invasive species

An invasive species is a living thing that moves into a new region. Species often become "invasive" as a result of human activities. Invasive species can threaten local plants and animals by competing with them for resources. Sometimes this can lead to the extinction of native species. Once invasive species become established, they can greatly change a habitat.

What: a plant or animal that is introduced into a different habitat by people on purpose or accidentally
How: species are introduced on ships, planes, suitcases, tents, cars, or are deliberately moved by people
Significance: can change existing habitats, push out or eat native wildlife, destroy plants, spread diseases, and cause many other problems

Image credits: European starling, courtesy of Dr. W. Dan Sudia, FLMNH Photo Gallery of Southeastern U.S. Birds African land snail, courtesy of Duane Meier, Honolulu Zoo, Wicked Willy photo gallery cat, courtesy of AMNH.