Lizards and the city: A community study of Lacertidae and Gekkonidae from an archaeological park in Rome

Abstract

Abstract The study of animal communities is mainly concerned with how the groupings of species are distributed in nature and the ways in which the members of these communities assemble and interact with each other. Pianka suggested that animals partition environmental resources in three basic ways: temporally, spatially, and trophically. Such differences in activities separate the niches, reduce competition, and presumably allow the coexistence of a variety of species in the communities. The present work compares the spatial, trophic and temporal niches of four reptile species, two geckos (Tarentola mauritanica and Hemidactylus turcicus) and two lizards (Podarcis muralis and Podarcis siculus) living in a same roman-age archeological park situated area inside Rome metropolitan area (central Italy), and sharing the same two-dimensional habitat (the roman aqueduct walls). The results showed an overall overlap among species higher than expected by chance for all considered ecological dimensions except for the spatial resource related to the vertical position on the wall. Surprisingly, despite living in a two-dimension habitat would expect an increase of interspecific interaction rate, no partition was observed between species with the most convergent ecological requirements. Although our hypotheses about lizard communities structuring and interactions in the urban habitat require further investigation, we think that our lizard community is based more on the ecological needs of each species rather than on species’ interactions. The observed spatial segregation between diurnal geckos and lizards would not support alone the interaction hypothesis. We speculated that the coexistence of ecologically overlapping species at the study area is allowed by a non-limiting availability of resources (above all food) that would result in the reduction of heterospecific competitive interactions and an overall wide overlap of resource use.