Muskrats are a pest to people and a solution to Michigan's invasive plant problem in wetlands

(FOX 2) - Muskrats are semiaquatic mammals native to North America. 

But even researchers that study their influence on habitats in the Great Lakes admit they are not the most beloved animal. 

"People don't have a lot of respect for muskrats in general," said Shane Lishawa, a research associate at Loyal University. "They commonly cause issues. Dikes — they'll burrow into them and they can cause erosion problems. They have a lot of effects that people are annoyed about."

But before muskrats were wrecking people's pontoon boats and causing problems for their human neighbors, the mammal was serving a vital role in Michigan's marshlands.

The ecosystem once dominated the Great Lakes. But decades of development has reduced the region's vital wetlands to a tiny fraction of what they once were. And that was before an invasion of hybrid cattails and nonnative water lilies took over the diverse environments. 

From Lishawa's vantage, what's old is new, and the muskrat could prove to be an elusive remedy to the pressures Michigan's wetlands are up against. 

Big picture view:

Muskrats "eat basically everything that grows," Lishawa said.

The mammal, measuring smaller than a beaver, is not one of nature's pickier eaters. They feed on a wide variety of vegetation and are active throughout the entire year. 

Lishawa was part of a research team that tried measuring the influence that muskrats had on wetlands and marshlands. Together, scientists spent a summer at the Munuscong State Wildlife Area in the eastern Upper Peninsula evaluating that influence.

"It's a really big coastal wetland complex. It's one of the largest in the Upper Great Lakes. That's a site that has a long history of cattail invasion," Lishawa said.

Invading Michigan wetlands

Historically, wetlands have been among the most productive and critical habitats in the Great Lakes. They serve as homes to an immense amount of wildlife, offering storage for heavy rains, purifying water, and recycling nutrients throughout the system.

Those same environments have also been treated like garbage dumps, Lishawa says, serving as homes for dumping. Michigan has also lost an estimated 50% of its coastal wetlands while land near the Detroit River has seen a 90% decline in the habitat, the U.S. EPA says.

While muskrats cannot build new wetlands, they can restore the current ones, Lishawa says. 

Of the habitats that are still around, "roughly 25 to 30% of all Great Lakes coastal wetland is dominated by phragmites, cattail, and reed canary grass."

These invasive plants push out native plants, lock up nutrients like phosphorus and nitrogen, and reduce biodiversity. That means fewer birds and fish thriving in the Great Lakes.

Dig deeper:

Because muskrats eat everything, Lishawa wanted to study if that included the troublesome plants taking over the region's wetlands.

In areas of the Munuscong State Wildlife Area where muskrats homes were observed, there was a 70% decrease in both hybrid cattail and European frogbit cover — which is one of the newer nonnative plants to invade the state.

While herbicides are the most common practice for controlling invasive plants, they still require intervention from humans. Muskrats do that all on their own.

"It's just nature doing what nature does, right? Muskrats are utilizing this resource," Lishawa said. "I think there is some potential for trying to promote muskrats. 

"Where we can encourage muskrats in these invaded sites, there will be ecological benefits as a result," he added.