Spatial Ecology of a Threatened Liolaemid Lizard: The Interplay of Intrinsic and Environmental Factors

Abstract

The spatial ecology of animals is influenced by the structure of their physical habitat, which affects the availability of refuges and microclimate, as well as the spatial positioning of resources. The use of the space of the lizard Liolaemus tandiliensis was investigated in the Tandilia mountains of the Pampas region. We radio-tracked 19 adult lizards and found that home range size and distance moved were significantly affected by sex, with males having a home range 34% larger and moving longer distances than females. These parameters were also influenced by structural and thermal features of specific microhabitat types. The habitat structure inside the home range showed relatively high coverage of rocks and low coverage of vegetation with respect to environmental availability. The thermal properties of the microhabitats were strongly associated with their occupancy, since individuals used microhabitats of high thermal quality that exhibited environmental temperatures deviating the least from the preferred body temperature range of L. tandiliensis. Small-scale structural heterogeneity and thermal gradients were available in the Tandilia mountains, so L. tandiliensis individuals may not need to move large distances and may sustain themselves within a relatively small home range (mean=74.52 m2). Our findings suggest that L. tandiliensis occurs in a delicate balance with its specific habitat. This study provides information that must be taken into account for conservation planning, especially in light of theincreasing anthropogenic degradation of the Tandilia mountains.