Thermal sensitivity of cold climate lizards and the importance of distributional ranges

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

“…As we predicted, P. tenebrosus reached their T o in both types of runs at temperatures within the thermal preference range (during LR) or near the lower T set of T pref (during SR). The T o was similar to what was previously reported for a small sample of this species ( T o = 35.4 °C, N = 3; Bonino et al, 2015a). There are only two other species in the genus Phymaturus for which TPCs have been published.…”

“…In the case of P. tenebrosus , in contrast to our predictions, the indices to estimate vulnerability to global warming are very high, indicating that lizards of this species cannot reach temperatures near their T o for locomotor performance or their T pref . So, as was also suggested for the congener P. extrilidus (Gómez Alés et al, 2018), the southernmost reptiles of the world ( L. sarmientoi and L. magellanicus , Fernández et al, 2011), and other liolaemids (Bonino et al, 2015a), our study species has a wide safety margin until fitness would decline, and may actually benefit from predicted climate warming for at least the next few decades.…”

“…Most recent studies in lepidosaurians have found negative effects of climate change, highlighting these animals’ vulnerability to temperature variation (Diele-Viegas & Rocha, 2018). However, it was also suggested that thermal tolerance breadths of ectotherms generally increase with latitude, and also that these ectotherms live at cooler temperatures than their physiological optima, so warming may enhance fitness in high-latitude species (Deutsch et al, 2008; Fernández et al, 2011; Sunday et al, 2014; Bonino et al, 2015a). In the case of P. palluma from the highlands of the Central Andes (Vicenzi et al, 2019) the T pref and T o are very similar to those found for P. tenebrosus in this study, but the indices to estimate vulnerability to global warming are substantially different.…”

“…Moreover, in recent years several studies have reported current and predicted future potential extinctions of lizards’ populations as consequence of rising temperatures (Sinervo et al, 2010; Kubisch, Fernández & Ibargüengoytía, 2016; Vicenzi et al, 2017). However, other authors suggest that the effects of rising temperatures may be less detrimental than previously postulated, especially in species with high dispersal ability (Araújo, Thuiller & Pearson, 2006) or in species occurring at high latitudes or altitudes like some liolaemids (Bonino et al, 2015a; Gómez Alés et al, 2018).…”

“…In this paper, we hypothesize that: (1) the preferred body temperature of P. tenebrosus ( T pref ) is correlated with its T o for locomotor performance, as postulated by the thermal coadaptation hypothesis (Huey & Bennett, 1987; Angilletta et al, 2006); (2) P. tenebrosus is capable of attaining high locomotor performance in the field by reaching and maintaining T pref in the field, as has been observed in other species of the genus (Corbalán, Debandi & Kubisch, 2013; Gómez Alés, Acosta & Laspiur, 2017; Vicenzi et al, 2017; Duran, Kubisch & Boretto, 2018); (3) the potential increase in temperature due to global warming will affect locomotor performance of the species, considering the narrow thermal performance breadth observed in other Phymaturus (Bonino et al, 2015a; Gómez Alés et al, 2018; Vicenzi et al, 2019), increasing their vulnerability to extinction. Consequently, we predict that the T o for locomotor performance will be included within the thermal preference range of the species, that P. tenebrosus is an efficient thermoregulator like other species of the genus, and that under a global warming scenario, locomotor performance will decrease, threatening the viability of the species.…”