Killing large predators to reduce livestock conflicts or benefit game populations has long been thought to be ineffective — and devastating for ecosystems — and a growing body of scientific literature criticizing the widespread practice is confirming those fears.
Most recently, this month, the Journal of Mammalogy — a highly respected international scientific journal and flagship publication for the American Society of Mammalogists — published a special collection of articles criticizing lethal control of predators such as wolves and grizzlies.
Today’s predator control is widespread in the American West and has its origins in barbaric 20th century, government-sponsored predator eradication programs. Those utilized poisons and bounties to drive grizzly bears and wolves to the brink of extinction.
Thanks to the protection of the Endangered Species Act — which has saved more than 99 percent of the plants and animals under its protection and put hundreds on the road to recovery — the grizzly bear and wolf have begun to recover. But as these large carnivores expand their population size and range, people have once again called for lethal control to address livestock depredations and inflate game populations.
In states where gray wolves have lost their federal protections, such as Idaho, state managers dead set on killing the predators established aggressive hunting seasons and lethal depredation controls. After the U.S. Fish and Wildlife Service proposed removing Yellowstone grizzly bears from the list of federally protected species, states like Montana moved quickly to establish hunting seasons.
Then there’s the coyote, a predator lacking protection at state or federal levels and a primary target of predator control programs across the U.S. Tens of thousands of these resilient predators are killed each year by a highly secretive arm of the U.S. Department of Agriculture known as Wildlife Services.
The numbers of predators killed by Wildlife Services is staggering. The latest kill report shows Wildlife Services in fiscal year 2015 killed more than 3.2 million animals, including 68,905 coyotes (plus an unknown number of pups in 492 destroyed dens), 385 gray wolves, 284 mountain lions, 731 bobcats and 3,437 foxes.
This level of human-caused mammalian predator mortality is damaging native ecosystems and biodiversity. The lead article in the Journal of Mammalogy’s special feature on lethal control — “Carnivore conservation: shifting the paradigm from control to coexistence” — summarizes studies on the essential role of apex predators like wolves and grizzlies and mesopredators like coyotes and foxes in maintaining ecosystem function. A well-known example is how wolf reintroduction to Yellowstone created a trophic cascade that enriched riparian songbird communities.
Given the ecological importance of wolves and other predators, scientists are calling for implementation of nonlethal methods to prevent livestock depredations.
The authors of “Adaptive use of nonlethal strategies for minimizing wolf-sheep conflict in Idaho” in the special feature document a seven-year pilot project in prime Idaho wolf habitat, highlighting the adaptive use of a suite of nonlethal deterrents to protect sheep. Those nonlethal methods reduced sheep depredation by more than three times the reductions seen on sheep allotments in Idaho that used lethal control.
Another study featured, “Cattle mortality on a predator friendly station in central Australia,” found that ending lethal control may in itself — even without implementing nonlethal methods — reduce livestock losses by simply enabling the predator’s social structure to stabilize.