t, it has a chance to roam far and wide and help recolonize long-lost habitat.
Grizzlies on the Move
Despite the formidable obstacles, Yellowstone grizzly bears are steadily expanding their range, often using the Centennial Mountains as a springboard to the west and to the north. Yellowstone grizzlies are now found throughout the Gravelley and Snowcrest ranges north of the Centennials.*
Meanwhile, the same grizzly dispersion dance is occurring 370 miles north, where another population based in and around Glacier National Park is also steadily expanding. The Northern Continental Divide Ecosystem of grizzly bears numbers about 960 and they are dispersing down river valleys and across mountain ranges. Intrepid young males range far and wide, making headlines in community newspapers.
“There are places throughout the ecosystems where bears probably haven’t been for over 100 years,” says Frank van Manen, a U.S. Geological Survey wildlife biologist and the supervisory research biologist for the Interagency Grizzly Bear Study Team, which conducts research on grizzlies and monitors their populations and death rates.
The gap between dispersers from the two grizzly populations is steadily narrowing. Wildlife biologists hope that Northern Continental Divide Ecosystem grizzlies, which have a strong genetic base supported by breeding with grizzly populations in Canada, will connect and breed with the Greater Yellowstone Ecosystem grizzlies, which have been isolated for more than 100 years.
“I think we are probably less than a decade away from that if the populations keep expanding like they have been,” van Manen says during an interview in his office near the Montana State University campus in Bozeman. “The edges of the distribution are now only separated by about 70 miles and that’s close to striking distance of a dispersing male. So we’re pretty close.”
One or more grizzlies dispersing possibly from the Northern Continental Divide population were sighted last year in the Upper Big Hole River Valley.
Caroline Byrd, executive director of the Greater Yellowstone Coalition, a Bozeman-based grizzly bear advocacy group that works to reduce conflicts between bears and humans, puts the distance between to the two populations at only 40 miles.
“There’s a lot of open habitat where there’s room for bears to expand and move through,” she says.
Allowing the Yellowstone and Northern Continental Divide populations — which have been separated for more than 100 years after grizzlies were hunted to the brink of extinction in the lower 48 — to naturally reconnect and interbreed would mark a monumental success for the Endangered Species Act, wildlife biologists and conservation groups say.
“I would consider it a victory for the Endangered Species Act, and a major stepping stone toward (grizzly bear) recovery,” says Dr. Jeremy Bruskotter, an associate professor at Ohio State University’s School of Environment and Natural Resources, whose extensive writings about the Endangered Species Act include an in-depth examination of how to define what part of a species’ range is protected.
“Eventual connectivity between populations would be a tremendous achievement,” adds Erin Edge from Defenders of Wildlife.
But that natural connectivity may never happen.
Feds Remove ESA Protections
The Trump Administration’s July 30 removal of the Yellowstone grizzly bear population from the endangered species list — a process begun years earlier under the Obama administration — sets up new barriers for natural grizzly connectivity. Conservationists and academic experts say it is another in a series of steps by the government to reduce the size of habitat considered necessary to recover threatened and endangered species.
The decision turns over management of Yellowstone grizzlies to Wyoming, Idaho and Montana, which all plan to institute regulated trophy hunting on the perimeter of Yellowstone and Grand Teton national parks. If state wildlife managers institute a hunt this year, which is currently considered unlikely, up to 20 bears could be legally shot. (See our story, “Yello