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NASA Studies Snow to Save Bison at Yellowstone National Park
NASA satellite data not only keep us in tune with climate changes and help officials track lots of natural disasters like wildfires and earthquakes. The space agency's technology can also now help Yellowstone National Park officials track and maintain one of the country's oldest and largest forms of wildlife – the mighty bison.

Photo of a bison in Yellowstone Park. Image right: This image is of an adult bison during the winter season in Yellowstone National Park. Click image to enlarge. Courtesy: National Park Service

Though tens of millions of bison once roamed freely across wide swaths of land that now make up Montana, Wyoming and Idaho, their numbers fell to fewer than 50 by the early 1900s. Now, the bison is making a slow comeback, thanks in part to NASA satellite data and computer modeling and U.S. Department of Agriculture's (USDA) snow information that is helping to track their migration based on melting snowpack -- dense snow accumulation -- which influences their movement.

From near extinction, the bison herd at Yellowstone -- the world's first national park -- has grown to number about 3,900 animals due to creative initiatives at the park to restore and maintain the population.

Scientists at California State University Monterey Bay (CSUMB) and Montana State University, Bozeman, and the National Park Service (NPS) have collaborated on a long-term, 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.

This image was created from NASA Landsat satellite
data and shows the migratory path of the bison herd in Yellowstone National Park. Image left: This image was created from NASA Landsat satellite data and shows the migratory path of the bison herd in Yellowstone National Park. Click image to enlarge. Credit: NASA

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 Yellowstone's borders. Ranch owners and others are concerned about the possible risk to nearby cattle from Brucellosis, a disease that many wild bison carry. Ranchers want to protect their herds, raised to be sold as meat and leather goods to stores. An inter-agency partnership has developed a management plan to address the issue of border crossing, requiring Park officials to move the animals off of private property, back onto public land, and sometimes to capture bison to prevent them from commingling with neighboring livestock.

"Our goal is to provide the latest snowpack information to park officials," said landscape dynamics expert Fred Watson, principal investigator of the project and assistant professor of science and environmental policy at CSUMB. "Ecologists try to best understand how animal populations respond to the changing conditions of the landscape where they live. Snow is a very important factor in the livelihood of all wildlife species in the ecosystem, including the Yellowstone bison population," said Watson.

Photo of a bison herd. Image right: The image shows a herd of bison foraging for food during the winter months at Yellowstone National Park. Click image to enlarge. Credit: National Park Service

The release of captive bison is timed to ensure a higher likelihood the animals will remain in the park. Knowing when and where the snow will melt is key to whether the bison will stay within park boundaries. To better inform the management team, park officials use a model of snowpack dynamics developed by Watson and his staff to provide the most up-to-date projections on snowpack distribution on winter range areas within the National Park.

"The National Park Service is not a traditional user of NASA information," said Watson. "But this is a great opportunity to use NASA technology to help the folks at Yellowstone."

Related Links:

+ Additional info and more images
+ National Park Service and NASA
+ Yellowstone Bison

Gretchen Cook-Anderson
Goddard Space Flight Center