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Killing predators might not be best way for farmers to protect livestock, study finds

Mountain lion stares down Sierra hikers in frightening encounter

Two trail runners from San Luis Obispo County were on their first day of an 11-day backpacking trip to hike the High Sierra Trail up to Mount Whitney in Sequoia National Forest when they spotted a mountain lion. See the frightening encounter.
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Two trail runners from San Luis Obispo County were on their first day of an 11-day backpacking trip to hike the High Sierra Trail up to Mount Whitney in Sequoia National Forest when they spotted a mountain lion. See the frightening encounter.

For many farmers and ranchers, the best way to deal with a predator is the lethal way — but a new study suggests there’s little credible evidence to support that position.

The study was recently published in the journal PLOS Biology.

“Twenty-one authors from 10 nations reviewed 114 peer-reviewed scientific studies measuring the effectiveness of lethal and non-lethal methods for reducing carnivore predation on livestock, one of the main causes of conflict between predators and people,” according to a release from the nonprofit Defenders of Wildlife, a member of which — Jennie Miller — was a senior author of the study.

“Just as we rigorously and repeatedly test medicines, vehicles and other devices for their effectiveness, we should test carnivore management methods before deeming how and when they can be used effectively,” Miller said in the statement.

Large predators populations have decreased around the world over the past 200 years, in large part due to run-ins with humans and livestock, according to a study published in the journal Science.

“Large carnivores face enormous threats that have caused massive declines in their populations and geographic ranges, including habitat loss and degradation, persecution, utilization and depletion of prey,” the Science study found.

The study published in PLOS Biology found that “livestock guardian dogs, livestock enclosures and fladry (a set-up involving a rope and several flags or strips of cloth) all were scientifically shown to be effective conflict deterrents.”

Grizzly bears in the Yellowstone ecosystem are thriving. The once-dwindling population of bears occupying areas of Idaho, Montana, and Wyoming has been steadily increasing since 1981, when recovery efforts under the Endangered Species Act began. M

Other methods “show promise,” the study found, but need additional scientific research in order to prove their effectiveness.

The two-year study examined more than 40 years’ worth of “lethal and nonlethal interventions for reducing predation on livestock” and found that there was a scarcity of solid, experiment-tested evidence for lethal interventions.

The study authors wrote they believe that scarcity is “due to the tendency for decisions about predator control to depend on factors other than evidence-based evaluation of whether a given intervention effectively protects livestock.”

Phil Davis, a fourth-generation cattle rancher in Cascade, Idaho, had four cows and calves killed in one week.

“We call on the scientific and agricultural communities to hold carnivore management to the highest standards of scientific integrity. When scientists, policymakers and livestock producers come together to make wise regulations, we’ll save money, time, livestock and carnivores alike,” Miller said in a statement.

Andrew Sheeler: 805-781-7934, @andrewsheeler
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