Warming upsetting wolf-moose balance

ISLE ROYALE NATIONAL PARK, Mich., March 5 (UPI) -- U.S. researchers said Friday global warming might be responsible for upsetting the balance among wolf and moose populations at Isle Royale National Park.

Wolves are up and moose are down in the park, the home of a 46 year study of predators and their prey.

The moose population has slid to 750 on this Lake Superior wilderness island park, down from 900 last year and 1,100 in 2002. In the meantime, the number of wolves has seesawed upward over the past decade and is now up to 29, as many as the park has seen since 1980 and 11 more than last year.

What's bad for moose has been good for the wolves, and moose throughout North America have been hit hard by warmer temperatures that began in 1998 with El Nino and never let up, according to Professor Rolf Peterson of Michigan Technological University, who has lead the study of Isle Royale's wolves and moose for 34 years.

"What we think is happening is that wolves are cashing in on moose vulnerability that's been induced by a warmer climate," Peterson said.