Potential benefits from global warming to the thermal biology and locomotor performance of an endangered Patagonian lizard

Abstract

Global warming can significantly affect many aspects of the biology of animal species, including their thermal physiology and physiological performance. Thermal performance curves provide a heuristic model to evaluate the impacts of temperature on the ecophysiology of ectotherms. When integrated with other thermal biology parameters, they can be used to predict the impacts of climate change on individual fitness and population viability. In this study, we combine holistic measures of thermal physiology and the thermal sensitivity of locomotor performance with environmental temperatures measured at fine scale to estimate the vulnerability to global warming of the endangered Patagonian lizard Phymaturus tenebrosus. Our results indicate that this lizard exhibits its preferred temperatures and maximum locomotor performance at higher temperatures than the mean temperature it currently experiences in its habitat. In addition, it exhibits a low effectiveness of thermoregulation, being a poor thermoregulator. In view of the results obtained, we suggest that the climatic conditions of Patagonia may be advantageous for P. tenebrosus to survive future global warming, since its thermal physiology and locomotor performance may improve under increasing in environmental temperatures in its habitat.

Vulnerability to climate change of a microendemic lizard species from the central Andes

“…At least a third (33%) of the recorded T e values were higher than the T pref during the warmest hours which increases the risk for these lizards of attaining near-lethal body temperatures close to their CT max . Accordingly, we found that their thermal safety margin (TSM = 3.57 °C) and warming tolerance index (WT = 8.8) were notably lower than reported in others liolaemid lizards from cold temperate environments such as Phymaturus tenebrosus (TSM = 15.58 and WT = 23.3 86 ) and P. calcogaster (TSM = 3.98 °C and WT = 10.67 °C 87 ). Therefore, these observations suggest that L. montanezi has a narrow TSM range to prevent it from reaching lethal temperatures 45 .…”

“…The lizards were placed individually in a 2 °C chest refrigerator with glass-top door cooled at constant rate (approximately, − 0.7 °C/30 s). During cooling, the lizards were turned onto their back (no more than four times per individual) until they reached CT min , considered as the T b at which the lizard was no longer able to right itself when placed on its back 86 .…”

“…In the same experimental system, the voluntary thermal maximum (VT max ) defined as the body temperature that induces a behavioral response seeking to cool down, was recorded 98 . Each lizard was monitored throughout the trials to record the critical thermal maximum (CT max ), defined as the temperature at the higher extreme of tolerance in which the lizard was no longer able to right itself when placed onto its back 27 , 86 , 99 . Finally, after the determination of CT min , VT max and CT max , each lizard was promptly removed from cooling or heating systems and steadily returned to room temperature to prevent the death of the individuals under study.…”

Thermal biology and locomotor performance in Phymaturus calcogaster: are Patagonian lizards vulnerable to climate change?

“…2005), P. tenebrosus (26.3°C, Cabezas‐Cartes et al . 2019) and P. zapalensis (Ibargüengoytía et al . 2008; Duran et al .…”

“…A similar prediction has been formulated for P. tenebrosus (Cabezas‐Cartes et al . 2019) and other temperate‐environment lizards from Europe such as Z. vivipara (Chamaillé‐Jammes et al . 2006) Podarcis muralis (Deutsch et al .…”