Bison help put the "Prairie” back in Prairie State

Bison grazing in the grasslands, USA.
© Richard Hamilton Smith

When bison return to Illinois this fall, they’ll be part of a conservation solution.

By Michelle Carr, State Director of The Nature Conservancy in Illinois

Growing up in the Midwest, I have fond childhood memories of hiking through the golden prairies that blanketed much of the region. It seems hard to believe that today these are the world’s most imperiled habitats; in Illinois, only one tenth of one percent of our iconic grasslands remains due to incompatible development and fragmentation. That’s why we’re enlisting an important new partner in our conservation and restoration efforts: bison.

Native bison will return to The Nature Conservancy’s Nachusa Grasslands preserve this fall. Located two hours outside of Chicago, the land that became Nachusa was once pristine prairie remnants broken up by miles of corn and soybean fields. The Conservancy saw these islands of untouched prairie as a unique opportunity to restore one of Illinois’ most important habitats, so in 1986, we made our first land purchase of 400 acres.

Nachusa was one of the first projects I visited when I started working for the Conservancy, and I was astonished by the conservation successes achieved there. Since that initial land purchase, the preserve has blossomed into 3,000 acres of high-quality prairie that is home to 700 native plant species and 180 species of birds. Thousands of staff and volunteer hours were spent over the past 28 years weeding invasive species, sowing native seeds, and restoring prescribed fire to make Nachusa what it is today—a place that reminds me of the prairies I hiked through as a child.

But a grazing animal like bison is needed to take restoration to the next level. Plain and simple: prairies need bison to thrive. With their wallowing and grazing, bison provide natural disturbances to the landscape that spread native seeds, aerate the soil, and help maintain the natural balance of prairie grasses and flowers. This, in turn, provides rare Ornate box turtles, regal fritillary butterflies, grasshopper sparrows, and other species the essential habitat they need to survive.

Bison closeup© A closeup look at a key conservation tool: American Bison. CREDIT: Richard Hamilton Smith

But bison’s return doesn’t just help turtles and butterflies. Prairies provide a wide range of benefits for people, too. The more bison help improve the landscape, the more the prairie will be able to:

    • Filter water and mitigate flooding

    • Store carbon

    • Protect biodiversity of plants and wildlife

    • Support local jobs and industries like tourism

    • Provide recreational opportunities

The bison benefit as well. Their reintroduction allows the Conservancy to contribute to the conservation of American bison as a species, one that was brought to the brink of extinction in the early 20th century. Nachusa’s bison will hail from the herd at Wind Cave National Park in South Dakota, the last line of genetically pure bison in the country. (Unlike most other American bison, animals from the Wind Cave herd have not been bred with cattle). As the herd grows and Nachusa’s bison are exchanged with those from other preserves, the genetic line will be preserved and strengthened.

While the Conservancy has more than 20 years of experience reintroducing bison throughout the Great Plains of Iowa, Kansas, Missouri, North Dakota, South Dakota, Oklahoma, Colorado, and Nebraska, this is the first time we will reintroduce wild bison to native Illinois prairie. The opportunity to study exactly how these animals affect the landscape and its plant, animal and insect populations is tremendous.

And, hopefully, this is one of many steps towards earning back our title of “the Prairie State.”

To learn more, visit

Bison help put the "Prairie” back in Prairie State
Bison roundup to help conservation efforts 2 hours outside Chicago, Illinois.

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