Nurturing Nature’s Balance

M.DaRocha©WCS

The grizzled shadow, the distant howl…do animals fear these signs by instinct, or from experience? A recent study by Wildlife Conservation Society scientist Dr. Joel Berger reveals that several large prey species, including moose, caribou, and elk, fear only predators they regularly encounter. If you take away wolves, you take away fear. And with no need to flee prowling predators, the migrant animals change their use of an ecosystem, with penetrating impacts. Berger’s finding could help shape efforts to reintroduce large carnivores in places they have been exterminated.

The goal of wildlife reintroduction isn’t simply to save a species but to restore the natural balance and functions of wild places. For example, in Yellowstone, the disappearance of wolves and grizzly bears allowed moose to become sedentary and over-graze areas. In turn, the change in vegetation caused a decline in migratory birds such as warblers and hummingbirds, which had previously fed on the same plants. By contrast, when wolves returned to Yellowstone, their presence changed elk distribution and coyote densities, and caused moose to become more wary. Overall, the wolf reintroduction increased the region’s biological diversity.

“It is not just changes in climate or disease that may alter our big remote wild landscapes, but also the actions of conservationists and public agencies to restore ecosystems by bringing back native carnivores to where they once thrived,” said Berger.

Berger’s study looked at 19 areas including the Russian Far East, Greenland, Canada, and the U.S. The study demonstrated that both the loss and return of predators have implications for conservation and ecosystem integrity. The research comes at a time when wolves are to be down-listed from federal protection after more than $23 million was spent to re-establish them in the northern Rocky Mountains. The states of Wyoming and Idaho have already proposed plans that would allow for the killing of as much as 85 percent of the formerly protected wolves. Conservationists who succeeded in rekindling fear of predators in prey species have a new concern. Will enough wolves survive to maintain a balanced ecosystem?

Dr. Berger’s study is published in the latest issue of the journal Conservation Biology.

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