WETLANDS
WETLANDS are any of an array of habitats—including marshes, bogs, swamps, estuaries, and prairie potholes—in which land is saturated or flooded for some part of the growing season. According to the U.S. Fish and Wildlife Service, wetlands contain water-loving plants (hydrophytes) and hydric soils. They serve many ecological and practical purposes. Wetlands provide habitat and breeding sites for fish, shellfish, birds, and other wildlife; help maintain biological diversity (biodiversity); reduce the effect of floods by diverting and storing floodwaters;
provide protection from storm waves and erosion; recharge ground waters; and improve water quality by filtering out sediments, excess nutrients, and many chemical contaminants. Wetlands provide recreational, research, and aesthetic opportunities such as fishing, boating, hunting, and observing and studying wildlife.
Since 1780 human activity has destroyed more than half the wetlands of the United States, which now make up only 5 percent of the land surface of the contiguous forty-eight states, or 104 million acres. Nevertheless, they are extremely productive, exceeding even the best agricultural lands and rivaling rain forests in quantity and diversity of plant and animal life. More than half of the saltwater fish and shellfish harvested in the United States—and most of the freshwater sport fish—require wetlands for food, reproduction, or both. At least half of the waterfowl that nest in the contiguous states use the midwestern prairie potholes as breeding grounds. Wetland dependent animals include bald eagles, ospreys, beaver, otter, moose, and the Florida panther.
Few people recognized the value of wetlands until the 1970s. Before then, most people considered wetlands to be wastelands. In an effort to make them more productive—primarily through agriculture or development—people destroyed them by draining, ditching, diking, or filling. Early legislation, such as the Swamp Lands acts of 1849, 1850, and 1860, allowed fifteen states on the MISSISSIPPI RIVER to "reclaim" wetlands for cultivation. By the mid-twentieth century, accumulating evidence, including U.S. Fish and Wildlife wetlands inventories in 1954 and 1973, made clear that destruction of wetlands was causing declines in fish and waterfowl. Federal, state, and local laws—notably the federal Clean Water Act of 1972 and amendments in 1977—attempted to regulate destruction.
Development, agriculture, and increasing pollution still threaten U.S. wetlands. One-third of wetland losses have occurred in midwestern farmbelt states. All but three states (Alaska, Hawaii, and New Hampshire) have lost more than 20 percent of their wetlands. Biologists and economists agree that preserving wetlands is less expensive than attempting to restore those that have been damaged, and experts still argue whether it is even possible to restore wetlands and how scientists might measure restoration. The economic and biological feasibility of restoration is debated each time a developer seeks permission to build on a wetland, thus destroying it, and offers (or is required) to attempt to rehabilitate a second site in return. Many biologists feel that because damaged sites cannot be returned to their previous states, it may not be acceptable to allow this tradeoff.
BIBLIOGRAPHY
Council of Environmental Quality. Environmental Trends. Washington, D.C.: Executive Office of the President, 1989.
National Research Council. Restoration of Aquatic Ecosystems: Science, Technology, and Public Policy. Washington, D.C.: National Academy Press, 1992.
