Study sees huge climate threat to tropical cloud forests

No place to go …

Tropical mountain forests in Australia could be nearly wiped out by global warming before the end of the century. Photo via the Wet Tropics Management Authority, Australia.

Staff Report

FRISCO — Scientists have long warned that mountain ecosystems are especially vulnerable to climate change, because as temperatures warm, species adapted to living atop mountains just won’t have anywhere to go.

A new study by Australian scientists appears to confirm those fears, concluding that the cloud forests in tropical forests are the most at risk. Many tropical, mountaintop plants won’t survive global warming, even under the best-case climate scenario.

The research, conducted by scientists with James Cook University and the Australian Tropical Herbarium focused on the Wet Tropics World Heritage Area in Queensland, which is projected to almost completely lose its ability to host the endemic plants that grow 1000 metres or more above sea level. by 2080.

Lead researcher Dr. Craig Costion said the findings have important implications for some rare and ancient species.

“They already live on mountain tops, they have no other place to go,” Costion said. “Our study indicates that the current climate on Queensland’s mountaintops will virtually disappear. What we don’t know is if these plants can adapt,” he said

The scientists looked at 19 plant species in the tropics found at least 1000 meters above sea level. They modeled three climate change scenarios in the region, ranging from conservative to extreme.

They found that, by 2040, the climate niche the species grow in would decline anywhere between a minimum of 17 percent and a maximum of 100 percent. By 2080, even using conservative assumptions, nearly half of the plants would not have what the scientists believe is a survivable climate.

The data show that between 2040 and 2060 eight to 12 species will be at risk of extinction. By 2080 no suitable habitat will exist within the region for 84 percent of the species studied under any emissions scenario.

Costion said there were some caveats on the findings. The researchers looked only at endemic trees and shrubs found solely above 1000 meters and for which there were the best records. They didn’t consider reasons for their presence on mountaintops apart from climate suitability. But Dr Costion said he was confident the scientists were not being alarmist.

“The 19 species represent most of the plants that are restricted to that habitat. It’s highly likely they are found only there because of the climate. There are plenty of other similar soil and substrate environments at lower elevations where they could grow but the climate is unsuitable,” Costion said.

The findings show well managed conservation reserves may be safe from many threats, but not from climate change, with the Wet Tropics World Heritage area seriously exposed, said co-author Professor Darren Crayn.

“The tropics contain most of the world’s biodiversity, and tropical mountains are particularly rich in unique and rare species. Managing for global threats such as climate change requires much better information. A redoubling of research efforts on these poorly understood landscapes would pay great dividends,” Crayn said.


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