Predicting the spread of starry stonewort in Minnesota
When starry stonewort – an invasive alga that can grow tall and dense while displacing native plants and interfering with recreation – was found on Minnesota’s Lake Koronis this summer, many feared that the effects would be monumental. Starry stonewort has yet to appear elsewhere in Minnesota, and MAISRC researchers wasted little time to better understand the threat posed by this nuisance species.
In order to determine which lakes are most at risk of invasion, MAISRC researchers Luis E. Escobar, Daniel Larkin, and Nicholas Phelps teamed up with Dr. Huijie Qiao, an expert in invasion ecology and biogeography at the Chinese Academy of Sciences in Beijing, to perform species distribution and ecological niche modeling of starry stonewort.
Researchers evaluated occurrences of starry stonewort in its native range of Europe and Asia as well as its introduced range of New York, Michigan, Indiana, Wisconsin, and Minnesota. They focused on examining the relationship between where starry stonewort is successfully invading and broad climate variables such as annual mean temperature, minimum temperature of coldest month, annual precipitation, and precipitation seasonality.
By characterizing what constitutes ideal environmental conditions for starry stonewort across the landscape, researchers were able to predict areas of suitable habitat in North America where it could potentially invade and persist if introduced.
“One of the most notable things we discovered through this modeling is that in the United States, starry stonewort is persisting in novel habitats – meaning that it is occurring in areas here that are climatically distinct from its native range,” said Dr. Larkin. “This could explain why it’s typically rare and sometimes even endangered in much of its native range but can act very aggressively here. It seems that conditions in portions of the upper Midwest and other regions in the U.S. are ideal for its growth and spread.”
The next step in this research is to focus in more specifically on Minnesota, taking into account more localized landscape and climatic variables. Researchers will look at the invasion risk for specific lakes, and will also investigate how climate change could impact the susceptibility of lakes in the future.
“Identifying areas of risk is crucial to inform prevention and early detection efforts when spring and boating season return,” added Dr. Phelps. “You can’t manage and prevent these invasive species on a hunch. We have to really know which areas are most at risk and stay one step ahead.”
The maps and accompanying numerical tables with estimated physiological tolerances will be completed this month. They will not only serve as a baseline for future research on this species in its invasion and native range, but will also be provided to the Minnesota Department of Natural Resources to inform prevention and early detection.
