Science shows multiple dynamics at work in wolf populations

Posted: Wednesday, July 11, 2012 

By Norman Bishop, guest columnist

 

In 1884, Montana set a bounty on wolves; in the next three years, 10,261 wolves were bountied (16 times the 2011 population of 637). Are we about to return to 1884, when EuroAmericans were in the process of annihilating Native Americans, the tens of millions of bison that were their life support, and wolves? In May, Gallatin County Commissioners Joe Skinner and Steve White held a hearing on their proposed predator policy, which could include setting bounties on wolves.
One speaker took some of the 13 minutes allowed him to express his view, among other things, that wolves were solely responsible for the decline of the northern Yellowstone elk herd from 18,000 to 4,000 animals (from 1995 to the present).

At many a hearing, I’ve heard hunters plead for “scientific management” of wildlife in Montana. Yet, they choose to ignore peer-reviewed studies, such as one from 2005: J.A. Vucetich, D. Smith, and D.R. Stahler, “Influence of harvest, climate, and wolf predation on Yellowstone elk, 1961-2004.” They wrote: “In the period following wolf reintroduction to YNP (1995-2004), the northern Yellowstone elk herd declined from ~17,000 to ~8,000 elk (8.1 percent year). The extent to which wolf predation contributed to this decline is not obvious because the influence of other factors (human harvest and lower than average annual rainfall) on elk dynamics has not been quantified. According to the best model, which accounts for harvest rate and climate, the elk population would have been expected to decline by 7.9 percent per year ... (C)limate and harvest rate are justified explanations for most of the observed elk decline.”

Montana Fish, Wildlife and Parks researchers Kenneth L. Hamlin and Julie A. Cunningham, and several scientists from Montana State, have contributed to our knowledge of large predator effects on the Gallatin elk herd. Hamlin and Cunningham's work was published in Monitoring and Assessment of Wolf-Ungulate Interactions and Population Trends within the Greater Yellowstone Area, Southwestern Montana, and Montana Statewide FINAL REPORT 2009.

They concluded: “Even where intensive data has been collected, there has been scientific and public debate concerning the impacts of wolf restoration on ungulate populations. Disagreement generally does not occur about the fact of declines in numbers of some ungulate populations, but disagreement about cause(s) or proportional shares of cause continues to exist. Data collected during intensive research for this project indicate that predation can affect elk population dynamics. This seems to occur when high ratios of predators to elk are reached, which has occurred most often in areas where both grizzly bears and wolves have increased rapidly in recent years in southwest Montana and the GYA. This has not occurred in all areas in southwest Montana and the GYA, and some elk populations are stable or increasing in the presence of predators.

“Nowhere are data adequate to 'scientifically' assign cause(s) for any declines that may occur. This is true because assignment of cause remains controversial even where substantially more data than routine MFWP aerial surveys are collected. ‘Control areas and circumstantial evidence’ will be the primary justifications for proposed management actions relative to predators. Lest some construe this as a criticism, it is not. Montana has more widespread counts of ungulates on an annual basis across a larger area than any other state and cannot do more with existing budgets and personnel. Realistic expectations and openness to monitored experimentation will be key to adaptive management of Montana’s ungulates, bears, cougars, and wolves.”

It’s not 1884. Multiple factors are responsible for elk dynamics. The science is there. Let’s use it to guide wolf management.

Norman A. Bishop is a retired resources interpreter for Yellowstone National Park and a board member of the Wolf Recovery Foundation. He lives in Bozeman.

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