Costly and time-consuming efforts to eliminate wolves that prey on sheep, cattle and other domestic animals are ineffective on a long-term, regional scale, according to an examination of wolf control methods in Alberta and several U.S. states by University of Calgary researchers.
Results of the study were presented at an annual meeting of wolf scientists, ranchers and wildlife managers near Yellowstone National Park.
Lead author Dr. Marco Musiani, an assistant professor in the U of C's Faculty of Environmental Design, said the findings could lead to changes in how ranchers and government wildlife authorities deal with problems relating to depredation of livestock by wolves.
Musiani said using lethal control to limit wolf numbers, and therefore curb depredation, requires 30 to 50 per cent of an area's wolf population to be destroyed year after year. Instead, programs to compensate ranchers and shepherds for stock lost to wolves can be used to offset costs to producers. Such programs convey funds from numerous citizens concerned with nature conservation to the ranchers affected by livestock losses.
"Killing that many wolves would be difficult," Musiani said. "If society wants to co-exist with wolves, it has to accept that there will be losses and address the real issue, which is that if ranchers lose some of their animals, or if animals are injured, it costs them money. There are also significant labour costs for increasing livestock surveillance to prevent attacks."
In addition, livestock producers and wildlife officials could plan activities to prevent wolf attacks during the high-depredation seasons, which are described in the study.
Musiani and colleagues analyzed wolf attack information from Alberta from 1982-1996 and in Idaho, Montana and Wyoming from 1987-2003. The data showed that the common practice of tracking down and killing wolves that prey on livestock did not result in decreased depredation rates regionally, or over the long-term. The study also found that wolf attacks appear to follow seasonal patterns that reflect the food needs of wolf packs and livestock calving and grazing cycles.
"This study shows that wolves are being killed as a corrective, punitive measure -- not a preventative one," Musiani said. "People hope that killing individual wolves that attack livestock will rid the population from offenders but this isn't happening. It seems other wolves simply take their place and you have the same problem over and over again," Musiani said. "To use a human analogy -- by putting criminals in jail we are going to obtain a decrease in crime? In many cases, probably not."
The paper "Seasonality and reoccurrence of depredation and wolf control in western North America" is published in the current issue of the Wildlife Society Bulletin and presented by Musiani at the18th Annual North American Wolf Conference at Chico Hot Springs Resort in Pray, Montana. The April 4-6 conference is sponsored by the Madison Valley Ranchlands Group, the Nez Perce Tribe, the Wolf Recovery Foundation, Yellowstone National Park and the conservation group Defenders of Wildlife. The study comes as several U.S. states consider removing the gray wolf from the federal endangered species list after populations that were once extirpated have been re-established.
Musiani has worked on the problem of wolves killing livestock in Canada, Italy, Poland, Portugal, Serbia, and the U.S, and has served as a United Nations consultant on the issue.
This story first appeared in ScienceDaily on April 5, 2006.