Rapid postfire color shift in a Mediterranean lizard

Abstract

Wildfires can abruptly cause dramatic changes in the physical environment, challenging the survival and persistence of animal populations. Animals can adapt to fast-changing environments through phenotypic plasticity, yet little is known about the extent of this capacity in postfire environments. We hypothesized that Mediterranean lizards in recently burned areas would develop a lighter coloration, potentially as a response to the increased overheating risk due to vegetation loss. We quantified dorsal luminosity and color composition of Psammodromus algirus in burned and adjacent unburned habitats at different times since fire. Lizards inhabiting recently burned areas displayed lighter dorsal coloration, particularly during the early stages of postfire succession, with the effect being more pronounced in larger individuals. Although alternative mechanisms (e.g., stress-induced responses or reduced crypsis requirements) cannot be entirely excluded, the direction, timing, and consistency of the observed shifts are most consistent with a thermoregulatory function. These findings suggest that phenotypic flexibility in dorsal coloration may be an important mechanism for ectotherms to persist in increasingly fire-prone landscapes.