Environmental heterogeneity shapes physiological traits in tropical direct-developing frogs

Area of Science:

• Ecology and Evolutionary Biology
• Climate Change Biology
• Herpetology

Background:

• Tropical ectotherms possess narrower physiological limits than temperate species, increasing vulnerability to climate change.
• Thermal tolerance varies even within tropical species along elevation gradients, indicating physiological sensitivity.

Purpose of the Study:

• To investigate how elevation and bioclimatic domains influence thermal sensitivities in the direct-developing frog, Craugastor loki.
• To determine variations in preferred temperature, critical thermal maximum, and critical thermal minimum across an elevation gradient.
• To assess the vulnerability of different populations to climate warming.

Main Methods:

• Analyzed the relationship between elevation, bioclimatic domains (temperature and precipitation), and thermal sensitivities in Craugastor loki.
• Measured preferred body temperature, critical thermal maximum, and critical thermal minimum across various elevations.

Main Results:

• Preferred body temperature moderately increased with elevation, with optimal thermal conditions found at mid-elevations.
• Critical thermal maximum decreased with increasing elevation, showing variability across bioclimatic domains.
• Critical thermal minimum exhibited less variability compared to the critical thermal maximum.

Conclusions:

• Lowland populations of Craugastor loki may be more vulnerable to rising temperatures due to their lower critical thermal maximum.
• The critical thermal maximum is influenced by high environmental temperatures across the elevation gradient and bioclimatic domains.