Volume 5, Number 43 - January 19, 2006
brought to you online by Pinedale Online
Wolf study based on assumptions
Recent press accounts reported that a study revealed that wolves aren't to blame for the decline in the Northern Yellowstone elk population and quoted a researcher as stating, "You don't need wolves in the picture at all to explain the population drop," and "Whether or not wolves had been introduced, you'd have seen fewer elk anyway."
The researcher was John Vucetich, a research assistant professor in the School of Forest Resources and Environmental Science at Michigan Tech.
Media accounts reported that hunters and drought are the two primary factors in the 40-percent drop in the elk population - not wolves.
But what many press accounts failed to reveal was that the study being cited was actually a population simulation model, not field research. The authors of the paper, including the MT professor and two Yellowstone National Park wolf biologists, built and assessed population models, "then used the best of these models to predict how elk dynamics might have been realized after wolf reintroduction had wolves never been reintroduced," according to the study, which was recently published in the journal Oikos.
After reviewing the research paper earlier this week, Wyoming Farm Bureau executive vice president Ken Hamilton said, "Just as I suspected, they went model shopping and got the results they wanted."
"I liken their model to the weather predictions in the Farmer's Almanac. Interesting, but you wouldn't want to make any decisions based on what you've read," Hamilton said.
Vucetich maintains, "Most of the elk killed by wolves would have died even if the wolves had not killed them," either from old age, disease or the effects of the drought. Hunters, on the other hand, kill more randomly than wolves, so they can have a bigger impact on the survival of the herd by taking out animals of peak reproductive capacity, according to MT. Vucetich suggested that "human harvest may have been super-additive," meaning that for every 1-percent increase in harvest rate, the population growth rate declined by more than 1 percent. But wolf predation was only "compensatory" incomparison, Vucetich maintained.
"It does matter that much if the elk decline is caused by human harvest," Vucetich said. "We share elk with wolves. Humans take elk for recreational purposes in many locations throughout the West. Wolves are restricted to a tiny portion of their former range and take elk for their survival. Given these circumstances, we have to decide how much sharing is right."
"But it doesn't matter if wolves cause elk decline or not," the researcher said. "They can coexist with elk, and they belong in the Yellowstone ecosystem.
According to the press release, Assistant Professor Michael P. Nelson, an environmental ethicist in the Department of Philosophy at the University of Idaho, predicted that Vucetich's work would not be readily accepted by some interest groups.
"One of the main motivators behind the effort to remove wolves from the endangered species list in the West is the assumption that they are largely responsible for noticeable elk herd reductions," Nelson said. "If that's true, then wolves are therefore linked to decreased hunter success rates, and therefore linked to decreased hunting tourism dollars. Vucetich's findings will be viewed as surprising because so many people are invested in the claim that wolves are responsible for elk herd reductions. Though they probably won't change their minds given this one study, it certainly does muddy the waters."
Hamilton pointed out that the reason the research will be disputed is because it is filled with assumptions and opinions, not data. Hamilton said, "The fundamental flaw in all of this is there have to be so many assumptions made just to get information into the model that by the time the model spits out a result, it's not much past a 800-number psychic reading.
Hamilton said: "What's frustrating is that policy makers, absent good information, will rely on a model like this which will result in wasted resources. The public needs to treat with a great deal of skepticism, as do policymakers. It's too bad the media won't."
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