The study of metabolism concerns the study of biological processes, their rates and requirements, and how they change and interact in different contexts. It is a basis for understanding the energetic requirements of species and how these requirements are affected by environment and evolution. Amphibians were found using visual encounter surveys across 10 field sites that spanned between 200 meters above sea level and 5,500 meters above sea level. Nine of these sites fall within the Manu Biosphere Reserve, with the tenth nearby in the mountainous areas of Vilcanota. Resting metabolic rates were determined by measuring the change in CO2 over time using an infrared gas analyzer in a closed system where the amphibian was unmoving for at least 30 minutes. Measurements were taken at night and during the day at ambient temperatures to examine thermal sensitivity of metabolic rate. Results were analyzed at the species level, across elevational ranges and among populations, to examine variation within species. Additionally, phylogenetic analyses at the genus and family levels were used to examine the extent to which metabolic characteristics are constrained by evolutionary history.
Results/Conclusions
A total of 102 species of amphibians in 14 families, including anurans, salamanders, and caecilians, were found across the 5,000 meter gradient. There exists substantial variation of resting metabolic rate within both individual species as well at higher taxonomic levels. This variation might reflect either plasticity in these characteristics, or genetic, heritable differences. This distinction is important in understanding future impacts, and potential species responses, of climate change and merits further study. Despite this variation, there do seem to be some general patterns among groups. The families Bufonidae and Dendrobatidae seem to have higher resting metabolic rates than other families, while Hylidae often had lower values. Salamanders were shown to have significantly lower metabolic rates, supporting the findings of similar studies conducted in temperate areas. These characteristics, their variation, and the potential for adaptation may be predictive for how amphibians, and which areas and species, will be affected by climate change.