Decline of Large Predators Could Have Ripple Effects for Wider Environment

Falling numbers of apex predators like wolves and mountain lions might be good news for the animals those carnivores prey on. But the resulting growth in populations of those carnivores eat has a negative impact on the wider environment.

More than 75 percent of the world’s large carnivores are declining, according to a new study.

“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 in a statement. “Many of them are endangered. Their ranges are collapsing. Many of these animals are at risk of extinction, either locally or globally.”

Large carnivores have largely been eliminated from the developed world, and Southeast Asia, southern and East Africa and the Amazon basin were areas seeing a decline in the species. And the effects of the losses could have wider ramifications.

“Ironically, they are vanishing just as we are learning about their important ecological effects,” added Ripple.

According to the Oregon State announcement, researchers documented the impact of cougars and wolves on the regeneration of forests and other flora around streams and rivers in Yellowstone National Park. The decline of predators led to an increase in “browsing animals such as deer and elk,” which leads to a “disruption of vegetation as well as “shifting” birds and other small mammals.

Similar effects have been seen in other areas where the Eurasian lynx, dingoes, lions and sea otters have been in decline, according to the research.  A lack of lynx has led to more roe deer, red fox and hare. The decline of lions and leopards led to an increase in olive baboons, which pose a threat to agriculture. In the waters off southeast Alaska, the loss of sea otters resulted a rise in sea urchins and the loss of kelp beds

There is hope, however, according to study. The researchers found that in some cases where large predators are reintroduced, such as the wolf restoration in Yellowstone, ecosystems show signs of recovery.

“I am impressed with how resilient the Yellowstone ecosystem is,” Ripple said. “It isn’t happening quickly everywhere, but in some places, ecosystem restoration has started there.”