Do anthropogenic disturbances affect the stress physiology and immunity of Liolaemus cuyumhue? The case of an endangered lizard from the Monte Desert of Patagonia.

In arid environments, hydrocarbon exploitation causes habitat alterations, affecting the availability of microhabitats for thermoregulation, predator evasion, and foraging opportunities. This is the first study to evaluate the effects of this anthropogenic disturbance on stress and immunological parameters in a liolaemid lizard, Liolaemus cuyumhue, an endemic and Critically Endangered species (Monte Desert, Patagonia, Argentina). During the spring-summer seasons, we compared the leucocyte profiles, heterophil-to-lymphocyte ratio (H/L), capture body temperatures (Tb), serum corticosterone concentrations (CORT), and body condition index (BCI) of adults from a site disturbed by hydrocarbon exploitation and an undisturbed site. We found that lymphocyte percentages were higher in lizards from the disturbed site, whereas heterophils, basophils, and monocytes were more abundant at the undisturbed site. The H/L differed significantly between sites and seasons, being higher at the undisturbed site and during spring. A significant negative association between H/L ratio and Tb was observed only at the disturbed site. CORT measured in adult males varied seasonally, being higher in summer, but showed no differences between sites. Our results suggest that individuals that survived and persisted in the disturbed site have been able to cope with environmental conditions, which at present do not appear to induce chronic physiological stress.