Cabinet-Yaak grizzly bear population recovering
Guest Commentary:
Recently, the Alliance for the Wild Rockies issued a press release stating they are considering filing suit because the United States Fish and Wildlife Service had decided not to list the Cabinet-Yaak Grizzly bear as endangered.
While they are entitled to their opinion and can do as they please, the population numbers they used to support their case were incorrect. It is vital to base decisions about the management of this population on credible data. That is why a large coalition of environmental groups, timber and mining companies, and county, state, tribal and federal agencies raised $1.7 million to support the Cabinet-Yaak DNA study headed by the non-partisan United States Geological Survey. We note that the Alliance for the Wild Rockies was not a contributor to this effort.
Because statistical estimates of grizzly bear population size are often misinterpreted and were used incorrectly in the Alliance for the Wild Rockies press release, in the following we provide a summary of the results of the study prepared by scientist Kate Kendall, the DNA study’s principal investigator.
“The 2012 DNA-based study of grizzly bear abundance in the Cabinet-Yaak ecosystem detected 42 different individuals and used mark-recapture methods to estimate the number of bears not sampled. Total estimated average population size (the average number of bears present at any one time) was 44.2 with a confidence interval of 42-65.
This means that the real population size is most likely to be 44 bears. The confidence interval indicates that there is a 95 percent chance that the true estimate falls between 42 and 65 bears. Because 42 different individuals were verified during sampling, we know the population cannot be lower than 42.
Calculation of average population size adjusts total population estimates downward in proportion to the amount of time part-time bears are present in the study area. The study also estimated the size of the super population, the number of full- and part-time residents in the Cabinet-Yaak ecosystem, at 48 bears with a 95 percent confidence interval of 44-62.
The preceding estimates were made using traditional mark-recapture models. Estimates made using spatially explicit capture-recapture models (a method developed more recently) are 43 bears present on average at any one time and 50 full- and part-time bears present.”
The United States Fish and Wildlife monitoring program has found that the grizzly bear population trend in the Cabinet-Yaak ecosystem has improved in recent years and is no longer declining. Service researcher Wayne Kasworm reported to our commission that in 2014 he personally documented a female grizzly with three cubs and another female with two cubs. Two additional females were released into the ecosystem this year from another population.
With a 95 percent probability that the true population size falls between 42 and 65 bears, an improving population trajectory and no known mortalities in 2014, we feel that substantial progress has been made in enhancing conditions for grizzly bears in the Cabinet-Yaak ecosystem under the protections offered by “threatened” designation and that the population is on the road to recovery.
- Tony Berget and Greg Larson are current Lincoln County Commissioners from Libby and Troy. Mark Peck is a commissioner-elect from Libby.