Sixteen grizzlies have been captured so far this year by teams gathering information that will be used this fall to decide whether to propose lifting federal protections of the bears in the Greater Yellowstone Ecosystem.
The Interagency Grizzly Bear Study Team captured the grizzlies in Montana and Wyoming, while efforts in eastern Idaho have just started. The team usually captures about 60 bears a year.
"We're evaluating whether the bear population is capable of being recovered at this time," said Chris Servheen, grizzly bear recovery coordinator with the U.S. Fish and Wildlife Service. "It will be ready this fall. If the answer is 'yes,' there will be a proposal to delist."
An estimated 740 grizzly bears roam the 19,000-square-mile Yellowstone ecosystem that includes portions of the three states plus Grand Teton National Park and Yellowstone National Park.
Servheen said information from the trapping and other studies will go into a Threats Analysis that includes threats to bear habitat, threats to the population, and how well the states could manage grizzly bears if federal protections are removed.
Threats also include natural deaths, the classification given for the death of a 22-year-old grizzly that died last week in Yellowstone National Park after getting into a fight with another bear. The bear that died had been previously trapped and fitted with a radio collar.
Grizzly bears were first listed as threatened under the Endangered Species Act in 1975. Surveys found about 260 grizzlies in the region in 1981, Servheen said, noting that the animals have tripled their population and doubled the area they occupy since that time.
Frank van Manen, team leader of the Interagency Grizzly Bear Study Team, said studies show the animals might have occupied all available habitat in the region. He said growth of the population in the last decade has fallen to less than 2.2 percent, compared to as much as 7.4 percent in previous decades.
"There are some indications that this slowdown of population growth is related to the fact that we have a large, high density population," he said. "At some point, it will reach carrying capacity of the ecosystem. There are indications that is happening."
Besides eastern Idaho, trapping is also underway in areas of Grand Teton National Park, the North Fork of the Shoshone River in Wyoming, and private land in the southern Madison Mountains in western Montana, officials said. Teams plan to start trapping on public land in the southern Madison range this weekend. Trapping in Yellowstone National Park starts Tuesday.
Gregg Losinski of the Idaho Department of Fish and Game said trapping areas are marked with signs that should be heeded, though remote cameras have recorded humans walking around baited culvert traps and even looking inside.
"We still see people going behind signs trying to investigate what's going on in the trapping area, and that's not a very smart thing to do," he said, noting there is also bait outside the traps that in past years have lured bears weighing more than 600 pounds.
Trapped bears are examined for health, and DNA samples are taken to determine relationships. Losinski said about a dozen bears in Idaho will be fitted with $3,500 GPS collars that give biologists information about a bear's location.
Federal Fish and Wildlife delisted grizzlies in the Greater Yellowstone Ecosystem in 2007, but a judge returned the protection two years later, saying the effect of the decline in whitebark pine trees on bears wasn't given adequate consideration. Whitebark pine nuts are a key food source for grizzlies as they prepare for hibernation.
One study showed that more than 70 percent of mature whitebark pines in one area died from insect attacks or disease. Scientists suspect warmer temperatures at higher elevations make the trees more susceptible.
But information from the trapping has shown grizzlies aren't dependent on whitebark pine and can find other food sources, van Manen said.
"What we found was that they had a lot of what we call ecological plasticity," he said. "They were able to respond to all these changes with no change in body condition, no change in population trend."
Servheen didn't have a date for when the agency might decide about delisting. He said if the agency recommends delisting, a comment period would follow.
"Grizzly bears are one of the greatest success stories under the Endangered Species Act," he said, noting people living in the region are part of the reason. "I think people like bears."
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