Invasion of the Wetland Snatchers: Nutria Eradication in the Watershed

January 2006 -- Throughout the Chesapeake Bay watershed, invasive species are increasingly becoming part of the local landscape. These invasives have taken a toll on native plants and animals, often crowding out or otherwise harming the existing native species.

One species that has damaged many local wetlands is the nutria, which has dined on and destroyed wetland grasses. Because wetlands are key to cleaning the Bay's waters, several organizations have worked on removing the rodents from the watershed. Blackwater National Wildlife Refuge is one such place; they eradicated nutria from their grounds, completing the multi-year project in 2004.

How did nutria impact Blackwater National Wildlife Refuge?

The nutria population grew very quickly and destroyed many of the wetlands in the area. Nutria was introduced to the area in the 1940's as an attempt to boost local trapping and fur farming activities. Since the introduction, the nutria population grew more quickly than they were hunted; a U.S. Fish and Wildlife Service report on the issue estimated that the nutria population expanded from fewer than 150 to more than 50,000 animals in Dorchester County between 1968 and the late 1990s. Additionally, nutria were out-competing native muskrat species, pressuring them to leave their native area.

With the abundance of marsh grasses, Blackwater provided an ideal habitat for the rodents. Nutria primarily dined on marsh grass roots, so in addition to killing the marsh grasses, the destruction of the roots destabilized and eroded wetland soil. Other creatures that depended upon wetlands, including young blue crabs, lost their habitat, and wetlands were unable to function properly as a result of all of these changes.

What did Blackwater officials do to remove nutria from its land?

Officials from Blackwater worked with private, state and federal organizations on a pilot program to eradicate nutria from the area. The program involved several phases, allowing officials to complete the necessary research and inform the public about the effort. If successful, officials expected that this program could be implemented in other areas of the country that nutria were impacting.

Was the eradication program successful?

Officials confirmed that nutria were eradicated from Blackwater in 2004 and that they were able to restore many of the area's destroyed wetlands. Authorities are now working to expand the eradication to other areas in Maryland and elsewhere in the United States.