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.
Dan Whipple is a contributor to Writers on the Range, a
service of High Country News in Paonia, Colorado
(hcn.org). He is a writer in the Denver area of
Colorado.
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