Invasive Species: The Basics

What are they?

Invasive species are defined by the state of Washington as a nonnative plant or animal that threatens or harms the local environment, local species, human health, or the local economy.

These species tend to spread quickly and can take over the area they are introduced to. Because this is not their native environment normal limiting factors, such as predators, aren't around to keep the newly arrived species in check. The competitive nature of these species in their host environments means that native species' populations can decline or be completely wiped out, when an invasive species moves in.

Other names for invasive species include aliens or exotics

Not all nonnative species are invasive; many of them are useful farm animals or crops.

Further Reading

http://www.invasivespecies.wa.gov/about.shtml
The Washington Invasive Species Council established in 2006 by the state legislature to provide planning, and coordination in the combat of harmful nonnative species.

http://www.invasivespecies.gov/main_nav/mn_faq.html
The National Invasive Species Council established in 1999 to provide the same services on a national level, as well as encourage similar lower level initiatives. It is made up of various high level federal organizations and works with federal and non-federal groups throughout the country.