New Predator in Yellowstone Reshapes Park’s Entire Ecosystem

Yellowstone National Park’s riverside cottonwoods stopped growing in the mid-1920s and 1930s. Same with willows and aspen. Shoots sprang up, lingered awhile, but never matured. Park officials suspected elk were eating the new growth, but culling the herd did not help. Beginning in the late 1990s, however, things suddenly began to change. The elk moved away from the streams, and trees and willows began to grow. Researchers wondered why. They ruled out drought, flood, fire or climate change. Only one answer remained. Wolves