Screen shot from a video explaining the results of a poaching study co-authored by Guillaume Chapron and Adrian Treves.
The findings of a new study co-authored by a UW-Madison researcher challenge the conventional wisdom that hunting is an effective tool for the conservation of predators. It could have implications for Wisconsin’s wolf hunt as well as wildlife management efforts around the world. The authors anticipate a backlash.
“We understand our results will be controversial because they challenge a dominant paradigm in wildlife conservation," says Guillaume Chapron, a researcher in Sweden who teamed up with Adrian Treves of UW-Madison.
Treves adds that he expects resistance from people with a vested interest in the status quo, including scientists. “We know we are confronting the wildlife establishment but it is our duty to give the public our best scientific assessment of what happened to their wolves.”
Chapron and Treves say they have conducted the first rigorous, quantitative test of the hypothesis that poaching — the illegal killing of predators — will decrease if government agents legally kill, or “cull,” the population.
They say their findings, which studied changes in wolf populations in Wisconsin and Michigan between 1995 and 2012 - when culling was first banned and then allowed and banned again, alternating a total of 12 times - showed just the opposite. “On the contrary, killing increases poaching,” says Treves.
Their article — “Blood Does Not Buy Goodwill: Allowing Culling Increases Poaching of a Large Carnivore” — was published today in the Proceedings of the Royal Society B. Chapron also created a short video to help explain the study’s methodology and implications to the general public.
Wisconsin’s gray wolves were legally hunted and trapped in 2012, 2013 and 2014 before a federal court decision put them back under the protection of the Endangered Species Act. But there are ongoing efforts to bring back a hunt.
Treves and Chapron did not test the effect of hunting and trapping on poaching, but suspect they would find similar findings if they did so. “If the government lowers the value of wolves with high quotas, low fees and a disrespect for the species, poachers may kill more wolves than they have in the past,” they say in a fact sheet released to reporters. “Moreover, if hunting is designed in a way that facilitates poaching, the government signal will be loud and clear: We are not enforcing anti-poaching laws, and we do not value wolves.”
The authors say that much of conservation policy in the United States and such countries as Norway, Sweden and Finland is driven by the notion that the illegal killing of predators will decrease with a legal hunt.
The U.S. Department of Agriculture, the U.S. Fish and Wildlife Service and the Wisconsin Department of Natural Resources made this claim in a 2006 report, “Final Environmental Assessment for the Management of Wolf Conflicts and Depredating Wolves in Wisconsin.” The report argued that the state should be able to implement “lethal and nonlethal” methods to “protect resources from wolf damage and to promote wolf conservation.”
“Wolf mortality due to poaching may decrease with the implementation of the depredation compensation program,” the 2006 report argues. “In the absence of a compensation program, it is more likely that wolves perceived to be causing depredation would be illegally killed. Illegal killing likely would be less selective and may remove more individuals than is necessary to curtail depredation activities.”
But Treves says that these theories were never put to a scientific test and in fact are not grounded in science. “It’s not just wrong. The opposite occurs.”
DNR spokesman Jim Dick declined comment, noting the agency’s general policy is not to comment on work conducted independently of the DNR. When a reporter noted the research was supported by the DNR and U.S. Fish and Wildlife Service under a 2010 cooperative agreement with UW-Madison and Treves, Dick still had no comment: “That agreement expired in September 2015.”
Treves and Chapron say their findings are relevant to current conservation debates. The U.S. Fish and Wildlife Service, for instance, argues in its February 2016 proposed rule to delist grizzly bears in Yellowstone Park that allowing bear hunting would promote the conservation of the bears by “minimizing illegal killing” and “promoting tolerance” of the bears.
“They’re saying that unless we give states the flexibility to cull and hunt them, tolerance will decline and poaching will increase,” says Treves. “It’s just not true.”
Treves is an associate professor of environmental studies and head of the Carnivore Coexistence Lab, which he founded in 2007. The lab conducts interdisciplinary research around the world with a vision to balance “human needs and carnivore conservation.”
He worked for 16 years in the field of wildlife policy and management before he started to question the assumption that hunting is an effective tool for the conservation of predators. “The more data collected, the less solid is that assumption,” he says. Treves says he came to his senses in 2012 and now feels an obligation to speak out.
“I realized I wasn’t really serving the public,” he says. “I was serving special interests and the government.”
For their study on poaching, Treves and Chapron identified the 12 periods from 1995 to 2012 when the federal status of wolves alternated between “delisted” and “relisted” and when culling in Wisconsin and Michigan was alternately allowed and banned.
They then studied wolf population growth during those periods with a model that controlled for biological reasons for population slow-downs. They ruled out wolf migration — it’s unlikely wolves would know to leave the state when culling is allowed — and density dependence – the idea that reproduction of wolves slows down as numbers go up.
“Each time the state had the authority to cull wolves, we found a decrease in the population growth of wolves,” says Treves, noting the annual average decreased by one-third to 12% annual growth during periods of culling. The researchers infer the cause is poaching as a matter of elimination. “The political message that government sends when wolves are no longer protected is enough to increase poaching,” he adds.
Without hard numbers of poaching incidents, the authors know their critics will attack their conclusions. But they are confident in their findings and point to other studies with similar results.
Treves, for instance, has also tested the common belief that people will be more tolerant of predators if a legal hunt is allowed. But he found through attitude surveys that Wisconsin’s first public hunting and trapping season for wolves “resulted in lower tolerance for wolves among a large sample of men living in wolf range.”
Treves says he and Chapron are not alone among scientists in taking on some of these sacred notions that undergird much of conservation policy.
“The traditions in wildlife management are finally being subjected to scientific scrutiny, and we are learning new things that will probably improve coexistence.”