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New maps aid conservation in Louisiana

Recent revisions to a federal report on the nation’s wetlands indicate that coastal areas are losing wetlands more quickly than the rest of the nation — none more so than those along the Gulf of Mexico.

The rate of the loss appears to be accelerating, too.

Among the findings: beginning in 2004, an estimated 5% of all saltmarsh habitat vanished to open waters along the Gulf of Mexico during a 4½-year period. Those losses represented nearly 100% of the nation’s entire saltwater wetland losses.

National Wetlands Inventory data from coastal Louisiana shows a majority of land identified as saltmarsh
Coastal Louisiana. Map by USFWS.

These findings are among the highlights of a review of more than 40 million acres of wetlands in coastal watersheds by the U.S. Fish and Wildlife Service’s (Service) Wetlands Status and Trends project.

These changes underscore what researchers for decades have known about the nation’s wetlands. The United States has lost over half of its original wetland area, and wetland loss continues.

From 1998 to 2004, coastal watersheds of the eastern United States, including the Great Lakes, lost about 60,000 acres of wetlands annually. From 2004-2009, that annual loss rate in the contiguous U.S. increased to 80,000 acres.

These habitat losses affect plants and animals. Shrinking wetlands, researchers say, have a direct impact on some animals, including migratory birds, and threatened and endangered species like the black rail.

Wetland maps produced by the Service’s National Wetlands Inventory (NWI) provide vital information needed by biologists to conserve these animals.

These maps were recently updated and posted to the publicly available Wetlands Mapper. Among the Mapper updates: a complete revision to Louisiana’s coastal wetland maps. This was no easy task. Louisiana has 7,721 miles of coastline — second only to Alaska and Florida. But these updates were vital. Louisiana is a hotspot of coastal wetland loss.

A map highlighting coastal wetland loss; the highest concentrations are along the Louisiana coast
Coastal watersheds of the upper Gulf of Mexico showing the magnitude of saltwater (intertidal) wetland loss to open water, 2004 to 2009. Map by USFWS.

These new data were produced in cooperation with private industry over the course of two years. They will lay the foundation for wetland conservation, research and monitoring along Louisiana’s changing coastline.

The NWI program works closely with field biologists to better understand how habitat distribution and changes affect species viability. That, in turn, helps determine conservation efforts.

Ducks Unlimited appreciates the program’s work, said Cassidy Lejeune, who manages conservation programs for the nonprofit’s south Louisiana region.

“The updated NWI maps provide improved precision of wetland habitats… that will enhance our conservation efforts,” she said.

Coastal wetland change also affects Service habitat conservation efforts, like the Coastal Barrier Resources System which partnered with NWI to produce the updated data.

Wetlands will continue to change, and the Service will be there to track these dynamics. The NWI program plans to release their next Wetlands Status and Trends report in 2022.

To learn more, visit the NWI homepage.


Mark Davis, public affairs specialist, (404) 679-7291

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