Wolf populations elsewhere provide clues to state’s future
By JOSEPH DITZLER
East Oregonian Publishing Group
Wolves, as they reclaim their role as top predators in Oregon, may change the landscape in ways anyone can see, according to scientists who study wolves and their environment.
Wolves encroaching from Idaho and Washington already live in Eastern Oregon in the Wallowa-Whitman and Umatilla national forests. But in terms of prime habitat, they may be more at home in central Oregon, on the eastern slope of the Cascade Mountains, according to a 2006 study by Ted Larsen, at the time an Oregon State University graduate student in landscape ecology.
“Their habitat is confined to where there’s food available, where there’s prey, and where human density is at a minimum,” said Larsen, now a contractor for the U.S. Environmental Protection Agency. “A study in Wisconsin found road density was a key factor.”
Road density? Not that wolves are fearful of crossing asphalt, but roads indicate human activity. The more roads, the more humans and the fewer wolves. The number of roads criss-crossing the environment, the number of prey animals present and the number of humans living in the area are all factors in determining good wolf habitat, Larsen said. But two factors rose above the rest, he said.
“Public lands and forest cover came out to be the most significant habitat indicators,” he added.
1,450 potential wolves
Larsen calculated that Oregon has 42,564 square miles of potential wolf habitat, enough to support a population of 1,450 wolves. This year, the Oregon Department of Fish and Wildlife officially counted 25 wolves but admits there are more. Confirming actual numbers of the elusive beasts is a challenge.
In Eastern Oregon, where four packs already roam, the landscape itself may change appearance over time due to their influence, said a research scientist familiar with wolf ecology. Bill Ripple and Robert Beschta, both of Oregon State University, studied the impact of wolves on Yellowstone National Park after the animals’ reintroduction there in 1995. Wolves, they wrote, created a “landscape of fear,” in which elk, once free to graze and browse indiscriminately, now must remain vigilant, heads held high and constantly on the move.
Aspen and willow, under less pressure from elk, recovered in the park. Likewise, Ripple said, he noticed a change in the landscape along streams. More trees and shrubs grew along the streams, which gave cover to small mammals and homes to beavers, which, in turn, created stream habitat for fish.
The phenomenon is called “trophic cascade,” in which the presence of a top predator creates an effect that cascades downward through the food chain. Open spaces, like mountain meadows, for example, began to fill in again with trees and shrubs, said Cristina Eisenberg, another of Ripple’s former graduate students and author of a book, “The Wolf’s Tooth: Keystone Predators, Trophic Cascades, and Biodiversity.”
Eisenberg said a meadow outside her home, a place where her family held picnics, since wolves returned has changed from close-cropped grass to trees and shrubs.
Wolves and humans
Catching sight of a wolf may be more difficult.
Wolves tend to avoid people but create conflict with them when they attack livestock animals and pets. Attacks on people, however, are rare. Eisenberg said she raised two children in wolf county without a worry.
“As a wolf biologist, I’ve been collaring wolves for several years, and have had hundreds of encounters,” she said. “I’ve not felt any threat; not once have I felt any kind of threat.”
In Minnesota, where wolves began a comeback in the 1970s, no wolf attacks on humans have been recorded in modern times, said Dan Stark, a large carnivore specialist for the Minnesota Department of Natural Resources. “There have been some incidents where they’ve documented some contact, but I think they’re pretty much explained by interaction with dogs,” he said.
Minnesota’s northern third holds the highest density of wolves in the Lower 48 states, 3,000 wolves over 35,000 square miles, Stark said. Much of it is forested public land that is logged, he said. Minnesota, unlike Oregon, does not have livestock grazing on public lands.
“We have estimates that there are maybe 7,000 farms, livestock producers, within wolf range,” Stark said. About 100 livestock animals, mostly calves, are eaten each year by Minnesota wolves. In response, the government removes 150-200 wolves annually, he said.
Wolf numbers are regulated in nature by the numbers of available prey animals, which are in turn regulated by the numbers of wolves in their environment, Eisenberg said. “It’s a total fallacy” that wolves wipe out all game species like elk and deer. Game species are managed like food crops for hunters, in numbers much higher than existed before the frontier was tamed, she said.
Elk numbers will decline but eventually stabilize, Eisenberg said. They won’t stay the same, but will find a dynamic equilibrium, rising and falling in numbers like a wave.
“It happens if humans are not involved and we let wolves and elk do their thing,” she said.