Scientific review critiques ‘shot-in-the-dark’ predator control

September 1, 2016

Most predator control methods implemented across North America and Europe have never been tested experimentally against accepted standards of evidence, suggests a new scientific review published today in Frontiers in Ecology and the Environment.

Thousands of bears, cougars, coyotes, wolves and other wild carnivores are killed across North America and Europe each year in hopes of preventing attacks on domestic animals. To test the effectiveness of these efforts and inform future policy and research, Adrian Treves, an associate professor of environmental studies at UW-Madison, with colleagues from the University of Ljubljana in Slovenia and University of Witwatersrand in South Africa, reviewed all of the scientific evidence available around predator control on North American and European farms.

The researchers found “surprisingly little reliable evidence” that government-sanctioned predator control programs are effective in preventing future livestock loss, Treves says. The team identified 12 experiments on lethal and non-lethal programs since 1978 that met scientific standards for experimental evidence. Twelve other experiments were set aside from the evaluation because of design flaws or accidental biases in the research.

“The majority of lethal
methods appeared to
waste time and resources,
and threaten predators
and livestock needlessly.”

Of the 12 studies the researchers examined, six demonstrated prevention of livestock predation, while four showed no effect on predation. Seven of the 12 studies tested lethal methods; of these, 71 percent detected no preventive effects against livestock attacks or detected counter-productive effects of losing more livestock.

“The majority of lethal methods appeared to waste time and resources, and threaten predators and livestock needlessly,” Treves says.

The authors note that non-lethal methods of predator control were generally more reliable and effective in preventing carnivore predation on livestock. They also suggest that further research into predator control by independent scientists would help provide the best available science to livestock owners and taxpayers, and reduce financial waste and animal suffering.

Earlier this year, Treves and Guillaume Chapron of the Swedish University of Agricultural Sciences conducted the first quantitative evaluation of a dominant theory in wildlife conservation – that liberalizing culling will reduce poaching, or illegal killing, and improve the population status of an endangered carnivore. The pair’s findings suggested that granting local authorities management flexibility for endangered species to address illegal behavior may instead promote such behavior.

As founder and director of the Carnivore Coexistence Lab in the Nelson Institute for Environmental Studies, Treves examines patterns of conflict with predators and human responses to these conflicts. He has previously studied the inclination to illegally kill wolves in Wisconsinchanges in attitudes toward wolves before and after an inaugural public hunting and trapping season in the state, and how to balance human needs with predator conservation.