Study: Killing wolves for eating livestock increases the number that get eaten the following year

[kpete]

A study by Rob Wielgus, director of Washington State University’s Large Carnivore Conservation Lab, and Kaylie A. Peebles has concluded that lethal removal of wolves caught or suspected of killing livestock may actually increase how many sheep and cattle wolves may eat the following year. That's counter-intuitive, as Wielgus readily concedes, but, he told Sarah Jane Keller at High Country News in early December: “I analyzed it like 50 times, with different statisticians and layers and layers of peer review because the results are kind of astounding:”

People have long assumed that fewer wolves lead to fewer depredations on sheep or cattle. And wildlife managers often say that lethal removal can be a salve for vitriol toward wolves, by providing a short-term solution for the harmed livestock producers, and by showing that states are actively managing the animals. It’s part of the reason some states allow wolf hunting, and why Washington, Montana, Idaho and Wyoming all lethally remove wolves that harm livestock. In 2013 the later three states killed 202 wolves for control purposes, or 8 percent of the population in all four states.

But when Wielgus and his coauthor looked at 25 years of data on lethal wolf control and livestock depredations from Idaho, Wyoming, and Montana they found that killing one wolf increases the odds of sheep depredation by 4 percent the following year. For cattle, it increased the odds by 5 to 6 percent. [...]

Wielgus suspects the answer may be found in wolf social dynamics. The animals may compensate for losing part of their pack by increasing reproduction and thus, the need to hunt for those new pups. Or wolves may become less efficient hunters in smaller groups and turn to dining on livestock. “I think the take home point is that social behavior and social systems of these large carnivores, pack dynamics, territory, all of that is a very important element to how wolves interact with their environment,” says John Pierce, chief wildlife scientist for the Washington Department of Fish and Wildlife. “As we move forward in wolf management we should carefully be studying that and don’t assume a linear relationship (between wolf removal and depredation).”

MORE:
http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0113505
https://www.hcn.org/articles/killing-wolves-to-protect-cattle-may-backfire

[fadedrose]

2. My first smile of the day ...

But you should consider being repentant once in a while....

[2naSalit]

3. Thank you for posting this.

I'll read carefully later and see if I can make this another ref study for this argument... on pack dynamics and the problem with lethal control methods used by state & federal management agencies.

There have been several non-lethal management tools developed but the management agencies and livestock industry won't use them. They might have to put in a little more effort to deter predators and would rather call on Wildlife Services to just go out and kill or establish a very long season on the predators at taxpayer expense.

But this is science so it may be overlooked by TPTB on principle alone.

[Blanks]

4. I don't know how many sheep and cattle they're killing...

But an increase of about +-5% seems an odd increase. Either they're killing a lot of livestock (from 100/year to 105/year) or there is some kind of weird averaging.