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.
Advances in genetics are bringing the concern in to sharper focus.
Preliminary results of a genetic population analysis commissioned by the National Park Service show three small federal conservation herds would almost certainly die off within 200 years under current wildlife management techniques.
Answers to protecting genetic diversity may lie in the transfer of bison between unlike herds or initiatives to create larger herds.
North America's bison squeezed through a genetic bottleneck of fewer than 1,000 animals in the late 1800s.