Yellowstone National Park will likely face numerous threats from global climate change, including the loss of plants, wildlife and fishing, according to a report released Thursday.

The Rocky Mountain Climate Organization and the Natural Resources Defense Council collaborated on the study, which highlights the 25 national parks most threatened by the effects of human-caused greenhouse-gas emissions. Grand Teton National Park, although not one of the 25 listed, would face similar problems, the authors said.

In addition to a loss of plants, wildlife and fishing, Yellowstone is “vulnerable to loss of ice and snow, a loss of water, more downpours and floods ... and overcrowding,” the report said. “In the future, sadly, visitors to Glacier, Grand Teton and Yellowstone will be less likely to see snow-capped mountains in summer.” 

Plant communities, particularly at high elevations, could decline, according to the report’s authors.

“Temperature increases have been greater atop mountains than at lower elevations,” the report said. “As mountaintop temperatures warm, plants adapted for survival there may not be able to tolerate the changed conditions and may have no nearby higher, cooler environments in which to disburse.”

A phenomenon called “sudden aspen decline” is also attributed to climate change.

The authors also bring up the mountain pine beetle epidemic, which is killing large swaths of lodgepole and whitebark pine trees in the Greater Yellowstone Ecosystem. Many researchers think the epidemic is exacerbated by warmer temperatures associated with greenhouse gases.

In a teleconference, Stephen Saunders, president of the Rocky Mountain Climate Organization and one of the study’s authors, specifically mentioned Yellowstone’s grizzly bear population as one of the species most vulnerable to warming temperatures because of the mountain pine beetle’s impact on whitebark pine.

“The nut of the whitebark pine is the most important pre-hibernation food for grizzly bears,” he said.

Canada lynx, bighorn sheep and pikas are also vulnerable, according to the study. In Yellowstone, cold-water fish such as trout are particularly imperiled because thermal features also have a warming effect on the park’s rivers.

“[In 2007], in Yellowstone’s Firehole River, temperatures topped 80 degrees Fahrenheit for several days and as many as a thousand trout died in the largest documented fish kill in the park’s 135-year history,” the report said.

“Global warming is impacting our parks now,” said Theo Spencer, senior advocate for the Natural Resources Defense Council. “We need to show leadership as one of the world’s two biggest emitters of greenhouse gasses.”

Bill Wade, chairman of the executive council of the Coalition of National Park Service Retirees, called national parks the “canaries in the mine shaft” for not just species but the economic viability of surrounding communities.

“As we lose national parks or their character is changed, it could potentially have a direct economic impact on surrounding communities and elsewhere,” he said.

Saunders called climate disruption “the greatest threat that our national parks have ever faced.”

“The National Park Service has not yet done what needs to be done to address climate change,” he said.

The report isn’t all bad news. The authors came up with a list of recommendations to help stem climate change itself or to lessen its impacts, including more funding for parks, establishing migration corridors between parks and creating new parks.

“I actually am a raging optimist on the climate-change issue,” Saunders said. “Our country has dealt well with bigger problems before.”

The report is available at www.rockymountainclimate.org.