Sunday, October 14, 2012

Crying wolf? Experts: State wolf hunt could have unintended consequences


Scientists say they don’t know how Wisconsin’s first organized wolf hunt, set to start Monday, will affect the formerly protected species.

The five-month hunt won’t put wolves — dropped as federal endangered species in 2011 — back on the list, but research hints at possible longer-term harm to the wolf population and even an increase in wolves killing livestock, researchers say.

“There are all sorts of questions,” said Peter David, a biologist with the Great Lakes Indian Fish and Wildlife Commission. “I’m concerned about the impact it is going to have and the lack of science built into the hunt.”

The state Department of Natural Resources will allow up to 201 wolves taken from a state population of about 850. That works out to about 24 percent of the wolf population, a higher percentage than in most other states that have scheduled or held hunts. In neighboring Minnesota, for example, the quota set for that state’s first hunt represents about 13 percent of the wolf population, or 400 animals out of 3,000.

Wisconsin’s wolf management plan still calls for a total population of 350, a number supported by hunting groups that pushed for the wolf season but questioned by biologists. Eventually hunting the wolf population from 850 animals down to 350, some scientists say, could push the number of wolves to a tipping point, beyond which their numbers might again quickly drop to the level that would put them back on the endangered list — 250 wolves.

“We don’t really know how a wolf population in this human-influenced landscape is going to respond to hunting,” said Tim Van Deelen, a UW-Madison wildlife biologist who has studied the state’s wolves extensively.

Total losses

Adrian Wydeven, a DNR wolf researcher who has helped manage the species’ recovery in the state, said it is important to remember the number of wolves killed during the hunting season has to be added to all the wolves killed in other ways throughout the year to get an accurate picture of how total human-caused wolf deaths are going to affect the statewide population.

Wisconsin population studies have shown 9 to 19 percent of the state’s wolves are illegally killed each year, 10 percent are killed in depredation control programs, and 3 percent to 4 percent are killed by vehicles, Wydeven said. Add those numbers to the 24 percent harvest quotas, Wydeven said, and total, human-caused mortality is likely to be between 46 percent and 57 percent. Research has shown that wolves can tolerate up to about 29 percent to 35 percent human-caused mortality rates before populations decline, Wydeven reported to the Natural Resources Board.

In that report, Wydeven said that since 2000, Wisconsin’s wolf population has increased at an annual rate of 11 percent to 12 percent each year. The addition of the hunt and a plan that kills depredating wolves will reverse that trend, he said, and result in a drop in the population — which is the idea at least for the initial hunts to help stop depredation on livestock.

Long-term effects

Even so, such initial reductions might do long-term harm to the state’s wolves in ways only hinted at in the research.

In his report, Wydeven cited studies that have shown eliminating certain individuals — those wolves that breed, for example — and reducing the size of packs can dramatically reduce pup survival. And the effect of removing breeders from packs was much more detrimental in smaller, recovering wolf populations similar to Wisconsin’s, according to studies.

Wydeven also cited studies in Canada’s Algonquin Park that showed excessive hunting mortality might disrupt the kin-based social structure of packs and encourage hybridization of wolves with other canids, such as coyotes. Great Lakes wolves are known to hybridize with dogs, something biologists want to avoid, partly because such wolf-dog hybrids can exhibit unwanted behavior such as lurking too close to humans and preying on livestock.

David said studies have shown as well that disrupting packs and removing alpha wolves can actually increase the likelihood the rest of that pack will be forced to prey on easier-to-capture livestock for food.

“There is certainly reason to believe that this hunt is going to be highly disruptive socially,” David said.

Research crucial

Van Deelen said all of these uncertainties heighten the importance of doing more research and collecting more data during the upcoming hunt. But that might be hard, he said, at a time when budgets are tight and the DNR is spending less money in many areas.

Carl Martin, chief of the DNR’s wildlife and forestry research section, said the agency will continue the population monitoring that has been part of the wolf recovery effort for 30 years. He also said the agency has formed a wolf monitoring committee and is working with budgets to come up with new ways to monitor the wolf pack during the season.

Agency researchers, for example, are likely to use genetics to monitor the makeup of wolf packs and are developing computer models to do population studies, he said.

While this research is crucial, some wonder if it might be too little, too late. Perhaps more such study should have gone into deciding whether a hunt is scientifically justified so soon after removing the wolf from endangered status, GLIFWC’s David said.

“I think people are going to look back at this, and it will have become a textbook example of how not to hold a hunt,” David said.