979. Timber harvests from wetlands. In: P.E. Greeson, et al. Wetland Functions and Values: The State of Our Understand- ing. Amer. Water Resources Assoc, pp. 598-605. Kadlec, J. A. and W.A. Wentz. 1974. State-of-the-art Survey and Eval- uation of Marsh Plant Establishment Techniques: Induced and Natu- ral. Vol. I: Report of Research. Tech. Rept. D-74-9. U.S. Army Engineers Waterways Expt. Stat., Vicksburg, Mississippi. Klopatek, J.M. 1978. Nutrient dynamics of freshwater nvenne marshes and the role of emergent macrophytes. In: RE. Good, D.F. Whigham. and R.L. Simpson (editors). Freshwater Wetlands. Eco- logical Processes and Management Potential. Academic Press. New York. pp. 195-216. Kusler, J. A. 1983. Our National Wetland Hentage. A Protection Gui- debook. Environmental Law Institute, Washington, D.C. 167 pp. Lee.C.R.R.E. Hoeppel.P.G. Hunt and C. A. Carlson. 1976. Feasibil- ity of the Functional Use of Vegetation to Filter, Dewater. and Remove Contaminants from Dredged Matenal Tech. Rept. D-76- 4. U.S. Army Engineers, Waterways Expt. Sta., Vicksburg, Mississippi. Lee. G.F.. E. Bentley, and R. Amundson. 1975. Effects of marshes on water quality. In: A.D. Hasler(editor). Coupling of Land and Water Systems. Springer- Verlag, New York. pp. 105-127. Leitch. J- A. 1981 . Wetland Hydrology: State-of-the-art and Annotated Bibliography. Agnc. Expt. Stat., North Dakota State Univ., Fargo. No. Dak. Res. Rept. 82. 16 pp. Leopold, LB. and M.G. Wolman. 1957. River Channel Patterns Braid- ed, Meandering, and Straight. U.S. Geol. Survey Prof. Paper 282- B. Lewis, R.. and J. Thomas. 1974. Proc. of the First Annual Conference on Restoration of Coastal Vegetation in Flonda. Hillsborough Com- munity College, Tampa, Florida. Lieth, H. 1975. Pnmary productivity of the major vegetative units of the worid. In: H. Lieth and R H. Whiltaker (editors). Productivity of the Biosphere. Springer- Verlag, New York. pp. 203-316. 27 Ludden, A, P.. D.L. Frink. and D H. Johnson, 19S3, Water storage capacity of natural wetland depressions In the Devils Lake Basin of North Dakota, J, Soil and Water Cons, 3S(I I: 45-48. MacDonald. P,0,. W,E. Prayer, and J,K, Clauser. 1979, Documenta- tion. Chronology, and Future Projections of Bottomland Hardwood Habitat Loss m the Lower Mississippi Alluvial Plain. Vol. I: Basic Report. Li.S. Fish and Wildlife Service, Ecological Services, Vicks- burg, Mississippi. 13-^ pp. Malcolm, J. 1978. Study of Wetland Drainage in Relation to Souris River Water Quantity and Quality as It Impacts J. Clark Salyer National Wildlife Refuge. U.S. Fish and Wildlife Service Special Report . Malcolm. J. 1979. Relationship of Wetland Drainage to Flooding and Water Quality Problems and the Impacts on J. Clark Salyer National Wildlife Refuge. U.S. Fish and Wildlife Service. Special Report. McHugh, J.L. 1966. Management of Estuarine Fishes. Amer. Fish Soc, Spec. Pub. No. 3: 133-154. Merrell, T.J., Jr. and K.V. Koski. 1979, Habitat values of coastal wetlands for Pacific Coast salmonids. In; P.E. Greeson. et al. Wet- land Functions and Values: The State of Our Understanding. Amer. Water Resources Assoc, pp. 256-266. Motts, W.S. and R.W. Heeley. 1973. Wetlands and groundwater. In: J.S. Larson (editor). A Guide to Important Characteristics and Val- ues of Freshwater Wetlands in the Northeast. University of Massa- chusetts, Water Resources Research Center. Pub. No. 31. pp. 5-8. Mundorff, M.J. 1950. Floodplain Deposits of North Carolina Piedmont and Mountain Streams as a Possible Source of Groundwater Supply. N.C. Div. Mineral Res. Bull. 59. Newton, R.B. 1981. New England Wetlands: A Pnmer. University of Massachusetts, Amherst. M.S. Thesis. 84 pp. Novitski, R.P. 1978. Hydrology of the Nevin Wetland Near Madison, Wisconsin. U.S. Geological Survey, Water-Resources Investiga- tions 78-48. 25 pp. Odum, E.P. 1961 . The role of the tidal marshes in estuarine production. N.Y. Stale Conservationist 15: 12-15. Odum, H.T., K.C. Ewel, W.J. Mitsch. and J.W. Ordway. 1975. Recy- cling Treated Sewage Through Cypress Wetlands in Flonda Uni- versity of Florida, Center for Wetlands, Gainsville. Occassional Pub. No. 1. Patnck, W.H., Jr., G. Dissmyer, D.D. Hook, V.W. Lambou, H.M. Leitman. and C.H. Wharton. 1981. Characteristics of wetlands ecosystems of southeastern bottomland hardwood forests In: JR. Clark and J. Benforado (editors) Report on a Bottomland Hard- wood Wetlands Workshop Lake Lanier, Georgia. June 1-5, 1980. National Wetlands Technical Council, Washington, DC pp. 64-89. Peters. D.S.D.W. Ahrenholz, andT.R. Rice. 1979. Harvest and value of wetland associated fish and shellhsh. In: Greeson, et al. Wetland Functions and Values: The State of Our Understanding. Amer. Water Resources Assoc, pp. 606-617. Seibert, P. 1968. Importance of natural vegetation for the protection of the banks of streams, rivers, and canals. In: Nature and Environ- ment Series (Vol. Freshwater), Council of Europe, pp. 35-67. Sigafoos, R.S. 1964. Botanical Evidence of Floods and Floodplain Deposition, Vegetation, and Hydrologic Phenomena. U.S. Geol. Survey Prof. Paper 485- A. Sloey. W.E., F.L. Spangler, and C.W. Fetter, Jr. 1978. Management of freshwater wetlands for nutrient assimilation. In: R.E. Good, et al. Freshwater Wetlands. Ecological Processes and Management Potential. Academic Press, New York. pp. 321-340. Smith, A.G., J.H. Stoudt and J.B Gollop. 1964. Prairie potholes and marshes. In: J. P. Linduska (editor). Waterfowl Tomorrow. U.S. Fish and Wildlife Service, Washington, DC. pp. 39-50. Stewart, RE. and HA Kantrud. 1972. Vegetation of Praine Potholes, North Dakota, in Relation to Quality of Water and Other Environ- mental Factors. U.S. Geol. Survey Prof. Paper 585-D. 36 pp. Stuber, P.J.R. 1983. User's Handbook for the Wetland Values Data- base. U.S. Fish and Wildlife Service. W/RMMG-83/W12. 47 pp. Swift, B L. 1980. Breeding Bird Habitats in Forested Wetlands of West-Central Massachusetts. M.S. Thesis, Univ. of Massachusetts, Amherst. 90 pp. Teal, J and M. Teal. 1969. Life and Death of the Salt Marsh. Audubon/ Ballantme Books. New York. 274 pp. Turner, RE, 1977, Intertldal vegetation and commercial yields of pen- aeid shnmp. Trans. Amer. Fish. Soc. 106: 411-416. U.S. Army Corps of Engineers. 1976. Natural Valley Storage: A Part- nership with Nature. New England Division, Waltham. Massachusetts. U.S. Department of the Interior. 1962. The value of wetlands to modem society. Proc. of Project MAR Conf., Nov. 12-16. 1962. Inter. Union for the Conserv. of Nature. Publication, New Series No. 3: 57-63. U.S. Department of the Intenor and Department of Commerce. 1982. 1980 National Survey of Fishing, Hunting, and Wildlife-Associated Recreation. Fish and Wildlife Service and Bureau of Census. 156 PP US, Water Resources Council, 1977. Estimated Flood Damages. Ap- pendix B. Nationwide Analysis Report. Washington, D.C. U.S. Water Resources Council. 1978. The Nation's Water Resources 1975-2000. Vol. 1: Summary. Washington, DC. 86 pp. Ven7, E.S. and D.H. Boelter. 1979. Peatland hydrology. In: P.E. Greeson, et al. Wetland Functions and Values: The State of Our Understanding. Amer. Water Resources Assoc, pp. 389-402. Wauer. R.H. 1977. Signihcance of Rio Grande nparian system upon the avifauna. In: R.R. Johnson and DA. Jones (editors). Impor- tance, Preservation and Management of Ripanan Habitat. A Sym- posium, U.S.D. A. Forest Service. General Tech. Rept. RM-43- pp. 165-174. Weller, M.W. and C. E. Spatcher. 1965. Role of Habitat in the Distn- bution and Abundance of Marsh Birds. Iowa Agnc. Home Econ. E.xp. Stn. Spec. Rep. No. 43. 31 pp. Wharton, C.H. 1970. The Southern River Swamp - A Multiple Use Environment. School of Business Administration, Georgia State University. 48 pp. Wharton, C.H. 1978. The Natural Environments of Georgia. Georgia Dept. of Nat. Res., Atlanta. 227 pp. Wharton, C.H. and W.M. Kitchens. 1982. The Ecology of Bottomland Hardwood Swamps of the Southeast: A Community Profile. U.S. Fish and Wildlife Service, Biological Services Program, Washing- ton, DC. FWS/OBS - 81/37. 133 pp. Williams, J.D. and C.K. Dodd, Jr. 1979. Importance of wetlands to endangered and threatened species. In: P.E. Greeson, et al. Wetland Functions and Values: The State of Our Understanding. Amer. Water Resources Assoc, pp. 565-575. Windom, H.L. 1977. Ability of Salt Marshes to Remove Nutrients and Heavy Metals from Dredged Malenal Disposal Area Effluents. Technical Rept. D-77-37. U.S. Army Engineers, Waterways E.xpt. Sta., Vicksburg, Mississippi. Winter, T.C. and MR. Cart. 1980. Hydrologic Setting of Wetlands in the Cottonwood Lake Area, Stutsman County, North Dakota. U.S. Geological Survey. Water Resources Investigations 80-99. 42 pp. Wolman, W.G. and L.B. Leopold. 1957. River Floodplains. Some Observations on Their Formation. U.S. Geol. Survey Prof. Paper 282-C. Woodhouse, WW., E.D. Seneca, and S.W. Broome. 1976. Propaga- tion and Use of Spartina altemitlora for Shoreline Erosion Abate- ment. U.S. Army Coastal Engineering Research Center. Tech. Rept. 76-2. 28 CURRENT STATUS AND TRENDS OF U.S. WETLANDS Current Status Wetlands exist in every state and their abundance var- ies due to climate, soils, geology, land use and other regional differences. Figure 25 shows the estimated ex- tent of wetlands within each of the 50 states. Alaska, Louisiana, and Florida contain the most wetland acreage. Other states with considerable acreage include Alabama. Arkansas, Georgia, Maine, Michigan, Minnesota, Mis- sissippi, North Carolina, South Carolina and Wisconsin. Smaller states like Delaware and New Jersey are also well represented by wetlands. In the mid-1970's, an estimated 99 million acres of wetlands existed in the conterminous United States (Frayer, et al. 1983). This amounts to an area equal to the size of California. Only 5% of the land surface of the lower 48 states contains wetland. Alaska and Hawaii are not included in these figures. Estimates of Alaska's wet- land resource vary, but 200 million acres probably exist. The abundance of major wetland types in the conter- minous U.S. is shown in Figure 26. Palustrine wetlands, including freshwater marshes and swamps, comprise 94% of the wetlands in the lower 48 states. In the mid- 1970"s, 93.7 million acres of palustrine wetlands were present, with over half of this acreage being forested wetland and about a third being emergent wetland. Re- maining palustrine wetland acreage equals an area about the size of California. By contrast, only 5.2 million acres of estuarine wetlands existed by the mid-1970"s. This amounts to an area approximately the size of Massachu- setts and represents only 0.3% of the land surface of the lower 48 states. , , , . OF M £ X ; C ( ) LEGEND I I Less than 5% 5-15% 15-250/0 Greater than 25% Fig. 25. Relative abundance of wetlands in the U.S. (1984). Percent of each state represented by wetland is shown. 29 MILLIONS OF ACRES 5 10 15 20 25 30 35 40 45 50 ESTUARINE INTERTIDAL FLATS ESTUARINE EMERGENT WETLANDS ESTUARINE FORESTED AND SCRUB— SHRUB WETLANDS PALUSTRINE EMERGENT WETLANDS PALUSTRINE SCRUB- SHRUB WETLANDS PALUSTRINE FORESTED WETLANDS OTHER PALUSTRINE WETLANDS Fig. 26. Extent of wetlands in the conterminous U.S. in the mid-1970's (from Frayer, et al. 1983). Estimates of the original wetland acreage present at this country's settlement vary, since the available infor- mation is scattered and largely incomplete. However, a very reliable account places this acreage at 215 million acres for the conterminous United States (Roe and Ayres 1954). Thus, today's wetland resource in the lower 48 states probably represents less than 46% of our original wetlands (Figure 27). 215 MILLION ORIGINAL ACRES Fig. 27. Original and remaining acreages of wetlands in the conter- minous U.S. (from Roe and Ayres 1954; Frayer, et al. 1983). 30 Forces Changing Wetlands Wetlands represent a dynamic natural environment which are subjected to both human and natural forces. These forces directly result in wetland gains and losses as well as affect their quality. Table 2 outlines major causes of wetland loss and degradation. Table 2. Major causes of wclland loss and degradation (Zinn and Copeland I9H2: Gosselink and Ban- nmnn 1980). Human Threats Direct: 1 . Drainage for crop production, timber production and mosquito control. 2. Dredging and stream channelization for naviga- tion channels, flood protection, coastal housing developments, and reservoir maintenance. 3. Filling for dredged spoil and other solid waste disposal, roads and highways, and commercial, residential and industrial development. 4. Construction of dikes, dams, levees and seawalls for flood control, water supply, irrigation and storm protection. 5. Discharges of materials (e.g., pesticides, herbi- cides, other pollutants, nutrien' loading from do- mestic sewage and agricultural runoff, and sediments from dredging and filling, agricultural and other land development) into waters and wetlands. 6. Mining of wetland soils for peat, coal, sand, gravel, phosphate and other materials. Indirect: 1 . Sediment diversion by dams, deep channels and other structures. 2. Hydrologic alterations by canals, spoil banks, roads and other structures. 3. Subsidence due to extraction of groundwater, oil. gas. sulphur, and other minerals. Natural Threats: 1. Subsidence (including natural rise of sea level) 2. Droughts 3. Hurricanes and other storms 4. Erosion 5. Biotic effects, e.g., muskrat. nutria and goose "eat-outs." Natural events influencing wetlands include rising sea level, natural succession, the hydrologic cycle, sedimen- tation, erosion, beaver dam construction and fire. The rise in sea level, for example, both increases and de- creases wetland acreage depending on local factors. Along the eastern shore of Chesapeake Bay. it is allowing coastal wetlands to establish in former upland pine areas, while permanently flooding wetlands at lowest eleva- tions. Rising sea level is one factor converting salt marshes to bay bottoms in Louisiana. Natural succession and fire typically change the vegetation of a wetland usually with no net loss or gain. However, fire in Alas- ka's permafrost wetlands may convert the area to non- wetland. Disturbance of the vegetative cover can cause the frostline to recede, and dry site plants may become established. The hydrologic cycle refers to the natural cycle of wet and dry periods over time . Great Lakes water levels, for example, fluctuate drastically on a roughly 20- year cycle. This adds an important dimension to wet- lands, making them vulnerable to drainage during dry periods. Similar conditions have resulted in wetland drainage in the Prairie Pothole Region. The activities of beavers create or alter wetlands by damming stream chan- nels. Thus, natural forces act in a variety of ways to create, destroy and modify wetlands. Human actions are particularly significant in determin- ing the fate of wetlands. Unfortunately, many human activities are destructive to wetlands, either converting them to agricultural or other lands or degrading their quality. Key human impacts include drainage for agricul- ture; channelization for flood control; filling for housing, highway, industry and sanitary landfills; dredging for navigation channels, harbors and marinas; reservoir con- struction; timber harvest; peat mining; oil and gas extrac- tion; strip mining; groundwater extraction; and various forms of water pollution and waste disposal. A few ac- tions do, however, create wetlands. Construction of farm ponds and, in some cases, reservoirs and irrigation pro- jects may increase wetland acreage, although valuable natural wetlands may be destroyed in the process. Marsh creation and restoration of previously altered wetlands can also be beneficial. Federal and state fish and wildlife agencies traditionally manage wetlands to improve their value to waterfowl. Wetland protection efforts serve to help maintain and enhance our Nation's wetland re- sources, despite mounting pressures to convert them to other uses. Recent National Wetland Trends Information on historical wetland gains and losses is limited and often subjective. The Service recently com- pleted a scientifically sound study of the current status and recent trends of U. S. wetlands between the mid- 1950's and mid-1970's (Frayer, et al. 1983). Ahhough the results of this study are valid at the national level, few comparable statistics exist for individual states. The fol- lowing discussions will summarize the results of the Ser- vice's national study and other regional studies. Specific problem areas where wetlands are in greatest jeopardy will be highlighted. 31 Recent Gains o < O WETLANDS GAINS + 3- + 2- ~ + 1- - ' ! ' ' ' HRP^ I ■ 1 ^^^ -■-- L— .1 ■- / y 0.5- - Wi- •'// -•y / / / / -1 - ■' / / / / / '// hi''''- ^ / / /// '// ^ / / ^ / / ' / / l.-'O-v. ^ / / ►'■■"■.■'* ' / / f'.';':- -2- '// '// &'•'■■ <' / / e.-:.- ^/ / '•";■?'."'■ /// '' // ^ / / (SiS ^ // ' / / ' / / ■'// ^ / / -3- ^ // ' / / ' / / ''/ / ' // ^ // ^/ / ^ / / ^ / / ' / / •" -4- ' / / ' / / ' / / ' / / ^ / / ' / / ' / / ' / / r , ' / / l\._. '// -5 - ' // '/ / ' / / ' / / ' / / ' / / ' // ' / / ■ / / -6- ■ / / WETLAND L OSJ >ES ' LEGEND ini PALUSTRINE OPEN WATER I PALUSTRINE FLAT 0 ESTUARINE WETLAND ^ PALUSTRINE EMERGENT WETLAND |g PALUSTRINE SCRUB— SHRUB WETLAND V\ PALUSTRINE FORESTED WETLAND Fig. 28. Net losses and gains in wetlands of the conterminous U.S. between the mid-50's and mid-70's (from Prayer, et al. 1983). Slight net gains in deepwater habitats — manmade lakes and reservoirs and coastal waters — and in two wetland types — inland flats and ponds — took place between the mid-50"s and mid-70"s (Figure 28). Lake acreage increased by 1 .4 million acres with 94% of this gain occurring in the eastern half of the country. These new lakes and reservoirs were mostly created from up- lands, although vegetated wetlands were also destroyed. Some new wetlands, however, have formed along the edges of these new waterbodies. During the same period, coastal open waters increased by 200,000 acres. Most of this gain came from Louisiana at the expense of coastal wetlands which are being perma- nently flooded at an accelerating rate. Causes of this change from marsh to open water are numerous and com- plicated and include natural rise of sea level, subsidence of the coastal plain, levee construction, channelization, and oil and gas extraction. Two wetland types experienced gains between the mid- 50's and mid-70's: inland flats and ponds. Two hundred thousand acres of unvegetated wetland flats and 2. 1 mil- lion acres of ponds were created. Pond acreage nearly doubled from 2.3 million acres to 4.4 million acres, pri- marily due to farm pond construction in the Central and Mississippi Fly ways. Most of this pond acreage came from former upland, although 145,500 acres of forested wetlands and 385.000 acres of emergent wetlands were changed to open water. Recent Losses Despite these modest gains, wetland losses were enor- mous. In the mid-1950's, there were an estimated 108. 1 million acres of wetlands in the lower 48 states (Frayer, et al. 1983). Just 20 years later, these wetlands were re- duced to 99 million acres, despite some gains in wetlands due to reservoir and pond construction, beaver activity, and irrigation and marsh creation projects. This loss of 9 million acres equates to an area about three times the size of Connecticut or twice the sizeof New Jersey. Actually, 1 1 million acres of our most valuable natural wetlands were destroyed, but these acreage losses were minimized by gains of 2 million acres of newly created wetlands, giving a net loss of 9 million acres. The average rate of wetland loss from the mid-50's to the mid-70"s was 458,000 acres per year: 440,000 acres of palustrine losses and 18,000 acres of estuarine wetland losses. This annual loss equals an area about half the size of Rhode Island. Agricultural development involving drainage was re- sponsible for 87% of recent national wetland losses, while urban development and other development caused only 8% and 5%- of the losses, respectively (Figure 29). Agriculture had the greatest impact on forested wetlands 32 8% Urban Development V 5% Other Development '^>yj: ^i 'J^i'^ysyo/o Agriculture oi;)^;-r~^' 0) 3 < o (0 o m 0) o re •^ o OT :\ r \/M > ' ■ / \ ', / \ - PALUSTRINE WETLAND TYPES Fig. 29. Causes of recent wetland losses (mid-1950's to mid-1970's) in the conterminous U.S.; losses to agriculture are highlighted (from Frayer, et al. 1983). and emergent wetlands, with losses of 5.8 and 2.7 million acres, respectively. In addition, 0.4 million acres of scrub-shrub wetlands were converted to agricultural use between the mid-50's and the mid-70's. The most extensive wetland losses occurred in Louisi- ana, Mississippi, Arkansas, North Carolina, North Dako- ta, South Dakota, Nebraska, Florida and Texas. Greatest losses of forested wetlands took place in the Lower Mis- sissippi Valley with the conversion of bottomland hard- wood forests to farmland. Shrub wetlands were hardest hit in North Carolina where pocosin wetlands are being converted to cropland or pine plantations or mined for peat. Inland marsh drainage for agriculture was most significant in the Prairie Pothole Region of the Dakotas and Minnnesota, Nebraska's Sandhills and Rainwater Basin and Florida's Everglades. Between the mid-50's and mid-70's, estuarine wetland losses were heaviest in the Gulf states, i.e., Louisiana, Florida and Texas. Most of Louisiana's coastal marsh losses were attributed to submergence by coastal waters. In other areas, urban development was the major direct man-induced cause of coastal wetland loss. Dredge and fill residential develop- ment in coastal areas was most significant in Florida, Texas, New Jersey, New York and California. Regional Historical Perspective While the national decline in wetlands is dramatic, losses in particular regions and states are even more star- tling. For example, California has lost over 90% of its original wetland resource (U.S. Fish and Wildlife Service 1977). Less than 5% of Iowa's natural wetlands exist and over 90% of the wetlands in Nebraska's Rainwater Basin have been destroyed (Bishop 1981; Farrar 1982). Only 20% of the original bottomland hardwood forests in the Lower Mississippi Alluvial Plain remain (McDonald, et al. 1979). Other states with less than half of their original wetlands or certain types include Michigan, Minnesota, Louisiana, North Dakota, and Connecticut (Table 3). By 1955, Michigan had lost 8 million acres of wetlands (Michigan Department of Natural Resources 1982). Ohio, Indiana and Illinois probably have lost over half of their wetlands, but supportive statewide data are not available. In selected areas of Illinois, wetland losses have been dramatic. For example, virtually all wetlands have been eliminated in the East-Central Region, Big Prairie Region and Green River Watershed, while 98% of Illinois' southern bottomland swamps have been de- stroyed (Illinois Department of Conservation 1983). 33 3.0 2.5-- 2.0 -- lOWAS NATURAL MARSHES 50.000 S 1 -- 26.500 0 5 CALIFORNIA S WETLANDS Early 1800 s + Estimates prror to 1900 range from 4 1 to 5 million acres Fig. 30. Historical losses of wetlands in Iowa (a) and California (b) (from Bishop 1981 and U.S. Fish and Wildlife Service 1977). In many areas, wetland destnjction was greatest from the mid-1800's to the early 1900's due to passage of the Swamp Land Acts of 1849, 1850. and 1860. These acts granted all swamp and overflow lands to 15 states: Ala- bama, Arkansas, California, Florida, Illinois. Indiana, Iowa, Louisiana. Michigan. Minnesota, Mississippi, Missouri, Ohio, Oregon and Wisconsin (Shaw and Fre- dine 1956). These states were to drain these wetlands for agriculture by constructing levees and drainage ditches. About 65 million acres had been transferred from the Federal government to the states by 1954. Historical losses of Iowa's and California's wetlands illustrate ac- celerated wetland destruction in the late 1800's and early 1900's (Figure 30). The original 1 3 states had retained all lands within their borders when the Federal government was established and Texas also kept all its land at the time of annexation. Interestingly, the extensive coastal wetlands of these 14 states were never owned by the Federal government and, by contrast, coastal wetland losses have been more re- cent. Between 1954 and 1978, the loss rate of coastal wetland doubled due primarily to post-war urban and industrial development in the U.S. coastal zone and to accelerated erosion and subsidence of Louisiana's vast coastal marshes (Gosselink and Baumann 1980). While wetland losses in some states or regions may have been heaviest at the turn of the century, loss rates remain high in many areas. Between 1955 and 1978, Kansas lost 40% of its wetlands (Elliott, U.S.F.W.S., pers. comm.). In Illinois, an estimated 20% of its wet- lands are destroyed every decade (Great Lakes River Ba- sin Commission 1981). About 6.7 million acres of Ohio's original wetlands have been drained, while overhalf of its wetlands along Lake Erie have been destroyed since 1954 (Weeks 1974). Kentucky's wetlands along the Mississippi and Ohio Rivers have been reduced by 37% in the past twenty years (Kentucky Department of Fish and Wildlife Resources 1983). Heavy annual losses are continuing in the bottomland hardwood forested wetlands of the Lower Mississippi Delta and accelerating in poco- sin wetlands along the North Carolina coast ( MacDonald. et al. 1979; Richardson, et al. 1981). Some examples of recent wetland loss rates are shown in Table 4. Recent trends in Delaware. Maryland, and New Jersey illustrate the effect of state wetland protection. Before passage of the Wetlands Act in 1973, Delaware was los- ing almost 450 acres of estuarine wetland each year. After the law, losses dropped to just 20 acres annually (Har- disky and Klemas 1983). Coastal wetland losses in Mary- land and New Jersey were also drastically reduced through wetland regulations. In addition to state laws, the Clean Water Act added a level of Federal protection to these wetlands nationwide in the early 1970's. Effective implementation of similar laws in other states has prob- ably reduced wetland losses substantially. Current Regional Development Pressures In the Northeast, coastal wetlands are now well pro- tected by state laws. Inland wetlands, however, continue to be vulnerable to development pressures in many areas. 34 although they are protected to varying degrees by the Federal government through the Clean Water Act and by a few states with wetland protection laws. Urbanization seriously threatens inland wetlands in northern New Jer- sey and near other growing urban centers. Peat mining and resort development are major causes of wetland losses in the Pocono Region of Pennsylvania. Agricultur- al impacts are greatest in the bottomland hardwood swamps of Delaware, Maryland and Virginia and in New York's mucklands. Agricultural drainage of wetlands is continuing to de- stroy large tracts of wetlands in the Southeast, especially in the Lower Mississippi Delta, Florida, and along the coastal plain of North Carolina. Bottomland hardwoods are being clearcut for timber, and then cleared and drained for crop production, chiefly soybeans. Pocosin wetlands are similarly used as well as being mined for peat. Many inland wetlands are being converted to pine plantations throughout the Southeast. Phosphate mining in Florida and North Carolina is destroying considerable wetland acreage. Puerto Rico's inland marshes ("savan- nahs") are being transformed into sugar cane farms. Coastal wetland destruction has slowed in most states with passage of protection laws, but enforcement may present problems. Agricultural development in the Midwest com belt and Great Plains remains the greatest threat, by far, to the remaining inland wetlands. Coastal marshes along the Great Lakes are continuing to be impacted by industrial, residential, and agricultural development. Although sev- eral of the Midwestern states have laws protecting certain wetlands or regulating certain activities in wetlands, agri- cultural drainage is still largely unregulated. In the western states, agricultural development remains the primary threat to wetlands. Drainage and irrigation impacts, such as the Garrison Diversion, continue at high Table 3. Examples of wetland losses in various states. State or Region Iowa's Natural Marshes California Nebraska's Rainwater Basin Mississippi Alluvial Plain Michigan North Dakota Minnesota Louisiana's Forested Wetlands Connecticut's Coastal Marshes North Carolina's Pocosins South Dakota Wisconsin Original Wetlands (acres) 2.333,000 5.000.000 94.000 5.000.000 Today's Wetlands (acres) 26.470 450.000 8.460 24.000.000 5,200,000 11.200.000 3.200,000 1,000,000 18,400,000 8.700,000 11.300.000 5.635.000 30.000 15.000 2,500.000 1.503.000* 2,000,000 1,300,000 7c of Wetlands Lost 99 91 91 78 71 60 53 50 50 40 35 32 Soiace Bishop (1981. pers. comm.) U.S. Fish and Wildlife Service (1977) Farrar (1982) MacDonald, et al. (1979) Michigan Department of Nat'! Res. (1982) Elliott, U.S. FWS, (pers. comm.) Univ. of Minn. (1981) Turner and Craig (1980) Niering (1982) Richardson, et al. (1981) Elliott. U.S. FWS. (pers. comm.) Wisconsin Dept. of Nat. Res. (1976) 10.000.000 6.750.000 *Only 695.000 acres of pocosins remain undisturbed; the rest are partially drained, developed or planned for development 35 Table 4. Examples of recent wetland loss rates. State or Region Lower Mississippi Alluvial Plain Louisiana's Forested Wetlands North Carolina's Pocosins Prairie Pothole Region Louisiana's Coastal Marshes Great Lakes Basin Wisconsin Michigan Kentucky New Jersey's Coastal Marshes Palm Beach County, Florida Maryland's Coastal Wetlands New York's Estuarine Marshes Delaware's Coastal Marshes * Loss rate after passage of state coastal wetland protection laws. rates. With increased tension over water rights, remain- ing wetlands may be deprived of sufficient quantities of water to function properly. This is especially true in Colo- rado where high population growth has increased demand for water. Urban and industrial development is destroying wetlands along the Great Salt Lake and near other urban centers. Along the West Coast, coastal wetlands are generally protected by state laws, yet they are still under heavy pressure for urban and industrial development. Inland wetlands remain subject to agricultural pressures, par- ticularly in California's Central Valley and the Great Ba- sin of Nevada, Oregon, and Idaho. Degradation of existing wetlands through urban and agricultural runoff remains a problem. Alaska's wetlands were once subject to very few devel- opment pressures. With the discovery of significant de- Loss Rate (acres/year) Simrce 165,000 MacDonald. et al. (1979) 87,200 Turner and Craig (1980) 43,500 Richardson, et al. (1981) 33,000 Haddock and DeBates (1969) 25,000 Fruge (1982) 20.000 Great Lakes River Basin Comm. (1981) 20.000 Wisconsin Department of Natural Resources (1976) 6,500 Weller(1981) 3,600 Kentucky Department of Fish & Wildlife Resources (1983) 3.084 50* Ferrigno, et al. (1973) J AC A Corporation (1982) 3,055 1,000 20* 740 444 20* U.S. Fish and Wildlife Service (1982) Redelfs (1983) O'Connor and Terry (1972) Hardisky and Klemas (1983) posits of oil and gas and the subsequent pipeline construction and energy development, many wetlands have recently been altered. The oil boom has also in- creased human population densities, resulting in in- creased pressure on wetlands for urban development. Increases in timber harvest, mining, and agricultural ac- tivities are also threatening large areas of wetland in Alaska. National Problem Areas While wetland losses and degradation continue throughout the country, there are several areas where wetlands are in greatest jeopardy from a national stand- point. These areas and their threatened wetland types include: (1) estuarine wetlands of the U.S. coastal zone, (2) Louisiana's coastal marshes, (3) Chesapeake Bay's 36 submerged aquatic beds, (4) South Florida's palustrine wetlands, (5) Prairie Pothole Region's emergent wet- lands, (6) wetlands of Nebraska's Sandhills and Rain- water Basin, (7) forested wetlands of the Lower Mississippi Alluvial Plain, (8) North Carolina's poco- sins, and (9) western riparian wetlands. Most of these regions are under intense pressure from agricultural inter- ests, while the effect of urbanization and industrial devel- opment is more localized. Northern New Jersey is used to illustrate these non-agricultural impacts. The following subsections summarize the nature of these national problems. Estuahne Wetlands of the U.S. Coastal Zone Estuarine marshes and mangrove swamps are highly regarded for their commercial and recreational fisheries value. Protecting these wetlands has, however, only re- cently received national attention. In the past, coastal 10 (/> lU E U < u. O (0 z o COASTAL WETLAND LOSS IN U.S. 0.2% loss/yr. 0.5% loss/yr. 1922 YEARS 1954 1974 Fig.31. Rate of coastal wetland loss in the conterminous U.S. (from Gosselink and Baumann 1980). Estimates include both estuarine and tidal freshwater wetland losses. wetlands were viewed chiefly as potential sites for devel- opment. Between the 1950's and the mid-I970"s, wet- land losses were heaviest (Figure 31). The National Marine Fisheries Service ( 1983) estimated annual fishery losses at $208 million due to estuarine marsh losses from 1954 to 1978. Accelerating wetland destruction aroused much public concern which led to the passage of tidal wetland protection laws in many coastal states and to stricter enforcement of existing Federal laws in the 1960's and the 1970's. Unfortunately, over half of the coastal wetlands in the lower 48 states have been de- stroyed. Nonetheless, estuarine wetlands are still sought after by developers for residential and resort housing, marinas, and other uses. Estuarine wetland losses have been greatest in 5 states: California, Florida, Louisiana, New Jersey and Texas. Louisiana is losing them at a rate of 25,000 acres per year due to coastal subsidence and other causes (Fruge 1982; see the following subsection for discussion). Outside of Louisiana, coastal wetland losses are directly related to population density (Gosselink and Baumann 1980). Ur- banization (i.e., residential home construction) has been responsible for over 90% of the losses directly attributed to human activites (Figure 32; Frayer,etal. 1983). Accel- erated urban development and increased groundwater withdrawals have resulted in salt water contamination of public water supplies in many coastal communities. n-= original' shoreline of SAN FRANCISCO BAT BEFORE FILLING AND DIKING EVCLOPWCHT COMWISI Fig. 33. The status of wetland filling and diking in San Francisco Bay prior to the mid-1960's (from Hedgpeth 1978). 37 Fig. 32. Filling ol esluarine wetlands lor reMdentmi housing in Long Island. New York and olher coastal areas was particularly heavy in the 1950's and 1960's. Wetland laws in most coastal states now protect these valuable wetlands. While most of the coastal wetlands exist along the Alaskan, Atlantic and Gulf coasts. San Francisco Bay represents an interesting example of tidal wetland alter- ation. San Francisco Bay is an important wintering area for waterfowl, especially whistling swans, pintails, shov- elers, canvasbacks, scaup, and ruddy ducks. About 25% of the continent's population of whistling swans winter here as does roughly 409r of North America's ruddy ducks (Bellrose 1976). Originally, more than 200.000 acres of coastal marshes existed in the Bay region. To- day, less than 20% remain (U.S. Fish and Wildlife Ser- vice and California Department of Fish and Game 1979). Most of the original wetlands were filled for urban and industrial development, while many remaining tidal marshlands were diked to create salt-evaporating ponds (Figure 33). Since 1976, coastal wetlands have been pro- tected through the California State Coastal Act. while the San Francisco Bay Conservation and Development Com- mission has been active in wetlands preservation since 1969. Efforts are now needed to restore degraded or modified wetlands to a more natural condition, so that they can once again serve as valuable fish and wildlife habitats. All coastal states in the lower 48, except Texas, have enacted special laws to protect estuarine wetlands. These laws vary considerably in their degree of protection, since a few exempt major activities that alter wetlands or apply only to state-owned lands. Section 10 of the River and Harbor Act of 1899 and Section 404 of the Clean Water Act of 1977 mandate a strong Federal role for protecting the Nation's coastal wetlands. Federal permits are re- quired for most types of construction in estuarine wet- lands. While the regulatory tools to protect coastal wetlands are in place, continued enforcement of existing laws is required to maintain the integrity of the remaining wetlands. In addition to regulation, the Coastal Barrier Resources Act of 1982 removes Federal subsidies and discourages development of approximately 700 miles of designated coastal barriers and adjacent wetlands. Its greatest impacts in reducing coastal wetland loss should occur in Alabama, Florida. North and South Carolina and Texas. Louisiana's Coastal Marshes Louisiana possesses roughly one-third of the coastal marshes in the conterminous U.S. (Turner and Gosselink 1975). The state's multi-million dollar commercial in- shore shrimp fishery is directly proportional to the area of intertidal emergent wetland (Turner 1979). Along most 38 coasts, salt marshes appear to be maintaining themselves through marsh building or accretion despite a worldwide rise in sea level. In Louisiana, however, this is not true as large expanses of coastal marshes are being permanently flooded by rising sea level (Figure 34). Vertical marsh accretion has not kept pace with coastal submergence over the past 30 years. The marsh is accreting at a rate of 0.33 inches yearly, while submergence is occurring at 0.5 inches per year (DeLaune, et al. 1983). The rate of subsi- dence here is more than five times as high as the average rate of global sea level rise over the past century ( Boesch. et al. 1983). Currently, an estimated 40 square miles or 25,000 acres of coastal marshes are lost each year (Fruge 1982). Besides direct losses, salt water intrusion is killing freshwater vegetation in tidal freshwater marshes and converting these types to more brackish wetlands or open water. It also has accelerated the advance of the preda- ceous oyster drill into productive oyster beds. The causes of Louisiana coastal marsh loss are numer- ous and complicated (Craig, et al. 1980). A combination of factors both natural and man-induced are responsible. Coastal subsidence, rise in sea level and the cyclical pro- cesses of Mississippi River Delta growth and deteriora- tion represent the major natural forces. The Mississippi River is trying to shift its course into the Atchafalaya River, but the U.S. Army Corps of Engineers is only allowing 30% of the Mississippi and Red River flows to be moved down the Atchafalaya. This is still enough to get some marsh building in Atchafalaya Bay. An estimat- ed 1 20.000 acres of marsh will be created here in the next 30 to 50 years, but this will not offset heavy marsh losses in other areas of Louisiana (Louisiana State University 1983). Man"s impacts include channelization and levee construction along the Mississippi River, canal dredging for navigation and energy operations, and subsidence from extraction of groundwater, minerals, oil and gas. Channelization and canal construction have increased marsh erosion and salt water intrusion along the coast. Man-made levees have disrupted the natural marsh build- ing process by preventing overflow of sediment rich waters. Efforts must be made to reduce man's adverse impacts on Louisiana's coastal marshes. Specific wetland preser- vation and restoration actions should be taken immediate- ly. These actions include diverting Mississippi and Atchafalaya River flows into areas experiencing salt wa- ter intrusion and accelerated wetland loss, creation of new marsh through careful placement of dredged materi- al, improved water management in existing marsh areas, and reducing petroleum industry canal dredging through increased use of directional drilling. Future research stud- ies should improve our understanding of the importance of causal factors and address mechanisms to improve the future for this rapidly diminishing resource. "MISSISSIPPI RIVER ACTIVE DELTA (195^ Courtesy of USFWS National Coastal Ecosystem Team i MISSISSIPPI RIVER ACTIVE DELTA 0978) | us RSH A WlDLfE SEHVCE WSnONAL COftSTW- ECOSrSTtMS TEAM SLCex. UXJGUNA US nSH « VflLDLFE SERVICE NATIONAL COASTRL ECOSYSrae TEAM SUXU,U3UISUVNA Fig. 34. Louisiana's coastal marshes are being permanently flooded by Gulf of Mexico waters at an accelerating rate. Example shows marsh changes between (a) 1956 and (b) 1978. 39 Chesapeake Bay's Submerged Aquatic Beds Situated in eastern Maryland and Virginia, Cliesapeake Bay is the largest estuary in the United States. Many rivers drain into the Bay including the Susquehanna, Po- tomac, Patuxent, James. York and Chester (Figure 35). The Bay once represented the primary overwintering area for canvasback ducks which fed on submerged aquatic vegetation (Figure 36). Fifty percent of the Atlan- tic Flyway population of canvasbacks were found in the Bay region (Stevenson and Confer 1978). While still among the more important overwintering areas for can- vasbacks, Chesapeake Bay is the single most important wintering ground in North America for whistling swans (Bellrose 1976). Canada geese and black ducks also use the Bay area in winter. Aquatic grass beds provide spawning areas forestuarine-dependent fishes like striped bass, shad and herring and offer shelter for their young. Important submerged plants include pondweeds, redhead grass, eelgrass, wild celery, waterweed. naiads, musk- grasses and Eurasian milfoil. Sea grass beds in the Bay have been declining since the 1960's. According to a recent study (Stevenson, et al. 1979) in Maryland, submerged aquatic vegetation de- creased by almost 65% from 1971 to 1978. A similar decline has also been observed in Virginia waters. At the mouth of the Susquehanna River, submerged grasses at a Susquehanna River PENNSYLVANIA Potomac River Rappahannock River Pocomoke River Fig. 35. Chesapeake Bay and its major tributaries. IfW* Fig. 36, Chesapeake Bay is one of the more important wintering areas for canvasbacks in North America. 40 once prime waterfowl feeding area Inave virtually disap- peared since 197 1 . Other areas have experienced declines in the numbers of plant species present. Since 1978, sub- merged aquatic vegetation appears to have stabilized, with a few areas even showing a slight increase (Orth and Moore 1981). Reductions in submerged vegetation have probably been the most important wintering habitat change which have led to declines in local populations of canvasbacks and redheads (Perry, et al. 1981). These changes point to a stressed ecological system. Although the causes of this vegetation decline are hard to pinpoint, researchers suggest a combination of natural and human-induced factors. Natural stresses include overgrazing by carp and cownose rays. Hurricane Agnes. a general warming of Bay waters, and natural diseases. In June 1972, Hurricane Agnes hit the Bay region. Its heavy rainfall lowered salinity in Chesapeake Bay and buried numerous grass beds with sediment carried by runoff. Human impacts on the submerged vegetation are largely from two general sources of water pollution: point and nonpoint sources. Point source pollution comes mainly from industrial and sewage treatment plant discharges, while nonpoint sources include failing septic systems. agricultural runoff or urban runoff. These sources cause increased turbidity and sedimentation, nutrient overload- ing, and chemical pollution which have reduced or elimi- nated aquatic beds from many areas. Channelization projects in bottomland hardwood forested wetlands have undoubtedly contributed to the problem by accelerating the discharge of agricultural runoff and eroded soil into the Bay. The problem of the Bay's submerged aquatic vegeta- tion is receiving special attention from the U.S. Environ- mental Protection Agency (EPA) and others. EPA established a Chesapeake Bay program to address this problem. Future studies should increase our understand- ing of the causes of the decline of submerged aquatic vegetation and will hopefully lead to improved watershed management to restore and maintain a healthy Chesa- peake Bay. Meanwhile, the governors of Maryland, Pennsylvania and Virginia have joined together to ad- dress water quality problems in the Chesapeake Bay wa- tershed. Only through interstate coordination and action can the Bay's problems be solved. South Florida's Palustrine Wetlands South Florida encompasses a 9.000 square mile area of lakes, rivers and wetlands which extends from Orlando south to the Florida Keys. While the Everglades domi- nates this region. Big Cypress Swamp, the Kissimmee River and Lake Okeechobee are equally important. Freshwater runoff from this area helps maintain the salin- ity balance of estuaries which support 85% of South Flor- ida's offshore fishery (Yates 1982). The wetlands are breeding grounds for many birds, notably wood and other ibises, roseate spoonbills, herons, egrets and Florida Fig. 37. Channelization of the Kissimmee River directly destroyed many wetlands and facilitated drainage of more than 100,000 acres of wetlands. ducks . They also support winter populations of numerous waterfowl, especially lesser scaups, ringnecks. blue- winged teal, canvasbacks, and wigeons. Rare and threat- ened animals depend on these wetlands, including the Florida panther. American crocodile, manatee, brown pelican. Everglades kite and southern bald eagle. The Everglades National Park was established to protect these natural resources. South Florida's waters and wetlands have been subject- ed to various uses for many years (Yates 1982). In the 1920"s, large wetland areas were drained and converted to sugar cane farms. Severe floods in 1928, 1947 and 1948 stimulated a massive flood control project in South Florida. The Central and Southern Florida Flood Control Project, authorized by Congress, required the U.S. Army Corps of Engineers to construct a network of nearly 800 miles of new or improved levees and 500 miles of canals. 41 This project completed drainage of the Kissimmee River wetlands, regulated Lake Okeechobee's water levels and drained and irrigated the Everglades Agricultural Area. Channelization directly destroyed 40,000 acres of wet- lands and facilitated drainage of more than 100,000 acres of contiguous wetlands (Figure 37; Thompson 1983). By reducing floods, the flood control project also accelerated filling of wetlands for urban expansion of coastal cities, especially in Dade, Broward and Palm Beach Counties, as well as increasing agricultural conversion of wetlands (Figure 38). For example, between 1972 and 1980, Palm Beach County lost 23 ,76'/ acres of wetlands to agriculture and 655 acres to urban development (U.S. Fish and Wild- life Service 1982) for a 7% wetland loss in just 8 years. Problems related to water supply have also resulted from this flood control project. Although three large im- poundments called "conservation areas" were construct- ed to maintain recharge of the Biscayne Aquifer and prevent salt water intrusion into public drinking water supplies, salt water intrusion remains a constant threat. Urban growth and agricultural development increase de- mand for water. Public wells have been constructed fur- ther west which have lowered the Everglades water table and have increased the flow of salt water into the Bis- cayne Aquifer. Besides public water supply problems, the flood control project has also seriously disrupted the natural hydrologic regime of the Everglades National Park. Levee L-29 completely blocked sheet flow of fresh- water into the Park in 1963. After much controversy and public debate, the Corps of Engineers in 1970 agreed to release a minimum of 3 1 5 ,000 acre-feet of water annually (Yates 1982). Park officials estimate that at least twice this amount is needed and that the water must be distribut- ed over a wider area and be released on a more natural regime. These changes are necessary to preserve the bio- logical integrity of the Everglades National Park. Wetland alterations in South Florida have created prob- lems for many fish and wildlife species. Periodic dis- charges of freshwater from the conservation areas have disrupted fish nursery grounds in estuaries. Colonial wad- ing bird populations have declined from about 1 .5 million in 1935 to about 0.25 million today. Alligators have been eliminated from many areas and frog populations have been critically reduced from a commercial harvesting standpoint (Marshall 1981). Possible effects of the Kissimmee River channelization and wetland drainage on local rainfall patterns have also been raised. Although quite controversial, some scien- tists have suggested that wetland drainage in South Flor- ida has reduced the mist of evaporation and plant transpiration which triggers rainfall from sea breezes. This condition may be responsible for recent severe droughts. in 1976, the Florida legislature passed a mandate to restore the Kissimmee River. They recognized that chan- nelization of this river among other things; increased the seriousness of water shortages and droughts, degraded water quality of Lake Okeechobee, eliminated vast acre- ages of wetlands, drastically reduced fish and wildlife populations and destroyed a beautiful, meandering river (Florida Conservation Foundation 1977). Ironically, the Hood control project actually increased the potential for catastrophic floods and rai.sed costs to ranchers and farm- ers. Florida's Save Our Rivers Act of 1981 created state funds to purchase threatened wetlands. The Nature Con- servancy, the Richard King Mellon Foundation, and Na- tional Audubon Society have also been active in wetland acquisition. In 1983, Governor Graham announced a multi-million dollar "Save Our Everglades" program to restore the ecology of the Everglades, which includes acquisition of 250,000 acres of wetlands and improving hydrology (Thompson 1983). He also stressed the impor- tance of Federal-state cooperation in achieving this goal. These efforts should be instrumental in preserving these fragile wetlands and their associated values. GULF OF MEXICO LEGEND [jTI Drained Wetlands EQ Remaining Wetlands ATLANTIC OCEAN FLORIDA BAY Fig. 38. Present extent of wetlands in the Florida Everglades; former wetlands are also shown (from Marshall 1981). 42 Prairie Pothole Region's Emergent Wetlands Prairie potholes are the most valuable inland marshes for waterfowl production in North America (Figure 39). Although the Pothole Region accounts for only 10% of the continent's waterfowl breeding area, it produces 50% of the duck crop in an average year and more than that in wet years (Smith, et al. 1964). The Prairie Pothole Re- gion extends from south-central Canada to north-central United States, covering about 300,000 square miles with roughly one-third in the United States. Due to glaciation thousands of years ago, the landscape is pock-marked with millions of pothole depressions, mostly less than two feet deep. These pothole wetlands serve as primary breeding grounds for many kinds of ducks including: mallard, pintail, wigeon, gadwall, shoveler, teal, canvas- back, and redhead. For example, in a study area in north- eastern South Dakota, researchers found an average of 140 ducks produced per square mile per year (Evans and Black 1956). In North and South Dakota, pothole wetlands original- ly covered 7 million acres. Today, only slightly more than 3 million acres remain. Over half have been de- stroyed by agriculture, irrigation and flood control pro- jects (Elliott pers. comm.). Iowa has lost more than 99% of its natural marshes (Bishop pers. comm.). Approxi- mately 9 million acres of potholes have been drained in Minnesota (Figures 40 and 41). Since pothole wetlands are surrounded by farmland, they have been drained to create additional cropland, mostly for wheat in the west and com in the east. Drainage in the Dakotas is largely done by open ditching in contrast to both open ditching and tile drainage in Minnesota and Iowa. These ditches drain into intermittent streams or highway right-of-way ditches. Highway ditches have been heavily used by local farmers to help drain wetlands. In western Minnesota alone, nearly 100,000 acres of wetland have been lost in this way (U.S. Fish and Wildlife Service 1975). In addi- tion, stream channelization sponsored by Federal flood control projects, such as the small watershed protection and flood prevention program (P.L. 83-566), have led to accelerated wetland drainage in the Pothole Region as they have elsewhere in the U.S. (Erickson, et al. 1979). Drainage data for the Dakotas and Minnesota obtained from the U.S. Department of Agriculture's Production and Marketing Administration show that 188,000 acres were drained with Federal assistance in 1949 and 1950 alone. Countless other acres were privately drained at the same time (Figure 42). Pothole wetland losses are esti- mated at more than 33,000 acres yeariy (Haddock and DeBates 1969). Among the remaining wetlands, the drier Fig. 39. Prairie pothole wetlands are the Nation's most valuable waterfowl production areas, (a) aerial view of potholes and fb) blue-winged teal. 43 ones (i.e., temporarily flooded) are often tilled during dry periods of the natural hydrologic cycle. Drought in the Prairie Pothole Region is largely re- sponsible for declines in waterfowl breeding populations. Drainage of potholes may have a similar but more lasting effect on breeding waterfowl. Each pothole drained leads to a further concentration of the breeding waterfowl pop- ulation. This could result in decreased productivity, re- duced size of the breeding population, and/or increased likelihood of diseases like avian cholera and botulism. Wetland drainage also destroys habitats important to in- vertebrates used as food by breeding waterfowl like pin- tail and blue-winged teal (Krapu 1974: Swanson, et al. 1974). Moreover, drainage eliminates the flood storage value of pothole depressions, thereby increasing flooding problems as in the James River basin of North Dakota (Sidle 1983). Agricultural activities on upland adjacent to potholes have also adversely impacted waterfowl production. Up- land grasses bordering wetlands provide valuable nesting cover for mallard and other dabbling ducks. Conversion of rangeland to cropland, which destroys these nesting areas, has been accelerating. Between 1965 and 1975, approximately one half of the rangeland in the Coteau du Missouri counties of North Dakota were converted to cropland (U.S. Fish and Wildlife Service 1984). Excavation of ponds (dugouts) in pothole wetlands is also a problem. Out of an estimated 55,855 dugouts in eastern South Dakota in 1976, 77% were in wetland ba- sins or streams (McPhillips, et al. 1983). Excavation and spoil deposition alter wetland hydrology which may re- duce waterfowl usage. More research is needed to evalu- ate potential impacts. The Fish and Wildlife Service has been active in pre- serving Prairie Pothole wetlands through acquisition, easement, and other programs. Recently, wetland acqui- sition in North Dakota was stopped for several years by state law. Due to a U.S. Supreme Court ruling against the state for this action, the Service's wetland acquisition is being resumed. The Federal government generally regu- lates filling of pothole wetlands 10 acres in size or larger, yet smaller isolated wetlands are largely unprotected. A 1984 settlement agreement between the Corps of Engi- neers and various environmental groups (National Wild- life Federation v. Marsh) provides an opportunity to improve regulation of agricultural conversion of pothole wetlands. The Service's acquisition and easement pro- gram and improved Federal regulation are needed to maintain valuable waterfowl producing wetlands, since pressures continue to convert such areas to agriculture. 44 ORIGINAL WETLANDS OF MINNESOTA LEGEND Peats (5.9 million acres) Poorly drained mineral soils (12.5 million acres ) Other soils (33.0 million acres) Water (2.9 million acres) Fig. 40. Original extent and distribution of Minnesota's wetlands (University of Minnesota 1981). EXISTING WETLANDS OF MINNESOTA 45 LEGEND Available peats (5.2 million acres) Available poorly drained mineral soils (3.5 million acres) Other soils, drained lands and pre- empting land uses (42.7 million acres) I I Water (2.9 million acres) Fig. 41. Present extent and distribution of Minnesota's wetlands (University of Minnesota 1981). Nine million acres of poorly drained soils- pothole wetlands— have been converted to agriculture. 46 Fig.42. Prairie pothole wetlands continue to be drained for agriculture. Wetlands of Nebraska's Sandhills and Rainwater Basin Wetlands within the Sandhills and Rainwater Basin of south-central Nebraska are important to migrating sand- hill cranes and waterfowl in the Central Flyway. About 2.5 million ducks and geese move through the Rainwater Basin each spring. Ninety percent of the mid-continent's white-fronted geese stage in wetlands of the Basin and central Platte each spring. Pheasants also depend on wet- land vegetation for nesting and brood habitat (Farrar 1982). Eighty percent of the continent's population of sandhill cranes depend on wetlands along 70 miles of the Platte and North Platte Rivers as staging areas during spring migrations (Figure 43). Whooping cranes, an en- dangered species, also roost in broad reaches of the Platte River's channels (U.S. Fish and Wildlife Service 1981). The Nebraska Sandhills Region is the largest sand dune formation in the western hemisphere covering approxi- mately 20,000 square miles. Formed primarily by wind action, the Sandhills consist of stabilized sand dunes, exposed groundwater lakes in the valleys, and perched mineralized lakes on poorly drained soils. The grassland economy of the Sandhills is primarily one of cattle graz- ing. Large acreages of subirrigated meadows with water tables close to the surface offer great potential for in- creased grazing and hay production through development of level ditching. Wetland destruction in the Sandhills has accounted for over 28.000 acres or 15% of the original wetlands (Nebraska Game and Parks Commission 1972). Wetland loss has resulted from drainage, tilling for pivot irrigation, and reduced groundwater levels from deep well irrigation. Decreases in riverflows of the Platte River by upstream diversions for consumptive uses in Colorado. Wyoming and western Nebraska have reduced channel width by 80- 90% in many areas. This condition has promoted growth of woody vegetation on former channel bars and islands. Sandhill cranes prefer roosting in shallows and sandbars where the channel is at least 500 feet wide and strongly avoid narrower channels. Reduction in natural channel width and increased growth of woody vegetation have caused crowding at remaining roost sites. This situation increases crane susceptibility to catastrophic losses due to 47 Fig. 43. Sandhill cranes on a Plane River roost at sunrise. severe storms and disease. If the trend continues, sandhill cranes may shift to the Rainwater Basin where avian cholera is already a serious problem. Native grasslands along the rivers have also declined. These areas provide important food for the migrating cranes (U.S. Fish and Wildlife Service 1981). The Rainwater Basin includes parts of 17 counties, roughly 4,200 square miles in extent. Wetlands fonned in depressions underlain by clay on the rolling plain. Origin- ally 4,000 marshes totaling 94,000 acres existed. Wet- land destruction accelerated after World War II due to improved earth-moving equipment and deep well irriga- tion. Agriculture intensified in the Basin with the help of Federal funds and technical assistance for wetland drain- age. By the late I960's, 18% remained and in 1981, less than 10% survived. Nine out of every ten wetlands have been drained or filled. Of those remaining, only 43% are protected by state or Federal wildlife agencies. Losses of Basin wetlands have forced ducks and geese to concentrate in the remaining wetlands. In 1980. about 80,000 waterfowl died due to avian cholera. This was the second largest cholera die-off reported in the country. During dry years with late winter storms, birds are forced to crowd in Basin wetlands, setting the stage for large die- offs. Waterfowl breeding populations have also been af- fected by wetland destruction. By 1975, the duck breeding population declined so much that the Nebraska Game and Parks Commission discontinued its aerial breeding bird survey. Efforts to protect remaining wetlands have recently been weakened. The Water Bank Program which pro- vides payments to landowners preserving important wa- terfowl wetlands has been funded at lower levels. Wetland protection under the Clean Water Act of 1977 has been reduced through regulatory changes. New regu- lations which may strengthen protection will, however, be proposed this year. Legal disputes between the Fish and Wildlife Service and others over water rights have affected management of 15,507 acres of waterfowl pro- duction areas in the Rainwater Basin. Along the Platte and North Platte Rivers, action is needed to protect native grasslands near river channels and to maintain channel 48 widths of 500 feet or more for suitable crane roost sites during migration. Acquisition and conservation ease- ments are useful tools. Forested Wetlands of the Lower Mississippi Alluvial Plain The bottomland hardwood forests of the lower Missis- sippi floodplain are among the Nation's most important wetlands. They are prime overwintering grounds for many North American waterfowl, including 2.5 million of the 3 million mallards of the Mississippi Fly way. near- ly all of the 4 million wood ducks and many other migra- tory birds. Numerous finfishes depend on the flooded hardwoods for spawning and nursery grounds. These wetlands also support many other wildlife, including deer, squirrel, raccoon, mink, beaver, fox and rabbit. They also play a vital role in reducing flooding problems by temporarily storing large quantities of water and by slowing the speed of flooding waters. In the process, these wetlands remove chemicals from the water such as fertilizers and pesticides and trap soil eroding from near- by farmlands. Onginally, the Mississippi Alluvial Plain included nearly 24 million acres of bottomland forested wetlands. By 1937, only 11.8 million acres or 50^7^ of these re- mained. Today, there are less than 5.2 million acres left, roughly 20% of the original acreage (Figure 44; MacDon- c O u. W Q o<