Bringing Bison Back to the Prairie

For more than 25 years, the Nachusa Grasslands have been a restoration and conservation success story for The Nature Conservancy in Illinois. More than 105 prairie restorations have been completed thanks to the work of a dedicated staff and a team of volunteers who have contributed an estimated 200,000+ hours of time. With a long-standing reputation and countless helping hands behind the project, the Conservancy has taken the next step in the restoration process: the reintroduction of native bison at Nachusa. The Nature Conservancy has more than 20 years of experience reintroducing bison throughout the Great Plains in Iowa, Kansas and Missouri, and other places including Mexico, North Dakota, South Dakota, Oklahoma, Colorado and Nebraska.

Nachusa Grasslands Preserve Director, Bill Kleiman, explains the positive effects that can be expected at Nachusa as a result of bison grazing.

Why were bison chosen instead of cattle?

Bill Kleiman:

We considered using cattle and talked to many Conservancy preserve mangers about these two related animals. We chose bison because the animal is well adapted to our climate. Additionally, bison can stand in an Illinois snow storm and keep grazing, they give birth without aid, and they only require access to water and an occasional mineral supplement. Bison also graze almost exclusively on grass, which will allow for more wildflowers to bloom.

How are “wallows” created by bison and what benefit do they provide to the restoration project?

Bill Kleiman:

Bison use their horns and hooves to create very shallow depressions that they like to roll in. The ecological benefit of the wallows is that they allow spring rains to form puddles that enable amphibians to breed, and annual plants to gain a foothold in the otherwise perennial plant dominated prairie.

What immediate effects do you expect to see as a result of bison grazing?

Bill Kleiman:

Visually, there will be grazing patches at random throughout the prairie instead of the current undisturbed sea of grass. Bison tend to maintain patches of season long “grazing lawns,” which will not burn during prescribed fires, because the grass will be too short. The following spring, lush grass will emerge from the blackened areas, creating new grazing lawns. Over time, this will create a random mosaic of grazing patches that will promote a wide diversity of plants and animals. Moreover, bison dung will attract certain beetles that we believe ornate box turtles will seek out.

What long-term effects do you expect to see as a result of bison grazing?

Bill Kleiman:

We hope for an increase in the rare prairie bush clover, which we are rather confident requires grazing disturbance to thrive. We may see the rare upland sand piper return to the prairie. Certain grassland birds such as the grasshopper sparrow will also prefer the grazed areas.

What can local community members expect?

Bill Kleiman:

For a quarter century we have been stewarding this landscape with vigor and passion and that will continue. Bison are herbivores, more bucolic than fearsome. We hope that people will enjoy the journey with us.


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