Factors affecting the spatial ecology of the lizard Liolaemus wiegmannii in the pampasic coastal dunes of Argentina

Home ranges of lizards are the result of both internal (body condition, reproductive status) and external factors, such as habitat features and resource availability. Habitat modification induced by introduced plants affects habitat use for lizards by changing food abundance, environmental temperatures or by homogenising the habitat structure. We compared the home range of the lizard Liolaemus wiegmannii in two situations: a partially forested habitat (20% of the total surface covered by Acacia longifolia) and a non-forested habitat. Twelve adult lizards were radio-tracked in the forested habitat and ten in the non-forested site. Home ranges were calculated using the minimum convex polygon method. The mean home range size was 37.80±17.95 m² and was not different between both habitat types. Home ranges of males were 1.6 times larger than those of females. Abundance of food was highest in the forested habitat, without an apparent effect on home range size. Home range in L. wiegmannii showed a marked association with mixed patches of native grassland, bare sand substrates and scarce coverage of exotic trees. Our data suggest that movements in L. wiegmannii may be mainly related to structural features (and their associated thermal cues) of specific microhabitat types. Although low levels of forestation with A. longifolia have less effect on the home range size and movements of lizards, we cannot ignore previous results showing that occurrence, abundance and body condition of L. wiegmannii are negatively affected by extensive forestation of exotic plants both at local and landscape scales in pampasic dunes.