David DeFranza, Treehugger.com
April 12, 2012

Towns, cities, suburbs, and rural areas all have at least one thing in common: An over abundance of deer and other large herbivores. The free-ranging herds cross busy traffic lanes, eat from gardens, and spread disease—among other things. But what can be done to control them?

The answer, according to a new study conducted by researchers at Oregon State University, is to cultivate healthy predator populations. Yes, this includes reintroducing wolves.

The researchers found that “there’s consistent evidence that large predators help keep populations of large herbivores in check, with positive effects on ecosystem health.”

Densities of large herbivores—like deer and moose—were six times greater in areas without wolf populations. In addition, they found that combinations of predators—like wolves and bears—had a greater benefit by allowing the species to work together to cultivate an “ecosystem of fear” amongst their prey.

“In systems where large predators remain, they appear to have a major role in sustaining the diversity and productivity of native plant communities,” Robert Beschta, a co-author of the study, explained “thus maintaining healthy ecosystems.”

Another interesting finding was that hunting by humans did little to control the populations of herbivores. The study found that the limited range and duration of human hunting was not effective at curbing the populations of hyper-abundant species. What is needed, the researchers concluded, were large, wide-ranging carnivores—most likely in large numbers.