Tropical rainforest and mountain species may be threatened by glob...( STORRS CT Contrary to conventional ...)

STORRS, CT Contrary to conventional wisdom, tropical plant and animal species living in some of the warmest places on Earth may be threatened by global warming, according to an article by University of Connecticut Ecologist Robert K. Colwell and colleagues in this week's (Oct. 10) issue of Science magazine.

As Earth's climate has warmed in recent decades, the geographical ranges of well-studied bird, butterfly, and plant species in the US and Europe have moved northward, following the gradual northward shift of their familiar climates. Other studies have shown that species in the US 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 warming climate on tropical plants and animals. Colwell's article in Science magazine this week may change that.

The report points out that tropical climates have warmed too (more than 3/4 degrees Centigrade [1.4 degrees Fahrenheit] since 1975), and climate models predict an additional increase of more than 3 degrees Centigrade (nearly 6 degrees Fahrenheit) over the next century in the tropical forests of Central and South America. This much warming would shift temperature zones uphill about 600 m (nearly 2000 feet) in elevation above sea level. Tropical species, like those at higher latitudes, will likely be driven to higher elevations by these changes, following the climate zones they are suited for.

Working their way up the forested slopes of a Costa Rican volcano rising nearly 3000 m (10,000 ft) above the coastal plain, Colwell and colleagues have collected data on the altitudinal ranges of nearly 2000 species of plants and insects.

They report that about half these species have such narrow altitudinal ranges that a 600 m (2000 ft) uphill shift would move these species into territory completely new to them, beyond the upper limits of their current ra
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