Biodiversity hotspots explained

Rainforest biodiversity and the protection of it depends ultimately on knowledge. Why do the tropics tend to possess greater biodiversity? Why do some areas of the tropical global belt, like certain sectors of the Amazon, have vastly more biodiversity than others? These questions are answered in a report published recently online in the journal Ecology Letters.

The study - led by John J Wiens, Associate Professor of Ecology and Evolution at Stony Brook University, New York - looks like it may well have unravelled a long standing mystery. For some 200 years, scientists have been scratching their heads over the issue of exactly why some areas of the planet have greater biodiversity than others.
Focusing its investigation on the evolution of tree frogs, the study found that a wealth of tree frog species is not explained just by the climatic conditions.
"We found that many tropical rainforest sites that are outside the Amazon Basin have no more species than do some sites in temperate North America," explained Professor Wiens.
"Tree frogs are a particularly important group to study for understanding amphibian diversity, because they can make up nearly half of all amphibian species in some rainforest sites. ........... at some sites in the Amazon rainforest, there are more tree frog species in a small area than there are across all of North America or Europe."
According to the report, the high biodiversity of Amazonian sites is related to different groups of tree frogs occurring together in the Amazon Basin for more than 60 million years. Tropical forest sites with relatively few tree frog species tend to be in areas more recently colonized by tree frogs.
Professor Wiens draws some wider conclusions: "The results suggest that the incredible biodiversity of amphibians in some sites in the Amazon Basin took more than 50 million years to develop .......................... if the Amazon rainforests are destroyed and the amphibian species are driven to extinction by human activities in the next few decades, it may take tens of millions of years for this incredible level of biodiversity to ever return."

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