Wood bison DNA spurs species debate
Dr. Matthew Cronin is a research professor of animal genetics at UAF. Cronin and his collaborators say DNA analysis does not support the designation of Wood bison and plains bison as different subspecies:
“The evidence for them being different enough to be designated a subspecies is, in my opinion, just isn’t there, either with genetics or with the historical mixing of the herds.”
Cronin, who is based at UAF’s agricultural research farm in Palmer, found that plains bison and Wood bison are genetically similar, and even found that some plains bison are more genetically different from each other than they are from Wood bison. He says that, decades ago, plains bison were introduced to the Canadian Wood bison herds:
“The Wood bison and plains bison were designated back sometime in the 18 or 1900s. But what’s in the literature, abundantly, is that 6700 plains bison were put into the herd of 2000 Wood bison in Canada in the late 1920s, so they were mixed. So we really can’t assess the original condition of the two groups.”
Cronin, who published his paper in the May edition of the Journal of Heredity, studied both plains and Wood bison in five states and in two Canadian provinces. Cronin admits that scientists often squabble over what designates a subspecies:
“The scientific community has debated the whole subspecies category and many if not most population geneticists like myself recognize the entire category has been used very subjectively, in other words, people have designated subspecies without a lot of rigourous scientific evidence. And that’s been going on since the late 1800s, so there’s a lot of subspecies for which there hasn’t been adequate analysis.”
Wood Bison are currently listed as threatened under the Endangered Species Act, which allows the listing of subspecies. US Fish and Wildlife spokesperson Cathy Rezabek . She says Fish and Wildlife contends the two groups of bison are separate:
“And we based our finding on the scientific information available, which indicated that there has been historical physical separation in their ranges, as well as behavioral and physical differences, and genetic differences.”
Rezabek says that the animals were down-listed from the threatened to the endangered designation about two years ago, and the final ruling on their status was made a year ago.
Cronin says the plains bison and Wood bison should be considered geographic populations, not subspecies. A special breeding program at the Alaska Wildlife Conservation Center in Portage has brought a herd there up to around 200 animals from 53 Wood bison imported from Canada in 2003. Currently Fish and Wildlife is working with the state on releasing some of the animals to habitat in other areas of the state.