Carnivores Returning Balance to Yellowstone?

Some scientists say the return of wolves and cougars to Yellowstone National Park is helping restore a landscape that was altered in their absence, which is allowing streams to return to a more natural state.
The widespread extermination of the two carnivores early last century meant the elk herds they prey on were able to grow in size. Those elk ate away willow plants and other vegetation along the park’s streams, causing erosion damage. But researchers from Oregon State University say that by knocking back elk numbers and changing their behavior, wolves and cougars have restored the park’s natural balance.
The researchers say willows are rebounding and streams are recovering, although it could take a long time to complete.
The findings are in a peer-reviewed study being published in the journal Ecohydrology.