Under a moderate warming scenario, some invasive species can become established in regions that are currently too cold to support them. One such species is the invasive parrot’s feather, a plant that could find suitable habitat across much of the lower Great Lakes by the end of the century, scientists say.
Parrot’s feather was first introduced in the United States as an ornamental plant for aquatic gardens in the 1890s, reaching the Great Lakes basin in 1962, according to Austin Bartos, the Michigan Sea Grant GIS analyst with the US National Oceanic and Atmospheric Administration’s Great Lakes Environmental Research Lab (GLERL). Bartos presented at the Joint Aquatic Sciences Meeting in May.
The Great Lakes region is historically the northern edge of the plant’s range. It’s found mostly in Ohio and southern Michigan along the western Lake Erie shoreline, and to some extent along the southern shores of Lake Michigan, near Chicago.
But parrot’s feather could be a troublesome invasive species in the region. Bartos said it’s a fast-growing plant that can easily take over a wetland or shallow area of water, covering the surface with its feathery leaves. This can shade out other plants, insects and fish that rely on light filtering into the water, reducing biodiversity. Parrot’s feather stands also can cause the water in an area to stagnate, increasing habitat for mosquitoes to spawn and making the surrounding area more susceptible to flooding.
Bartos’ main duties with Michigan Sea Grant involve working on the Great Lakes Aquatic Non-Indigenous Species (GLANSIS) database, which lists and describes 192 known non-native species in the basin. There are an additional 19 species that are indigenous to the Great Lakes but have expanded their range in recent decades.
According to the US Environmental Protection Agency, about 10 percent of non-native species become invasive, which marks them as a species that can crowd out native species and damage the ecosystem unless controlled. The GLANSIS database puts that percentage even higher, with 64 species (or 31 percent) being considered invasive due to having significant environmental or socioeconomic impacts on the lakes.
While working on new products that use GLANSIS, Bartos came across parrot’s feather. Reading about the climate limits on its current range, he felt it would make a good example case on how climate change can impact the distribution of invasive species.
“This was my first foray into species distribution modeling since I started my position at Sea Grant, but it was an interesting project to see what was out there and for utilizing our database,” Bartos said.
Several different climate projections exist, based on how much nations across the globe emit greenhouse gases in coming decades. For the parrot’s feather model, Bartos used what’s known as the RCP 7.0 projection, which expects a moderate-low reduction in greenhouse gas emissions.
Under this model, by 2040 parrot’s feather could find suitable habitat along Lake Huron and the northern shores of Lakes Michigan, Erie and Ontario, with further expansions north as time goes on. By 2080, Bartos’ model suggests that parrot’s feather could even find suitable habitat along Lake Superior’s southern shore, as well as within Lake Huron’s Saginaw Bay and Georgian Bay.
Bartos stressed that the model could be further refined. While it takes water depth into account, for example, it could be enhanced by more information on suitable water temperatures, snow/ice cover and additional data on current parrot’s feather infestations .
He is developing models for the climate projections with extreme high and low greenhouse gas emissions to get a picture of the potential future minimum and maximum ranges for the species. Bartos hopes to submit his data to a scientific journal by the end of 2022.
This model could be useful in identifying at-risk areas and species for future management actions, Bartos said, as well as help in the search for new populations of parrot’s feather around the Great Lakes.
A habitat suitability projection for parrot’s feather in the Great Lakes basin using the extreme high and low climate models. Credit: Austin Bartos
Kevin Bunch is a writer-communications specialist at the IJC’s US Section office in Washington, D.C.