Bison Management in Yellowstone Park

Bison (Bison bison) in Yellowstone National Park have increased in number from around 500 animals in the early 1970’s, to over 3,000 in the early 1990’s. Three major subpopulations exist, each with discrete summer ranges but which come together on winter ranges. At higher population numbers, movements of bison beyond park boundaries during winter are common. Since Yellowstone bison are known carriers of brucellosis, these movements are of concern to federal and state agencies in charge of control or eradication of livestock diseases.

One of the most important issues surrounding bison is the fact that they carry brucellosis. The potential, although unlikely, transmission of brucellosis to cattle has generated a cascade of secondary social facts associated with this. The potential, harmful consequences to the cattle imply important economic costs to the ranchers, and to the regional industry. The States surrounding Yellowstone value all aspects of the cattle industry because it is their most sustainable resource. Yellowstone has a potential pool of brucellosis, which the inhabitants of Montana, and to a lesser degree, Idaho and Wyoming, see as a threat to their economic interests. Public outcry on this issue skyrocketed in the winter of 1996-1997 when shooters from Montana Department of Livestock killed over 1100 buffalo as they wandered outside Yellowstone National Park in search of food during the severe winter.

Every political problem has the potential to create a conflict of jurisdiction between institutions. In this case, it is federal government, the States and the special interest groups. In addition to the problem itself (bison brucellosis), there is a battleground where weaker actors (like the States) put pressure over more powerful ones (like the federal government) with whom they have a long confrontational history.

Each economic conflict mobilizes actors in the political arena. Every interest lobbies in order to reach a favorable position, using politics to do so. This political arena is the playground where federal government, States government, agencies and environmental groups deal with their differences. Overall, the bison and brucellosis issue is a biological fact affecting all economic, social and political arenas.

Management of brucellosis in bison could potentially be complicated by transmission of the disease between elk and bison. Scientists from Montana State University are assessing the potential for such interspecies disease transmissions in the Madison-Firehole area of YNP. This area was selected because it is the major wintering ground for approximately 1000 bison as well as and estimated 600-800 nonmigratory elk