Predator control is a wildlife management policy specifically aimed at reducing populations of predatory species either to protect livestock or boost populations of game animals. Coyotes, bobcats, grey and red wolves , bears, and mountain lions have been the most frequent targets. Historically, efforts were centered in government-run programs to hunt, trap, or poison predators, while bounties offered for particular predatory species encouraged private citizens to do the same. Over time, however, it has become apparent that predator control is disruptive of ecosystems and often inefficient.
Predator control is based on a lack of understanding of the complex interactive mechanisms by which natural environments sustain themselves. Control efforts take the position that prey populations benefit when predators are removed. In the long term, however, removing predators is generally bad for the prey species and their ecosystems. The conservationist Aldo Leopold , noticing the devastating effects of overgrazing by deer, realized as early as the 1920s that shooting wolves, although it led to an immediate increase in the deer population, ultimately posed a threat to the deer themselves as well as other fauna and flora in their environment . Another example can be found in the undesirable consequences of killing significant numbers of coyotes. Immediate benefits rebound not only to livestock but also to populations of rabbits and other rodents, which are normally controlled by predation. Since rabbits compete with livestock for the same rangeland, an explosion in the rabbit population simply means that the land can sustain fewer livestock animals.
In 1940, the U.S. Department of the Interior initiated a large-scale program against livestock predators, particularly aiming at the coyote and relying heavily on poisons. The poison most widely used in bait was sodium fluoroacetate, also called "compound 1080," which is highly persistent and wreaks havoc on many animals besides the coyote, including threatened and endangered species . Moreover, when a poisoned coyote dies, the carrion enters the food chain/web , with lethal effects primarily on scavengers. Eagles, including the rare bald eagle , are particularly hard-hit by efforts to poison coyotes.
Rising environmental awareness has caused continuing controversy over predator control. By 1972, the governmentappointed Committee on Predator Control concluded that the use of poisons had unacceptably harmful consequences. Government agencies discontinued the use of poisons, and poison was banned on public lands. Nevertheless, private citizens, mostly ranchers and hunters who feel that their interests have been sorely overlooked, have continued using poisons with little regard for the law. In the 1980s the government started taking a less progressive stance, and in 1985 the Reagan administration reinstituted the use of compound 1080 in "livestock collars." While nonpredatory species will not fall victim immediately, the poison still enters the food chain with every coyote killed.
In spite of aggressive methods, the fight against coyotes has mostly been unsuccessful. Even after decades of predator control, total annual losses are given in the hundreds of thousands of animals (mostly sheep and goats) by ranchers who claim they lose as much as 25 percent of their lambs to predators each year. Conservationists and supporters of wildlife say these numbers are inflated, but, even if they are accurate, the cost of lost livestock is significantly lower than the cost of the government's predator control programs. Conservation groups argue that it would be much cheaper to give up on predator control and reimburse ranchers for livestock lost to predation.
Besides killing predators, ranchers also have a number of other options when it comes to protecting their livestock. Sheep can be protected by letting it graze together with cattle or other animals too big for coyotes to handle. Llamas and donkeys have also been suggested for the purpose. Trained guard dogs are an effective deterrent to coyotes as well.
Although predator control can clearly have devastating consequences, it is by no means a thing of the past. Recently, Alaska began implementing a program to shoot 1000 wolves (out of a total population of 7000 wolves in the state). The program, which is to remove the wolves from a vast, centrally located stretch of wilderness over a period of five years, will have government agents tracking and shooting packs of wolves from the air. Private citizens are also allowed to shoot wolves. The object is to boost moose and caribou herds for hunting and tourist purposes. The view that the value of animal resources lies primarily in their usefulness to human beings still motivates many government policies and individual behaviors.
[David A. Duffus and Marijke Rijsberman ]
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