As the state prepares for its first wolf hunt, scientists say they don't know what effect the five-month hunt beginning Monday will have on Wisconsin wolves.
One hunt won't put wolves — removed from the federal endangered species list last year — 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 has set a quota of 201 wolves out of a total 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.
The 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 drop quickly once again 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 wildlife biologist at UW-Madison who has studied the state's wolves extensively.
Adrian Wydeven, a DNR wolf researcher who has helped manage the wolf population's recovery, 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, Wydeven said, have shown that 9 percent to 19 percent of the state's wolves are killed illegally each year, 10 percent are killed in depredation control programs, and 3 percent to 4 percent are killed by vehicles. 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. He said the addition of a plan that kills depredating wolves and a hunt will reverse that trend and result in a drop in the population — which is the idea at least for the initial hunts to help stop depredation on livestock.
Even so, such initial reductions may do long-term harm to the state's wolves in ways that are so far 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 impact pup survival. And the impact of removing breeders from packs was much more detrimental in smaller, recovering wolf populations similar to Wisconsin's, according to studies.
Also, Wydeven cited studies in Canada's Algonquin Park that showed excessive hunting mortality may 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 some studies have also shown that disrupting packs and removing alpha wolves can actually increase the likelihood that remaining wolves in 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.
Van Deelen said all of these uncertainties heighten the importance of doing more research and collecting more data during the upcoming hunt. But that may 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 doing 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. He said the agency's researchers, for example, are likely to use genetics to monitor the makeup of wolf packs and are developing computer models to do population studies.
While all of this research is crucial, some wonder if it may be too little, too late. Perhaps, said David, with GLIFWC, more such study should have gone into deciding whether a hunt is scientifically justified so soon after removing the wolf from endangered status.
"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.