Killer Heat
Global warming caused an infectious disease that killed
entire populations of amphibians reports
Steve Connor. 6000
species of
amphibians were wiped out by a devastating skin
infection caused by fungus. This was identified in 1990.
Average temperatures in the tropics as elsewhere have
increased giving rise to growth of chytrid fungus. Rapid
demise of many frogs and toads is linked to climatic
changes says Arturo Sanchez-Azofeifa of University of
Alberta (Canada) in Nature. The killer fungus expands its
niche to obliterate the amphibians.
Some 1856 species of amphibians are threatened and hundreds
are facing extinction. The chytrid fungus wiped out at
least 67% of brightly coloured harlequin frogs in the
Americas in last 17 years. Alan Pounds, the lead author of
the study in Nature compares the disease as the bullet with
the climatic change acting as the pull on the trigger.
Rise in
temperature causes cloud cover causing cooler days
and warmer nights helping growth of fungus. The discovery
also cleared a paradox that suggested that fungus thrived
in cooler temperatures. It was actually found that the
fungus was vulnerable to extremes in temperature and any
moderation in the extremes unleashes it. A cause for
concern for human health in a warmer world is for real now.
It is ironic that the African-clawed toad used for research
was itself host to the chytrid fungus and helped in its
proliferation around the globe. Prof. Blaustein of the
Oregon State University lamented how the proliferation of
one species of amphibians through trade led to the
extinction of others thanks to human ingenuity.