SAN FRANCISCO -- A deadly fungus, and not climate change as is widely believed, is the primary culprit behind the rapid decline of frog populations in the Andes mountains, according to a new study published today in the journal Conservation Biology.
Frogs living at higher elevations can tolerate increasing temperatures, researchers found, but their habitats fall within the optimal temperature range for Batrachochytrium dendrobatidis, or Bd, a harmful pathogen they have only encountered relatively recently. The disease caused by Bd, chytridiomycosis, has led to the recent decline or extinction of 200 frog species worldwide.
The results have implications both for researchers trying to understand the rapid decline in frog populations across the globe and for conservationists looking to save the animals, said Vance Vredenburg, associate professor of biology at San Francisco State University and co-author of the study.
"Our research shows that we can't just automatically point our finger at climate change," he said. "We need to look carefully at what is causing these outbreaks."
The research was conducted at Wayqecha Biological Station on the eastern slopes of the Andes, located near Manu National Park in southern Peru. To measure frogs' tolerance to the changing climate, researchers placed them in water baths of varying temperatures, then flipped them on their backs. If a frog quickly flipped itself back over, that meant it was able to tolerate the warmer water. If not, researchers knew the frog had become overwhelmed and unable to deal with the change.
Researchers also measured the temperatures at which conditions are optimal for the growth and spread of Bd and found that the highland frogs' habitats lay right within that range.
"This really suggests that the fungus is driving a lot of the declines in this place," said Alessandro Catenazzi, assistant professor of zoology at Southern Illinois Unive
|Contact: Jonathan Morales|
San Francisco State University