Population dynamics of the Italian crested newt (Triturus carnifex) over a fine-spatial scale

In the second half of the twentieth century, a major revolution in agricultural practice has taken place causing widespread biodiversity decline. The main factors behind this phenomenon are: overexploitation of resources, the introduction of alien species, pollution, climate change, habitat degradation and fragmentation, which are the two most important factor. Particularly, habitat fragmentation threatens many species through gene flow reduction among populations, intensifying problems linked to inbreeding and genetic drift. The landscape plays an important role in mediating the dispersion and the shaping of the distribution of species and communities. Dispersal can have a potentially profound effect on the dynamics of populations. It promotes gene flow, which is integral to the persistence of animal populations by enhancing genetic diversity and allowing for the recolonization and rescue of declining populations. At a local scale, the dynamics of a population depends on connections with other local populations. Changes in the recolonization potential of isolated populations can influence local genetic diversity. 6 The aim of the present study is to investigate the population dynamics of the Italian crested newt (Triturus carnifex) at a fine scale in central Italy. To this aim, three main aspects will be analysed which are: spatial genetic structure of the local T. carnifex population, connectivity among sites, population size. Subsequently, a comparison between Lissotriton vulgaris meridionalis and Triturus carnifex population dynamics were performed in order to investigate if the same environmental features act differently on shaping the spatial genetic structure of the two newt species. I found great differences in the spatial genetic patterns of the two species, which can be explained by their different dispersal abilities. An asymmetrical migration among populations of T. carnifex has been revealed, maybe due to population density. The sex ratio within T. carnifex populations was frequently equal and estimates of population census size (Nc) were higher than the breeding effective population size (Nb) as estimated the linkage disequilibrium method.