NWRC Invasive Species Research

Invasive plants and animals have been recognized as playing a large part in the loss of wetland and coastal habitats. Scientists at the National Wetlands Research Center are researching several invasive species.

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Asian carp

Four Asian carp species are now established in the United States (common carp Cyprinus carpio, grass carp Ctenopharyngodon idella, bighead carp Hypophthalmichthys nobilis, and silver carp Hypophthalmichthys molitrix). After introduction, they spread quickly, became abundant, and hurt native fishes either by damaging habitats or by consuming vast amounts of food. Common and grass carps destroy habitat and reduce water quality for native fishes by uprooting or consuming aquatic vegetation. Silver carp commonly jump out of the water and into or over boats, injuring boaters.

Chinese tallow tree (Triadeca sebifera)

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. NWRC scientists are investigating the role birds play in the dispersal of Chinese tallow and exploring the value of tallow fruit to wintering birds. Researchers also use satellite data to map and monitor invasive species within the native landscape.

Common reed (Phragmites australis)

Common reed is native to North America and is one of the most widespread plant species in the world. It is invasive in many regions because it replaces other plants to become the dominant species. In 2002, three distinct genetic lineages were identified. One line found in North America is closely related to European and Asian strains of Phragmites australis. NWRC research indicates that the Eurasian lineage can displace plants from other lineages and may significantly alter native Gulf Coast plant communities and the animals that live there.

Feral Swine (Feral Hogs, Feral Pigs)

Feral swine are a problem across the Southeast and the Western United States. They can have a significant impact on ground-nesting birds, impact various plant species, increase soil erosion, and can change entire ecological systems. Feral swine are able to harbor and transmit diseases and parasites to both livestock and humans. NWRC researchers, in cooperation with the US Fish and Wildlife Service and the Louisiana Department of Wildlife and Fisheries, are collecting geospatial data to model habitat destruction by feral swine.

About Feral Swine
Coping with Feral Hogs (Louisiana Department of Wildlife & Fisheries information sheet; PDF; 943 KB)

Island applesnail (Pomacea insularum)

Exotic applesnails significantly impact wetland plant communities and rice agriculture due to their voracious grazing. They are also a potential vector for disease transmission to humans and animals. The snail tolerates a range of salinities and temperatures and can forage both in and out of water through the use of a gill and lung. Egg masses are laid on solid surfaces (e.g. dock pilings, plants) just above the water line. Once established, they are very difficult to remove.

NWRC Researchers are working to (1) conduct rapid assessments of IAS distributions, (2) develop integrated pest management approaches and (3) modelling potential range expansion to identify at risk DOI lands using a variety of approaches. (contact: Dr. Jacoby Carter)

Nutria (Myocastor coypus)

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. The USGS studies worldwide nutria distribution and eradication, maps nutria destruction, and develops computer models to predict damage and simulate management options.

Purple loosestrife (Lythrum salicaria)

Purple loosestrife is a perennial plant native to Eurasia, where it grows along streams and rivers. Seeds were inadvertently brought to North America in the ballast water of ships. Purple loosestrife was also intentionally planted throughout North America for its ornamental flowers but has since escaped cultivation to spread to wetlands. When purple loosestrife invades a wetland, the species sometimes becomes more dominant than the original native wetland species.

Additional resources

Barataria Terrebonne National Estuary Program, Exotic Invasive Species
Center for Bioenvironmental Research, Portals and Pathways: Invasive Species in Louisiana
National Biological Information Infrastructure, Invasive Species Information Node: Knowledge to Identify, Describe, Manage, and Control Invasive Species
National Biological Information Infrastructure, Central Southwest & Gulf Coast Invasive Species
United States Department of Agriculture, National Invasive Species Information Center, State Laws and Regulations, Louisiana
United States Geological Survey, Invasive Species Program
United States Geological Survey, Nonindigenous Aquatic Species

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