Report summarizes recent research related to grizzly delisting
Laura Lundquist
(Missoula Current) Two grizzly bear experts have compiled dozens of biological findings discovered after the federal Grizzly Bear Recovery Plan was published that should be considered to help grizzly bears survive a fraught future.
Two weeks ago, conservation consultant Mike Bader of Missoula and Paul Sieracki, geospatial analyst and wildlife biologist of Priest River, Idaho, released a 27-page technical report titled “Spatiotemporal Dimensions of Grizzly Bear Recovery” that reviews all the grizzly bear research that has occurred since the U.S. Fish and Wildlife Service published its 1993 Grizzly Bear Recovery Plan. Among other things, several studies have documented the need for grizzly bear populations to be connected across a large area of suitable habitat so the species can persist in high enough numbers to remain genetically healthy.
In 1975, the U.S. Fish and Wildlife Service gave grizzly bears endangered species protection. But instead of designating critical habitat as the Endangered Species Act requires, the agency designated five grizzly recovery areas in the Northern Rockies and wrote a Recovery Plan based on those areas in 1993.
Fast-forward 30 years, and only two of those areas - the Greater Yellowstone and the Northern Continental Divide ecosystems - have grizzly bear populations of adequate size. Two areas - the Bitterroot and Northern Cascade ecosystems - officially contain no resident bears, although there have been sporadic sightings.
However, even if all the recovery areas contained a few hundred bears each, that still wouldn’t be enough bears to ensure the populations could survive more than a handful of generations, according to several studies outlined in the report.
The first reason is, unlike wolves, grizzlies are slow to reproduce. On average, sows have only two cubs every two years and a 2024 Montana Fish, Wildlife & Parks research paper found that about half of all cubs die within the first year. That means grizzly populations can’t bounce back well after a decline.
A decline can accelerate in smaller populations, because genetic inbreeding further lessens the likelihood that individuals will survive and reproduce. Knowing this, geneticists have developed methods to estimate how large, isolated populations of various species have to be to ensure genetic health.
University of Montana professor emeritus Fred Allendorf published papers in 2002 and 2019 that calculated 3,000 to 5,000 grizzlies were necessary to ensure the population would keep enough genetic variation to survive long-term, that is more than a century. The Fish and Wildlife Service estimates the Greater Yellowstone and Northern Continental Divide populations are close to 1,000 bears each. The federal Recovery Plan and Conservation Strategies set population maximums at 800 to 1,000 bears in each area.
Other recent research shows that grizzly bears use large ranges, so larger populations require more room. But some of the recovery areas, the Cabinet-Yaak and Selkirks, are small to begin with. In addition, they are surrounded and permeated by a vast system of roads.
Roads effectively reduce the area bears can use, even in good habitat, because bears avoid roads in order to avoid people. Bader and Sieracki published a 2022 study that showed the extensive road network in the Cabinet-Yaak area and northern Idaho overall contributes to illegal poaching and habitat fragmentation. A 2024 U.S. Geological Survey study found about 85% of bear deaths are human-caused.
If bears were allowed to move unhindered outside the recovery areas, the resulting connectivity and gene flow between populations would create a “meta-population.” That would allow the requirement for 3,000-5,000 bears to be spread across the recovery areas and each recovery area would need fewer bears. A 2023 University of Utah study in the journal “Nature” estimated that providing habitat connectivity between Glacier and Yellowstone parks would make the likelihood that large mammals could persist into the future 4.3 times greater.
But the plans put forward by the states of Montana, Wyoming and Idaho and the province of Alberta, Canada, don’t provide much protection for grizzlies outside the recovery areas.
Last week, Montana Fish, Wildlife & Parks released its final environmental impact statement for the state grizzly bear plan, which would keep bear populations in each recovery area at “near recovery levels” - for example, the Northern Continental Divide recovery population is 800 bears. Outside recovery areas, FWP would evaluate whether any bear found would contribute to connectivity, although the details of that evaluation weren’t explained. “Where that likelihood is low, FWP will be quick to recommend (or implement, if appropriate) control when conflicts arise,” according to the EIS.
FWP didn’t consider an alternative action where grizzlies wouldn’t be tolerated outside of recovery zones. But the EIS said FWP “might conceivably consider an alternative approach” where “grizzly bears would not be tolerated (i.e., would be removed
when possible) outside these areas regardless of their behavior or conflict status.”
Finally, the Bader-Sieracki report points out that the 1993 U.S. Fish and Wildlife Service Recovery Plan came out at a time when the agency didn’t factor in increasing human population growth or the effects of climate change, which include increasing heat, drought and wildfire. Both of these factors are having increasing negative effects on grizzly habitat and resources.
Three other grizzly bear experts reviewed the Bader-Sieracki report and are calling on the Fish and Wildlife Service to incorporate the research conducted since 1993 prior to considering delisting of one or more populations. The reviewers include Yellowstone area naturalist and author Doug Peacock; David Mattson, former supervisor of Yellowstone grizzly bear field research and retired U.S. Geological Survey senior scientist; and Frank Lance Craighead, former director of the Bozeman-based Craighead Institute.
“The report pulls together the best available scientific data and understanding of a complex ecological problem - what is needed to maintain a viable population of a species - to present a logical roadmap of how to achieve that solution. The solution, however, will do more than maintain grizzly bears into the future. It will maintain the ecological integrity of the core of our continent,” Craighead said. “This roadmap shows us the things that are needed to keep bears, and our planet, healthy, on this one continent. Similar efforts are needed worldwide.”
Contact reporter Laura Lundquist at lundquist@missoulacurrent.com.