Abstract
Iran is at the convergence between three biogeographic realms and is widely known for its immense faunal and floral diversity. Moreover, the relationship between climatic niche and biogeographic history is one of the keys to understanding current patterns of distribution and endemism. It is also a central element in the assessment of the vulnerability of species to current climate change, the inclusion of which in conservation strategies is even more critical in mountain reptiles whose dispersal capacities are reduced. The purpose of the thesis was to study the influence of evolutionary history and climatic changes on the structure and distribution of several snakes found in two biodiversity hotspots in Iran, the Caucasus and the Irano-Anatolia. The phylogeographical analysis was conducted on three snakes (Gloydius halys caucasicus, Natrix tessellata and Hemorrhois ravergieri) using mitochondrial and nuclear sequences A strong genetic structure was identified with four lineages observed for G. h. caucasicus, three lineages for N. tessellata and five lineages for H. ravergieri. Our molecular dating and historical biogeographic analyses indicated that Iranian lineages arose between 11 Mya and 0.63 Mya, thus indicating the influence of Quaternary paleo-climatic oscillations (last 2.8 Mya) as well as more ancient events (extensive drought at 9-10 Mya or the Messinian crisis at 5Mya). The distribution of seven snake species inhabiting Iranian mountains was modelled using species distribution models under present and future, (2070, average from 2061 to 2080) climate conditions to identify areas favorable to each species. Our results forecast that the climatically-suitable areas of the mountain-dwelling snake species studied are expected to face considerable, mostly elevational, changes. On that account, present evidences suggest that species’ distributions will undergo long-term changes which are predicted to accelerate dramatically under anthropological pressure. Based on our results regarding genetic diversity, future distribution and definition of significant evolutionary units among studied taxa, conservation issues are discussed in relation with the effectiveness of the current protected area network in Iran.