Once a species is removed from the endangered species list, as the northern Rockies gray wolf was back in 2011, obtaining accurate annual population estimates is a critical component of the ensuing 5-year monitoring process put in place under the Endangered Species Act.
In Idaho and Montana, for a variety of important reasons, the wolf population estimates compiled by state officials simply can’t be trusted.
When you take a close look at how those population estimates are being calculated, as a group of researchers did in a study published last month in the journal Science, it raises serious questions about whether wolf management in the northern Rockies relies on verifiable, science-based methods.
That’s why the Center for Biological Diversity, where I work, and four other conservation organizations filed a petition requesting that the U.S. Fish and Wildlife Service continue monitoring northern Rocky Mountain gray wolves for another five years. The existing monitoring program expires in May.
Federal and state wildlife officials have continued to contend that the more than 2,300 wolves killed by hunters or trappers in the two states in recent years have not hurt the health of wolf populations.
But in contrast to the U.S. Fish and Wildlife Service conclusion that wolves are being managed appropriately, the study’s 14 authors found that aggressive hunting and trapping polices have led to a declining wolf population, as indicated by decreasing pack sizes, disruption of social organization of packs, and reductions in juvenile survival.
The researchers also identified significant flaws in how the two states count wolves, pinpointing significant problems with how Idaho and Montana estimate wolf populations.
In order to determine the estimated wolf population, for example, Idaho uses a mean or median pack size to estimate wolves in packs that are documented with incomplete member counts. What that means is that they only count the number of wolves in several packs — 27 in 2014 — then use the median pack size (6.5 in 2014) to extrapolate the wolf population based on the presence of 77 packs. Thus, while Idaho officials only actually saw 184 wolves last year, they nevertheless assert that Idaho had a minimum count of 770 wolves.
This untrustworthy counting methodology leaves a large margin for error and has a strong probability of overestimating the actual wolf population. The fact that despite liberal wolf hunting and trapping seasons, harvest totals have decreased by almost 25 percent since delisting, strongly suggests the population is not stable but declining.
Although Montana uses more robust methods for arriving at population estimates, the researchers found that the state’s determination of a perceived increase in the wolf population from 2008 to 2011 is likely the result of Montana adding additional staff and volunteers to monitor the wolf population during this period in conjunction with the initiation of a program to gather wolf-sightings from the public.
As a result, the Fish and Wildlife Service’s conclusion that Montana’s strategies have not significantly increased threats to the northern Rockies wolf population is not supported by the data.
What the available research does make clear is that in the face of aggressive hunting and trapping polices, it’s impossible to determine whether gray wolves in Idaho and Montana are continuing to recover without federal protection.
That’s precisely why the 5-year monitoring period must be extended. If you follow the science and the law, there’s really no other option.
Andrea Santarsiere is a staff attorney at the Center for Biological Diversity’s Victor, Idaho, office, where her work focuses on protecting carnivores.