Gulf wetlands disappearing

By: National Oceanic and Atmospheric Administration and National Marine Fisheries Service, 2008

According to a 2008 government report*, Gulf wetlands are disappearing at six times the rate of Atlantic coastal watersheds, despite a net overall gain of wetlands in the U.S.

The report looks at national wetland trends between 1998 and 2004.

A summary is reprinted here. To read the full report visit the Fish and Wildlife Service website at Wetlands Report.

Executive Summary:

The National Oceanic and Atmospheric Administration’s National Marine Fisheries Service, in cooperation with the U.S. Fish and Wildlife Service, analyzed the status and recent trends of wetland acreage in the coastal watersheds of the United States adjacent to the Atlantic Ocean, Gulf of Mexico, and Great Lakes.

Sample plots were analyzed using digital high-resolution imagery to identify wetlands and land use changes observed between 1998 and 2004.

Results indicate that there were an estimated 39.8 million acres (16.1 million ha) of wetlands in these coastal watersheds in 2004. This represented 38 percent of the estimated total wetland acreage of 107.7 million acres (43.6 million ha) found in the conterminous United States.

Coastal watersheds experienced a net loss in wetland area.

There was an estimated wetland loss of 361,000 acres (146,200 ha) in the coastal watersheds of the eastern U.S. between 1998 and 2004. This equated to an average annual net loss of about 60,000 acres (24,300 ha) over the 6-year period of this study.

Gulf of Mexico coastal watersheds exhibited substantial losses in freshwater wetlands.

This rate of loss was 6 times higher than the rate of freshwater vegetated wetlands losses in the Atlantic coastal watersheds. The estimated losses for all wetland types in the Gulf of Mexico were 25 times higher than those estimates for the Atlantic over the course of this study.

There was a net gain of an estimated 24,650 acres (10,000 ha) in the Great Lakes coastal watersheds over the same period of time.

In the time period encompassed by this study, trends suggested the country as a whole was gaining wetlands. From 1998 to 2004, wetland gains in the conterminous United States were estimated to have been 32,000 acres (12,960 ha) annually.

The fact that coastal watersheds were losing wetlands despite the national trend of net gains points to the need for more research on the natural and human forces behind these trends and to an expanded effort on conservation of wetlands in these coastal areas. This point was highlighted in a 2008 report on wetland conservation by the Council on Environmental Quality.

*Stedman, S. and T.E. Dahl. 2008. Status and trends of wetlands in the coastal watersheds of the Eastern United States 1998 to 2004. National Oceanic and Atmospheric Administration, National Marine Fisheries Service and U.S. Department of the Interior, Fish and Wildlife Service. 33 p.