A key scientific report about how wildlife respond to snowmobiles and snowcoaches in Yellowstone National Park recommends that park officials keep "traffic levels at or below those observed during the last three years."

But the preferred alternative of a newly published draft winter use plan recommends a daily cap of 720 snowmobiles in Yellowstone -- almost triple the average number of snowmobiles in Yellowstone (250) in the past three years.

"It amazes me how park officials are climbing out onto a limb and sawing it off," said Bob Seibert, former west district ranger for 14 years in Yellowstone. Seibert said low numbers of snowmobiles in recent years get the vast majority of credit for improved conditions in the parks, "so why are they pushing for more?"

Yellowstone and Grand Teton officials meet this morning in Cody with "cooperating agencies" -- representatives of surrounding counties and the states of Wyoming, Montana and Idaho -- to explain how Park Service officials came to prefer an alternative which essentially extends the primary points of its current temporary winter plan. The plan limits the numbers of snowmobiles to the previous cap of 720 per day in Yellowstone and 140 per day in Grand Teton and the John D. Rockefeller Jr. Memorial Parkway; requires best available technology to limit noise and air pollution; and requires commercial guides within Yellowstone itself.

In addition, the preferred alternative would limit snowcoaches in Yellowstone to 78 per day, requiring those vehicles to meet sound and emissions requirements -- a new condition. The plan would also close Sylvan Pass to all motorized winter use because of safety concerns about avalanches.

The report about how wildlife responds to snowmobiles and snowcoaches said that "bison respond less frequently (20 percent) to snowmobiles and coaches than swans (43 percent), elk (52 percent), coyotes (61 percent), or bald eagles (83 percent) due to fewer vigilance responses." A vigilance response is defined as movement in reaction to the appearance of over-snow vehicles.

The report further noted that as winters wore on, bison seemed to become more habituated to vehicles, while elk exhibited greater sensitivity.

And in a passage that should comfort snowmobile advocates, the scientists who conducted the study said, "There was no evidence that snowmobile use during the past 35 years adversely affected the demography or population dynamics of bald eagles, bison, elk, or trumpeter swans ... Thus, we suggest regulations restricting levels and travel routes of (over-snow vehicles) were effective at reducing disturbances to these wildlife species below a level that would cause measurable fitness effects."

Greg Mumm, executive director of Blue Ribbon Coalition, an advocate for recreational vehicle use, said that comment is in line with "common sense observations" made by snowmobilers.

"I'm no scientist, but wildlife do seem to habituate to their surroundings," he said.

That misses the point, said Bill Wade, executive director of the Coalition of National Park Service Retirees.

"There are two kinds of disturbance to wildlife," he said, "and greater emphasis has been put on the disturbances that result in animals fleeing" from snowmobiles and snowcoaches.

The other disturbance is habituation -- wild animals becoming used to humans and over-snow vehicles, he said. "It is almost worse to have habituation," said Wade, because wild animals are changing their natural behavior in response to human activity.

Either way, disturbance that leads to fleeing or habituation is unnatural, he said. And no disturbance of wildlife is the legal mandate of the Organic Act that founded the National Park Service, as well as the management policy recently reaffirmed by Interior Secretary Dirk Kempthorne, Wade said.

Seibert said interactions between people and wildlife have improved since the old days when more than 1,000 snowmobiles could run through Yellowstone on a given day.

"That's when we had what was termed the 'bison ping-pong' effect" -- bison fleeing down a road from a swarm of snowmobiles, only to reverse course when they encountered a swarm from the other direction, he said.

"Why we never had people get hurt is just amazing," he said.

What is still unknown to scientists is how wildlife are responding internally to the stress created by encountering over-snow vehicles, Seibert said.

"We should be erring on the side of conservation," he said.

NewsTracker

* Last we knew: The National Park Service has proposed essentially maintaining the current restrictions on snowmobiling in Yellowstone and Grand Teton national parks.

* The latest: A scientific report recommends winter traffic levels "at or below those observed during the last three years."

* What's next: Park officials meet today in Cody with officials from surrounding states and counties.