Phylogeography and population genetics of the European pond turtle Emys orbicularis and the Sicilian pond turtle Emys trinacris

Global environmental change is widely well-know. It consists in marked alteration of the abiotic environment due to massive land use, chemical pollutants and emerging climate change, but also consists in the transformation of the composition of biotic communities. Biodiversity is undergoing deep and complex effects which are difficult to oppose for economic, cultural and aesthetics reasons. The European pond turtle is the only Palearctic representative of Emydidae that inhabits the Americas, and despite its broad range, is a threatened species. In most countries, pond turtles had a breakdown in the 18th or 19th century, above all caused by human activities, and are often already extinct locally. Knowledge on the status of Emys orbicularis and its conservation actions is varied. The European pond turtle has so far been studied at the European level but only recently have fine-scale phylogenetic studies been conducted at just a few Italian sites. I studied phylogeography and population genetics of the genus Emys in Italy (the sole endemic turtle) using a comprehensive sample set. The aim of this work is to reconstruct patterns of dispersal and colonization of Italian turtles following the last glacial period that brought their current distribution to our country and characterized levels of genetic divergence among the main Italian natural populations, through the analysis of the mitochondrial DNA control region and microsatellite markers. This knowledge is essential for identifying genetically diversified units, evolutionary significant units (ESU) and to encourage conservation plans, given that, despite the rise in attention and actions for safeguarding this species in recent years, there are many populations living in unsuitable areas. Moreover, acquiring this information allowed us to build a genetic database used to define the origin on Italian territory of individuals kept in captivity and then assist reintroduction programs or demographic reinforcement of natural populations. We also performed a study on a Greek population of 314 Emys orbicularis in the nature reserve of Lake Kerkini (Macedonia), highly impacted by human activities and inhabiting a series of ponds along a river within a few kilometers from each other to assess a fine-scale population genetic structure and movements of turtles among ponds to provide additional information on patterns of dispersal along linear habitats. My results demonstrated the division of Italian turtles into three clusters, mostly identifiable with the subspecies of E. o. galloitalica, E. o. hellenica and the species Emys trinacris, which, however, showed various degrees of admixture and certain past gene flow (increasing towards the south) which nowadays has become difficult due to high fragmentation. The populations that merit immediate attention, having the lowest values of genetic diversity, were in Sardinia, Sicily and the recent rediscovered population of Albenga. Phylogeographic data prove the existence not only of a primary refugia in the South but also of a secondary refugia, in a less rigid glacial period, in Tuscany and Latium, sources from which the dispersion started via wide wetlands that characterized the Italian coastal areas, and have disappeared today, as have the populations who inhabited them, because of the great reclamations started in the early twentieth century. Another unproven fact to date is the differentiation of Sardinian populations notwithstanding the past connection with Tuscany, and we also consider the hypothesis for introduction to be likely unreliable. The extensive genotyping of Emys Italian populations done through our research is important given that translocations of turtles were and are at present not negligible, and given the vulnerability of the species. Our results have been successfully used in planning the reintroduction of several animals from recovery centers back to nature and will surely continue to contribute to the awareness of reintroducing individuals. Finally, a study on Kerkini Lake populations, that display medium high values of genetic diversity, showed significant differences between males and females in their movements and relations between different ponds, and also that gene flow is favored by streams. This highlights the importance of land reinstatement that separates the ponds from cattle invasion and the importance of riverine connections especially during the breeding season which coincides with the period of greatest water withdrawal by surrounding farms. Population status of the European and Sicilian pond turtle is highly diversified and, although still not critical in many countries, requires further investigation that includes using molecular techniques in order to understand the subtle dynamics, and to intervene in the best way possible for the conservation of the species.