Are lizards sensitive to anomalous seasonal temperatures? Long-term thermobiological variability in a subtropical species

Abstract

Alterations in thermal niches have been widely associated with the Anthropocene erosion of reptiles’ diversity. They entail potential physiological constraints for organisms’ performance, which can lead to activity restrictions and impact fitness and demography. Reptiles are ectotherms which rely on seasonal periodicity to maximize the performance of biological functions. Despite it, the ecological implications of shifts in local temperatures are barely explored at the seasonal scale. This study aims to assess how changes in air temperature and substrate temperature affect the activity, body temperature (Tb) and thermoregulation patterns of the sand lizard, Liolaemus arambarensis (an endangered, microendemic species from southern Brazil), throughout a four-year period. Field surveys were conducted monthly on a restricted population in a sand-dune habitat. The annual fluctuations of the seasonal temperatures led to significant changes in the activity and Tb of L. arambarensis and shaped thermoregulation trends, suggesting biological plasticity as a key factor in the face of such variability. Lizards tended to maintain seasonal Tb in mild and harsh seasons through increased warming/cooling efforts. Anomalous winter conditions seemed especially critical for individual performance due to their apparent high impact favouring/constraining activity. Activity and thermoregulation were inhibited in frigid winters, probably due to a vulnerable physiology to intense cold spells determined by higher preferred body temperatures than Tb. Our results warn of a complex sensitivity in lizards to anomalous seasonal temperatures, which are potentially enhanced by climate change. The current work highlights the importance of multiannual biomonitoring to disentangle long-term responses in the thermal biology of reptiles and, thereby, to integrate conservation needs in the scope of global change.

The Thermal Biology of Takydromus kuehnei Indicates Tropical Lizards From High Elevation Have Not Been Severely Threatened by Climate Change

“…The seasonal variation in higher T a under lower T e (Table 1 and Figures 1, 2) appears opposite to the general knowledge that the body temperatures of lizards are subject to ambient temperatures (Huey, 1982). Lizards have different thermoregulatory strategies to adapt to seasonal temperatures (Vicente Liz et al, 2019). Lizards may select a low body temperature in the hot season to avoid exposure to ambient heat temperatures (Firth and Belan, 1998).…”

“…Lizards may select a low body temperature in the hot season to avoid exposure to ambient heat temperatures (Firth and Belan, 1998). The higher selected body temperatures in the mild season are probably because mild-season temperatures can relieve lizard exposure to the critical thermal limits (Huey, 1982;Vicente Liz et al, 2019). Accordingly, lizards may enhance activity and facilitate the maintenance of the optimal temperature at a low cost in a mild season (Huey and Slatkin, 1976).…”

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

“…The mean T s was significantly higher than T b and T a and, T b s only increased according to the air temperature, suggesting the usage of air temperature on thermoregulation 64 , 65 . Cooling by convection is common in some psammophilous species of Liolaemus inhabiting sandy environments from Brazil ( L. occipitalis 66 ; L. lutzae 67 ; L. arambarensis 68 ), and Argentina ( L. wiegmannii 69 ; L. koslowskyi 70 ; L. olongasta 71 ; L. acostai 72 ; L. sarmientoi 73 ; L. ruibali 74 ; L. chacoensis 75 ; L. scapularis 76 ). Indeed, downslope winds with strong convection are common phenomena observed along the eastern slopes at medium or high elevations in the Andes, especially from midday and thenafter 77 .…”

Thermal biology of two sympatric Lacertids lizards (Lacerta diplochondrodesandParvilacerta parva) from Western Anatolia

“…This seasonal difference was much more pronounced for T ex as P. parva shows higher T ex for both July and August with high significance (Table 1) while for T b this effect was marginally significant for August (Table 2). The relatively stable state of T b compared to the difference in T ex between months indicates that the role of behaviour in maintenance of optimal body temperature might be important, as the higher amount of difference between T b and T a in warmer periods of year might indicate a higher frequency of overheating avoidance (Vicente Liz et al, 2019). Given that both of these two species are diurnal with most active times being spring and summer, efficient thermoregulatory behaviour is crucial for heat avoidance while maintaining an optimal body temperature for foraging and metabolism (Huey and Pianka, 2018; Sepúlveda et al, 2014).…”