Getting your Trinity Audio player ready...

By Kristi Marohn, Minnesota Public Radio News

A new report suggests Minnesota has made small strides in slowing the loss of critical wetlands, although increased precipitation could be a factor.

The Minnesota Department of Natural Resources uses aerial imagery to analyze how much wetland area has been gained or lost. Its most recent report looked at changes from 2006 to 2020, when Minnesota had a net gain of about 43,000 wetland acres.

“Relative to our total amount of wetlands, it’s kind of a small area,” said Amy Kendig, biometrician and wetland research scientist at the DNR. “But it’s definitely positive that we’re seeing net gains and that the wetland losses are declining over time.”

Wetlands play a key role in storing floodwater, filtering out pollutants, preventing erosion and providing habitat for waterfowl and other wildlife.

The recent gains are tiny compared to Minnesota’s historical wetland losses. It’s estimated that the state has lost half of its original pre-settlement wetlands due to draining or filling.

“If we continue to gain at the rate that we saw with this report, it would take actually thousands of years to get back to those historic wetland extents that we had pre-settlement,” said Jennie Skancke, wetland programs coordinator at the DNR.

About half of the gains were emergent wetlands in agricultural areas that transition between being wet and dry, with rooted upright plants such as cattails. Kendig said the aerial images showed many of those changes were the result of direct action by landowners.

“That suggests that there’s active action going on in agricultural land to convert it,” she said. “That can be things like removing drain tile, or just allowing wetlands that would exist otherwise to be there ,or active restoration.”

The gains suggest that Minnesota’s legal protections for wetlands, along with programs that protect and restore wetlands through conservation easements, are having some success, Skancke said.

In 1991, Minnesota enacted the Wetland Conservation requiring no net loss of wetlands. The law requires landowners to make up for draining or filling wetlands by creating or restoring wetlands elsewhere.

Last year, the U.S. Supreme Court narrowed the definition of wetlands that fall under the Clean Water Act, meaning some wetlands across the country are losing federal protections, Skancke said.

“We really hope that we can continue to maintain or have these small gains,” she said. “I think that’s really a win that a lot of other states may not be able to talk about.”

Minnesota is experiencing more frequent and extreme rainfalls due to climate change. Increased precipitation could help explain the wetland expansion, especially if landowners are deciding to put frequently wet areas into conservation easements.

“We don’t think necessarily that’s the cause, but we see that correlation,” Skancke said. “That could result in people making different decisions about land management.”

The next report will reflect the years 2021 to 2023 when the state experienced a severe drought.

The report also notes that while Minnesota is achieving its goal of no net loss of wetlands, there was a loss of forested wetlands or swamps, whose benefits may not be replaced completely with other types of wetlands.