Increasing numbers of bison in Yellowstone National Park in recent years have become a barrier to ecosystem recovery in the iconic Lamar Valley in the northern part of the park, according to a study by Oregon State University scientists.
In the valley, foraging by bison exerts 10 times the environmental pressure of elk, historically the area’s dominant herbivore – that’s a problem because bison are powerful “ecosystem engineers.”
Large numbers of bison disrupt species distribution across shrub steppe and grasslands. They do so via what they eat, trample and rub their horns and bodies on – i.e., tree bark. Thus, bison have tremendous capacity to limit the structure and composition of woody plant communities. MORE
Header image: Bob Beschta, OSU.