Petrosyan V., F. Osipov, V. Bobrov, N. Dergunova, E. Nazarenko, A. Omelchenko, F. Danielyan & M. Arakelyan

Analysis of geographical distribution of the parthenogenetic rock lizard Darevskia armeniaca and its parental species (D. mixta, D. valentini) based on ecological modelling. pp. 173-190 plus Supplementary data.

Abstract. Studies of geographical distribution of parthenogenetic Darevskia armeniaca and its parental species D. mixta and D. valentini can extend our knowledge in terms of their biology and prediction of expansion of their ranges owing to increasing anthropogenic impact and global climate change. We studied the rock lizards of the genus Darevskia because their ecology, biology and potential ranges have not been well studied. Our objectives were: (1) to create maps of the potential geographical distribution of the lizard species; (2) to identify bioclimatic, topographic and landscape variables that determine their potential ranges; (3) to establish similarities and differences in ecological conditions of lizard localities between the parthenogenetic lizard and its parental species. We extended the available published data set with our own field survey records to assess effects of environmental factors on ecological niches of the lizards and their distribution in Transcaucasia and Asia Minor using methods of ordination and species distribution models (SDMs). Our results show that the main drivers regulating the distribution of Darevskia spp. are climatic, topographic and land cover/use. High SDM performance estimated as a Boyce index ~0.917 proved that we had incorporated the most important predictor variables for describing ecological niches of the lizard species. We used an ordination method to compare niches in terms of their overlap, similarity, and niche shifts of the parthenogenetic species relative to its parental species. Habitat preference of D. mixta was determined by altitude, vegetation type, high precipitation during the warmest season, low humidity variation, and low insolation. Habitats of D. valentini were predicted to be located at the highest altitude in the zone of subalpine meadows, low temperature during the dry months, low precipitation during the warm months, an average coefficient of seasonal variation in humidity, high insolation, and a short distance to roads. We suggest that the centroid of the niche of the “daughter” species, D. armeniaca, occupies an intermediate position along environmental gradients relative to that of its parental species with only one exclusion. The coefficient of humidity variation in D. armeniaca differed from that of its parental species. In general, we predicted that ecological niches of parthenogenetic and parental species overlapped by 36%, however, the ecological niche of D. armeniaca was similar to that of its “paternal” species D. valentini. We demonstrate that the parthenogenetic D. armeniaca prefers mountain forest, meadow, steppe and human-disturbed habitats, while the “maternal” species D. mixta inhabits mainly forest habitats and the “paternal” species D. valentini commonly occurs in mountain meadow and mountain steppe habitats in the subalpine zone. These results can be used by environment conservation organizations to preserve the most important habitats of these lizards.

Key words. Squamata, Lacertidae, reticulate evolution, unisexual species, bisexual species, sympatry, modelling.