Continuing research suggests that boats rather than birds are the primary means for introducing aquatic invasive species into Wisconsin lakes.
“The fact that accessible lakes are the ones that are invaded indicates that these species are moved by boaters,” said Alex Latzka, a graduate student at the University of Wisconsin’s Center for Limnology (CFL).
“While birds could transport invasive species from one lake to another, our finding that remote lakes do not have invasive species strongly indicates that birds are not an important factor.”
Scientists at CFL and Wisconsin Department of Natural Resources are two years into a five-year study that explores the spread and distribution of exotic plants and animals in the state’s inland lakes. They hope that their monitoring of 450 lakes will uncover trends in dispersal of invasives such as Eurasian water milfoil that will allow time and funds to be better utilized toward protecting those waters where only native species are present.
“People often think that the lakes that are the most worthy of our protection and most susceptible to invasion are the pristine wilderness lakes,” Latzka said. “With those kinds of lakes are iconic in the Wisconsin northwoods, they are not the lakes most vulnerable to invasive species.”
Additionally, a lot of variability exists within lakes that have human development. For example, just 30 percent of fisheries with public access have water milfoil, while fewer than 20 percent zebra mussels. Those are promising numbers since both species have been in the state for decades.
Also encouraging is the fact that the number of lakes with invasive species remained about the same for the first two years of the study.
By finding out why these invaders have not spread to all lakes with human development and by pinpointing fisheries most at risk, scientists hope to better predict and, ideally, prevent the additional spread of invasives.
(This article appeared originally in B.A.S.S. Times.)