Tropical plant and animal species living in some of the warmest places on Earth may be threatened by global warming, according to an article in the Oct. 10 issue of journal Science.

As the Earth's climate has warmed in recent decades, the geographical ranges of well-studied bird, butterfly and plant species in the United States and Europe have moved northward, following the gradual northward shift of their familiar climates, said the article by Robert Colwell and his colleagues from the University of Connecticut.

Other studies have shown that species in the United States and Europe have shifted to higher elevations as temperature zones on mountains have moved upward.

In contrast, surprisingly little attention has been given to the effects of a warming climate on tropical plants and animals.

The report pointed out that tropical climates have warmed by more than 0.75 degrees centigrade since 1975, and climate models predict an additional increase of more than 3 degrees centigrade over the next century in the tropical forests of Central and South America.

This much warming will shift temperature zones uphill about 600 meters in elevation above sea level. Tropical species, like those at higher latitudes, will likely be driven to higher elevations by these changes, from the climate zones they are suited for, it said.

Forest turned fields are seen on the flank of hills in the northern province of Samneua in April 2008. Global warming is driving tropical plant and animal species to higher altitudes, potentially leaving lowland rainforest with nothing to take their place, ecologists argue in this week's issue of Science. [Agencies]

The researchers collected data on a 3,000-meter altitudinal range of nearly 2,000 species of plants and insects. They reported that about half of these species have such narrow altitudinal ranges that a 600-meter uphill shift would move these species into territory completely new to them, beyond the upper limits of their current ranges on the mountainside. But many may be unable to shift -- most mountainside forests in the tropics have been severely fragmented by human land use.

Only further research can estimate the risk, but the impact of global climate change on some tropical rainforest and mountain species could be significant, the report said.

(Xinhua News Agency October 10, 2008)