Originally made up of two distinct herds, researchers now believe the Yellowstone bison should be managed as a single, interbreeding population.
Researchers from the Texas A&M College of Veterinary Medicine and Biomedical Sciences (VMBS) have found that the bison in Yellowstone National Park, the only continuously wild population of American bison in the United States, now form a single, interbreeding population, originating from multiple historic herds.
Just two decades ago, population genetic studies indicated that Yellowstone bison maintained distinct breeding patterns and existed as two separate herds within the park. However, a recent study published in the Journal of Heredity reveals a shift in their breeding behavior. Based on these new findings, VMBS researchers recommend managing the Yellowstone bison as one unified, interbreeding herd.
“This finding certainly has a direct impact on the long-term conservation and management of this iconic bison population,” said Dr. James Derr, a professor in the VMBS’ Department of Veterinary Pathobiology (VTPB).
Bison in Yellowstone, like others across North America, experienced a severe population decline known as the “population bottleneck” of the 19th century. By the early 1900s, American bison numbers had dropped by 99.9%, with only 23 wild bison known to have survived in Yellowstone following extensive poaching.
A Conservation Success Story
“In one of the greatest wildlife conservation success stories of all time, a small number of domestic bison from western Montana and the Texas Panhandle were introduced in 1902 to existing animals in Yellowstone in the hopes that they would create a stable and thriving population in the world’s first national park,” Derr said.
Today, Texas A&M researchers report that the Yellowstone bison population functions as a single, genetically healthy group, with numbers typically ranging between 4,000 and 6,000 individuals.
“There has long been a debate among conservationists about how to best manage genetic diversity in Yellowstone bison,” said Dr. Sam Stroupe, a VTPB postdoctoral researcher.
“To get a clearer picture, we examined samples from the two major summer breeding groups and two major winter ranges,” he said. “These are where we would expect to see examples of genetic difference and overlap; however, Yellowstone bison today are clearly one interbreeding herd.”
With the completion of this study, management decisions can be based on accurate information about the breeding structure and overall genetic health of the population to ensure the long-term stability of this iconic bison herd.
The researchers hope that this new information will prove useful to Yellowstone’s bison conservation experts as they continue to manage and monitor this flagship population of the U.S. national mammal.
Reference: “Genetic reassessment of population subdivision in Yellowstone National Park bison” by Sam Stroupe, Chris Geremia, Rick L Wallen, P J White and James N Derr, 13 September 2024, Journal of Heredity.
DOI: 10.1093/jhered/esae050
The study was funded by the National Park Service and the Houston Safari Club Foundation.
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4 Comments
I don’t feel good
They keep changing my words and everything
How is this an achievement? They’ve lost genetic diversity. Whoever wrote this does not understand basic science.
It was the intended outcome from the time William T. Hornaday (New York, New York) and Theodore Roosevelt formed the American Bison Society in 1902 w only the unconfirmed existence of a genetically diverse heard free ranging along the Columbia Plateau region of the western foothills of the continental divides Mission Mountain Range numbering several hundred descendants from a couple dozen. Orphaned calves rounded up after conflict was avoided in aprx 1870 near Malta, MT. Where local tribes voiced their resorting to their horses and dogs for food because there were nothing but rotting corpses of what was millions, Kootenai and Selis hunting parties utilized the orphaned calves along the return trip imprinting on hooves and w ease willfully in tow w the horses hooves the calves traversed the plains and the divide thru glacier national park to the mission valley south of flathead lake where they were safe from poach e rs and predators for generations and quickly grew to several hundred genetically diverse populations they were stolen, initially rounded up in advance of the Dave’s Act 1910 homesteading surplus lands after tribes were allotted acres per individual, th e stories have been shared my maternal grandparents and it was their parents, parents whom led the last of the bison to the flathead River valleys where they free roamed and remained due to the mountains non all sides adult bison dread for they are too top heavy as adults for steep terrain, no acknowledgement has been given to those who did what they did as a final attempt to preserve what would have otherwise been picked off by predators and poachers