Short term spatial structure of a lizard (Darevskia sp.) community in Armenia

Abstract

Factors driving the spatial patterns of communities of sedentary organisms are still poorly understood. In this context parthenogenetic animals are useful to test the contribution of sexual and interspecific interactions on spatial patterns. As such, mixed communities of asexual and sexual species are expected to be spatially organized as a single sexual species, with sexes randomly distributed and mutually independent. During the reproductive period, we determined the instantaneous spatial structure in a community of Darevskia rock lizards from Armenia composed of one sexual species (D. valentini), two asexual species (D. armeniaca, D. unisexualis), and their hybrids. We also analysed the specific composition of clusters and the species segregation by habitat. We used the Ripley’s K distance function to measure clustering spatial patterns, and the Delaunay’s triangulation to identify the clusters and their specific composition. We estimated the spatial segregation among species by calculating the overlap between species pairs, by comparing pairwise distances from males to other males and from males to females, and by comparing the frequencies of both sexes and reproduction modes (asexual and sexual) in plant cover and height using log-linear models. Species displayed a clustered spatial structure, with parthenogens (mainly D. armeniaca) or their hybrids in all clusters. Females and males were concentrated in areas with medium plant cover. D. armeniaca and D. valentini were the species with the highest overlap. Males were closer to males than to females. This community displays an instantaneous spatial pattern resembling a population of a single sexual species. Spatial statistics offer new insights to analyse the spatial structure of species communities.