Between 80 and 100 percent of livable habitat will disappear from a major panda enclave in China.
Climate change is likely to decimate bamboo populations in an isolated region of China that serves as home for nearly 20 percent of the world's wild giant pandas.
As a result, according to new projections, between 80 and 100 percent of livable panda habitat will disappear from the region in China's Qinling Mountains by the end of the 21st century.
The new findings illustrate how environmental impacts can reverberate through the food web.findings
"Ninety-nine percent of food that pandas eat in the wild is bamboo," said Jack Liu, an ecologist at Michigan State University in East Lansing. "If there's no bamboo, then pandas can't survive."
"I think probably there is hope, but only if we take active measures at once," he added. "If we don't, then probably not. It really depends on what we will do."
With fewer than 1,600 individuals left living in the wild, giant pandas are one of the most endangered species in the world. But most panda-conservation research has focused on human impacts, said Liu, who has been studying pandas and their habitats for 17 years.
To find out what kind of influence climate change might have on the adorable fur-balls, he and colleagues zeroed in on the Qinling Mountains, which provides about a quarter of available habitat for wild pandas.
Using a wide range of climate models, the researchers projected likely changes in three main species of bamboo, which make up more than 90 percent of bamboo in the region. Bamboo plants are highly sensitive to temperature changes.
Under every scenario, the researchers report today in the journal Nature Climate Change, dramatic declines in bamboo would likely spell big trouble for pandas. Estimates for how much suitable habitat would disappear ranged from 80 to 100 percent, depending on the climate scenario used.
Despite the relatively large amount of panda habitat currently available in the Qinling Mountains, the region is isolated from other suitable habitats. That means that if their food source were to disappear, pandas that live there would have nowhere else to go. The region's remoteness also makes it unlikely that new species of bamboo would be able to get their seeds there.
The results suggest that conservationists must consider climate change as well as human impacts when planning how best to protect pandas, Liu said. One possible solution would be to cultivate and plant heat-tolerant bamboo in the region.
But even if researchers find bamboo that will continue to grow with warming, said Stanford ecologist Terry Root, they'd also need to ensure that pandas could get sufficient nutrients from those plants. And that's not necessarily a sure thing.
Because pandas are so charismatic and popular, Root added, they provide a poignant example of scenarios happening to all sorts of species all over the world.
"Most biologists think we're standing on the edge of a mass extinction event," she said. "If pandas can bring attention to that, it's absolutely fantastic. This is a horrible thing to say, but I think this is a wonderful study because what it's doing is showing us how we need to actually understand what we're doing to the climate, because we're not just doing it to the climate."
Again and again, ecologists are documenting how changes to one species create domino effects that resonate through the rest of the ecosystem in unexpected ways.
"It's going on all over the place, we just haven't noticed it," Root said. "Actually noticing it in an iconic species like the panda is super unfortunate, but maybe it will get people to understand what's going on. It's a wake-up call."