Climate change may threaten biodiversity in tropics

As a result, lowland populations in the tropics may soon experience decreases in biodiversity and species richness, in part because no other species are adapted to the climate.

And species at higher elevations may run out of room to climb higher.

Colwell said the projection contradicts the assumptions of many researchers, who believe species in the tropics would not be affected as harshly by climate change.

"The current conventional wisdom even among scientists is that tropical species will be OK despite global warming because in ancient times -- 5 to 50 million years ago -- the climate was warmer and there were tropical forests," he said.

"We argue this is not so clear. That there needs to be much more research done to see if this is the case," he said.

In a separate study in the same journal, researchers at the University of California-Berkeley compared recent changes in small mammal populations at Yosemite National Park in California to a study done in 1918.

Not surprisingly, they found mammals like shrews, mice and ground squirrels have moved to higher elevations or clustered themselves in smaller, more hospitable regions.

They saw shifts in about half the species studied.

So far, the population movements have not changed the biodiversity in the park, the researchers said, but they have changed the populations of animals interacting with one another.