Scientist Looks for Signs of Tourist-Induced Stress in Park Wildlife

Animals in Yellowstone National Park are under a microscope. They are watched by tourists, and by researchers studying their reaction to tourists.

One of those watching is Amanda Hardy, a graduate biology student from Montana State University, who wants to know whether elk and bison are stressed by having all eyes on them.

Finding the proper evidence is not easy when elk and bison often are not watching back. Often they just stand there, grazing away as hordes of snowmobilers cruise by.

The truth, she hopes, lies in the animals’ feces and urine, which she has collected over the last two winters to analyze for stress hormones.

Her research rejuvenates an old debate over whether tourists are loving their wildlife to death. But the answer is complex, largely because living in the wild is stressful as well.

The three-winter study stems from a lawsuit filed by the Fund for Animals and others that contended the National Park Service needed to adequately study its wildlife before creating policy on winter recreation.

Last week, the park service announced it was banning snowmobiles from most national parks. Key reasons include air pollution, noise and wildlife impacts. But it deferred a decision on Yellowstone and neighboring Grand Tetons until November, pending winter-use studies.

Winter is a popular season here for humans and wildlife, especially around Old Faithful. Bison and elk come to the geyser area to graze because the geysers are so hot they melt snow, revealing grass.

It is also the region that tourists converge on, and when blanketed by snow, its stark, surreal beauty makes it seem like another planet.

The result is something disturbing, perhaps for animals, but also for people who consider the fear of humans as a natural sign in wildlife.

“I’m sort of uncomfortable being so close to wild animals because I think it takes away some of their wildness,” said D.J. Schubert, a biologist for the Fund for Animals in Phoenix.

So far, Hardy has found that in the winter of 1998-1999, elks excreted more stress hormones on days when there were more tourists.

Winter visitor numbers are only a fraction of summertime tourism. But winter months are critical because the animals are at their most vulnerable, having eaten little food and using what little energy they have to keep from freezing or starving.

Tourists, although often seemingly ignored by wildlife, might be disquieting enough to sap animals of precious energy. Stress at the breaking point can cause creatures not to reproduce, or to die.

So far, no evidence exists of chronic levels of stress, at least in elk, which were studied because they are more likely to encounter visitors and don’t migrate like bison.

Adult female elk tracked for the study are breeding nearly at their maximum, which is a good sign, according to Bob Garrott, a wildlife ecology professor at Montana State University who is overseeing Hardy’s study and others for Yellowstone.

“It doesn’t look like it is chronic at this time,” Garrott said.

Conservationists say the study is important because winter recreation is rising. In January 1963, only three snowmobiles entered the park. Last winter, 62,531 snowmobiles cruised Yellowstone, and those passengers represented more than half the 130,564 visitors, according to park figures.

The highest year for winter traffic was the winter of 1993-1994, when there were 143,523 visitors, including 87,682 on snowmobiles.

Prior studies indicate that when it comes to frightening animals, cross-country skiers do more harm than snowmobilers because they can approach the animals quietly and stray from groomed trails.

Hardy is conducting her research in the busiest stretch of the park, the area around the West Entrance that consists of about 45 miles of prime snowmobiling road.

Hardy does not want to become part of the study and taint its conclusions. As a result, she tries to watch the animals from a distance. She waits for them to leave before collecting their droppings.

She also conducts surveys of how far the animals stay from the roads and trails, and keeps tabs on 35 radio-collared elk. The 36th elk was recently killed by a wolf.

“I’ve watched a lot of silly things. I saw a guy throw snowballs at an elk once,” Hardy said.

But even in the summer, when there is plenty of grass far away from crowds, some bison and elk stay put in the thick of visitors, near the traffic jams and snapping cameras.

“It almost comes down to personality,” Hardy said.

One explanation is that tourist hot spots are far from wolves and predators.

“I’ve wondered if these human-contact areas provide a predator shelter,” Hardy said.

Worse than camera-happy visitors, conservationists say, are the roads that are groomed in the winter to accommodate them.

Keeping the roads open allows too many bison to travel them easily, causing more bison to survive during the winter months and not allowing a natural die-off that creates carcasses for wolves to feed on, they contend. Also, the bison are being led down paths that contain sensitive plants and lead to Montana, which permits the shooting of stray bison suspected of carrying disease.

A separate study by MSU is examining how extensively bison use the groomed trails and what, if any, effect it is having. Those findings are expected to be released this spring.

“I think we could continue to have winter use of the park but pull back to focus on what is really special and unique instead of recreation, and protect Yellowstone resources, which we are not doing at this time,” said Mary Meagher, an expert on Yellowstone bison from Gardiner, Mont.

The project has taken Hardy, a 29-year-old biologist, dangerously close to a rockslide and swept her down a river she was trying to cross in teeth-chattering temperatures.

“There are cutoffs,” she said. “We don’t go out in anything past 25 degrees below, and we don’t cross any rivers beyond 10 below.”

Despite the rigors, Hardy conducts her study with a loving touch.

“Hi sweetie. Isn’t she beautiful?” she says, stopping her pickup truck on a road to view an elk. Both watch each other intently. Hardy takes some notes, then moves on.

Animals have their limits. Bison, some of the most low-key of the wildlife Hardy has observed, grind their teeth when stressed out. Once, Hardy was charged by a bison while cross-country skiing in the back country.

Humans also seem to have a breaking point, especially at the end of the day when they are in a hurry to get their snowmobiles back to the rental agency and are no longer impressed by the sight of wildlife.

“There’s so much wildlife here that by the end of the day, people are just seemingly cruising,” she said.