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.
"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 University and the lead author of the study. He was recently a post-doctoral fellow at SF State when much of the research took place.
Climate change, however, isn't let completely off the hook. Although Bd poses less of a threat to frogs in the lowlands, this study suggests that species at lower elevations are more susceptible to climate changes, putting them at risk if they are unable to adapt or move to higher altitudes.
"It's terrible news," Vredenburg said. "The frogs at the top of the mountain are in trouble because they are experiencing a novel pathogen. The guys at the lower elevations are not in trouble from the fungus, but they're really susceptible to changes in climate."
Vredenburg said Bd was likely introduced into this area of the Andes by human activity, and the results of the study indicate research and conservation efforts should focus on understanding and stopping the spread of the disease. Methods of doing so could include stopping the transport of live amphibians across borders, he said. But understanding the disease also has important implications for human health.
"This pathogen is like no other in the history of the world. Bd outbreaks make bubonic plague look like a slight cough," he said. "We need to understand the basic biology that's driving this terrible pathogen because it's the same biology that drives diseases that affect humans."
Vredenburg has studied the impact of Bd for more than a decade. His research has tracked the spread of the disease through the Sierra Nevada and beyond and shown that some species of frogs are relatively immune to its effects while others are highly susceptible. Future research will focus on those species to learn how they are able to escape Bd's harmful effects and see how that knowledge can be used to save other amphibians.
"Thermal Phsyiology, Disease and Amphibian Declines on the Eastern Slopes of the Andes" was published online in Conservation Biology on Dec. 13. Vredenburg co-authored the study with Catenazzi and Illinois Wesleyan University Assistant Professor of Biology Edgar Lehr. The research was funded by the Amazon Conservation Association, the Rufford Small Grants Foundation and a grant from the National Science Foundation.
Vance T. Vredenburg is an associate professor of biology at San Francisco State University. He is also a Research Associate at the Museum of Vertebrate Zoology at the University of California, Berkeley and California Academy of Sciences. Vredenburg is the co-founder of AmphibiaWeb.org, an online bioinformatics project promoting science and conservation of the world's amphibians.
SF State is the only master's-level public university serving the counties of San Francisco, San Mateo and Marin. The University enrolls nearly 30,000 students each year and offers nationally acclaimed programs in a range of fields -- from creative writing, cinema and biology to history, broadcast and electronic communication arts, theatre arts and ethnic studies. The University's more than 219,000 graduates have contributed to the economic, cultural and civic fabric of San Francisco and beyond.
Jonathan Morales | EurekAlert!
Innovative genetic tests for children with developmental disorders and epilepsy
11.07.2018 | Christian-Albrechts-Universität zu Kiel
Oxygen loss in the coastal Baltic Sea is “unprecedentedly severe”
05.07.2018 | European Geosciences Union
A new manufacturing technique uses a process similar to newspaper printing to form smoother and more flexible metals for making ultrafast electronic devices.
The low-cost process, developed by Purdue University researchers, combines tools already used in industry for manufacturing metals on a large scale, but uses...
For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.
To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...
For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.
Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...
Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.
A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...
Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.
"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....
13.07.2018 | Event News
12.07.2018 | Event News
03.07.2018 | Event News
20.07.2018 | Power and Electrical Engineering
20.07.2018 | Information Technology
20.07.2018 | Materials Sciences