After years of neglect and government-mandated kills, wolves are thriving again. And according to scientists, that's good news for the park's ecosystem. Here's why wolves matter.
Wolves are once again a force in Yellowstone National Park. Less than 20 years ago, there wasn't a single one. Now, thanks to federal- and state-mandated policies, 97 roam the land - with a record high of nearly 38,000 tourist sightings in the wild last year. Previously, growing numbers of elk threatened the park's vegetation, but with a predator back in the picture, trees, plants and many animal species are thriving.
"Take wolves out and things begin to change, and not for the better," says wildlife ecologist Cristina Eisenberg. Still, not everyone is happy. Ranchers complain about attacks on livestock outside the park, and hunters worry about dwindling elk. Despite this, the benefit of wolves to animals and plants in the park is becoming clear.
Consider these facts:
Last year, wolves killed 268 animals, including 211 elk. The hunt leaves its mark -- and its not all destructive.
Elk herds have declined by as much as 50 percent and they spend more time on the move and less time grazing.
Without elk munching on saplings, aspen, willow, and cottonwood can grow to maturity.
More willows mean more habitat and food for beavers - who dam streams and make more ponds.
Streams also thrive, thanks to the roots of trees and shrubs that keep erosion at bay.
More ponds and healthy streams mean more habitat for frogs, fish, insects and reptiles.
Wolves hunt most successfully in the winter, when food is scarce for most species. Their kills provide leftovers for all kinds of scavengers.
Many songbirds, like warblers and flycatchers, nest midcanopy in younger trees, particularly aspen. These stands harbor four to five times as many species as older growth.
This piece was first published in Men's Journal, November 2011.