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U.S. Fish and Wildlife Service
Division of Ecological Services
1 Federal Drive
Fort Snelling, MN 55118
Phone: (612) 713-5467
E-Mail: Tom_Magnuson@fws.gov

Imperiled Ecosystems | Invasive Species | Water-Related Issuesdesign only
Emerging Issues | Great Lakes-Big Rivers Region Priority Species

Invasive Species

Invasive species are organisms that have moved beyond their natural habitat and are competing with native species for food and territory. In the Great Lakes – Big Rivers Region invaders range from beetles to purple loosestrife to Asian carp. Invasions can be accidental or intentional, but the risk to native species is great in either instance. Invasive species compete with native species, alter habitats, change predator/prey relationships, and transmit foreign diseases and parasites. Invasive species also can cause a myriad of problems, including food chain disruptions, reduced biological diversity and clogging of water intakes (increased weed growth) and cannot be easily eliminated from many biological systems. Prevention, early detection and rapid response are essential elements to preventing major damage to ecosystems and the economies.

Photo of invading purple loosestrife plants - Photo credit:  U.S. Fish and Wildlife Service / John and Karen Hollingsworth
Purple loosestrife plants have invaded this stand of native wetland vegetation.

The spread of invasive species is considered one of the most serious ecological problems facing the United States in the 21st century. Factors that contribute to invasive species are the variety of climates and habitats in the United States as well as the large volume of international travel and trade. The Ancient barriers of the past – oceans, rivers, mountain ranges, etc., – have been breached. All regions of the country have been impacted by invasive species. Invasive species cause huge losses in the agricultural, livestock and fisheries industries. Economic losses and expenditures resulting from the invasion or introduction of invasive species in the United States were estimated at $97 billion in 1991. Current estimates are at $138 billion per year.

Photo of a native mussel encrusted with zebra mussels - Photo credit:  U.S. Fish and Wildlife Service
Native mussel encrusted with zebra mussels

Photo of a sea lamprey on a lake trout - Photo credit:  U.S. Fish and Wildlife Service
Sea lamprey on a lake trout

For more information, please visit these sites:

  • This link opens in a new windowInvasivespecies.gov
    Invasivespecies.gov is the gateway to Federal efforts concerning invasive species. On this site you can learn about the impacts of invasive species and the Federal government's response, as well as read select species profiles and find links to agencies and organizations dealing with invasive species issues. Invasivespecies.gov is also the Web site for the National Invasive Species Council, which coordinates Federal responses to the problem.

  • This link opens in a new windowWeeds Gone Wild: Alien Plant Invaders of Natural Areas
    This site provides a compiled national list of invasive plants infesting natural areas throughout the U.S., background information on the problem of invasive species, illustrated fact sheets that include plant descriptions, native range, distribution and habitat in the U.S., management options, suggested alternative native plants, and other information, and selected links to relevant people and organizations.

  • This link opens in a new windowU.S. Fish and Wildlife Service Invasive Species Page
    Invasive species are infiltrators that invade ecosystems beyond their historic range. Their invasion threatens native ecosystems or commercial, agricultural, or recreational activities dependent on these ecosystems. They may even harm the health of humans. This page contains information about invasive species, plus Injurious Wildlife Species Rulings.
Last updated: August 6, 2015