Another great reason for Wyo. wolves

Chris Conway reports in the New York Times Science section Aug. 5 that wolves may be at the root of a resurgence of aspens in Yellowstone National Park's Lamar Valley.

Elk eat aspen shoots. Wolves eat elk. The 6,500 elk in the park can't eat in peace with wolves around, ready to pounce. So many of the aspen shoots are surviving to grow in peace.

At least that's the theory posited by scientists at Oregon State University:

"...the study found that an 'ecology of fear' has helped to restore balance to the valley, protecting young aspen shoots from browsing elk for the first time in decades. William J. Ripple, a professor in the university’s College of Forestry and an author of the study, said aspens were recovering in areas where it would be difficult for elk to escape a wolf attack. 'We think these elk need to balance the risk of being killed versus eating in their favorite places. So it’s a trade-off between food and risk in an ecology of fear,' he said.