How Wolves Completely Changed Yellowstone Rivers—A Biologist Explains

Yellowstone’s 1995 gray wolf reintroduction reduced elk browsing pressure across the park.

As elk changed their behavior, willow, alder, aspen, and cottonwood began to recover along riversides.

Stronger riparian growth helped stabilize streambanks and alter river conditions.

The case is a classic trophic cascade showing how top predators can reshape entire ecosystems.