Study Reveals Most Effective Techniques For Protecting Livestock from Predators

Note: Yale School of the Environment (YSE) was formerly known as the Yale School of Forestry & Environmental Studies (F&ES). News articles and events posted prior to July 1, 2020 refer to the School's name at that time.

While conducting doctoral research on livestock predation in rural India, Jennie Miller ’15 Ph.D., watched herders spend day in and day out with village cattle, yet continue to lose livestock to tigers, and she wondered whether there might be more effective methods than animal husbandry to prevent these attacks. But, she says, there was a lack of empirical research to help herders determine which methods work best. And, critically, those methods that work best for, say, protecting sheep from wolves in Montana might not effectively protect cattle from tigers in India.
“If livestock owners can’t choose the most efficient tool for handling their problem predator and protecting their livelihood, how can we possibly expect them to peaceably coexist with large carnivores in their backyards?” she said. “Livestock owners spend immense resources on stopping carnivore attacks but may never know whether the costs were truly worthwhile.”
Miller, currently a postdoctoral researcher at Panthera, along with colleagues from the Yale School of Forestry & Environmental Studies (F&ES), decided to examine the scientific literature to see what techniques appeared to work best. They reviewed 66 peer-reviewed research papers that tested the efficacy of both lethal and non-lethal methods of preventing carnivore attacks.
Livestock owners spend immense resources on stopping carnivore attacks but may never know whether the costs were truly worthwhile.
— Jennie Miller ’15 Ph.D.
Their study, which appeared last week in the Wildlife Society Bulletin, suggests the most consistently effective techniques are light and sound devices, night enclosures, shock collars, electric and non-electric fences, and translocation.
The paper also reveals a tendency among researchers to focus on predation by Canids, such as wolves, in North America, Europe, and Africa. It is critical, the authors say, to increase rigorous testing of techniques across species, especially bears and cats, and in more diverse regions including Asia and Latin America.
“This paper shows that if we step back and take a broader look, we can draw common threads among the different contexts and derive some working principles to help guide more effective control of livestock depredation, and minimize the need for lethal control of these iconic animals,” said Oswald Schmitz, Oastler Professor of Population and Community Ecology at F&ES.
Miller, lead author of the study, says they were surprised at how few studies had quantitatively measured the effects of methods, especially the usefulness of human guards and lethal control — techniques that involve large financial and time costs and can have detrimental impacts on human health and carnivore populations. But she also acknowledged the practical challenges of conducting empirical research on livestock predation.
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“A major problem is that no livestock owner wants to be the control site, the farm that loses livestock, while all the neighbors’ animals are safe from predators. But it doesn’t have to be like that if researchers and farmers can set up before-and-after studies,” she said.
The key, the authors suggest, is to have long-term studies that repeatedly test — and publish — methods. For example, human guards and lethal control — which involve high financial and time costs, and implications for human and animal wellbeing — were quantitatively tested by only one study each.
“Chronic conflict between large carnivores and livestock not only limits the long-term viability of many carnivore populations — it also carries economic and emotional costs for the livestock producers and others involved in these conflicts,” said Arthur Middleton ’07 M.E.M., Assistant Professor at UC Berkeley Department of Environmental Science, Policy and Management and one of the co-authors. “All these are important to alleviate, no matter how long it takes.”
Other authors include Kelly Stoner ’14 M.E.Sc., Mikael Cejtin ’13 M.E.Sc., and Tara Meyer ’15 M.E.Sc.
– Timothy Brown    203 436-9503