Wetlands on the Edge

Threatened by development, pollution, and rising seas, coastal marshes face an uncertain future
by Matt Young

While most of North America's waterfowl breed far inland on the prairies and in the boreal forest, many of the birds raised in the interior of this continent can be found much of the year on coastal wetlands. From Chesapeake Bay and the Mississippi River Delta to Puget Sound and Lake Erie, coastal wetlands provide vital habitat for a great number and variety of waterfowl. The birds flock to the coasts for the same reasons people do: a favorable climate, pleasant living conditions, and good seafood.

Acre for acre, coastal wetlands are among the richest ecosystems on Earth, rivaling tropical rainforests and greatly exceeding the most fertile farmland in biomass production. These varied wetlands, which include tidal marshes, swamps, and open-water flats and shoals, owe their productivity to their unique location along the coastlines of large bodies of water. Coastal wetlands receive a constant supply of organic matter and nutrient-rich sediments delivered by rivers and tides, nurturing food webs that support a profusion of aquatic life. In estuaries and deltas where fresh and salt water meet, diverse plant and animal communities flourish in wetland zones with varying levels of salinity. These rich environments often yield huge quantities of prime waterfowl foods like eelgrass, wild celery, widgeon grass, various pondweeds, and innumerable small invertebrates.

Coastal wetlands not only provide food and habitat for waterfowl and other wildlife but also serve as nurseries and spawning grounds for an abundance of fish and shellfish. Collectively, coastal wetlands produce more than three-quarters of the seafood caught in the nation's waters. Moreover, coastal wetlands provide recreation for millions of hunters, anglers, birders, boaters, and photographers who annually contribute billions of dollars to the U.S. economy in pursuit of their hobbies. Coastal wetlands also help protect communities and vital infrastructure from flooding and storm damage and filter pollutants and sediments in water.

Despite their immense value to people and wildlife, coastal wetlands are among North America's most threatened habitats. Thousands of square miles of marsh have already been lost or degraded, and many remaining coastal wetlands are threatened by various forms of development. In the future, another looming threat–rising sea levels–could have far-reaching impacts on coastal wetlands and the fish and wildlife that depend on them (see sidebar).

Ducks Unlimited has long recognized the importance of coastal wetlands to waterfowl and people. Guided by the latest science, DU is working with many partners to plan and deliver long-term conservation initiatives in key coastal ecosystems. Following is an overview of major threats facing coastal wetlands in several especially important areas to waterfowl and DU's efforts to conserve these fragile environments for current and future generations. 

U.S. Gulf Coast

The U.S. Gulf Coast has approximately 3.5 million acres of tidal wetlands, roughly 2 million acres of which are found in south Louisiana. These extensive marshes and the adjacent coastal plain host upwards of 14 million ducks and 2 million geese–including large portions of the continent's migrating and wintering gadwalls, green-winged teal, redheads, lesser scaup, and blue-winged teal as well as resident mottled ducks. In recent years, the Louisiana Gulf Coast has become ground zero for both coastal wetland loss and the efforts to conserve these threatened habitats. Levees built along the lower Mississippi River have limited and contained historic flooding, robbing coastal wetlands of the sediments that once sustained them and leaving the marsh highly vulnerable to erosion, subsidence, and rising sea levels. In addition, networks of manmade canals funnel saltwater into interior wetlands, hastening the loss of freshwater and intermediate marsh of vital importance to waterfowl. Since the 1930s, more than 1,900 square miles of these vital wetlands have been lost to the Gulf, and marsh loss continues at an alarming rate. Several recent hurricanes have also taken a toll on Gulf Coast wetlands, resulting in a net loss of more than 200 square miles of marsh in Louisiana alone.

To help turn the tide of wetland loss along the U.S. Gulf Coast, Ducks Unlimited works with a broad coalition of state and federal agencies, corporations, foundations, and private landowners to conserve these vital waterfowl habitats. DU leverages funding from partners such as CN, the Louisiana Department of Wildlife and Fisheries, Ron and Jackie Bartels, the ExxonMobil Foundation, Freeport-McMoRan Foundation, Delores George LaVigne, the Irene W. and C.B. Pennington Foundation, Shell Oil Company, and TransCanada to secure North American Wetlands Conservation Act (NAWCA) grants for coastal restoration. Over the last four years, DU has secured more than $15 million for wetlands conservation projects in Louisiana. Since beginning conservation work in Louisiana during the late 1980s, DU has helped to conserve nearly 100,000 acres of coastal wetlands in the state. In neighboring Texas, DU and partners have conserved an additional 170,000 acres of wetlands along the Gulf and adjacent coastal prairies with funding from NAWCA, the Texas Parks and Wildlife Department, Jim and Cherie Flores, the Dr. Edward D. and Sally M. Futch Charitable Foundation, Houston Endowment, The Meadows Foundation, Billy and Alice Oehmig, and Richard and Jenny Schimpff.

DU uses several approaches to restore and enhance coastal wetlands along the Gulf Coast. In southwestern Louisiana, DU and its partners directly restore coastal marsh by building earthen terraces in shallow, open-water areas where marsh once existed. Terraces help restore wetland habitat by reducing wind-driven wave action, which causes coastal erosion, and improving water clarity, which fosters growth of a variety of beneficial aquatic plants. DU also helps restore and enhance managed coastal wetlands on both public and private lands along the Gulf Coast. This includes the installation of water-control structures and pumps and the repair and maintenance of levees used to manage water and salinity at optimum levels for waterfowl and other wildlife.

In addition, a grant from The McKnight Foundation has enabled DU to work in cooperation with the Louisiana Governor's Office of Coastal Affairs and other partners to advocate for controlled diversions of the Mississippi River in southeastern Louisiana that can rebuild and maintain coastal marsh. One example is the Davis Pond Diversion Structure, completed by the U.S. Army Corps of Engineers in 2002. Located on the west bank of the Mississippi River 22 miles upstream from New Orleans, the structure is used to divert up to 10,650 cubic feet (or about 80,000 gallons) of sediment-laden river water per second into Barataria Basin. Over a 50-year span, the project is expected to preserve 33,000 acres of marsh and benefit more than 750,000 wetland acres. In total, eight small- to moderate-scale diversions have been completed, and 12 more have been proposed or are in the design phase. Many additional large-scale diversions will be necessary to sustain Louisiana's coastal wetlands in the face of future sea-level rise.

Atlantic Coast

The Atlantic coast ranks second after the Gulf in both abundance and density of coastal wetlands. Of the estimated 2.2 million acres of tidal wetlands along the U.S. Atlantic coast, among the most important for waterfowl are located in Chesapeake and Delaware bays and along the shores of New Jersey and Long Island. Located in the heart of the Atlantic Flyway, these wetland-rich coastal ecosystems support the majority of the continent's wintering black ducks, Atlantic brant, and greater snow geese, as well as continentally significant numbers of mallards, scaup, green-winged teal, and other migratory birds.

The mid-Atlantic coast is also home to millions of people. In this densely populated region, vast areas of coastal wetlands have already been dredged or filled, and many remaining wetlands have been impacted by shoreline development. In addition, widespread wetland drainage and clearing of forests in coastal watersheds have degraded water quality in estuaries, killing beds of eelgrass and other submersed aquatic plants that are vital to waterfowl and fisheries. In the future, rising sea levels could erode barrier islands and beaches and drown coastal marshes, compounding wetland losses in the region. Under some sea-level rise scenarios, Chesapeake Bay could lose over 80 percent of its remaining coastal wetlands.

To help provide improved habitat for waterfowl and create a healthier environment along the Atlantic coast, DU is working with a number of state and federal agencies, conservation groups, and many other partners to restore and enhance high-value coastal wetlands on national wildlife refuges, state wildlife management areas, and other public lands. This habitat work includes the restoration of historic tidal flows in coastal marshes, management of moist-soil impoundments for foraging waterfowl, and control of invasive vegetation.

DU also helps private landowners in coastal watersheds to restore and enhance wetlands, plant upland grass buffers, reforest riparian corridors, and protect key wetlands and shoreline habitats with conservation easements. In Maryland, for example, DU and partners such as the USFWS, Maryland Department of Natural Resources, the Waterfowl Festival Inc., Corporate Wetlands Restoration Partnership, private landowners, and others have restored more than 53,000 acres of wetlands and associated uplands. This habitat not only supports waterfowl and other wildlife but also reduces sediment levels in rivers and streams, improving water quality in Chesapeake Bay.

Important coastal wetlands exist in many other areas along the Atlantic coast. In the South Atlantic region, large numbers of waterfowl migrate and winter on Currituck, Pamlico, and Albemarle sounds in North Carolina; the ACE Basin in South Carolina; and Mosquito, Banana, and Indian River lagoons in Florida. Along the North Atlantic coast of the United States and Canada tidal wetlands also support significant breeding populations of black ducks, mallards, green-winged teal, wood ducks, and other waterfowl species. DU is actively working to conserve vital coastal wetland and watershed habitats in each of these areas. To date, DU and its partners have conserved approximately 190,000 acres of waterfowl habitat in the mid-Atlantic region, 270,000 acres in the South Atlantic region, 117,000 acres in Atlantic Canada, and 20,000 acres in the North Atlantic region of the United States.

Pacific Coast

Compared to the Gulf and Atlantic coasts, the Pacific coast has a relatively small acreage of wetlands, largely because of its rugged topography. The relative scarcity of Pacific coastal wetlands makes them especially important to wildlife and people. These varied habitats support millions of breeding, migrating, and wintering waterfowl as well as some of the world's richest fisheries of immense cultural and economic importance.

The Pacific Northwest is a high-priority conservation area for Ducks Unlimited. Washington's Puget Sound and its surrounding watershed support peak numbers of more than 500,000 dabbling ducks as well as tundra and trumpeter swans, Pacific brant, Wrangel Island lesser snow geese, and several species of sea ducks. Unfortunately, Puget Sound has already lost more than 60 percent of its original salt marshes and more than 90 percent of other coastal wetland types. These losses far exceed the national average, and if future sea-level rise estimates hold true, half of the remaining tidal flats and brackish marshes along the Oregon and Washington coasts may be lost by the end of this century.

DU is actively working with many partners to restore coastal wetlands in the Pacific Northwest. Major private funding for these efforts has been provided by Stan and Kristine Baty, The Boeing Company Charitable Trust, Roy T. and Susan W. Christopherson, Eric and Holly Dillon, Scott and Lisa Gunning, Fred W. Hines Jr., and Rory and Joyce McCallum. Extensive research has documented that coastal wetland restoration not only benefits waterfowl but also fisheries and a variety of other wildlife. For example, a partnership involving DU, the USFWS, and the Nisqually Indian Tribe recently restored 762 acres of coastal wetlands on Washington's Nisqually National Wildlife Refuge, the largest estuary restoration effort ever completed in the Pacific Northwest. This project will provide valuable new habitat for migrating and wintering waterfowl, federally threatened Chinook salmon, and many other fish and wildlife species. Other major funding partners in this $10 million project included the National Fish and Wildlife Foundation, U.S. Environmental Protection Agency, National Oceanic and Atmospheric Administration (NOAA), Washington Department of Fish and Wildlife, Washington State Salmon Funding Recovery Board, Larry and Marg O'Neil, Topics Entertainment (Greg and Carol James), and Wildlife Forever Fund.

Another important DU objective in the Pacific Northwest is protecting undeveloped agricultural lands adjacent to important coastal waterfowl habitats. DU recently received support from the M.J. Murdock Charitable Trust to launch a new farmland easement program on Washington's Puget Sound designed to help mitigate future impacts of sea-level rise on coastal wetlands. This program will complement similar land protection work being conducted by DU Canada in British Columbia's Fraser River Delta and other waterfowl-rich areas along the British Columbia coast.

DU also has an active coastal wetlands conservation program in California. A key focus area is the San Francisco Bay estuary, which supports 50 percent of the Pacific Flyway's diving ducks including large numbers of wintering canvasbacks. As in much of California, this estuary has lost more than 90 percent of its historic wetlands. Ducks Unlimited is working with many partners–including the USFWS, California Department of Fish and Game, California Wildlife Conservation Board, State Coastal Conservancy, and NOAA–to restore coastal habitat surrounding the estuary. Over the last five years, DU has completed or initiated 40 projects at a combined cost of $41 million that will collectively conserve more than 18,000 acres of coastal wetlands and associated habitats in California.

While DU and its partners are making significant progress in conserving coastal wetlands in many areas of North America, the future of these fragile waterfowl habitats remains tenuous. Ultimately, the fate of our coastal wetlands will be determined by how well we manage future population growth and development along our coasts, how committed we are to clean air and water, and how proactively we respond to the realities of sea-level rise. As society debates how to address these challenges, our coastal wetlands and the waterfowl that depend on them hang in the balance.


The Other Coastal Wetlands

Some of North America's most important coastal wetlands are located far from the ocean. The Great Lakes watershed contains extensive coastal marshes that support continentally significant populations of black ducks, mallards, canvasbacks, redheads, scaup, tundra swans, and Canada geese. Sadly, development, pollution, and invasive species like common reed (phragmites) have degraded many of the region's historic wetlands.

To help sustain and increase waterfowl populations in the Great Lakes watershed, DU is working with partners like the North American Wetlands Conservation Council, the Dean L. and Rosemarie Buntrock Foundation, The Herbert H. and Grace A. Dow Foundation, and Rollin M. Gerstacker Foundation to conserve coastal wetlands and associated shoreline habitats in several major focus areas. Through science-based strategic planning, DU has identified a need to conserve at least an additional 200,000 acres of wetlands and native grasslands in the U.S. portion of the Great Lakes watershed and more than 80,000 acres of freshwater coastal marsh in Canada. DU is hopeful that the Great Lakes Restoration Initiative, a $475 million commitment to restoring the Great Lakes recently passed by Congress and signed by the president, will be a catalyst for widespread restoration of wetlands and waterfowl habitat throughout the Great Lakes basin.