January 11, 2006
CORRECTED:Climate-change fungus is wiping out frogs – study
Please read in paragraph 8, "Canada's University of
Alberta" instead of "University of Arizona."
A corrected version follows.
By Patricia Reaney
LONDON (Reuters) - An infectious fungus aggravated by
global warming has killed entire populations of frogs in
Central and South America and driven some species to
extinction, scientists said on Wednesday.
In research that showed the effects of rising temperatures
on delicate ecosystems, a team of researchers found that a
warming atmosphere encouraged the spread of a fungus that has
wiped out species of harlequin frogs and golden toads.
"This is the first clear evidence that widespread
extinction is taking place because of global warming," Dr Alan
Pounds, an ecologist of the Monteverde Cloud Forest Preserve in
Costa Rica, said in an interview.
"Climate change is already altering the dynamics of
infectious disease and causing species to disappear."
Pounds and his team established the link between global
warming and the disappearance of frogs in the cloud forests of
Costa Rica by analyzing sea surface and air temperatures, which
rose by 0.18 degrees per decade between 1975 and 2000.
Warmer temperatures increased cloud cover over the tropical
mountain which the scientists believe promoted conditions to
spur the growth of the chytrid fungus that kills frogs.
They are confident that global warming is a key factor in
the disappearance of many amphibian populations in tropical
"There is absolutely a linkage between global warming and
this disease -- they go hand-in-hand," said Dr Arturo
Sanchez-Azofeifa, of Canada's University of Alberta and a
co-author of the research published in the journal Nature.
"With this increase in temperature, the bacteria has been
able to increase its niche and wipe out large populations of
amphibians in the Americas," he added in a statement.
About a third of the 5,743 known species of frogs, toads
and other amphibians are classified as threatened, according to
the Global Amphibian Assessment.
Up to 167 species may already be extinct and another 113
species have not been found in recent years. Habitat loss is
the greatest threat to amphibians but fungal disease is also a
Andrew Blaustein, of Oregon State University, and Andy
Dobson, of Princeton University in New Jersey, described the
research as a breakthrough.
"The powerful synergy between pathogen transmission and
climate change should give us cause for concern about human
health in a warmer world," they said in a commentary in Nature.
"The frogs are sending an alarm call to all concerned about
the future of biodiversity and the need to protect the greatest
of all open-access resources -- the atmosphere," they added.