The Nature Conservancy. Protecting nature. Preserving life.™

A stormy day at Dunn Ranch © Noppadol Paothong

Bison herds played a critical role in keeping grasslands healthy and thriving for centuries.

The Conservancy’s Dunn Ranch Prairie, located in the heart of the Grand River Grasslands in northwest Missouri, has begun one of the most dramatic phases of prairie restoration: the reintroduction of bison onto the landscape. The herd is restoring key processes, such as soil disturbance and selective grazing, which are important for keeping grasslands healthy.

Why Bison?

Bison are integral components of tallgrass prairie ecosystems. The reintroduction of bison at Dunn Ranch Prairie is the final link in restoring a fully functioning prairie ecosystem.

Bison grazing patterns promote native plant diversity. Bison graze on dominant sedges and grasses and avoid broadleaf and flowering plants (called forbs); this results in a biologically rich prairie. In contrast, cattle primarily consume forbs, allowing sedges and grasses to grow unchecked.

Bison behavior, such as wallowing, tree horning, and roaming while grazing, increases diversity in grassland species. Even fire, a regular occurrence in the Grand River Grasslands, is shaped by the grazed and trampled areas left by bison herds.

Bison are an iconic American species. Before they were hunted to near extinction in the late 1800s, bison roamed the Great Plains for nearly 10,000 years. Bison are a part of Missouri’s natural heritage.

Bison at Dunn Ranch

Thirty-six bison were brought to Dunn Ranch Prairie in October of 2011. Eight more were born in the spring of 2012, and fourteen more were born in 2013. Each year, some bison are traded with other Conservancy preserves to maintain genetic diversity.

Bison at Dunn Ranch Prairie come from a herd that is disease free. All bison entering or leaving the herd are tested for brucellosis, tuberculosis, anaplasmosis, and bluetongue. An annual roundup is conducted to test and, if necessary, treat bison for any diseases or parasites. Calves are routinely vaccinated for brucellosis.

The Conservancy has more than 25 years of experience in bison management. Bison on Conservancy preserves are managed in a safe, ecologically appropriate, respectful manner which emulates natural herd structures as closely as possible.

Safety is a top priority for the Conservancy. The bison are confined to Dunn Ranch Prairie. Fencing exceeds industry standards in all areas, and is inspected daily.

Bison at Dunn Ranch Prairie have not been crossbred with cattle. Standard genetic testing has not detected any cattle DNA in the Dunn herd. Most bison today have traces of cattle DNA.

Bison at Dunn Ranch Prairie will benefit the local community. Visitors and ecotourists patronize nearby businesses, and the Conservancy hires local contractors and makes purchases locally whenever possible. The site provides school groups and other visitors with engaging opportunities to learn about grassland ecology. Although the organization is tax-exempt, the Conservancy voluntarily pays taxes for the Dunn property annually.

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