Do Predator Culls Really Save Livestock?

Every year — over the bodies of dead mountain lions, wolves, coyotes and bears — officials assurethe public that “culls” are necessary for livestockprotection. They often frame thiseuphemistically phrased”predator control” as an unfortunate decision, but one backed with science and a thorough understanding of predator dynamics.

It turns out, though, that those officials may be full of baloney.

A new study published in “Frontiers in Ecology and the Environmentsuggests that the research they’re relying on isn’t actually all that great. Lead researcher Adrian Treves ofthe University of Wisconsin, Madison, has some questions about how those studies were conducted — and whether their results arereallyall that applicable.

You’ve probably heard the logic: Ranchers keeping sheep, cattle and other livestock beginlosing members of their herds to “problem” predators, so officials step in to kill some of the offendersin order to protect the financial interests of the agricultural community.

As is often the case, humans win out. In September, for example, Norway announced a dramatic wolf cullto protect its extremely large sheep population.

Earlier this month, predators in Nevada actually got areprieve as a result of a lawsuit challenging the methodology of science used by Wildlife Services, a division of the U.S. Department of Agriculture — not to be confused withtheFish and Wildlife Service.

So is it true?

To know the answer to that question, we need research — and a lot of it. But it’s not enough to simply conduct a study, argues Treves, who performeda meta-analysis of over 100 studies on the subject.

Treveswas particularly concerned about the lackof randomization. While it can be challenging to implement such a process in the field, itprovides vitally necessary information.

In this case, the question is whether removing predators really hasa substantive impact on livestock losses, or whether leaving predators intact yields a similarresult.

Trevesrefers to this as a “gold standard,” and it’s one of the underlying tenets of a huge variety of research methodologies. After all, if doing nothing has the same result, it’s pretty clear that there’s another cause for the problem that researchers are trying to solve.

But the flaws Trevesraises aren’t just about randomization.

He also found issues with how studies were constructed, from the number of animals in the pastures selected for research to a lack of pre-cull research and subsequent follow-up monitoring.

Treves is not alone in questioning whether culls really work, as researchers have raised concerns about increases in predator numbers following culls, as well as a spike in predation.

As humans expand their territory, these are dilemmasthat willarise evenmore frequently, making it critical to use robust scientific methods to examine the interactions between predators and livestock.

Critics of Treves’findings–including some of the researchers he challenged– argued that his own work had flaws, such asa failure to consult with outside experts and misleading evaluations of some of the studies involved.

This sort of peer discussion only makes scientific research stronger. It highlights the fact that multiple studies — including literature reviews like this one — are necessary to explore and verify information.

Treves’ workisn’t designed to be a definitive study, but hopefully it will open the door to more thoughtful study construction in the future, as well as promotemore careful examinationof previous research on the topic.

Just because certain researchsuperficially confirms assumptions — “killing predators reduces livestock losses” — doesn’t mean that those findings are the correct or finalconclusion.

Photo credit: brainfreezer

87 comments

Robert N.
Rob Chloe Sam N2 years ago

I agree Kathryn Mitchell.

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Kathryn Mitchell
Kathryn Mitchell2 years ago

Leave the predators alone! It's the ranchers' faults if they can't keep track of their livestock!!!

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Marie W.
Marie W2 years ago

NO

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Peggy B.
Peggy B2 years ago

TYFS

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Peggy B.
Peggy B2 years ago

I agree with Jetana Allison.

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Pablo B.
.2 years ago

tyfs

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Jetana Allison
Jetana A2 years ago

Stop public lands grazing, which is truly welfare ranching, and harmful to Western ecosystems. Predators are essential for the health of wildlife populations! And no one needs trophies--a disgusting practice!

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Philippa Powers
Philippa Powers2 years ago

I don't think culling does anything good.

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sandy Gardner
sandy Gardner2 years ago

Thanks!

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Elaine W.
Elaine W2 years ago

Noted.

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