July 17, 2020
by Johnathan Hettinger
Scientists established a grizzly bear mortality rate that allows for a stable population of the threatened species. Wildlife managers are increasingly exceeding it.
Brad Orsted normally avoids naming bears, but Nervous Nelly wasn’t an ordinary bear.
Over the past decade, dozens of grizzlies, like Nelly, have headed each fall to the fields of private ranches in the Tom Miner Basin in Montana’s Gallatin Range, just north of Yellowstone National Park.
In the fall of 2015, logging trucks were traversing the ranches, and most of the bears that congregated in the area got so they wouldn’t even appear to notice the trucks jostling down the dirt roads. But at the sound of anything abnormal, Nelly would stand up, alert. The mother grizzly would round up her three cubs, born that year, and run into an area of trees until the disturbance had passed.
So on November 15, 2015, when Orsted heard that an elk hunter had shot and killed a mother grizzly who stood up near him, he knew it had to be Nelly. And he wasn’t optimistic about the cubs’ future.
“I knew they were goners,” said Orsted, a wildlife photographer in Gardiner and one of a group of wildlife watchers who frequented Tom Miner Basin looking for grizzlies. The U.S. Fish and Wildlife Service agreed. In its 2015 annual report, the Interagency Grizzly Bear Study Team, which oversees the species due to its threatened listing under the Endangered Species Act, recorded the incident as four mortalities — one known and three probable.
Grizzly bear cubs, which usually stay with their mothers for multiple years, often don’t know how to den, and die after being orphaned.
On Thanksgiving Day, Orsted and a friend went to Tom Miner Basin. They’d heard the cubs wouldn’t leave their dead mother’s side (the Montana Department of Fish, Wildlife and Parks didn’t retrieve the body because a harsh winter was already setting in). Though it would likely be illegal, Orsted planned to move Nelly’s body to a snow den in an attempt to save the cubs.
After snowshoeing into the basin in sub-zero temperatures, Orsted and his friend struggled to find the body or any sign of the cubs. As they were about to return home, they found cub tracks heading up the mountain. The three cubs were going to den.
The next year when Orsted returned to Tom Miner Basin, two yearling grizzlies showed up. He didn’t have any hard evidence that they were Nelly’s offspring, but they had returned to where Nelly had taught her cubs to find a consistent source of food. The field offered caraway roots, a carrot relative, that would provide nutrition for the bears.
Grizzly bears, the apex predator in the Lower 48, hadn’t frequented the area until about a decade prior, when a die-off of whitebark pine trees led to a decline in whitebark seeds, the grizzly’s main food source.
Orsted photographed and filmed the bears that year. They came back in 2017, and again in 2018. They stood out because they appeared bolder, less concerned about humans than other bears — a trait that could get them into trouble.
On Sept. 28, 2018, Orsted saw the bears for the last time. Not long after, agency records show that two subadult grizzlies were “removed” by wildlife managers a few miles up the road for frequenting human sites, one on Oct. 2 and the other on Oct. 16. The orphans, which had beaten the odds for two years, were unable to escape the area’s growing human footprint, and they were killed because of it.
To Orsted, that’s the modern story of the grizzly bear in the Greater Yellowstone Ecosystem.
MORE THAN 300 GRIZZLIES KILLED IN THE PAST FIVE YEARS
Nervous Nelly was the 12th and final female bear recorded killed in the Greater Yellowstone Ecosystem in 2015, pushing female grizzly mortality that year to 10.8% of the population. Under Endangered Species guidelines in place at the time designed to ensure the species’ survival, no more than 7.6% of the GYE’s female grizzly population could be killed in a given year.
Grizzly bears have been dying in record numbers in recent years, the result of increased conflicts with livestock, homes and other human-dominated sites. In four of the past five years, more bears were killed than is optimal for population stability, according to federal data. Almost every single death is related to human causes.
In fact, more than 300 bears have died in the past five years, according to federal data. By comparison, in the 10-year stretch from 2000 to 2009, 269 bears were killed in the same area, according to federal data.
The species is protected under the Endangered Species Act, one of the nation’s most powerful laws protecting imperiled species from extinction. Under the ESA, wildlife managers must follow certain criteria to help ensure the species’ recovery.
When Lewis and Clark headed up the Missouri River, as many as 50,000 grizzlies roamed in the American West. When the population was first protected under the ESA in 1975, there were as few as 136 bears in the Greater Yellowstone Ecosystem. Today, about 700 bears live in the area, which encompasses parts of Montana, Wyoming and Idaho.
The Greater Yellowstone Ecosystem is one of just two places in the Lower 48 where grizzlies exist in large numbers. An additional 1,000 or so grizzlies live in the Northern Continental Divide Ecosystem, which includes Glacier National Park.
State and federal officials say the grizzly population in the GYE is recovered.
But two attempts by the U.S. Fish and Wildlife Service to remove ESA protections have been overruled by federal judges who determined that the agency’s analyses of the bear population’s recovery were flawed.
Most recently, in 2018, a federal judge in Missoula ruled to restore the protections, determining that the Yellowstone population was not genetically viable in isolation, according to the very studies used by the agency to justify delisting.
Even so, state and federal grizzly bear managers maintain the population is recovered. While admitting they erred in the delisting process, the federal government and the states of Montana, Wyoming and Idaho have appealed parts of the 2018 decision. Last week, the 9th Circuit Court of Appeals upheld the 2018 decision.
David Mattson, a leading grizzly researcher who worked on the Interagency Grizzly Bear Study Team for two decades, said wildlife managers seem to focus more on getting grizzlies delisted than on recovering the species. Mattson’s studies and testimony have provided evidence used to block the delisting of Yellowstone grizzlies.
Mattson said Yellowstone grizzlies will go extinct within the next 40 generations without an increase in genetic diversity, either via the introduction of bears from other areas or by natural connection with the Northern Continental Divide Ecosystem.
Fred Allendorf, a professor emeritus of biology at the University of Montana, has found that as many as 5,000 bears are needed for a population to be genetically viable.
MANAGEMENT SHIFT ALLOWS MORE BEAR DEATH
Despite these studies and repeated federal court rulings, bear managers are still managing the population according to the 2016 conservation strategy, a document created to guide how bears would be managed after delisting. According to that strategy, a minimum population of 500 bears must be maintained, though current management practices aim to maintain a population of about 675 to 747 bears.
Under the 2016 strategy, wildlife managers changed allowable mortality levels to increase the number of bears that can be killed each year. Prior to the change, the bar was set by a 2012 study from the Interagency Grizzly Bear Study Team that recommended a maximum mortality of 7.6% of female bears and 15% of independent males as the baseline for maintaining a stable population in the GYE.
The new allowable mortality rate allows 9% of independent females and 20% of independent males to die each year.
In fact, 10.8% of female grizzlies died in 2015. In 2016, 16.7% of independent age male grizzlies died. In 2017, 8.4% of female grizzlies died. In 2018, 15.3% of independent age male grizzlies died. The majority of bears that die are killed by wildlife managers as a consequence of predation on livestock or visiting human sites, according to a Montana Free Press analysis of federal data.
Louisa Willcox, a Livingston-based grizzly bear advocate for more than 30 years, said the population is at a tipping point, and increased mortality could put the species’ survival at risk.
But not all wildlife managers agree.
Frank van Manen, team leader of the Interagency Grizzly Bear Study Team, said grizzly bear mortality should be viewed through a longer lens than just a few years’ worth of statistics.
“Importantly, there were no 3 consecutive years that thresholds were exceeded,” van Manen said in an email. “Given the biology of grizzly bears, data should be evaluated not based on single years but on longer-term trends. With that in mind, the mortality rate for independent females from 2002-2019 is 6.9% and for independent males for 2002-2019 is 10.0%. Thus, long-term trends are below mortality thresholds.”
Even with the changes in allowable mortality, Van Manen said, he does not believe the species is in danger of extinction.
”There are no indications that current mortality levels represent a concern for the population,” he said. Survival rates of independent female and males during 2014-2019 are “very much in line with those of other healthy grizzly bear populations in North America,” he said.
Even so, Mattson counters, the data from recent years are trending toward higher mortality, even as federal judges have repeatedly determined that the current population of bears is not genetically diverse enough to survive in the long-term.
And Willcox pointed out that in the NCDE, where there are more bears, wildlife managers deem 5.3% total mortality for independent-aged bears to be sustainable — much lower than recommended mortality rates for the GYE’s smaller population.
WHERE BEARS ARE DYING
Dan Thompson, large carnivore supervisor for the Wyoming Fish and Game Department, said that more bears are being killed in recent years because there are simply more bears. While population estimates for the GYE have hovered around 700 bears since the mid-2000s, Thompson said those estimates are conservative and undercount the actual number of bears.
“I don’t feel it reflects the number of bears out there,” Thompson said.
Bear population estimates are conducted within a Demographic Monitoring Area, a wide swath of mostly public land where grizzly recovery is monitored. Increasingly, bear mortalities are occurring outside the DMA.
According to the Interagency Study Team’s 2018 annual report, the amount of private land that grizzly bears frequented inside and outside the DMA tripled from 2002 to 2018.
Mattson said expansion of the population’s range does not necessarily indicate that there are more bears. Rather, the existing population of grizzlies are moving into new territories to adapt to declines in food sources in recent years, including whitebark pine, Yellowstone cutthroat trout, and elk in Yellowstone.
Thompson, though, disputes the new-territory theory. He said there are in fact more bears on the landscape now than ever.
Either way, as grizzly bears appear in more human-dominated landscapes, “They are much more prone to conflict,” Thompson said. “They do have an increased population size and increased distribution. Once they move beyond some of those areas, they come into a potential for a lot more bad situations between grizzly bears and humans.”
Earlier this year, 399, perhaps the most famous grizzly bear in the world due to her propensity to hang out near roads around Grand Teton National Park, emerged from her den with quadruplets at the age of 24.
Tom Manglesen, a wildlife photographer, has taken photos of 399 over the course of 15 years. He said he’s never seen anything like the bear jams that have accompanied appearances by 399 this year, which are often hundreds of cars long.
While 399 is well-loved, she is not insulated from the issue of bear mortality. Mangelsen and other 399 experts estimate that at least half of her 22 offspring have died, either killed by hunters in self-defense, removed by management for livestock depredations, or, in at least one case, hit by a car. Only one of her cubs, 610, is documented to have become a mother herself.
“It’s really difficult for bears to survive,” Manglesen said. “Her lineage is gone.”