Physiological constraints to climate change: insights from the effects of temperature on standard metabolic rate in larval salamanders

To this end, SMR was determined using volume of oxygen consumption during closed-circuit respirometery trials conducted at 5 °C increments between 5 and 25 °C. 4. Standard metabolic rates were influenced by temperature, with a range of temperature-independent SMRs observed at those temperatures above each species’ laboratory-determined thermal preference. Concordant with their thermal preference (15.70 °C) and more narrow geographic range, E. wilderae exhibited a smaller scope of temperatures at which SMR was temperature-independent relative to E. cirrigera and showed depressed metabolic rates at the highest temperature tested. 5.

Our results provide a mechanistic link for an ecological predictor of climate change susceptibility (i.e., range size) and indicate that physiological specialization that occurs in species of narrow geographic ranges may preclude adaptations to climate change.