The use of non-invasive fecal DNA sampling to assess the genetic status of the Greater Yellowstone Area bison populations

Bison are an important component of the Great Plains ecosystem and North American Tribal cultures. Concern for the continued existence of wild bison has been generated by conservation status reviews, which reveal they are ecologically extinct from over 90% of their former habitats. Of the estimated 450,000 bison in the United States, 95% of them reside on private ranches where they have been subjected to hybridization with cattle and domestication. Seven of ten public bison herds show evidence of hybridization. Wild bison are at risk of genomic extinction as a result of bottlenecks, hybridization, and domestication. Bison restoration is a high priority, and genetically viable source populations must be identified. The Greater Yellowstone Area (GYA) bison represent a legacy for conservation of wild bison because they are the only population that has continuously occupied prehistoric range. Prior studies of these bison, which relied upon sampling animals outside of the parks, suggested the presence of three distinct subpopulations, and no hybridization. However, this study was unable to determine how population structure was distributed on the landscape. We developed a non-invasive approach for sampling feces from bison in the field for use in genetics studies. This has allowed us to sample bison within their specific geographic breeding ranges with minimal human interference. We hypothesized that fidelity to breeding areas could result in differential genetic signatures between the northern and central interior breeding groups of Yellowstone bison. Alternatively, genetic diversity could be uniformly distributed throughout the entire geographic range. The genetic data, provided by fecal DNA samples, has provided evidence to suggest genetic differences between breeding groups within Yellowstone, and allowed us to assess their genetic status for future conservation efforts.