Genetically pure bison thriving in Nebraska

Genetically pure bison thriving in Nebraska

WOOD RIVER — Reddish-brown calves on short but energetic legs race across grass fields oblivious to the fact they are the first genetically pure American bison born in an unknown number of decades on Shoemaker Island, an 11-mile-long stretch of prairie habitat surrounded by the Platte River.

Thirty to 60 million bison once roamed much of North America, according to the U.S. Fish and Wildlife Service. But the wild bovid were nearly wiped out during the 19th century due to a combination of hunting, slaughter, habitat loss and disease often spread by cattle.

From 1872 to 1874 hunters killed an average of 5,000 bison a day.

By 1889, zoologist William Hornaday estimated the population had fallen to just more than 1,000 animals, with 85 ranging free, 200 on federal land, 550 in Canada and the remaining 250 or so in private herds or zoos. Congress in 1884 tasked the Army with protecting from poachers the 25 that remained in Yellowstone National Park.

Once on the brink of extinction, bison have made a remarkable comeback, with a current population of about 500,000, and generally are considered a conservation success.

But only about 1 percent of those bison are genetically pure, Crane Trust President Chuck Cooper says.

“As a pure species, there are only 5,000 bison left in the world,” Cooper said recently as he looked through binoculars at a yearling bull that was satisfying an itch by rubbing his head on an old water well southwest of Grand Island.

“We almost hunted the bison into extinction into the late 1800s. Then in the 1900s, we almost bred them into extinction.”

Ranchers working to preserve bison began breeding them with cattle in an effort to create a hardier cross.

A study done by Texas A&M College of Veterinary Medicine found that more than 90 percent of private herds had mitochondrial DNA from cows. That study has helped birth a movement to conserve bison as a genetically distinct species.

One of the few herds to test pure was at T.R. Hughes II’s RimRock Ranch near Crawford in the Nebraska Panhandle. The former president of Hughes Brothers Inc. of Seward, Hughes died in March.

Forty-one of his bison arrived at the Crane Trust in January and now roam about 1,200 acres of natural prairie near the Platte River.

The nonprofit manages about 10,000 acres and dedicates itself to protecting habitat for whooping and sandhill cranes, as well as other migratory birds and wildlife through land management, science and outreach and education.

But the trust had long lacked the prairie’s top herbivore — bison, which graze and leave hot meals for other wildlife. Their hooves churn the ground and the depressions left by their wallowing attract bugs and birds.

“Bison was the dominant species. It was here for thousands of thousands or millions of years. Part of the goal here is to restore it to a historical prairie and that is difficult to do without the dominant grazer,” Cooper said.

The Crane Trust plans to do long-term monitoring studies of bison, vegetation and other animals in the ecosystem.

The herd has given birth to six calves since May 8. Cooper expected another two or three to be born over Memorial Day weekend and said the herd could grow by as many as 13 before calving season is over.

It’s hard to say exactly how many of the animals are pregnant; they aren’t given tests or examined by a veterinarian. The Crane Trust plans to allow them to live and interact with the riparian forests, prairie grasses and wetland ecosystems with as little human intervention as possible.

“We’re going to let the bison be bison,” Crane Trust senior director Brice Krohn said.