Conserving Genetic Diversity in Yellowstone Bison

Yellowstone bison are among the most genetically diverse populations of plains bison in North America. The sometimes large-scale culling of bison at the boundary capture facilities raises concerns among park managers about how well they are protecting this valuable genome. Staff at Yellowstone is collecting samples and collaborating with academic scientists at the University of Montana and Texas A&M University to survey the gene structure and determine the distribution of genetic diversity among the geographically distributed groups of bison throughout the park.

Prevailing science suggests that Yellowstone bison consist of a single population, with 2-3 distinct, but not fully segregated; breeding herds. This likely reflects the population bottleneck and subsequent isolation of endemic and reintroduced bison herds during the late 1880s through the 1970s, and strong female fidelity to breeding areas. Retaining adequate levels of genetic diversity is necessary for bison to adapt to a changing environment.

Cumulative available scientific evidence suggests that the conservation of an overall bison population of 2,500– 4,500 (i.e., 1,000–2,000 bison in each of the central and northern herds) should retain 90–95% of genetic diversity and alleles in Yellowstone bison over the next 200 years. Evidence suggests that periodic large-scale removals are the most important negative impact to the genetic diversity of the Yellowstone bison population.