The reintroduction of the gray wolf to Yellowstone National Park has helped increase an important food source for the threatened grizzly bear, according to the Los Angeles Times.
A study published Monday in the Journal of Animal Ecology show what species are eating in the national park. According to the study, wolves were reintroduced to the park in 1995 after a 70-year absence, and they preyed on elk herds that grazed on trees and shrubs.
The elk populations increased while the wolf population decreased, and so did the accessibility of much need berries.
"The grizzly bear uses some of the same plants that the prey of the wolf uses," said William Ripple, an Oregon State University professor of forest ecosystems and lead author of the study, the LA Times reports. "The reintroduction of one top predator is potentially affecting another top predator through this food web."
Ripple's research team at OSU and Washington State University compared the amount of fruit found in grizzly bear droppings to elk numbers before and after the wolf reintroduction.
"Over a 19-year period, they found that the average proportion of fruit in grizzly scat rose significantly after wolves returned to Yellowstone and the elk population fell," according the LA Times.
Ripple's work showed aspens declined after wolves were eliminated from the park in the 1920s, the LA Times reports. The reintroduction of wolves saw elk populations decrease, and an increase of aspen, cottonwood and willows in some parts of the park.
The wolves return has also increased the population of beavers.
"We're in the early stages of this ecosystem recovery. This is what we call passive restoration," Ripple told the LA Times. "We put the wolf back in and then we let nature take its course...It may not be a panacea or a big silver bullet as a food item for the grizzlies."
To read more about the LA Times report, click here.
