As publicity about various invasive species, both aquatic and terrestrial, grows, it is important to understand exactly what an invasive species is.  There is a plethora of words used in the media to describe problematic plants and animals, including invasive, exotic, non-native, noxious, alien, and weed.  These words are often used interchangeably as if they all have the same meaning.  In reality, many have unique definitions and their misuse can lead to public mis-education.
A non-native plant or animal is a species whose native range, or the area it was found before human influence, is someplace other than where it currently is found.  For example, the ring neck pheasant is non-native to Minnesota.  It was imported from China in 1881.  The words “exotic” and “introduced” are often used interchangeably with “non-native”.
An invasive plant or animal is a species that causes economic or environmental harm or harm to human health.  Some invasive species may be native.  For example, poison ivy is native to Minnesota, but it can cause harm to humans who are allergic to it.
Most invasive species that are in the news (Emerald Ash Borer, Asian Carp, European Buckthorn, Zebra Mussels) are species that are both non-native and invasive.  Many introduced species do not flourish in their new habitat, but there are a few that are able to reproduce exponentially.  These are the species that cause the most trouble and receive the most attention.
The Minnesota DNR has undertaken campaigns to fight invasive species on various fronts.  The current “Play Clean Go” campaign teams educational media material with a law against moving unapproved firewood to try to prevent or slow the spread of the Emerald Ash Borer, a non-native invasive beetle that threatens to kill all of Minnesota’s ash tree species in a similar epidemic as Dutch Elm Disease.
On the aquatic front, new boat inspections and fines for transporting invasive species have received a lot of attention.  Movement of boats, docks, and other lake or river equipment between waters is a major factor in the spread of curly leaf pondweed, milfoil, and zebra mussels.  To prevent the infestation of currently clean waters, boaters are required to clean visible plants and animals from their equipment, drain all the water from the boat and containers, and dump unwanted bait in the trash.  These are three simple steps that will help boaters avoid a fine and, more importantly, keep invasive species from spreading to new waters.
As you read or watch future stories about invasive species, keep in mind the differences between non-native and invasive.  The non-native ring neck pheasant is not invasive; it hasn’t caused any harm.  It is an exception.  Zebra mussels, curly leaf pondweed, milfoil, asian carp, faucet snails, and other aquatic species have the potential to cause irrevocable harm to the waters of Minnesota.  For more information about all of Minnesota’s non-native invasive species, visit