In a state with 15,000 lakes and 84,000 miles of rivers and streams, it can be difficult to know where to focus efforts to protect freshwater ecosystems. That’s especially the case with aquatic invasive species (AIS), plants like Eurasian water milfoil and animals like the zebra mussel, that can have a profound impact on native habitats and cost state and county governments millions of dollars in the fight to try to slow or prevent their spread.
That’s why a team of researchers at the UW-Madison Center for Limnology have upgraded and re-launched the AIS Smart Prevention Tool, an online, interactive map that helps pinpoint water bodies where invasive species are likely to thrive.
“If you’re [a county] invasive species coordinator, you want to know what subset of lakes you are responsible for that, for example, you should focus your zebra mussel prevention efforts on,” Vander Zanden says. Some Wisconsin counties have hundreds, if not thousands, of lakes – far more than state and county employees could properly monitor – so this tool “helps them not be distracted by worrying about everything, everywhere simultaneously.”
By combining what they already know about the lakes they manage, like which non-invaded water bodies are heavily used by boaters and anglers (which is often how invasive species hitch a ride to new waters), lakes associations and resource managers can use the tool to identify the places where invasives are likely to thrive if they do show up and target their monitoring efforts there.
The current version of the tool includes an interactive online map designed by Mike Spear, a UW-Madison graduate student in Vander Zanden’s lab. The map, Spear explains, is a way to visualize the Center for Limnology’s state-wide computer models at a lake-by-lake scale. Spear and his team used data from existing research projects on a half dozen of the state’s known invasive species (including his own work on zebra mussels) as well as Wisconsin Department of Natural Resources databases on water chemistry, temperature and habitat in Wisconsin’s waters.
By comparing an invasive species’ preferred conditions for survival with what is known about conditions in a specific lake or stream, the team can predict if that body of water would be a suitable home for each of the six invasive species.
For example, most lakes in northern Wisconsin lack enough calcium in their water for zebra mussels to grow and build their shells. On the map, this results in a whole lot of blue-colored lakes in the northern third of Wisconsin but, Vander Zanden cautions, “It’s not as simple as ‘in northern Wisconsin zebra mussels won’t invade and in southern Wisconsin they will,’ he explains. If you zoom in to a finer scale, he says, what you often see is a lake that likely can’t support a population of zebra mussels right next to a lake that can.
“Given what we know and to the extent that we can predict these things,” Vander Zanden says, “we are classifying these lakes in regards to the environmental suitability of that habitat.” While it’s not perfect, he admits, it is the best estimate that science can currently provide and, hopefully, it will help the people who work to protect our waters “prioritize and figure out how they’re going to make decisions about preventing the spread of aquatic invasive species.”
The AIS Smart Prevention Tool is available here: https://uwlimnology.shinyapps.io/AISSmartPrevention2/
The researchers would also like to credit Hilary Dugan, Jake Walsh, Monica Papes, Tommy Shannon and Daniel Haryanto for their work on the project.