A FUNGAL epidemic that is wiping out amphibian populations could be driven by global warming.
Alan Pounds at the Monteverde Cloud Forest Reserve in Costa Rica and his colleagues have found a strong correlation between the timing of frog extinctions and changes in sea surface and air temperatures in the tropical mountains of Central and South America.
Increased cloud cover in the mountains is making for cooler days and warmer nights. These conditions favour the growth of the pathogenic fungus Batrachochytrium dendrobatidis, which thrives between 17 and 25 掳C (Nature, vol 439, p 161). The fungus dehydrates its victims and is believed to have driven 74 out of 110 species of Atelopus harlequin frogs to extinction in recent years.
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Pounds had suspected that the sudden proliferation of B. dendrobatidis might be linked to climate change, but the exact relationship was unknown (New Scientist, 8 May 1999, p 32). 鈥淕lobal warming is loading the dice in favour of this disease-causing fungus,鈥� he says.
Shifts in host-parasite interactions caused by climate change could pose a greater threat to biodiversity than had previously been imagined. Estimates that a quarter of land animals and plants may suffer climate-related extinction by 2050 are now looking conservative, Pound says.
