Genetics program for Badlands bison

Variations key to healthy herd

Bison are one of the most visible animals in the North Unit of Theodore Roosevelt National Park. The herd usually numbers about 300 animals. Kim Fundingsland/MDN

WATFORD CITY – They used to roam the continent by the millions and almost became extinct, but today small herds of bison survive at several places in the United States. Included on the list of locations is both the North and South Units of Theodore Roosevelt National Park,

It is there, in the protective setting of a national park, that visitors can observe and photograph the great animals that are an enduring symbol of the Old West. Rugged, powerful, sometimes ornery, bison are symbols of survival too.

When bison numbered in the millions genetic diversity was a given. Today though, with herds of limited size isolated from other bands, it takes a special effort to insure a herd is as diverse as possible.

“In recent years we’ve embarked on research to understand how we can develop meta-population management,” said Blake McCann, wildlife biologist, T.R. National Park.

The bison herd in the T.R. North Unit usually numbers about 300. When it exceeds that number, considered to be the carrying capacity of the park, a round-up is held to remove excess bison and distribute them to Native American tribes and certain conservation partners of the National Park Service. However, managing the herd goes far beyond just making sure the population doesn’t get too large.

“We’re planning on bringing in Fish and Wildlife Service bison from the Rocky Mountain Arsenal National Wildlife Refuge in Colorado,” said McCann. “We’ll watch over the coming year to monitor new gene forms that are currently not present in the herd and how they move through the herd.”

A few years ago bison from Badlands National Park in South Dakota were also introduced into the North Unit to further efforts to provide genetic diversity in the herd. The Rocky Mountain bison are a continuation of that effort. Without the addition of new animals in the herd, inbreeding could lead to what is referred to as “genetic drift,” a loss of genetic variation that, unchecked, could lead to the demise of the herd.

While visitors to the park may not be able to tell one bison from another, biologists can by tracing genetic diversity. The park’s bison will be closely monitored to insure they remain a diverse herd.

“It will be very exciting to be part of that project,” said Grant Geis, chief ranger. “The data and info that comes out of that will be very interesting. It will preserve genetics and help the genetics of the bison.”

An animal that is unique to the North Unit is Texas longhorn cattle, a small band of which generally roams flat area of land adjacent to the Little Missouri River, not far from the entrance to the park. The longhorns were placed in the park to help illustrate the history of the famed Long X Cattle Trail that wound its way through a portion of what would later become a National Park.

“They are a demonstration herd, non-native animals on the landscape to represent a historic scene,” said McCann. “The nice thing about the cattle is that they are all males, so we don’t have the same breeding challenges with them as we do with the bison.”

“The longhorns seem to be a logical fit for our park,” added, Geis.

The longhorns have been in the park for many years. Due to natural mortality occasional replacements have been acquired, two of which came from the Dakota Zoo in Bismarck within the past few years.


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