Yellowstone herd also contains two distinct populations.
It has long been postulated that Yellowstone bison are important because they remain the only continuously free roaming herd but their importance has been elevated with the disclosure of a recent report which says that they are also the only genetically pure herd among those managed by the Department of Interior.
Not only this, but the Yellowstone population actually consists of two distinct populations which has extraordinary management implications. Currently the management plan for Yellowstone bison does not take in to account the two distinct populations leading to the possibility that management actions could have a disproportionate impact on one population over that of the other. These kinds of impacts can be profound genetically and can lead to loss of genetic diversity over time. The management activities can also have disproportionate impacts on herds because they can eliminate entire maternal groups, groups of closely related cow/calf groups, which are routinely captured and slaughtered on the northern and western boundaries of Yellowstone Park.