Banner Graphic a collage of images representing various USGS activities

from the July/August 2000 issue of People, Land & Water, the employee news magazine of the Department of the Interior

Cogongrass, Chinese Tallow Tree Invade Coastal Prairie Habitats

Gaye Farris, USGS, Lafayette, Louisiana

USGS researchers are studying how prescribed fire may help control the invasive Chinese tallow tree.

The Chinese tallow tree, one of the greatest threats to habitat in the South, rapidly replaces native plants and trees, radically altering marsh, forest, and coastal prairie ecosystems. In the coastal prairie (central Louisiana to southern Texas) tallows threaten restoration. Less than 1 percent of the original coastal prairie remains, and it is the sole habitat of the federally endangered Attwater's prairie chicken and exclusive wintering ground of the federally endangered whooping crane.

In addition to performing research on Chinese tallow, USGS scientists from the National Wetlands Research Center are examining whether prescribed fire might be a useful tool in controlling tallow in the Lacassine National Wildlife Refuge in Louisiana, and Brazoria National Wildlife Refuge in Texas.

USGS scientists also study the highly flammable cogongrass. An invasive from Asia infesting Gulf Coast wetlands, savannas, and forests, cogon is considered one of the 10 worst weeds worldwide and a pest in 73 countries. Scientists study how management practices in wet-pine savanna affect cogon invasions in the Mississippi Sandhill Crane and Grand Bay National Wildlife Refuges and examine moisture responses in greenhouse experiments.

Results show vegetation disturbance should be avoided in early spring to help keep seeds from reaching the surface and that preventing seed movement into uninfested areas is critical. Research on how congongrass and other invasive grasses interact with native communities is ongoing.

The invasive nutria, or coypu, causes problems in coastal marshes and baldcypress swamps, especially in Louisiana. Introduced from South America for their fur, they now number in the millions because of the fur trade collapse. Nutria feed on the tender roots of plants, seedlings, and saplings, completely stripping vegetation in areas where they are concentrated. In 1999, USGS and the State of Louisiana documented nutria destruction of vegetation in more than 100,000 acres of Louisiana coastal marsh that will probably degrade to open water without sufficient plants to hold the soil together. USGS studies worldwide nutria distribution and eradication, maps nutria destruction and develops computer models to predict damage and simulate management options. Future research includes field studies in Jean Lafitte National Park and Preserve, Barataria Unit, to document nutria impacts at different densities.

image of plant with berries image of a nutria, a beaver sized animal from South America

The plants berries have been used for centuries in candlemaking, cooking, and industry.

The nutria, a beaver sized animal from South America,
destroys wetlands by eating tender roots, saplings, and
seedlings.

Biological Aliens Home || Director's Message || Bugging Purple Loosestrife || Cogongrass, Chinese Tallow ||
Exotic Crayfish || Exotic Mussels || Hawaii: A Model || Leafy Spurge || Mapping Invasive Plants ||
Non-native Grasses and Fire || Pepperweed || Prescribed Fire || Saltcedar || Spring Brings Hope


The plants berries have been used for centuries in candlemaking, cooking, and industry.		The nutria, a beaver sized animal from South America, destroys wetlands by eating tender roots, saplings, and seedlings.