Bison Ecology & Management education module - Page 2

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Bison are a strong symbol of the American West. They once numbered in the millions, roaming the North American plains. Eventually, millions dwindled to thousands, and thousands dwindled to hundreds as the pressures of European westward expansion, hunting, and land use change converged. By 1894 only 23 wild bison remained in the United States. Those few animals found refuge in the remote Pelican Valley of Yellowstone National Park. Over the next century, extensive restoration efforts in the Park brought bison back from the brink of extinction. Wild bison in Yellowstone National Park now number in the multiple thousands. They are a true conservation success story. Yet, they are also a management dilemma.

Bison, like all wild animals, do not recognize invisible boundaries, such as those of Yellowstone National Park. In certain winters, they roam beyond boundaries, crossing roads and entering populated areas. Of their own free will, they most likely would return to the resource-rich Park in a few weeks or months. But, weeks or months is not soon enough in the eyes of most people. In addition to the physical risk they impart on humans, bison pose a risk to livestock through the potential transmission of the disease brucellosis. This disease can wreak havoc on domesticated livestock, causing cattle to abort their young and diseased animals to weaken the herd. The current management policy that addresses these concerns involves efforts to contain, and then cull animals as they reach the Park boundaries.

Are current policies the best policies? Can we increase our understanding of bison ecology and behavior to better inform management decisions to decrease culling? Specifically, what factors cause bison to leave the boundaries of Yellowstone National Park? By using spatial technology to visualize scientific field data, computer modeling data, and remote sensing data, we can begin to explore patterns of bison distribution and movement.

There are numerous factors that influence bison. In addition to natural environmental factors and the risk of disease, there is an ongoing controversy surrounding winter recreation in the Park, and the effects of winter road use by snowmobiles on bison movements and range expansion, including trans-boundary movements, bison condition, and population dynamics. What impact do groomed winter roads have on bison? Do they facilitate bison leaving the Park? Or maybe they don’t make any difference to bison.

This case study provides an introduction to the integration of science, technology, and policy as a framework to address pressing environmental management issues in Yellowstone National Park. We analyze scientific data and information using web-based spatial technologies to better understand current bison management dilemmas and controversies. Specifically, we address bison distribution and movement in relation to:

  • The risk to livestock of transmission of the disease brucellosis from bison moving beyond park boundaries, and
  • Criticism of the effects of winter road use by snowmobiles on bison movements and range expansion, including trans-boundary movements, bison condition, and population dynamics.



This section will provide a list of concepts covered so a teacher can quickly assess and correlate to their curriculum requirements.

Herbivore movement,
Predator-prey interactions
Animal population and management
Snowpack/animal interactions,
Plant phenology,
Human-wildlife conflicts.




29 Nov 2006 Webmaster