We are Losing our Large Carnivores, Researchers Say

About 75 percent of 31 large carnivore species are now declining, according to a new study. Also, some 17 percent are being forced to stay on half the territory they once roamed.

The study, conducted by researchers at the Oregon State University, many carnivores living in key biological hotspots such as Southeast Asia, southern and East Africa and the Amazon are now losing their habitat.

"Globally, we are losing our large carnivores," said William Ripple, lead author of the paper and a professor in the Department of Forest Ecosystems and Society at Oregon State University.

According to a related study, big cat conservation organization Panthera said that there are 250 adult lions in West Africa.

"Many of them are endangered," he said in a news release. "Their ranges are collapsing. Many of these animals are at risk of extinction, either locally or globally. And, ironically, they are vanishing just as we are learning about their important ecological effects."

For the study, researchers looked at data from scientific reports. They closely studied data on African lions, leopards, Eurasian lynx, cougars, gray wolves, sea otters and dingoes, whose disappearance is likely to have a drastic effect on the entire ecosystem.

Previously, a study had found how increasing number of goats and sheep in the Mongolian Steppes is turning the grassland into desert.

Carnivores keep the number of herbivores in check and prevent a population explosion of "grass eaters". Researchers documented environmental impacts of losing major carnivores such as cougars and wolves on the growth of vegetation Yellowstone and other national parks in North America. Their study showed that fewer hunters led to an increase in the number of grazers such as deer and elk. Higher number of grazers has an impact on several other small animals.

The team of researchers, which included authors from United States, Australia, Italy and Sweden, has called for an international initiative to conserve large predators.

The 3,400-mile dingo-proof fence in Australia enabled researchers to see how the absence of a predator affects an ecosystem. Also, the decrease in number of lions has led to an increase in the number of olive baboons, which destroy crops. Sea otters' low population in southeast Alaska has been co-related with an explosion in the population of sea urchins.

"Nature is highly interconnected," said Ripple in a news release. "The work at Yellowstone and other places shows how one species affects another and another through different pathways. It's humbling as a scientist to see the interconnectedness of nature."

The study is published in the journal Science.