In the United States, over $137 billion is spent annually as a result of invasive species. Since its inception in fiscal year 2004, the Wisconsin aquatic invasive species grant program has invested about $9 million in grants to reimburse local projects to monitor and control invasive species. The vast majority of these funds are being spent on lakes. Very little is being done in Wisconsin to increase our understanding about the impacts invasive species are having on our rivers.
What we do know is that they
• outcompete native vegetation creating a bland landscape
• harm our native invertebrates, fish and other wildlife species
• change the hydrology of rivers
• destabilize streambanks
• clog waterways
• cause lost recreational opportunities and more.
Below are four examples invasive species causing damage in Wisconsin and nearby states.
Japanese knotweed, once established near along a streambank, can quickly spread downstream creating an impenetrable wall, out-shading all native vegetation. This has occurred on the Sheboygan River and on many others statewide. If detected early, the spread can be prevented.
 Photographer: Laura MacFarland, River Alliance of Wisconsin
Reed canary grass is a well established invasive species. It has dominated thousands of miles of streambank throughout the state degrading natural habitat. It serves as a example of the potential invasive species have to outcompete native vegetation and dominate the landscape.
 Photographer: Stephen L. Solheim
The New Zealand mudsnail is a tiny (1/8 inch) snail that has devastated western streams. They displace native invertebrates that serve as an important food source for fish. Providing very little nutrition themselves, they have caused fisheries to decline. They have been found in Lake Michigan and Lake Superior. It is important that we detect their migration inland quickly when it occurs and educate fishermen and others to help prevent their spread throughout the state.
 Photographer: Dan Gustafson
Bighead Carp and Silver Carp swim close to the surface of the water and jump in response to boat motors. Boaters, anglers, and others recreating on the water risk severe injury if struck by one of these fish. Bighead carp eat plankton and have the potential to deplete zooplankton populations. That in turn will harm native fish such as paddlefish, bigmouth buffalo, and gizzard shad. They were recently discovered in the Mississippi River near La Crosse.
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