Loss of predators tied with deforestation

Washington - The unbridled growth of moose, deer and other herbivore populations is contributing to deforestation thanks to the loss of predators such as wolves.

This loss has allowed animal populations to greatly increase, crippling the growth of young trees and also reducing biodiversity, researchers have concluded.

Densities of large mammalian herbivores were six times greater in areas without wolves, compared to those in which wolves were present, the European Journal of Wildlife Research reports.

“These issues do not just affect the United States and a few national parks,” said William Ripple, professor of forestry at the Oregon State University, who led the study, according to an Oregon statement.

“The data from Canada, Alaska, the Yukon, Northern Europe and Asia are all showing similar results. There’s consistent evidence that large predators help keep populations of large herbivores in check, with positive effects on ecosystem health,” added Ripple.

They also found that combinations of predators, such as wolves and bears, can create an important synergy for moderating the size of large herbivore populations.

“Wolves can provide food that bears scavenge, helping to maintain a healthy bear population,” said Robert Beschta, professor emeritus at Oregon and study co-author.

“The bears then often prey on young moose, deer or elk - in Yellowstone more young elk calves are killed by bears than by wolves, coyotes and cougars combined,” he added.