By KIRK JOHNSON
SEATTLE — The anti-wolf billboards that went up this week in eastern Washington State are not at all subtle. Two glaring yellow eyes peer out at the top, with an elk and other animals below, leading, left to right, toward a laughing little girl in a swing next to what appears to be her dog. The text reads: “The wolf … who’s next on their menu?”
But supporters of the idea that wolves and people must find new ways to coexist also have ammunition to fire back, in a surprising new report published Wednesday. A statistical studyof 25 years of records across several states by researchers at Washington State University concludes that traditional wolf management — killing some wolves to reduce their impact on livestock like sheep — mostly does not work.
Killing wolves, the analysis suggests, may in fact make things worse as packs adapt, move around and increase their reproduction rates — and then kill even more livestock the year after their numbers have been reduced.
Gray wolves have thrived since the introduction by federal wildlife managers of 66 animals in Wyoming and Idaho in the mid-1990s, with nearly 1,700 in at least 320 packs now spread across the northern Rockies region. And with the wolves’ peripatetic nature — there are now an estimated 50 here in Washington — a new chapter of a very old fight has begun.
Jamie Henneman, a spokeswoman for the group backing the billboard campaign, Washington Residents Against Wolves, said that the new study, published by the journal PLOS ONE, was “not clean science.” She said it seemed to have a predetermined pro-wolf conclusion because the research was supported by the State Legislature, which has supported a big increase in wolf population.
“Frankly, it is a bit shameful,” said Ms. Henneman, who also speaks for a group called the Stevens County Cattlemen’s Association.
The study’s lead author, Rob Wielgus, an associate professor of wildlife ecology and director of the Large Carnivore Conservation Lab at Washington State University, said he believed that the anti-wolf forces do not really want serious wolf management at all.
“They just want to get rid of wolves,” he said. “Livestock lobbyists are pretty much vehemently opposed to my research,” he added. “But in terms of hard science, it stood the test.”
Part of what makes the wolf story different in Washington is that in a 2011 plan the state wildlife management agency largely embraced the idea of allowing the wolf population to expand. The goal was 15 packs in three zones spread across the state, with five to 10 wolves typically in each pack. Once those goals are reached, state protection would be reduced.
The governments in some other Western states, notably Wyoming and Idaho, have fought wolf expansion or allowed hunting at levels that some conservation groups have said could threaten long-term population stability.
Ms. Henneman said the urban-dominated Legislature fell for a “fairy tale,” about wolves in the wild, and that eastern Washington, where wolf numbers are concentrated, would pay the price.
“We think Washington has the best wolf management plan in the West,” said Mitch Friedman, the executive director of Conservation Northwest, a nonprofit group based in Bellingham, Wash. And Professor Wielgus’s research, Mr. Friedman said, reinforces the idea that thinking differently is good not just for wolves, but for ranchers and residents as well.
In the study, Professor Wielgus and the co-author, Kaylie A. Peebles, assessed the effects of wolf mortality on reducing livestock depredations in Idaho, Montana and Wyoming from 1987 to 2012.
The numbers of livestock killed, of wolf breeding pairs and of wolves killed each year were correlated. The conclusion, the paper said, is essentially that wolf pack stability is crucial to controlling the impact of wolves on livestock. Wolf packs disrupted by culling can reorganize, which may lead to more breeding, the paper said, with more livestock killed in the year after a wolf reduction than before.
“Things aren’t as intuitive as one might expect,” said John Pierce, the chief wildlife scientist at the Washington Department of Fish and Wildlife, which reviewed the paper.
Mr. Pierce said that while the study offered a fascinating glimpse into large-scale wolf management, the next crucial step was to get a better understanding of the dynamic within each highly adaptable, social wolf pack. But given the strong emotions surrounding anything wolf-related, he added, the paper “has a potential to stir the pot.”