Data from: Divergent physiological acclimation responses to warming between two co-occurring salamander species and implications for terrestrial survival

Small differences in physiological responses are known to influence
demographic rates such as survival. We tested for differences in the
physiological acclimation responses of two closely-related salamander
species that often co-occur, Ambystoma maculatum and A. opacum.
Specifically, we measured changes in critical thermal maxima (CTmax),
standard metabolic rates (SMRs), and respiratory surface area water loss
(RSAWL) following exposure to three temperature treatments under
laboratory conditions. While the magnitude of RSAWL and CTmax acclimation
responses to warming did not differ between the study species, SMR was
maintained across acclimation temperatures among A. maculatum, but
declined among A. opacum acclimated to warmer temperatures. Metabolic
compensation may facilitate maintained A. maculatum activity levels during
warm periods following the relatively cool spring breeding season. In
contrast, metabolic suppression may allow A. opacum to conserve energy
when exposed to surface conditions during fall breeding and nest guarding.
We simulated how these different SMR responses would likely alter
post-metamorphic survival in our study species using previously collected
data representing six weeks under relatively warm seminatural conditions.
Our simulation indicated that, following warming and under identical study
conditions, metabolic compensation may allow juvenile A. maculatum to
maintain survival likelihoods, whereas metabolic depression may cause
juvenile A. opacum to experience increased survivorship. These findings
underscore that comparable physiological responses among ecologically
similar, sympatric species cannot be assumed. Further, results of this
study suggest that metabolic responses may play an important role in
amphibian species persistence as temperatures increase due to habitat
modification and climate change.