Invasive species come in many forms, including plants, fish, mussels, and insects. They are called invasive because they invade healthy ecosystems and crowd out native plants. Invasive species are not native, so they have no natural predators or controls to keep their population in check. Invasive species are especially hardy, fast-growing, and adapted to different growing conditions, which makes them difficult to control once they are established.
Invasive species don't just hurt plants and animals. The National Invasive Species Council estimates that invasive species cost the United States over $100 billion each year. They impact forestry, agriculture, shipping, tourism, and many other important industries. Invasive species can also be harmful to your health, and your ability to enjoy the outdoors. To find more about invasives species go to http://dnr.wi.gov/topic/invasives/