Ecologia térmica e comportamento de construção de abrigos de Liolaemus lutzae (Lacertilia, Liolaemidae) em três áreas de restinga no estado do Rio de Janeiro, sudeste do Brasil: os efeitos de fatores extrínsecos e intrínsecos

Abstract

Extrinsic factors affect the thermal ecology and the behavior of lizards in the habitat, and local environmental features can cause alterations in the body temperature (Tb) and in the behavior of these animals. However, intrinsic factors also represent an important influence to its biology, as well as phylogenetic factors. Liolaemus lutzae (Liolaemidae) is a lizard species occurring restricted to restingas in the state of Rio de Janeiro (between the Restinga da Marambaia in the municipality of Rio de Janeiro and the restinga da Praia do Peró in the municipality of Cabo Frio), living exclusively in the halophilous-psammophilous-reptant vegetation zone the beach area of the restinga (subject to relatively high environmental temperatures and intense and constant winds). In this area, the lizards live restricted to a stretch of few meters of restinga sheltering themselves digging burrows in the sandy substrate. I evaluated the importance of environmental heat sources, wind intensity, sex, ontogeny, snout-vent length (SVL), and body mass to the Tb and the activity rate of lizards L. lutzae (evaluating the occurrence of seasonal variation), in studies carried out in the municipality of Arraial do Cabo, state of Rio de Janeiro, southeastern Brazil. Furthermore, I analyzed if the behavior of L. lutzae driving the openings of its burrows was affected by environmental factors in the restingas of Reserva Ecológica Estadual de Jacarepiá and of Parque Natural Municipal de Grumari, both in the state of Rio de Janeiro. The activity of the lizards extended throughout the day (0600h to 1800h), with peak between 1100h and 1300h (with seasonal variations). Mean Tb of the active individuals was 31.7 ± 3.4 °C, and varied along day and seasonally. In both seasons the Tb of the lizards was related to the microhabitat temperatures (substrate and air). Wind intensity influenced the Tb of the lizards (causing its decrease), and the mean wind intensity affected the number of active lizards (decreasing its activity).There were inter-sexual differences in the SVL, with males larger than females, though females had higher body mass relative to the corresponding SVL, compared to males. The Tb also differed inter-sexually (males hotter than females), and ontogenetically (youngest hotter than adults after removed the effect of SVL). There were relationships between the Tb and the SVL and between the Tb and the body mass, with larger lizards having higher Tb (caused by the thermal inertia of the bodies). The variability in the Tb of the lizards seems to reflect the interaction among local environmental features, intrinsic factors, and the phylogeny of the species. The openings of the burrows were located mainly close to the seashore (possible due to the less compacted substrate), predominantly in sloping terrains, and had a general trend of orientation influenced by the terrain slope. The behavior by L. lutzae of orienting the entrance of their retreats to the descendent direction of the slopes may be advantageous to render them less vulnerable to potential threats and disturbances coming from the surface.