New research shows the decline of some of the world's largest herbivores could lead to "empty landscapes" in our most diverse ecosystems.
The recent analysis focused on 74 large herbivore species, especially those from Africa and Asia, Oregon State University reported.
"Without radical intervention, large herbivores (and many smaller ones) will continue to disappear from numerous regions with enormous ecological, social, and economic costs," said William Ripple, Oregon State University distinguished professor in the College of Forestry. "I expected that habitat change would be the main factor causing the endangerment of large herbivores. But surprisingly, the results show that the two main factors in herbivore declines are hunting by humans and habitat change. They are twin threats."
Kent H. Redford, then a post-doctoral researcher at the University of Florida, first used the term "empty forest," which suggested that while fauna may appear plentiful, its loss imposed a long-term threat to ecosystems.
"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."
The findings showed 25 of the largest wild herbivores now occupy only about 19 percent of their historical ranges. This is primarily due to competition from livestock production, which has tripled globally since 1980 and reduced the amount of accessible land. Hunting is also believed to play a significant role in the species' decline.
"The market for medicinal uses can be very strong for some body parts, such as rhino horn," Ripple said. "Horn sells for more by weight than gold, diamonds or cocaine."
The effects of this devastating species decline is predicted to include a reduction in food sources for large carnivores, diminished seed dispersal for plants, more severe and frequent wildfires, slower soil nutrient cycling, and habitat changes for smaller animals.
"It is essential that local people be involved in and benefit from the management of protected areas," the researchers wrote. "Local community participation in the management of protected areas is highly correlated with protected area policy compliance."
The findings were published in a recent edition of the journal Science Advances.
