ZIMMERMAN, Minn. (WCCO) – The Sherburne National Wildlife Refuge is a recreation destination.
Manager Steve Karel says the refuge has several different attractions for folks who love the outdoors.
“This refuge has got recreational uses like hunting and fishing, birdwatching,” Karel said. “And then there’s some hiking trails and wildlife drive.”
But this summer, some of the biggest animals there are cows.
About an hour north of the Twin Cities, the refuge is more than 30,000 acres of oak savanna and wetlands. But some invasive plant species are threatening to change this habitat.
So they’re trying a new way to control the undesirable plants, letting cows eat them.
Manager Tony Hewitt says thick bushes, like American Hazel, are one of the problems he sees. Left unchecked, the woody vegetation makes it almost impossible to walk.
The cows eat the Hazel, as well as grass, which makes the grass grow back stronger.
“They knock back the woody vegetation, and that’s the biggest thing that we’re working on here in our oak savanna habitat,” Hewitt said.
Long ago, buffalo, elk and white tail deer used to graze in the area. The cattle now perform the same function, which is what managers would like to see at the refuge – an oak forest with a grass floor.
Some wetlands in the refuge are completely covered in cattails. But open water is possible if cows are left to grazing.
“Not only does their eating of the vegetation help, but the actual hoof action in the wetlands actually cuts up that vegetation and opens up pockets for other plants to develop,” Karel said.
Keeping the cows where they are needed requires fencing, which is paid for by fees charged to cattle owners. The farmers get well-fed cows in the bargain, and the refuge gains custom-made fences.
“We’ve lowered the top…of the top wire – the barbed wire – and then on the bottom we put smooth wire, and we’ve raised it up to 14 inches so wildlife can get underneath there, and also any hunters that want to get in there,” Hewitt said.
Refuge managers say they also use fire to control unwanted vegetation, but they say the cows are working so well that they may expand the program.