Annual reports of the Bureau of Biological Survey and books like Michael J. Back in 1915, the words "ecology" and "environment" were unknown. Instead, we recommend that WS and its government partners involved in wildlife conflict management emphasize training livestock producers in methods of nonlethal control, with sparing use of lethal control by methods that are species-specific, and cease all lethal control in federal wilderness areas and for the purpose of enhancing populations of common game species.The agency's goal was to eliminate predators to foster game populations of deer and elk, and to reduce losses by stockmen who raised sheep and cattle. Lethal predator control is not effective at reducing depredation in the long term. Reducing their populations, locally or globally, risks cascading negative consequences including impoverishment of biodiversity, loss of resilience to biotic invasions, destabilization of populations at lower trophic levels, and loss of many ecosystem services that benefit human society directly and indirectly. Many are important species in their native ecosystems (e.g., ecosystem engineers such as prairie dogs and beavers, and apex predators such as gray wolves). Since 2000, Wildlife Services (WS), an agency of the US Department of Agriculture, has killed 2 million native mammals, predominantly 20 species of carnivores, beavers, and several species of ground-dwelling squirrels, but also many nontarget species. We recommend that policy makers suspend predator control efforts that lack evidence for functional effectiveness and that scientists focus on stringent standards of evidence in tests of predator control.įor more than 100 years, the US government has conducted lethal control of native wildlife, to benefit livestock producers and to enhance game populations, especially in the western states. Only two non-lethal methods (one associated with livestock-guarding dogs and the other with a visual deterrent termed " fladry ") assigned treatments randomly, provided reliable inference, and demonstrated preventive effects. Of those twelve, prevention of livestock predation was demonstrated in six tests (four non-lethal and two lethal), whereas counterintuitive increases in predation were shown in two tests (zero non-lethal and two lethal) the remaining four (one non-lethal and three lethal) showed no effect on predation. Twelve published tests – representing five non-lethal methods and 7 lethal methods – met the accepted standard of scientific inference (random assignment or quasi-experimental case-control) without bias in sampling, treatment, measurement, or reporting.
We also reviewed a selection of tests from other continents to help assess the global generality of our findings. To inform future policy and research on predators, we systematically evaluated evidence for interventions against carnivore (canid, felid, and ursid) predation on livestock in North American and European farms.
However, many of these methods are implemented without first considering experimental evidence of their effectiveness in mitigating predation-related threats or avoiding ecological degradation. Livestock owners traditionally use various non-lethal and lethal methods to protect their domestic animals from wild predators.
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