Evidence is mounting that wild North
American bison are gradually shedding their genetic diversity across many of the isolated herds overseen by the U.S. government, weakening future resilience against disease and climate events in the shadow of human encroachment.
The extent of the creeping threat to herds overseen by the Department of Interior — the backbone of wild bison conservation efforts for North America — is coming into sharper focus amid advances in genetic studies.
It does not include Yellowstone National Park's herd of some 5,000 unfenced bison, the largest federal conservation herd that's seen by millions of people who visit the park annually.