Invasive Species
Making Themselves At Home in Wisconsin's Lakes and Landscapes

Wisconsin faces an onslaught of invasive species from other regions and countries. These non-native plants, animals and pathogens displace native species, disrupt ecosystems, and harm recreational activities such as fishing, boating, and hiking. They also damage commercial, agricultural, and aquacultural resources.

Because they lack the predators and competitors they faced in their homelands, invasive species can spread rapidly and aggressively. Controlling invasive species is difficult, and getting rid of them is often impossible. People play a major role in spreading invasive species, and can also help keep them from spreading. We can save our favorite places if we all do our part!

Learn more about a few of the invaders that have been making headlines this summer:

• Hydrilla is an invasive aquatic plant that was confirmed for the first time in Wisconsin in summer 2007. It was found in a private artificial pond, and the Department of Agriculture, Trade, and Consumer Protection is taking the lead in responding. See their press release (exit DNR) for more information.
• VHS, a fish disease that can kill a broad range of Wisconsin’s native fish. It has recently been found in Lake Michigan and the Winnebago system.
• Spiny Water Fleas are an invasive species of zooplankton that can disrupt ecosystems and harm native fish populations. They have recently been found in a second inland lake in Wisconsin.
• Emerald Ash Borer is a forest beetle that has already killed 20 million ash trees in the Midwest.

Find more information about other invasive species on these pages:

• Plants
• Animals

The Good News About Invasive Species

The good news is that many places in Wisconsin don’t have the most common and troublesome invasive species. For instance, only a small fraction of our 15,000 lakes have Eurasian water-milfoil or zebra mussels. There is a lot that people can do to prevent the spread of invasive species, and we have a lot left to protect!

How You Can Help

Whether your passion is boating or bicycling, fishing or flowers, there are some simple steps you can take to keep from spreading unwanted species around. There are also many volunteer opportunities for those who want to get more involved in the fight to keep our lakes, forests, prairies, and wetlands free of invasive species. We need your help!

Contact Information

• Department Contacts
• Wisconsin Council on Invasive Species
• Invasive Species Team