Wild Bison Return To Colorado’s Great Plains

December 17, 2020
Bison bulls arrive at their new home on the Heartland Ranch Nature Preserve in Bent County.Bison bulls arrive at their new home on the Heartland Ranch Nature Preserve in Bent County.Courtesy Southern Plains Land Trust
Bison bulls arrive at their new home on the Heartland Ranch Nature Preserve in Bent County.

Ten bison now roam in their new home on the range in southeastern Colorado.

Seven adult females, two adult males and a male calf were part of Colorado State University’s research herd bred to conserve the genetics of North America’s original bison. These animals are genetically pure descendants of the 30 million north American bison that were nearly hunted to extinction more than a century ago.

The ten transferred bison are now on the 25,000 acre Heartland Ranch Nature Preserve in Bent County. It’s part of the Southern Plains Land Trust's six prairie wildlife refuges. 

The trust’s executive director, Nicole Rosmarino, said bison are a keystone species that help shape and restore the shortgrass prairie ecosystem.

“They're very mobile, so they create a mosaic of less grazed areas and more grazed areas,” she said. “They also maintain grasslands by knocking out trees and shrubs. They take dust baths, which, because they're massive beasts, create depressions in the earth, which can give rise to seasonal ponds. When the rains come, [that] benefits wildflowers, butterflies and spadefoot toads.”

Rosmarino said the refuge is one of the best remaining intact shortgrass prairie habitats in the southern plains.

“It's not flat. These are rolling grasslands, with a lot of topography, and therefore a lot of different microhabitats,” she said.

The area is home to rare species, some which are found nowhere else on the planet, such as a flower called the Colorado green gentian. Rosmarino said bringing the bison back to this part of their historic range will help the ecosystem and support the area’s flora and fauna.

The new conservation herd will be kept separate from a herd established in 2015 at the refuge known as the sanctuary herd, which is not a breeding herd, according to Rosmarino. The sanctuary herd is not considered a pure genetic source.

She said an important goal for this project is to expand the land base needed to maintain the bisons’ needs.

“They need ample space to be able to get their groceries and their water.”

The trust is looking to expand the Heartland Ranch preserve to 43,000 acres over the next four years at a cost of about $5 million. 

The Southern Plains Land Trust currently manages six prairie preserves in Southeastern Colorado covering more than 32,000 acres of native grassland.

The bison project is a joint effort by Southern Plains Land Trust, Colorado State University and Defenders of Wildlife.

Editor's Note: A previous version of this story misspelled Nicole Rosmarino's name.

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