People will sometimes use the terms non-native and invasive interchangeably when in fact they have two very different meanings. A non-native species may or may not be an invasive and harmful. However, an invasive species is a non-native that negatively impacts the ecosystem it invades. Here are a few key differences:

• A non-native species is an animal or plant that didn’t originate in a particular area or habitat. These species were intentionally OR accidentally introduced; but, they have little or no negative impact on that ecosystem. Many non-native species are harmless or even beneficial. One example is brook trout. Brook trout are not native to Wyoming but they have been intentionally introduced in numerous locations across the state for fishing. In these cases, they contribute to the fishery, provide diversity and have no negative impact to the particular water where they were introduced. An example of this would be the Pole Mountain area near Laramie where numerous creeks and ponds are specifically managed as brook trout fisheries.
• An invasive species is a plant or animal that did not originally occur in a particular area or habitat.  These species too, were intentionally OR accidentally introduced. However the difference is that invasive species have a negative impact on the ecosystem and ecology into which they were introduced. Invasive species are harmful. We work hard to keep many harmful invasive species, like quagga mussels, out of Wyoming and spend considerable resources combating those that have made their way into the state such as salt cedar and cheatgrass.