Selected microhabitat and surface temperatures of two sympatric lizard species

Abstract

Many small lizards live in structurally and thermally heterogeneous environments where they can select preferred microhabitats and surface temperatures to optimize their activity. We examined microhabitat selection and analyzed surface temperatures selected by two ecologically similar lacertid species, Iberolacerta horvathi and Podarcis muralis, at three sites and in different ecological contexts: allotopic and syntopic conditions. We examined their microhabitat and spatial thermal selection by using high-precision geolocation techniques to locate the lizards and record surface temperatures with temperature data loggers. Microhabitat and thermal availability differed among sites: the I. horvathi allotopic site had more rock surfaces and was coldest; the P. muralis allotopic site had more ground surfaces and was warmer; and the syntopic site had the greatest surface and thermal heterogeneity. Our results highlight the differences in microhabitat selection between the two species, most notably in surface selection, but also in thermal characteristics. I. horvathi preferentially and almost exclusively selected rocks. P. muralis chose soil, but with a more general use of microhabitats. I. horvathi lizards chose colder temperatures than those available, while P. muralis chose higher temperatures than those available. Both species showed no differences in microhabitat selection between allotopic and syntopic sites, which could not be explained by differences between sites. Our results provided new insights into the difference in surface temperature selection between two lizard species that may be adapted to different environments.