In spite of the threat of climate change and a fungus lethal to most amphibians, the high-altitude frogs and toads are surviving, according to the Wildlife Conservation Society (WCS) and other groups.
Researchers once fearful of the complete disappearance of three frog and toad species in Peru’s glaciated Cordillera Vilcanota as a result of the double threat of chytrid fungus (Batrachochytrium dendrobatidis).
This fungus is a pathogen wreaking havoc on amphibian populations worldwide and rising temperatures have found that, surprisingly, the animals continue to breed and survive.
“Due to the changing climatic conditions of this montane habitat and the presence of chytrid fungus reported in our previous study in 2007, we had expected to see a collapse of frog species over time,” said Dr. Tracie Seimon, a molecular scientist for WCS’s Zoological Health Program based at the Bronx Zoo and one of the lead authors of the study.
“What we’re seeing now in these amphibian populations is contrary to our initial hypothesis, and the frog decline may even be reversing.”
Seimon and her team mounted nine expeditions between 2003 and 2015 to seven areas within the Cordillera Vilanota, the second largest tropical mountain region with extensive glaciation, to gauge the impacts of chytrid and rapidly changing environmental conditions on high-elevation amphibians.
The long-term monitoring study has focused on three species of alpine frog: the marbled water frog (Telmatobius marmoratus); the Andean toad (Rhinella spinulosa); and the marbled four-eyed frog (Pleurodema marmoratum).
To conduct the surveys, the researchers looked for amphibians in streams, ponds and along hillside transects in each study area.
Adult frogs and toads, and tadpoles that were encountered were measured, examined for signs of illness, photographed and released unharmed.
The researchers also collected skin swabs to test for the presence of chytrid fungus; samples were analysed with a portable molecular laboratory (roughly the size of a briefcase) capable of identifying chytrid fungus and other pathogens in real-time using a DNA-amplification technique called polymerase chain reaction (PCR).
In the past, such investigations required transporting samples from the field to an established laboratory to confirm the presence of pathogens.
The researchers also took repeat photographs to document the landscape change, and captured data on the ecological changes occurring in the Cordillera Vilcanota range, including increasing temperatures, the accelerated recession of glaciers, and vegetation changes in amphibian habitat.
In spite of these changes and the continual presence of chytrid fungus throughout the study period, the three amphibian species have persisted, so appear to be adapting to the shifting environment.
“The apparent resilience of these particular amphibian populations provides us with a case study of how species can adapt to a rapidly shifting ecosystem, all of which can help inform management strategies on how to best protect vulnerable montane species in an era of climate change,” added Seimon.
The authors asserted that protecting and maintaining the connectivity between wetlands in the Cordillera Vilcanota range will be crucial for the persistence of high-elevation amphibian species as environmental conditions there continue to change.
The authors of the study titled “Long-term monitoring of tropical alpine habitat change, Andean anurans, and chytrid fungus in the Cordillera Vilcanota, Peru: Results from a decade of study” are: Tracie A. Seimon of WCS; Anton Seimon of Appalachian State University; Karina Yager of Stony Brook University; Kelsey Reider of Florida International University; Amanda Delgado of Museo de Historia Natural, Peru; Preston Sowell of Ausangate Environmental LLC; Alfredo Tupayachi of Universidad Nacional de San Antonio Abad del Cusco, Peru; Bronwen Konecky of the University of Colorado; Denise McAloose of WCS; and Stephan Halloy of the Ministry of Primary Industries, New Zealand. Source: WCS