Oregon State College of Forestry professor Bill Ripple published a study last year which proved that 60 percent of the world’s largest carnivores were at risk of extinction, and in a new report published in the journal Science Advances, Ripple revealed that 60 percent of the world’s largest herbivores are also within extinction risk.

After analyzing population data from the International Union for Conservation of Nature, Ripple and his research team found that a majority of large plant-eating animals are at risk of extinction, a frightening realization since many of these species are vital elements of the food web across areas of Africa and Southeast Asia which cannot be replaced by small species. This raised extinction risk is the result of a mixture of hunting and habitat loss due to deforestation and the spread of livestock.

“I was surprised by the fact that so many of these large animals were consider threatened,” Ripple told The Huffington Post. “Most of the very large herbivores have already been wiped out in developed countries.”

Despite the troubling findings reported in his study titled “Collapse of the World’s Largest Herbivores,” recent responses to biodiversity catastrophes have made Ripple optimistic about conservation. He told the Post that Rep. Peter DeFazio’s bill to reinforce the illegality of the wildlife trade and Yao Ming’s efforts to combat shark fin soup in China are both positive signs of change, but hopes that wealthy individuals worldwide will donate to help further protect newly-endangered species.

“One of the bottom-line issues is, the people in the rich countries need to come help rescue these animals,” said Ripple. “They need to help.”