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

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.

Effects of Climate and Latitude on Age at Maturity and Longevity of Lizards Studied by Skeletochronology.

Longevity and age at maturity are key life-history traits, directly linked to fitness attributes such as survival and reproductive output. It has been proposed that these traits are strongly influenced by environmental factors, such as temperature, seasonality, and precipitations, which determine the existence of a continuum of life-histories that goes from the "slow" life histories characterized by late maturity and high longevity of cold and highly seasonal climates to the "fast" life histories characterized by early maturity and low longevity, typical of the tropical climates. However, large-scale studies that address these topics in lizards are scarce and most of them are based on heterogeneous data, which may overlook the real patterns. Using skeletochronology, we studied age at maturity and longevity of two species of Phymaturus lizards, Phymaturus aguanegra from the Andes and Phymaturus zapalensis from the Patagonian steppe (Argentina). Then, we confronted longevity and age at maturity in these species with published skeletochronology-based data on 46 other lizard species to examine possible association of these life-history traits with latitude and mean annual temperature, thermal amplitude, and precipitations. Both Phymaturus species showed late sexual maturity (7 and 8-9 years, respectively) and high longevity (16 and 14-15 years, respectively) in coincidence with the other species of the genus studied up to date. The phylogenetic comparative analysis revealed that the most important variable in the determination of longevity patterns in the species studied was latitude: at higher latitudes lizards tend to live longer. In contrast, age at sexual maturity was dependent on mean annual temperature most, especially in males, as lizards from hotter climates mature earlier than lizards from cold sites.

Slow life histories in lizards living in the highlands of the Andes Mountains.

In the highlands of the Andes, lizards must balance precisely the allocation of energy for growth and reproduction to ensure their survival. We studied the individuals' age, growth rates, age at sexual maturity, and maximum life span of the viviparous lizard Phymaturus antofagastensis, endemic of cold and harsh environments at high altitudes in the Andes Mountains of Catamarca province, Argentina. We also estimated key life history parameters like reproductive effort, lifetime reproductive effort, net reproductive rate, and relative reproductive time in P. antofagastensis as well as in other Phymaturus to compare the interplay among growth, maintenance, and reproduction in species that live across a latitudinal and altitudinal gradient. We found that females and males of P. antofagastensis mature late in life, at 6-7 years old, respectively, and some individuals reached 20 years of age. Adult females showed higher specific growth rates than males and an adult life span of 9 years which, due to their biennial reproduction, results in an estimated production of only four litters in life. This species exhibits one of the highest lifetime reproductive efforts described for lizards. Our results indicate the existence of a tradeoff between the number of reproductive events throughout life and reproductive effort devoted to each event in Phymaturus, related to the phylogenetic group. The palluma group shows low reproductive effort but high number of reproductive events throughout their lives, whereas the patagonicus group shows high reproductive efforts in low number of reproductive events.

Consequences of volcanic ash deposition on the locomotor performance of the Phymaturus spectabilis lizard from Patagonia, Argentina.

The locomotor performance of lizards depends on their morphological and physiological adaptations to the habitat. However, when the habitat changes dramatically, for example, by a volcanic eruption, the performance of lizards may be affected. We registered the vegetation cover, the surface covered by ash, the presence of crevices suitable for Phymaturus and the rocks slopes to analyze the effects of ash accumulation produced by the eruption of Puyehue-Cordon Caulle volcanic complex on microhabitat use and availability of the Phymaturus spectabilis lizard. In addition, we studied the effect of ashes and slope on the locomotor performance of P. spectabilis by registering the maximum speed in sprint runs and long runs under four different treatments (cork and on the level, ashes and on the level, cork and slope, and ashes and slope). P. spectabilis selected microhabitats unvegetated, with crevices and steep slopes. Regarding locomotor performance, the speed of lizards was negatively affected by the presence of ash only in sprint runs on the level and in long runs with slope. The slope had a negative impact on the speed in all the treatments. These results show that the presence of volcanic ashes in the substrate might have affected the locomotor performance of the lizards, especially in long runs, and hence, the interaction of individuals with the environment, that is, escaping from predators and social behavior.