It takes courage to live on Montana's short-grass prairie (大草原). The native people successfull, adapted to the difficult environment over many centuries. For the last 150 years, wild animals have given the basic habitat up to cows, which makes this rare habitat decline ecologically.
Today, though, parts of the landscape are being shaped by a different resident—the North American plains bison (野牛). Tribes and conservation organizations have recently started bringing the bison back. And scientists studying the returns are discovering that getting the 900 kg grazer back in its native ecosystem could be a key to the future of the prairie.
An adult bison eats about 11 kg of grass a day. The grasses adapt to their search for food. Vegetation across the plains uses the nutrients in their waste. Birds pull out their fur from bushes to keep the heat of nests from passing out.
Bison also shape the land literally. They roll in the dust and create muddy areas that hold water after rainstorms. After the bison move on, insects flourish in these pools and become a feast for birds and small mammals. Pronghorn antelope survive by following their tracks through deep winter snows.
Plains bison spent thousands of years engineering a distinctive grassland ecology from Northern Canada through Montana to Mexico. But more than a century ago, this influence suddenly stopped. A few decades of killing led the number of bison to fall suddenly from 60 million to barely 800 living wild in the US and Canada by
1889.
Today, however, bison are getting a second chance. Tribal reservations are at the forefront of their recovery, taking extra bison from Yellowstone National Park and restoring them to treaty lands. Now some scientists are keeping close watch on the changes of the lands after the return of bison.
