Overall, Minnesota's wetlands are healthy – but outside of northern Minnesota, many are contaminated or have been taken over by invasive species, Minnesota Pollution Control Agency reports found.
Minnesota has 10.6 million acres of wetlands – nearly 20 percent of the state's land cover, the MPCA notes. (To put that into perspective, that covers more area than the state's lakes and rivers combined.)
And thanks to Minnesota's Wetland Conservation Act passed in 1991, the quantity of wetlands hasn't changed much.
That's good news, the MPCA says, because wetlands filter water, help control flooding and provide a home for various animals (including ducks, geese and insects.)
But the health of the wetlands can affect how they contribute to the ecosystem – and the MPCA found that the quality of Minnesota's wetlands varies "drastically" by region. (See the table at the bottom of the page.)
Where things are good, bad
Wetlands in northeast and north-central Minnesota – where nearly 75 percent of the state's wetlands are located – are thriving, thanks in part to less development and lighter land use, the MPCA says.
But it's the opposite in the rest of the state, where 80 percent have degraded vegetation quality.
The wetlands are being taken over by invasive cattails and reed canary grass, among other invasive species, which push out the native plants that provide a habitat to many animals, according to the reports. Runoff from fertilizers and road salt are also affecting them.
“Excess phosphorus and nitrogen levels from runoff pose a significant threat to the biological integrity of these wetlands,” Michael Bourdaghs, MPCA research scientist and author of one of the reports, said in the news release.
Because of the decreasing quality of some of the state's wetlands, the MPCA is recommending a greater emphasis on wetland protection to ensure they are able to support watershed health and animal habitats.
Bourdaghs says the best conservation strategy is preserving healthy wetlands instead of destroying them and replacing them somewhere else (which current regulations allow), but doing so would require a change in the way wetlands are protected, the Star Tribune says.
Read more about the state's wetland regulations here.