WGFD works toward delisting of grizzly bears in Wyo, Greater Yellowstone AreaWritten by Saige Albert
Cheyenne – The process of delisting grizzly bears was described as ongoing by Wyoming Game and Fish Department (WGFD) Chief Game Warden Brian Nesvik during the Jan. 29 Wyoming Game and Fish Commission meeting.
“All the interested parties are close to agreement on a sliding scale recovery criteria for grizzly bears that would ensure very conservative mortality limits when the bear population is lower and increased flexibility when populations are higher. Mortality limits are separate for adult females, adult males and dependent young,” Nesvik said. “When population levels are at or above the upper end of the sliding scale, Commissions of Idaho, Montana and Wyoming would have more flexibility in how they manage discretionary mortality.”
He also emphasized, however, that no authority has been granted to set seasons for hunting to this point.
A delisting rule has also not been published. If a draft delisting rule is published, the public will have an opportunity to weigh in on grizzly bear management.
In ongoing discussions between Idaho, Montana, Wyoming and the U.S. Fish and Wildlife Service (FWS) over what a delisted grizzly bear population might look like in the Greater Yellowstone Area, Nesvik noted that many different aspects of management have been considered.
For example, he said that Idaho, Montana and Wyoming have drafted a Memorandum of Agreement (MOA) that each state believes provides a solid, biologically-sound framework to consider in allocating discretionary mortality limits between the states, if each state’s Commission elects to utilize it.
“The MOA is a significant commitment by the three states, if signed by the Commissioners, for managing for recovered populations of grizzly bears,” he said.
The Interagency Grizzly Bear Study Team has worked since the 1970s to solidify a population-level management concept for grizzly bears, according to Dan Thompson, WGFD large carnivore section supervisor, who commented, “We contribute to the ecosystem-wide monitoring of the population and lead conflict management throughout Wyoming in all areas where we have jurisdiction.”
One important factor in discussing grizzly bear delisting is conservative population estimates, Nesvik said.
“We have discussed continuing to use a more conservative population estimator – sometimes referred to as the Chao2 model,” he said. “It has been used for quite some time, and our managers are familiar with the model.”
Wyoming bear managers have long used the model to accurately predict changes in population trends for grizzly bears.
“We have always had a trend toward an increasing population – whether that is a more aggressive increase or a stable increase,” Nesvik said. “Suffice it to say, this estimator is conservative and one that grizzly bear managers are comfortable with.”
A new addition for the state of Wyoming is the adoption of a demographic monitoring area (DMA), which outlines biologically and sociably suitable habitat for grizzly bear populations.
“The adoption of the DMA allows for greater flexibility outside its boundaries and a more conservative approach within areas where there is more suitable grizzly habitat,” Nesvik explained.
Grizzly bears are managed and monitored within the DMA, but the distribution of bears extends beyond the boundaries of the area.
He summarized, “In other words, bears that occur inside the DMA would be counted toward the population and mortality limits, and those bears that exist outside the DMA would not be subject to mortality limits outlined in the recovery criteria. Any grizzly bear population estimates the public may have seen recently are for inside the DMA only.”
Flexibility would be allowed in habitat that is less suitable – ecologically and socially – for grizzly bears.
Thompson noted that obtaining population counts for grizzly bears isn’t as easy as other species, like elk.
“We do capture bears for monitoring and conflict resolution,” he said.
Bears are counted using observational flights.
“We look at movement patterns and distribution,” Thompson explained. “We also look at conditions and diet when evaluating grizzly population health.”
By following females with cubs of the year using the Chao2 model, wildlife managers estimate survival, sex, age and reproduction to estimate populations.
Using the model, population increases of between four and seven percent were seen in the 2000s.
“We have seen that taper off to two percent, which is more indicative of a population that has reached carrying capacity,” Thompson noted.
At the same time, he also noted a 40 percent increase in the distribution of bears has been seen since 2004.
“We have an increased density of bears outside the areas we are monitoring for,” Thompson added. “We use the bucket analogy, which is simplistic, but it makes sense. We can only dump so much water into a bucket before it starts spilling over.”