 long-simmering controversy and litigation. The agency delisted the bears in 2007, but environmentalists sued and federal court decisions put the bears back on the endangered list in 2009.
At that time, the court ruled that the Fish and Wildlife Service failed to evaluate the impact of the collapse of whitebark pine forests throughout the Yellowstone region. The pine seeds serve as a major food source for some grizzlies. The agency spent the next few years studying the impact.
In 2013, the Interagency Grizzly Bear Study Team found no relationship in the decline of whitebark pine and the overall health of grizzly bears, which are famous for being opportunistic omnivores and very flexible in their diet. A second study in 2015 came to similar conclusions.
“We are not seeing for either males or females that the percent of body fat is declining, which would have to happen for these changes in food resources to start taking a toll on the population,” van Manen, one of the authors of each study, says in an interview.
Now, one of the key points of contention is whether the population in and around Yellowstone can be considered recovered in isolation from several other populations in the lower 48 that remain very much a work in progress.
The American Society of Mammalogists and the Society for Conservation Biology sent a joint letter in May 2016 opposing the Fish and Wildlife Service’s then-proposed piecemeal strategy of removing the Yellowstone grizzlies from endangered Species Act protections before the entire grizzly population in the lower 48 states is recovered.
“In our professional judgment,” the letter stated, “both the best available science regarding carnivore recovery and the plain language of the ESA obligate USFWS to manage the metapopulation of grizzlies in the lower 48 states, not just each population individually.”
A metapopulation is a group of populations of the same species that are separated by space. These spatially separated populations interact with individual members moving from one population to another.
“What conservation geneticists have argued for some time is that the focus ought to be on preserving for the long term the whole metapopulation,” says Bergstrom, the Valdosta State professor. “Then, you have to look at how each subpopulation plays into that ultimate goal.”
Van Manen says he isn’t concerned about the loss of genetic diversity if the Yellowstone and Northern Continental bears are prevented from naturally connecting. He says there is no indication now or in the near future of genetic depression with the Yellowstone bears.
He points to a 2015 research paper that concluded the Yellowstone population is “sufficiently large to avoid substantial accumulation of inbreeding depression, reducing concerns regarding genetic factors affecting the viability of the Yellowstone grizzly bears.”
And if genetic depression becomes a factor, van Manen supports the approach of translocating bears. “There would be an easy solution by moving animals from another ecosystem into Yellowstone and make sure they breed and produce offspring. It only takes a few animals in every generation to do that.”
The same research paper states that over many generations the grizzly population “could benefit from increased fitness following the restoration of gene flow particularly given the unpredictability of future climate and habitat changes.”
Conservation groups including Defenders of Wildlife and Greater Yellowstone Coalition stated in a 2015 letter to the U.S. Forest Service concerning grizzly recovery plans that relying on “human assisted trans-location does not support the notion that the [Yellowstone] population has been restored to where it is again a secure self-sustaining member of its ecosystem.”
That supports the conservation researchers’ contention that natural grizzly bear dispersal between the subpopulations helps strengthen the entire metapopulation and would support creation of a healthy regional ecosystem that can support the West’s largest predator and other species such as wolverines.
“So, from the standpoint 