STATUS O F WE1 By]ulion Iosephson U S . wetlands are critical ecosystems. They help regulate and maintain the hydrology of the nation’s waterways by storing and releasing floodwaters. They help maintain water quality by storing nutrients and reducing sediment loads and erosion, and sometimes even abate water pollution because of this characteristic. Wetlands also provide habitat for many species of plants and animals (1). But what are wetlands? Wetlands mean one thing to a farmer, another to an ecology professor, and yet something else to a government official. Here we will use the US. Fish and Wildlife Service’s [F&WS)definition ( I ) : “Wetlands are lands where saturation is the dominant factor determining the nature of soil development and the types of plant and animal communities living in the soil and in its surface.” F&WS is required by federal law (2) to update reports on the status and trends of U.S. wetlands and deepwater habitats in the contiguous 48 states on a 10-year cycle. Its 1991 report ( I ) updates a previous report completed in 1982 (3). The report’s authors describe it as “a statistically valid effort to estimate the nation’s wetland resources and provide indications of gains and losses for 14 categories of wetland and deepwater habitats.” From the mid-1970s to the mid1980%the United States sustained a net loss of more than 2.6 million acres (1.05 million hectares [ha]) of wetlands. By the mid-1980s, an estimated 103.3 million acres (41.8 ha) of wetlands remained of which 97 million acres (39.3 million ha) were freshwater wetlands and 5.5 million acres (2.5 million ha) were coastal wetlands. Freshwater wetlands suffered 98% of the losses. Compare these remainders with the total of 220 million acres (89.1 million ha) of wetlands estimated to have covered what is now the contiguous United States in 1780. Conversion to agricultural use accounted for about 54% of wetland losses during the study period (I), whereas “other” uses made up much of the balance of the losses. “Other” means wetlands either converted for urban use or cleared and drained but not yet put to an identifiable use. By comparison, 87% of existing wetlands had been convert422 Environ. Sci. Technol., Vol. 26, NO.3, 1992
ed to agricultural use from the mid1950s to the mid-1970s. Data on wetlands changes were obtained through random samples of 3629 plots photographed from the air. Photographs taken during the mid-1970s (mean year 1974) and the mid-1980s (mean year 1983) were analyzed to detect gains and losses in area. Changes were recorded as natural or manmade. Dahl and his colleagues [ I ) acknowledge that aerial photography is not always available for successive years for the same plot of land; therefore, they did not develop estimates of annual rates of wetland loss. They did, however, suggest a method of calculating the annual loss from 1983 vs. 1974 estimates of existing wetlands area, and they suggest a net annual wetlands loss figure of 290,000 acres (117,400ha) (I). The report‘s authors believe that since the mid-l980s, “indications are that wetland losses are slowing.” For example, “From 1987 to 1990, programs to restore wetlands under the 1985 Food Security Act have added about 90,000 acres [36,437 ha] to the nation’s wetlands inventory’’ ( 4 ) . In mid-December, the National Research Council published a report that recommends that the federal government initiate a program
for an “overall gain” of 10 million acres (4.04 million ha) by 2000 and for the restoration of aquatic ecosystems (5).Many experts believe that this goal is technically achievable, but doubt that the political will to achieve it currently exists. References (11 Dahl, T. E.: Johnson, C. E.: Frayer,
(2)
(3)
(41
(5)
W. E. Wetlands: Status and Trends in the Conterminous United States. Mid1970’s to Mid-1980’s; U S . Department of the Interior. Fish and Wildlife Service: Washington, DC, 1991. Emergency Wetlands Resources Act of 1986 116 U.S.C. 3931(a11. Frayer, W. E. et al. Status ond Trends of Wetlands and Deepwater Habitats in the Conterminous United States. 19503 to 1970’s: Colorado State University: Fort Collins, CO. 1983. U.S. Fish and Wildlife Service. United States Department of the Interior Budget Justifications, F.Y. 1992. U.S. Department of the Interior. Fish and Wildlife Service: Washington, DC, 1991. National Research Council. Restomtion of Aquatic Ecosystems: Science, Technology, and Public Policy; National Academy Press: Washington, DC, 1991.
Julion Josephson is an associate editor on the Washington staff of ES&T.
