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 preserve, located in the heart of the Grand River Grasslands in northwest Missouri, is entering one of the most dramatic and exciting phases of prairie restoration: the reintroduction of bison onto the landscape. The bison’s presence on the prairie is restoring ecological processes, such as soil disturbance and selective grazing, which are integral components of natural grassland communities.

Why Bison?

Bison are integral components of tallgrass prairie ecosystems. The reintroduction of bison at Dunn Ranch 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-seven bison were brought to Dunn Ranch in October of 2011. Thirty more will be brought to the preserve in 2012. The bison are relocated from existing Conservancy preserves in South Dakota and Iowa.

Bison at Dunn Ranch come from a herd that is disease free. All bison entering or leaving the Dunn Ranch herd will be tested for brucellosis, tuberculosis, anaplasmosis, and bluetongue. An annual roundup will be conducted to test and, if necessary, treat bison for any diseases or parasites. Calves at Dunn Ranch will be 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. To maintain genetic diversity, bison are swapped amongst Conservancy herds on an annual basis.

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

Bison at Dunn Ranch are genetically pure. There are over 400,000 bison in public and private herds in the United States, but the herd at Dunn Ranch is unusual because it is one of only eight herds in the country that have not been crossbred with cattle (based on standard genetic testing).

Bison at Dunn Ranch will benefit the local community. Visitors to Dunn Ranch patronize nearby businesses, and the Conservancy hires local contractors and makes purchases locally whenever possible. The site also 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 Ranch property annually.

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