EDITORIAL: ‘Trophic cascade’ of effects Study says wolves play a role in saving other species

Science provides yet another insight into the positive impacts of healthy wolf populations on the landscape.

Wildlife biologists have understood for years the balancing effects that wolves have in ecosystems.

Among other things, these majestic predators play a vital role in the food chain by reducing coyote and cougar populations; by benefiting grizzly bears and other animals that feed on wolf kills; and by culling the sick and dying from deer and elk herds and restoring their natural foraging patterns.

Now, as wolf populations grow in Oregon and elsewhere throughout the West, it’s increasingly clear that wolves play an important role in saving other threatened and endangered species.

The Canada lynx is a case in point. The animal was listed as threatened in 2000 under the federal Endangered Species Act. At the time, scientists attributed the shrinking lynx population to a decline in the number of snowshoe hares, the primary food of the lynx. Other possible factors included attacks by coyotes, which also prey on hares, and habitat changes, including the shrinkage of the mountain snowpacks where the lynx find refuge.

In a study published Monday in Wildlife Society Bulletin, Oregon State University scientists say it appears that wolves are helping to restore the lynx population by reducing the number of coyotes, therefore ensuring that there are more snowshoe hares available for the lynx to eat.

Wolves roamed the Northern Rockies for centuries until they were exterminated across most of the West, including Oregon. The gray wolf was reintroduced into the region in 1995, and there are now more than 1,700 wolves in Idaho, Wyoming, Montana and Oregon — an impressive resurgence, but still a relatively small number for nearly 400,000 square miles of territory.

Before wolves were restored to the Rockies, the population of coyotes and other smaller predators expanded dramatically throughout the West and elsewhere in the country, including the Midwest.

Studies have shown these “mesopredators” had impacts on everything from rabbits and lizards to birds and rodents.

As wolves recovered, coyote populations declined — Yellowstone National Park’s coyote population initially dropped by 50 percent, scientists say. Fewer coyotes has meant more snowshoe hares for the Canada lynx and presumably, what scientists call a “trophic cascade” of effects on other species.

The OSU study underscores the importance of a successful legal challenge to an unprecedented move by Congress earlier this year that stripped gray wolves of their endangered status across most of the Northern Rockies. The move by federal lawmakers flew in the face of the Endangered Species Act’s purpose, which is to base protections on science and to leave such decisions to wildlife biologists and researchers.

Many scientists, environmental groups and other wolf advocates make a compelling argument that wolf populations across the Northern Rockies have not yet reached sustainable levels.

The intervention by Congress lifting protections puts not only the long-term survival of wolves at risk but, as OSU’s study indicates, the benefits that they provide for other threatened and endangered species as well.