Non-lethal methods found effective for predator control

A new study shows that non-lethal methods of predator control can be highly effective in protecting livestock from predators and in turn, saving predators from people.

Published in the Wildlife Society Bulletin, the study addresses the issue that top predators like wolves, bears, lions and tigers have declined dramatically around the world over the past century and one major driver of these declines is retaliatory killing by people following predator attacks on domestic livestock.

By examining 66 published, peer-reviewed research papers that measured how four categories of lethal and non-lethal mitigation techniques influenced attacks on livestock, researchers found that the most consistently effective tools were guard dogs, electric fencing, electrified fladry, namely electric fence with hanging colored flags, light and sound devices, shock collar, and removal of predators, which includes both killing and translocation to other places.

The categories of predator control techniques for livestock protection include preventive livestock husbandry, predator deterrents, predator removal, and indirect management of land or wild prey.

"Livestock owners spend immense resources on stopping carnivore attacks but may never know whether the costs were truly worthwhile," said Jennie Miller, a researcher at Panthera who will become a postdoctoral researcher at the University of California, Berkeley, in the Department of Environmental, Science, Policy and Management in January next year.

The new study found that preventive husbandry and deterrents were most effective in reducing livestock losses. These methods, however, showed wide variability due to a suite of external factors, such as how well equipment was installed and maintained. Husbandry methods ranged between 42 percent and 100 percent effective, while deterrents ranged anywhere from highly effective to wholly ineffective.

Lethal predator control has received particularly little study and monitoring, the study's authors pointed out. "In spite of lethal control being very widely used, it really hasn't been studied well enough to make scientific comparisons with other, non-lethal methods, which is surprising," said Arthur Middleton, an assistant professor in the UC Berkeley Department of Environmental Science, Policy and Management and a study co-author.

The authors suggest the lethal management method should receive closer monitoring and more rigorous testing.

Large carnivores are critical as they can stabilize entire ecosystems. Despite their importance, 77 percent of the 31 largest terrestrial carnivores are declining in population, with 61 percent listed by the International Union for the Conservation of Nature as vulnerable, endangered or critically endangered.

"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," Middleton was quoted as saying in a news release from UC Berkeley. "All these are important to alleviate, no matter how long it takes." Endit