Anecdotal wolf data is convenient – except when it isn’t

For years, the US Fish and Wildlife Service has disregarded empirically based calculations of population size that call for thousands of wolves to maintain a viable population. Instead, they preferred to point to anecdotal "case histories" of small, isolated populations of wolves as support for their incredibly low recovery goals for wolves in the northern Rocky Mountains (NRM): 30 breeding pairs and 300 wolves in the three state area of Montana, Idaho and Wyoming. 

In particular, the Service has repeatedly pointed to the wolves on Isle Royale as an example of a small (~50) population of isolated wolves that have persisted for decades.  In their 1994 Environmental Impact Statement, the Service wrote, "One wild wolf population has been especially instructive about the population viability of the species....the Isle Royale wolf is important to note that the Isle Royale population thrived for 30 years and is still present."

When the Service removed the Rocky Mountain wolves from the endangered species list in 2008, they dismissed any concerns about future genetic problems by again relying on the existence of small populations including Isle Royale stating, "The potential lack of genetic connectivity between wolves in Y(ellowstone) N(ational)        P(ark) and wolves in the rest of the NRM DPS is not considered a threat ... because much smaller extant wolf populations with much lower genetic diversity have persisted for decades or even centuries .... Even a wolf population on Isle Royale National Park that started from possibly 2 founders in 1949 and remained very small (<50 wolves) has persisted until the present time."

However, a recent study has documented severe inbreeding in the Isle Royale wolves resulting in approximately one third of the wolves experiencing vertebral deformities - some of which are associated with pain and partial paralysis. 

Now what does the government have to say? Suddenly, the population that they have long used as a comparison for the Rocky Mountain wolves, is not "comparable."

In an article in the Cody Enterprise titled, "Court uses flawed data in wolf case", one of the lead biologists working on wolf recovery for the National Park Service backs off the long-held comparison to Isle Royale, "The genetic argument in this region is moot because it isn't Isle Royale."  

So before genetic problems were documented on Isle Royale, the government used it as an example of why genetic problems won't affect the northern Rocky wolves.  But now that genetic problems have been documented on Isle Royale, they say it is completely irrelevant.  What is irrelevant is the use of anecdotes over data for the sake of convenience.

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Image:  Isle Royale wolf spines, with permission by Heidi Devos,