Improving Western Minnesota Wetlands By Taking On An Invader That Arrived In Plain Sight

Submitted/ This Enstrom model helicopter used by Minnesota Conservation Officers has been outfitted with spray equipment and put into service this last week to apply herbicide on non-native cattails in five wildlife management areas in Kandiyohi County as well as two areas in the Lac qui Parle refuge and Danvers Slough.

WILLMAR – An Enstrom-model helicopter normally used by Minnesota Conservation Officers to catch bad guys breaking our game laws has been at work in the area taking on a completely different nemesis.

Plants turned bad.

The helicopter was called into action to spray herbicide on dense stands of cattails in five wildlife management areas in northern Kandiyohi County this week. Previously, it took on cattails at two sites in the Lac qui Parle refuge and sites in the Danvers Slough north of Benson.

Cattails choke the targeted wetlands. The herbicide is being used to knock some of them out, and  once again provide open water areas in the wetlands. This should allow submergent and other, native vegetation to re-establish itself amidst the monoculture of cattails.

“The primary goal is to get these areas used more often by waterfowl,’’ said Cory Netland, wildlife manager with the Minnesota Department of Natural Resources in New London. Patches of open water and a diversity of native plants provide the habitat needed to attract waterfowl.

Ditto for waterfowl hunters. The thick cattail growth has made it impossible for duck hunters to access open water and their prey in these targeted wetlands. If the herbicide application is successful, the targeted cattail will not emerge in 2018 and hunters season should have access to these areas.

And yes, these cattails are plants gone bad.

Unfortunately, we’ve lost virtually all of our native cattails in the region. It’s happened right under our noses over the last four or five decades. Two species of cattails, a non-native narrowleaf cattail (Typha angustifolia) and a hybrid cattail (Typha x glauca) have aggressively crowded out the wideleaf cattails native to the area.

All of the marshes between Minneapolis and Willmar visible from U.S. Highway 12 are hybrid cattail monocultures, according to Lee E. Frelich, director, the University of Minnesota Center for Forest Ecology. Frelich is among those who have been pointing out the adverse consequences of this aggressive invasion.

Tribune Tom Cherveny / Non-native stands of hybrid and narrowleaf cattails have crowded out native species in wetlands throughout the region and formed monocultures resulting in less diversity of birds and other wildlife.

According to Frelich, the invasive cattails grow taller than native species and block the views of our lakes and wetlands. They outcompete most of the native plant species, such as rushes and sedges and many flowering plants, and form extensive monocultures.

The monocultures result in less diversity of birds and other wildlife. And, by crowding out flowering plants such as verbena, boneset and joe pye weed, pollinator habitat needed by butterflies and other desirable insects is lost.

There are even cases where the invasive cattails can form floating mats and eventually cover shallow lakes, Frelich added.

Netland said 290 acres of cattails in five waterfowl management areas- Oleander, Follies, Burbank, Dietrich Lange and Ringo-Nest- are being sprayed in Kandiyohi County. Two sites in the Lac qui Parle refuge totaling about 131 acres, and two areas in Danvers Slough area- were also sprayed.

The herbicide application was timed to catch the cattails just before they transport their food energy into their roots for the winter. Netland said it will not be possible to know if the application is successful until next year.

If it is, he’s hoping to plant wild rice seeds gathered from other wetlands in the area into some portions of these wetlands. His main goal is to see the wetlands returned to a natural mix of open water and scattered stands of emergent vegetation.

He said it could require follow-up herbicide spraying in the coming years to effectively remove the targeted cattails.

The invasive cattails are not without value: They do provide winter cover for deer and pheasants. But the loss of the cattails in the sprayed areas will be negligible, Netland noted. The acres being sprayed represent only a tiny percentage of the cattails in the areas.

Frelich said the invasive cattails tend to grow in wetlands that receive excess nutrient runoff, which is a problem throughout agricultural and urban areas of southern Minnesota. Minnesota’s native cattails can still be found in waterbodies in the northern half of the state. The native cattails are now very rare to find throughout our region, according to Netland.

An important note: These non-native cattails are not classified under state law as an invasive species. Consequently, permits are required to remove the cattails from lakes or marshes.

The goal of the spraying project is to replace a mono-culture of non-native cattails with a balance of open water and a mix of vegetation like cattails, bulrush,and submergent vegetation.