File this Washington Post story under “unintended consequences,” maybe. Researchers in Yellowstone Park are noting that as wolf populations are rebounding, the number of trees is growing too:
The return of gray wolves has dramatically altered the landscape in portions of Yellowstone National Park, as new trees take root in areas where the predators have curbed the size of foraging elk herds, according to scientists in a new study.
Stands of aspen, willow and cottonwood are expanding in areas where for decades dense elk populations prevented new growth, said study author William Ripple from Oregon State University.
Wolves have spin-off benefits, too, the researchers said: As trees grow taller, the stands provide more habitat for yellow warblers and other songbirds and more food for beavers, which in turn construct ponds that attract fish, reptiles and amphibians.
The phenomenon has been described as a “landscape of fear” in which a predator’s pursuit of prey has a cascading effect across the ecosystem.
“Landscape of fear” is probably not the best way to label this as a good thing. I doubt the yellow warblers have much to be afraid of.