A very thorough resource on invasive species.
Visit Calumet County Invasive Species Website
Definition of invasive species
An invasive species is a non-native species that can become capable of establishing a native population and whose introduction causes or is likely to cause economic or environmental harm. This includes any viable life stages or parts of the plants that could aid in dispersal of these species of plants, animals, and pathogens, none of which are native to the state of Wisconsin.