BOZEMAN — Grizzly bears in the Yellowstone National Park region are thriving and have the potential to continue to thrive in the long term, according to a study by the Interagency Grizzly Bear Study Team.
The study, published in Molecular Ecology, looked at 729 bears and found that estimates of effective population — the number of bears passing genes to the next generation — in the Greater Yellowstone Ecosystem has quadrupled since the 1980s, growing from 100 to about 450.
Researchers also found that genetic diversity in the population was stable.
That means gene variations that can help grizzlies evolve and adapt have a better chance of being passed on to new generations of bears in the ecosystem, which includes parts of Wyoming, Montana and Idaho.
The genetic variations are important for the continued survival of the bears and their ability to adapt to environmental changes, the study said.
Pauline Kamath, a geneticist and one of the study’s authors, said the results are good for the grizzly bears and highlight their restoration as a conservation success.
This study comes as the U.S. Fish and Wildlife Service is said to be mulling a delisting rule for the threatened species. The bear was first listed as threatened under the Endangered Species Act in 1975 and has been hailed as one of the law’s biggest successes.
The most recent U.S. Geological Survey estimated the total Yellowstone grizzly population at 757 bears, though most government experts believe it’s higher.
Kamath told the Bozeman Daily Chronicle (http://bit.ly/20laLfw ) that the stability in genetic diversity is some of the most significant good news in the study.
“As you lose genetic diversity you lose specific gene variants that will allow populations to adapt,” she said. “The less diversity you have, the less you have to work with basically.”
Grizzly bears only live in a few places around the Northwest, and the Yellowstone region bears aren’t connected to any of them, limiting genetic diversity.
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