Wednesday, December 13, 2017

A grizzly bear moves among evergreen trees in a winter landscape.

Grizzly bear numbers, food sources stable

PRAY – Their food sources are stable, and so is the Yellowstone grizzly bear population, a federal wildlife official said Thursday at the Yellowstone Grizzly Bear Coordinating Committee’s fall meeting at Chico Hot Springs Resort.
 
The GBCC is the new name of a multi-agency committee formerly called the Yellowstone Ecosystem Subcommittee, according to a news release issued in advance of the meeting, which was held Thursday afternoon and Friday morning. The group met to discuss its new charter as well as to hear about current grizzly bear research, which was provided by U.S. Geological Survey research wildlife biologist Frank van Manen.
 
The name change reflects the committee’s new duties, which are managing the Yellowstone grizzly bear population as a species newly removed – or “delisted” – from protections of the Endangered Species Act. Citing increased grizzly bear numbers and evidence of expanding territory, the U.S. Fish and Wildlife Service sought delisting of the species last year, which was finalized in June of this year.
 
The committee will oversee management of grizzlies, which may include licensed hunts in future years, in the three states – Montana, Wyoming and Idaho – that surround the grizzly’s main habitat in Yellowstone National Park.
 
Van Manen presented information Thursday and Friday on grizzly bear population numbers, mortality, food sources and their likelihood of intermingling with the Northern Continental Divide grizzlies that live in and around Glacier National Park.
 
The grizzly population this year, in the demographic monitoring area, or DMA, is estimated at 718 bears, van Maren said. The DMA extends around Yellowstone encompassing federal and private lands around the park. Van Maren shared how the bear population is estimated, based on a combination of observation and scientific population models based on the number of bears observed. The actual number of bears could range between a low estimate of 640 bears to a high of 796, he said.
 
Van Maren said the genetic diversity among Yellowstone’s bears is lower than some other North American populations, but that the issue is not “critical.”
 
Critics of delisting the Yellowstone bears cite concerns about the lack of genetic diversity of Yellowstone’s bears, isolated as they are from other populations.
 
Showing a map of the NCD and YNP bears, van Maren said 70 miles separate the outer reaches of the two ecosystems. Male grizzlies are the more likely to disperse farther afield, van Maren said, and human efforts such as conservation easements could make the dispersal safer for the bears. There are currently no plans to move bears, or “translocate” them, from one ecosystem to the other, but rather to allow any such migration to occur naturally, he said.
 
Critical grizzly bear food sources were also discussed – cutthroat trout, whitebark pine seeds and Army cutworm moths.
 
Van Maren praised Yellowstone National Park for its continuing efforts to remove non-native lake trout, which compete with native cutthroat trout, from Yellowstone Lake. Cutthroat trout populations, after declining for several years, have stabilized recently, van Maren showed in data presented at the meeting. Bear activity has increased on the streams where cutthroat spawn, he said.
 
Another important food source for Yellowstone grizzlies is the Army cutworm moth.
 
“There’s no documentation of the (moth) food source declining,” he said.
 
Whitebark pine trees are in decline due to mountain pine beetle infestations, but overall, it was a “relatively good year” for food sources this year, van Maren said.
 
Anecdotally, it was generally a good year for bear food sources, with berry production up, he added.
 
Bear deaths in the past year totaled 46, he said, with 39 human-caused, three natural deaths and four that were unable to be determined. Most are in the fall and are “hunter-related,” van Maren said. Nine bears were killed by being struck by vehicles.
 
Caroline Bird, executive director with the Bozeman-based Greater Yellowstone Coalition, told the committee Thursday during the public comment portion of the meeting that the organization had issued a “report card” on grizzly management, providing a passing grade of “C,” she said. The GYC has not formally opposed delisting, but continues to monitor the plan.
 
“In the last three years, 150 bears have died in conflict with humans,” Bird said. “We can do better.”
 
Dan Wenk, Yellowstone’s superintendent, said the meeting was successful in outlining how the GBCC is going to operate in the future and provided current research on grizzly bears, especially concerning “connectivity” between Yellowstone and Glacier grizzlies.
 
“Anything we can do to enhance linkage is good,” he said.
 
More information is available on the Interagency Grizzly Bear Committee’s website at www.igbconline.org.
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