Federal officials are now moving to delist the largest carnivores of the Greater Yellowstone Ecosystem, citing rising population levels of grizzly bears and wolves as evidence of conservation success. However, the authors of the study say that a simple increase in numbers of wolves and bears does not necessarily mean full ecological recovery. The authors looked at how these formerly absent predators are interacting with moose populations, and found that predator/prey relationships in (GYE) may show signs of dysfunction.
"The current justification that Yellowstone grizzly bears and wolves should now be removed from their protected status because we have enough of both species now is incomplete," said WCS researcher Joel Berger, one of the co-authors of the recent study. "Recovery should be defined by a suite of ecological processes rather than a simple headcount."
For the past 75 years, ungulates such as moose, elk and bison living in the Greater Yellowstone region have lived in an ecosystem free of wolves--which were recently re-introduced in 1995--and grizzly bears--which have recolonized former habitat such as the Jackson Hole area.
Berger and co-author Sanjay Pyare used female moose as an indicator of ecological functionality. They exposed moose to predator sounds and smells, but observed little reaction. Moose in an area of the Kenai Peninsula where moose were fenced in to protect them from predators showed the same disregard for wolf and bear signs.
By contrast, moose living in mainland Alaska, an environment where predators have existed without interruption, displayed agitated responses and often fl
Contact: Stephen Sautner
Wildlife Conservation Society