Decline of Large Herbivores Could Lead to 'Empty Landscape'

Scientists fear that the decline of the world's largest herbivores, especially in Africa and parts of Asia, could lead to an "empty landscape" in some of the most diverse ecosystems on the planet, according to a new study.

Many populations of animals such as rhinoceroses, zebras, camels, elephants and tapirs are diminishing or threatened with extinction in grasslands, savannahs, deserts and forests.

After studying 74 of the largest herbivore species - those that weigh more than 220 pounds on average - the researchers found that "without radical intervention, large herbivores (and many smaller ones) will continue to disappear from numerous regions with enormous ecological, social, and economic costs."

"I expected that habitat change would be the main factor causing the endangerment of large herbivores," lead author William Ripple from Oregon State University said in a statement. "But surprisingly, the results show that the two main factors in herbivore declines are hunting by humans and habitat change. They are twin threats."

While trees and other vegetation may exist, plant-eating animals need more than just that to survive. According to the researchers, the loss of forest fauna alone poses a long-term threat to ecosystems on which herbivores rely.

"Our analysis shows that it goes well beyond forest landscapes," Ripple said, "to savannahs and grasslands and deserts. So we coin a new term, the empty landscape."

Out of the 4,000 species of known terrestrial herbivores, which inhabit every continent except Antarctica, those found in developing countries like Southeast Asia, India and Africa are most threatened by habitat loss.

Astonishingly, 25 of the largest wild herbivores now occupy an average of only 19 percent of their historical ranges.

And thanks to competition from livestock production - which has tripled globally since 1980 - herbivores can't access land, forage and water in some areas. Not to mention livestock has put them at a higher risk of contracting transmitted diseases. (Scroll to read on...)