YELLOWSTONE NATIONAL PARK -- While bear biologists readily acknowledge how important whitebark pine nuts are to grizzly bears, they also say that a reduction in this key food can be offset by the bear’s use of other foods.

Some conservationists, however, say that is a dangerous assumption, one which could endanger the animals recently removed from federal Endangered Species Act protection. That's because the whitebark pine is continually hammered by drought, blister rust and a global warming-accelerated outbreak of mountain pine beetles, which shows no sign of abatement.

“Regarding the level of science information on the whitebark pine and the mountain pine beetle, I wouldn’t send the delisting document out for review -- I’d return to the author for more work," said Jesse Logan, a retired entomologist for the U.S. Forest Service. “It is more than sloppy science. It is misleading science.”

 Those harsh words, made before reporters at a pine beetle workshop sponsored by the Natural Resources Defense Council last month, are backed by a formal declaration from Logan. He has a doctoral degree in entomology from Washington State University and has special expertise in modeling mountain pine beetle population dynamics for the Forest Service.

The Interagency Grizzly Bear Study Team says whitebark pine seeds are arguably the most important fattening food available to grizzly bears during late summer and fall.

Logan has published more than 100 scientific articles, and many of the publications dealt directly with the effect of weather and climate on mountain pine beetle activity in whitebark pine. The federal government's grizzly bear delisting document cites his work.

However, “in my professional opinion, the delisting decision does not employ the best available science regarding (mountain pine beetle) and whitebark pine, and reaches conclusions (that) are not consistent with the best available science or my own scientific work," Logan said.

Among the issues where Logan finds fault:

* “In general terms, much of the scientific foundation of the document is obsolete.” He says the catastrophic loss of whitebark pine in the greater Yellowstone ecosystem is a recent and fast-moving event -- so much that scientific literature no longer reflects reality in the field.

* “Estimates made of mountain pine beetle impacts on whitebark pine, the adequacy of statistical methods used to estimate mountain pine beetle caused mortality, and the adequacy of future monitoring of mountain pine beetle mortality are misleading, made on faulty assumptions, and do not employ best science principles and/or technology.”

Chris Servheen, who has been the grizzly bear recovery coordinator for the U.S. Fish and Wildlife Service for the past 23 years, was asked in an e-mail if he had any comments or rebuttals, in general or specifically, about Logan’s declaration. Servheen responded, “Can’t do that.”

He did, however, write that while climate change is changing whitebark pine distribution and abundance, there's no indication that decline will be catastrophic for grizzlies.

“There are changes happening in the ecosystem,” Servheen wrote. “Natural systems are always a dynamic situation.”

As an example, he noted that blister rust has all but eliminated whitebark pine in the northern Continental Divide ecosystem in northwest Montana, which has a minimum count of 545 bears and is expanding -- an indication that bears can flourish without whitebark pine nuts.

“We know there will be significant changes in whitebark pine due to climate change,” Servheen wrote. “The issue is not if there will be declines in whitebark pine due to climate change. The issue is how grizzly bears will respond to these changes. Can we detect these grizzly responses, and can we develop management responses as necessary to address the needs of the bears? We believe we have a system in place to do exactly these things.”

Louisa Willcox, Wild Bears Project director for the Natural Resources Defense Council in the Yellowstone ecosystem, disagrees with the comparison of Yellowstone and northern Montana bears.

Yellowstone bears have survived poor whitebark pine cone production years, but they've never seen bad years that go on and on and on, she said. Besides, northwest Montana has a different suite of foods than Yellowstone, including berries, and high-calorie whitebark pine seeds can’t be replaced with lower-calorie foods including roots.

Diana Six, an entomologist based at the University of Montana, said she was troubled by how bear biologists have looked at the rapidly changing world of whitebark pine and mountain pine beetles.

Six said she’d received a call from Servheen, a fellow faculty member at the University of Montana. “I told him what I’d seen (regarding mountain pine beetle attacks on whitebark pine). The impression that I got from him is that these outbreaks come and go, that they’re a natural part of the system.”

Six said the current situation is anything but normal. “Mountain pine beetles are acting like an exotic invader,” she said.

“We have this huge disconnect between bear biologists and entomologists,” said Doug Honnold, lead attorney for the EarthJustice environmental law firm in Bozeman, Mont., and a critic of grizzly bear delisting.

Honnold said the Endangered Species Act requires a predictive analysis, looking ahead a century to see whether there are serious threats to a species’ continued existence. The grizzly bear delisting document, he said, is very much a retrospective look at where the bear has come from, rather than where it is going.

Looking back, Honnold said, the grizzly has made great progress, but looking forward, there are great dangers to the grizzly -- most notably threats to its habitat and to key food sources including the whitebark pine.