8.2 PRSR 10-07-2020 - Laserfiche WebLink

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The DNR and the Minnesota Zoo have been carefully growing a herd of genetically pure Plains bison, which has been in the state since the 1960s, over the last eight years or so. They now have about 150 of the animals spread out over three locations: Blue Mounds State Park in Luverne, Minneopa State Park in Mankato and at the zoo. They’ll forage around these parks for up to 11 hours a day, eating “so much of the grass that they change what the structure of the vegetation looks like,” Quinn said. The bison walk as they eat, on the move together in a herd, mowing down some of the denser clusters and leaving more space and sunlight for flowers and other plants. Everything they eat takes fuel away from future wildfires, helping to manage the intensity of the flames. Sometimes they wallow, throwing their 2,000- pound bodies into the earth and tearing up anything that might be growing, which exposes fresh soil to seeds and sun. “That’s really how these pioneer species of grass grow,” Quinn said. “Certain grassland birds need these sparser areas, where others prefer the denser areas. This wallowing is how you get both on a landscape.” Bison can pack down the earth, too, when they wallow and turn what had been vegetation into small watering holes that become crucial breeding grounds for insects, frogs and other amphibians. Seeds even get stuck on their fur, which is also used for birds’ nests, and carried throughout the prairie. But with limited space, too many bison will degrade a prairie, stripping it bare, Quinn said. The magic number seems to be around one bison for every 8 to 10 acres, meaning Dakota County’s park near Hastings could expect to hold somewhere around 15 animals within an area that would be fenced off. Nurturing the herd It takes about 500 bison to have enough genetic diversity to keep a sustainable herd that won’t collapse on itself due to inbreeding, Quinn said. With populations maxed out at the zoo and the state parks, the only way to get Minnesota’s herd to that number will be to create a network of scattered parks, adding places like Dakota County into the mix, he said. Dakota County’s plan cleared a major hurdle last month when the commission that helps decide how to spend the state’s Environment and Natural Resources Trust Fund dollars every year recommended granting $560,000 for the project. If lawmakers OK the financing in the spring, the bison could be in the park by fall of next year, Lewanski said. If the project moves forward, the county will need to be ready for an influx of visitors. Since Minneopa introduced the bison in 2015, annual attendance at the state park has jumped by about 70%. The park has a road that winds through the center of the bison area, and visitors can drive to within a few feet of the animals, depending on where the herd decides to walk that day. Dakota may not have enough room to make its own bison road, but there are enough trails and parking space that viewing the animals shouldn’t be a problem, Lewanski said. He said his hope is that bison will start a positive cycle both in the ecosystem of the prairie and with the people who come to see them, who may stay to learn more about the restoration and efforts to bring back other rare but less loved animals, such as bull snakes. “People think ‘prairie restoration’ and they think plants,” Lewanski said. “But it’s not only the plants. It’s bringing back as many of these animals as possible.”