Billings, Mont. • The return of wolves and cougars to Yellowstone National Park is helping restore a landscape that had been altered in their absence and allowing streams to return to a more natural state, according to a new study.
The widespread extermination of wolves and cougars early last century meant elk herds that the carnivores prey on were able to grow in size. The swollen herds ate away willow plants and other vegetation along the park’s streams, causing erosion damage.
But in recent years, resurgent populations of wolves and cougars have restored the park’s natural balance by knocking back elk numbers and changing the herds’ behaviors, according to Robert Beschta and William Ripple of the Oregon State University College of Forestry.