Does ecophysiology mediate reptile responses to fire regimes? Evidence from Iberian lizards

Abstract

Background.Reptiles are sensitive to habitat disturbance induced by wildfires, but some species frequently show opposing responses. The functional causes of such variability have been scarcely explored. In the northernmost limit of the Mediterranean bioregion, a lizard species of Mediterranean affinity (Psammodromus algirusandPodarcis guadarramae) increase in abundance in burnt areas whereas Atlantic species (Lacerta schreiberiandPodarcis bocagei) decrease.Timon lepidus, the largest Mediterranean lizard in the region, shows mixed responses depending on the locality and fire history. We tested whether such interspecific differences are of a functional nature; namely, if ecophysiological traits may determine lizard response to fire. Based on the variation in habitat structure between burnt and unburnt sites, we hypothesise that the Mediterranean species, which increase density in open habitats promoted by frequent fire regimes, should be more thermophile and suffer lower water losses than Atlantic species.Methods.We submitted 6–10 adult males of the five species to standard experiments for assessing preferred body temperatures (Tp) and evaporativewater loss rates (EWL), and examined the variation among species and along time by means of repeated-measures AN(C)OVAs.Results.Results only partially supported our initial expectations, since the medium-sizedP. algirusclearly attained higherTpand lower EWL. The two small wall lizards (P. bocageiandP. guadarramae) displayed lowTpand high EWL while the two large green lizards (T. lepidusandL. schreiberi) displayed intermediate values for both parameters.Discussion.The predicted differences according to the biogeographic affinities within each pair were not fully confirmed. We conclude that ecophysiology may help to understand functional reptile responses to fire but other biological traits are also to be considered.