30 Jul 2013:
Return of Yellowstone Wolves
Triggers Surge in Grizzly's Prized Berries
The reintroduction of wolves at Yellowstone National Park has caused a cascade of ecological effects that has led to the regrowth of berries
, an important food source for the park’s grizzly bears, scientists say. Writing in the Journal of Animal Ecology
, scientists from Oregon State University and the University of
Yellowstone National Park
Grizzly bear at Yellowstone Park
Washington report that the percentage of fruit found in bear scat has nearly doubled during the month of August in recent years. According to researchers, this reflects a recovery of berry bushes triggered in large part by the wolves, which have reduced overbrowsing by the park’s elk herds. “Wild fruit is typically an important part of grizzly bear diet, especially in late summer when they are trying to gain weight as rapidly as possible before winter hibernation,” said William Ripple, a professor at Oregon State University. The removal of wolves for most of the 20th century triggered the demise of the park’s young aspen and willow trees, as well as berry-producing shrubs, scientists say. According to the report, berries may be so important to the health of bear populations that their recovery could mean a lifting of the species’ “threatened” status under the Endangered Species Act
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