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Elk not ruining the park, scientists say
BY MIKE STARK, Gazette Wyoming Bureau
3/27/02
Stepping into a debate that's been churning for more than eight decades, the nation's top scientific panel says Yellowstone National Park's northern range isn't overrun with elk or being grazed to death.
The long-awaited report from the National Research Council, the research arm of the National Academy of Sciences, was intended largely to answer criticism that there are too many elk in the northern region, that grasslands are deteriorating beyond recovery and that erosion has been abnormally accelerated.
"The report says that we've got the science on hand to show that isn't the case," said John Varley, Yellowstone's chief scientist. "Fifteen years ago, our critics were saying this place was, ecologically, going to hell in a hand basket. And now the NRC is saying, well, no."
The 158-page report released Tuesday is not an examination of policies at Yellowstone, but of whether park officials have the science to back up their policies.
"One clear and important message is as far as we can tell, ungulates are not causing severe and irreversible damage to the greater Yellowstone ecosystem," said David Policansky, the NRC's director for the Yellowstone study.
Though Yellowstone managers were vindicated on some issues in the report, they drew criticism on a few others.
The scientific panel said Yellowstone researchers don't have enough evidence to back up their claim that climate changes over the last century are a major factor in the decline of aspens in the park.
"The committee could find no evidence that weather changes are responsible for that," Policansky said.
The panel said the park falls short in its research on willows and struggling aspen populations.
"We knew we had a long way to go on the aspens and willows," Varley said, but he said the criticism on climate research came as a surprise. "I thought our evidence was stronger than that."
Though not faulting management at the park, the report also points out concerns over declining pronghorn antelope populations and sagebrush near the northern boundary that's dying out.
Varley said he hopes Tuesday's report will finally quiet some of the criticisms that have swarmed around the effects of elk.
"In a perfect world, we'd hear the end of two things: 'too many elk' and 'overgrazing.' But that isn't going to happen," Varley said. "It'd be nice if we could squeeze down the rhetoric a little and get down to a discussion of the facts."
Years in the making
After years of intense debate, Congress in 1998 asked the National Academy of Sciences to delve into questions about Yellowstone's northern range. The research council recruited the nation's top experts - most of them from universities across the country - to volunteer their time on the study, Policansky said.
The report was subjected to "exhausting and exhaustive review," he said.
Most of the emphasis was placed on how the northern ecosystem has been affected by the Park Service's "natural regulation" approach, or "letting nature make most of the decisions," as Varley characterized it.
Specifically, the science panel wanted to see what effect elk and bison were having on the landscape and vegetation.
Some of the criticism that the north range was being overgrazed stemmed from comparing areas within the park to nearby ranches, Policansky said. "But the goals of each of those are different," he said - one is for production for human uses, the other for preservation of a natural environment.
Still, increasing elk and bison populations over the past few years have prompted questions over Yellowstone's natural regulation policy. Some worried that the northern winter range was being overgrazed and that areas along streams and rivers were suffering.
Clearly the animals have had an effect, but Tuesday's report concludes that any degradation of the landscape falls within a "natural range of variability."
The northern range, the report said, "is not on the verge of crossing some ecological threshold beyond which conditions might be irreversible."
There are lingering questions, though, over a severe reduction in the number of aspens in the northern range.
"Aspen are not regenerating because they're being eaten, primarily by elk," Policansky said.
Though there's a large stock of tree-sized aspen that are more than 80 years old, the species could die out if more young ones don't get a chance to grow, the report said.
Scientists speculated that aspen may have flourished until about 1920 because elk migrated out of the park in severe winters and gave the trees a chance to grow. Wolves also may have reduced the elk population or forced them to move around the park more.
Under that theory, the recently reintroduced wolves may allow more aspens and willows to flourish, the report said.
"Wolves are a very interesting wrench thrown in the works. I don't mean to say it's unnatural," Policansky said, "but it will change things. It's really unpredictable."
To find out whether fewer elk would boost aspen growth, the report suggested that wildlife managers could experimentally reduce the number of elk outside of the park through increased hunting. Though it might be a popular move among hunters, it could muddle what researchers know about the wolves' effect on elk.
Inside the park, the panel suggested fencing in aspens rather than taking the more extreme measure of allowing elk to be hunted.
Shaping the future
The report also focused on public perception.
The park might be better served if it did away with a formal natural regulation policy because it seems to create so much debate, the study said. Not only is the term interpreted in many ways, Policansky said, but "it makes people focus on whether the policy is being adhered to."
Instead, the scientists suggested simply practicing natural regulation and "maybe then there'd be more debate on simply whether it's working," he said.
The panel also said the park should do more to educate the public about the experiments that are being conducted and how they might shape how the park is run.
"You need to have people understanding how complicated things are," Policansky said.
Varley added that the report gives the park some good marching orders, especially its recommendations about what areas need more study. That includes looking at climate changes, sagebrush reductions near the park boundary, struggling aspens and willows and declining pronghorn populations.
"They form the research agenda for the next 10 or 15 years, and we'll be pursuing them," Varley said.
BY MIKE STARK, Gazette Wyoming Bureau
3/27/02
Stepping into a debate that's been churning for more than eight decades, the nation's top scientific panel says Yellowstone National Park's northern range isn't overrun with elk or being grazed to death.
The long-awaited report from the National Research Council, the research arm of the National Academy of Sciences, was intended largely to answer criticism that there are too many elk in the northern region, that grasslands are deteriorating beyond recovery and that erosion has been abnormally accelerated.
"The report says that we've got the science on hand to show that isn't the case," said John Varley, Yellowstone's chief scientist. "Fifteen years ago, our critics were saying this place was, ecologically, going to hell in a hand basket. And now the NRC is saying, well, no."
The 158-page report released Tuesday is not an examination of policies at Yellowstone, but of whether park officials have the science to back up their policies.
"One clear and important message is as far as we can tell, ungulates are not causing severe and irreversible damage to the greater Yellowstone ecosystem," said David Policansky, the NRC's director for the Yellowstone study.
Though Yellowstone managers were vindicated on some issues in the report, they drew criticism on a few others.
The scientific panel said Yellowstone researchers don't have enough evidence to back up their claim that climate changes over the last century are a major factor in the decline of aspens in the park.
"The committee could find no evidence that weather changes are responsible for that," Policansky said.
The panel said the park falls short in its research on willows and struggling aspen populations.
"We knew we had a long way to go on the aspens and willows," Varley said, but he said the criticism on climate research came as a surprise. "I thought our evidence was stronger than that."
Though not faulting management at the park, the report also points out concerns over declining pronghorn antelope populations and sagebrush near the northern boundary that's dying out.
Varley said he hopes Tuesday's report will finally quiet some of the criticisms that have swarmed around the effects of elk.
"In a perfect world, we'd hear the end of two things: 'too many elk' and 'overgrazing.' But that isn't going to happen," Varley said. "It'd be nice if we could squeeze down the rhetoric a little and get down to a discussion of the facts."
Years in the making
After years of intense debate, Congress in 1998 asked the National Academy of Sciences to delve into questions about Yellowstone's northern range. The research council recruited the nation's top experts - most of them from universities across the country - to volunteer their time on the study, Policansky said.
The report was subjected to "exhausting and exhaustive review," he said.
Most of the emphasis was placed on how the northern ecosystem has been affected by the Park Service's "natural regulation" approach, or "letting nature make most of the decisions," as Varley characterized it.
Specifically, the science panel wanted to see what effect elk and bison were having on the landscape and vegetation.
Some of the criticism that the north range was being overgrazed stemmed from comparing areas within the park to nearby ranches, Policansky said. "But the goals of each of those are different," he said - one is for production for human uses, the other for preservation of a natural environment.
Still, increasing elk and bison populations over the past few years have prompted questions over Yellowstone's natural regulation policy. Some worried that the northern winter range was being overgrazed and that areas along streams and rivers were suffering.
Clearly the animals have had an effect, but Tuesday's report concludes that any degradation of the landscape falls within a "natural range of variability."
The northern range, the report said, "is not on the verge of crossing some ecological threshold beyond which conditions might be irreversible."
There are lingering questions, though, over a severe reduction in the number of aspens in the northern range.
"Aspen are not regenerating because they're being eaten, primarily by elk," Policansky said.
Though there's a large stock of tree-sized aspen that are more than 80 years old, the species could die out if more young ones don't get a chance to grow, the report said.
Scientists speculated that aspen may have flourished until about 1920 because elk migrated out of the park in severe winters and gave the trees a chance to grow. Wolves also may have reduced the elk population or forced them to move around the park more.
Under that theory, the recently reintroduced wolves may allow more aspens and willows to flourish, the report said.
"Wolves are a very interesting wrench thrown in the works. I don't mean to say it's unnatural," Policansky said, "but it will change things. It's really unpredictable."
To find out whether fewer elk would boost aspen growth, the report suggested that wildlife managers could experimentally reduce the number of elk outside of the park through increased hunting. Though it might be a popular move among hunters, it could muddle what researchers know about the wolves' effect on elk.
Inside the park, the panel suggested fencing in aspens rather than taking the more extreme measure of allowing elk to be hunted.
Shaping the future
The report also focused on public perception.
The park might be better served if it did away with a formal natural regulation policy because it seems to create so much debate, the study said. Not only is the term interpreted in many ways, Policansky said, but "it makes people focus on whether the policy is being adhered to."
Instead, the scientists suggested simply practicing natural regulation and "maybe then there'd be more debate on simply whether it's working," he said.
The panel also said the park should do more to educate the public about the experiments that are being conducted and how they might shape how the park is run.
"You need to have people understanding how complicated things are," Policansky said.
Varley added that the report gives the park some good marching orders, especially its recommendations about what areas need more study. That includes looking at climate changes, sagebrush reductions near the park boundary, struggling aspens and willows and declining pronghorn populations.
"They form the research agenda for the next 10 or 15 years, and we'll be pursuing them," Varley said.
