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Climate Change May Be Tipping Balance Against Imperiled Puerto Rico Frog

The Puerto Rico tropical frog known to hikers as the mountain coqui has been struggling for decades to survive against the onslaught of the frog-killer fungus Batrachochytrium dendrobatidis. But now, climate change may be tipping the balance against the embattled amphibian, according to research announced today by Cornell University.

“Scientists studying disease and climate change as part of a special multidisciplinary team at Cornell University are heading to the mountains of Puerto Rico–hoping to learn what a struggling frog species can tell us about the danger changing weather patterns present to ecosystems around the globe,” the Ithaca, New York-based university said in a news statement.


Photo of mountain coqui frog courtesy of Alberto López.

“The frog species, known as the mountain coqui to the hikers they serenade at night and Eleutherodactylus to researchers, has for decades battled a lethal fungus to a standstill,” said Ecology and Evolutionary Biology Professor Kelly Zamudio. “The coqui populations endure the drier winter months when stress makes them vulnerable to the imported fungus Batrachochytrium dendrobatidis, or Bd, then rebound when the wet season returns to their tropical forest home.

“But now, climate change may be tipping the balance in this biological standoff,” Zamudio said.

Zamudio, whose lab is looking into climate change and disease with the support of the Academic Venture Fund administered by the Cornell Center for a Sustainable Future, has teamed with graduate student researcher Ana Longo, Cornell’s statement added.


Photo of Ana Longo in the field courtesy of Alberto López.

“During her master’s degree work at the University of Puerto Rico, Longo followed how climate change altered weather patterns in the Caribbean. She found that periods of drought during the winter months from December through April have grown longer, with rainless spans once rarely longer than three days now stretching up to nine or 10 days. That puts the coqui under added stress, and stressed frogs are less likely to survive when Bd comes calling. To make matters worse, the frogs sometimes retreat at ‘clumping sites’ to ride out the droughts, helping spread the fungus among weakened populations,” Cornell explained.

Like a Train Wreck

“It’s like a train wreck,” Zamudio said, adding that Bd is responsible for almost half of the more than 190 frog species extinctions observed in the past half century.

In the next phase of the work through Zamudio’s lab, Longo will return to Puerto Rico in January 2011 to examine whether climate change is undermining one technique the frogs use to battle the fungal infections, Cornell added.

“Called ‘behavioral fever,’ the ectothermic, or cold-blooded, frogs use their environment to elevate body temperature and battle disease. Now, it seems that longer and less predictable winters driven by climate change may be stripping the frogs of this defensive tool as well.

“Zamudio and Longo said their goal is to understand this two-pronged threat to the coqui in the mountains of Puerto Rico, because other tropical frog species throughout Central and South America are showing the same infection patterns,” Cornell said.

“If we lose these frogs, we lose a link in the food chain … and that has community consequences for entire ecosystems.”

“If we lose these frogs, we lose a link in the food chain,” Zamudio said, “and that has community consequences for entire ecosystems.”

The Center for a Sustainable Future’s Academic Venture Fund has awarded more than U.S.$2 million to Cornell researchers since 2008 to promote multidisciplinary research into real-world issues of sustainability. The center was created in 2007 to apply a multidisciplinary approach to problems related to energy, the environment and economic development.

Posted by David Braun from media meterials provided by Cornell University.

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