Ever since he ate Little Red Riding Hood’s grandma and blew down the houses of two-thirds of the little pigs, the wolf has been Big and Bad. Everyone knows what big teeth he has.
But can those gleaming incisors explain the startling decline of elk herds in the Yellowstone area?
Some people think so. Hunters and some wildlife managers are howling that the wolf, reintroduced into the ecosystem in 1995, is responsible for the roughly 50 percent decline in the northern Yellowstone elk herd.
Here are the numbers, as compiled by the Northern Yellowstone Cooperative Wildlife Working Group: In December 2006, there were 6,738 elk on Yellowstone’s northern range. This was lower than the January 2005 number of 9,545, and it’s a whole lot lower than the 19,359 elk counted in January 1994, the year before wolves were introduced.
Case closed, then. Before wolves, nearly 20,000 elk; after wolves, less than 7,000. Wolves are obviously a threat to both elk and the hunters who want to kill elk.
But upon closer examination, that conclusion is premature at best. “People give wolves these supernatural powers,” says Ed Bangs, Yellowstone wolf recovery coordinator. “It’s not about reality, and it’s not about wolves. It’s about what people think reality is and how they perceive wolves.”
One reality is that the state of Montana deliberately reduced the Yellowstone area elk population by issuing a larger number of hunting permits. The state made that decision because 19,000 elk – or even 9,000 – can’t be supported by the area. In fact, the Montana elk plan calls for a winter population that’s only 3,000-to-5,000 elk north of the park.
Another reality is the climate. In a 2005 paper in the journal Oikos, Michigan Tech University biologist John Vucetich and coauthors found that drought and hunters killing elk accounted for almost all of the decline in elk in the northern Yellowstone area between 1995 and 2004. But they considered hunting much less an impact than drought, estimating that for every elk shot by hunters, the population declined by 1.55 elk.
“To the extent that harvest and climate largely account for the decline in elk abundance,” they wrote, “wolf predation would have been ... numerically minor.”
Which is not to say wolves have no effect on game populations. Each adult wolf kills an average of 22 elk a year. There are now about 96 adult wolves in Yellowstone, so they take just over 2,000 elk a year. But the overall impact on population is less than the total number would suggest, because research shows that wolves often kill prey animals that are less likely -- for one reason or another -- to contribute to the elk gene pool in the following year. If the elk population is declining, wolf predation may accelerate the decline. If it’s growing, they may slow the growth.
One thing is sure: Wolves cause their prey to act more like wild animals. Elk spend a little more time in cover in the presence of wolves, and are more wary on open ground. This chivvying around has other impacts as well: It makes it harder for hunters to find them.
Oregon State University forestry professors William Ripple and Robert Beschta found that wolves prevent elk from spending too much time in Yellowstone’s degraded stream banks and riparian areas munching on tender saplings, with the result that these areas are recovering nicely from years of overgrazing. Ripple and Beschta call this situation, unfortunately, “the ecology of fear,” which may spur wolf advocates to come up with a happier description.
Before the federal government brought wolves back to Yellowstone, there was one beaver dam in Yellowstone. Now there are 10, because willows are growing better. Beavers have something to eat, streams are healthier, and we can thank wolves for the improvement.
The wolf controversy “isn’t about wolves or predators,” says Bangs. “This is about human values and what people think they want. People want to reduce elk density by shooting elk, not by having wolves. It’s a social and philosophical question. How much hunter success is enough? How much do you share with mountain lions and grizzly bears and wolves? The questions aren’t really biological.” For now, at least, we can’t target wolves as the primary elk killers. Blame that old standby, the weather, and Montana hunting policy for baring the bigger teeth.