An endangered species can't afford to bite the hand that's trying to save it. But tigers are doing just that in Nepal, where villagers have restored degraded landscapes to create more habitat for the big cats. New research shows that tigers have recolonized the rejuvenated forests and started killing people at an alarming rate, fraying the fragile relationship between man and beast.
Hunting and habitat destruction have reduced the world's wild tiger population from 100,000 a century ago to 5000 or so today. The holdouts are squeezed into 7% of their former range, surrounded on nearly every side by roads, villages, and fields. In the 1990s, the Nepalese government began designating forests around existing reserves as buffer zones, giving tigers more room to roam. Local communities have banded together to manage these recovering woodlands, determining how to use their resources, such as firewood and grass for livestock feed. Each park gives a portion of its revenues to these community organizations.
In 1996, the buffer-zone management program came to Royal Chitwan National Park, a UNESCO World Heritage site along Nepal's southern border with India. Community groups pulled livestock off the land, and within 2 years the overgrazed buffer zone came to life--but so did conflicts between people and tigers. Researchers investigated 88 fatal tiger attacks on humans that took place in Chitwan from 1979 to 2006. They found that killings soared once the buffer-zone forests bounced back, from an average of 1.2 people per year in the first 2 decades to 7.2 thereafter. The killing rate jumped nearly threefold inside the park and more than ninefold inside the buffer zone, the team reports in this month's issue of Biological Conservation.
For tigers, there is good news. "We can call this a conservation success story, because tigers are breeding in the buffer zone now," says ecologist and lead author Bhim Gurung of the University of Minnesota, Twin Cities. That may be because prey numbers in the buffer zone have also increased due to conservation efforts, encouraging tigers to settle there.
But the spike in attacks threatens the success of the management program, Gurung says, because local people are more likely to hunt or poison tigers when killings rise. To reduce the violence on both sides, Gurung and his colleagues recommend that biologists or land managers educate villagers about tiger behavior and the risks of harvesting wood and other resources from the forests. Any potential problem animals should be fitted with radio collars, the team adds, so people know where the cats are and can stay out of their way.
The study gathers "the most complete record of human killing by tigers in any part of the [tiger's] range," says Eric Dinerstein, vice president of conservation science at the World Wildlife Fund in Washington, D.C. However, Dinerstein wishes the authors had tried to account for the effect of human population growth in their analysis. Tigers may be killing more people now in Chitwan, he says, simply because there are more people to kill.