Grainy photographs of America's Old West recall a time when large bison herds migrated across wide prairie lands, 30 million strong, with the changing seasons determining their path and destination. Now, NASA satellite data and computer modeling and U.S. Department of Agriculture (USDA) information are helping track the remnants of this once mighty herd in Yellowstone National Park as they migrate with the melting snowpack.
The Yellowstone bison are the only herd in lower North America to survive since prehistoric times. Hunting and later poaching dwindled their number down to fewer than 50 animals by 1902. Prior to 1700, millions of bison roamed through Montana, Wyoming and Idaho in areas that later became Yellowstone National Park, the world's first national park. The bison herd at Yellowstone has grown to about 3,900 animals thanks to creative initiatives at the park to restore and maintain the population.
Scientists at California State University Monterey Bay (CSUMB) and Montana State University at Bozeman, and the National Park Service (NPS) have collaborated on a five-year, NASA-funded project that uses NASA satellite data and computer modeling to help park officials better understand the relationship between snow accumulation and the way it melts during the period when bison migrate between habitats at lower and higher elevations.
Every winter, the deep snow in Yellowstone drives most bison to lower elevations as they embark on their quest for food. In this search, some bison will migrate beyond the Park's borders. When bison are outside the boundaries of Yellowstone, the management authority on the northern boundaries of Yellowstone shifts to the State of Montana. Conflicts can arise between people who value conservation of the bison and the ranch owners and others who concerned about the possible risk to nearby cattle from Brucellosis-infected bison.