A combined palaeomodelling approach reveals the role as selective refugia of the Mediterranean peninsulas

The northern Mediterranean reptiles and amphibians show contrasting biogeographic histories during the Plio-Pleistocene. The influence of European climate changes on the evolution of the biogeographic ranges of taxa with a rich fossil record is determined herein combining different proxies to obtain well-supported palaeoclimatic scenarios. Ecological Niche Modelling through the ensemble modelling approach was used to reconstruct the climatic niche of selected reptile and amphibian genera, combining modern occurrences with seven independent bioclimatic variables. The obtained model was then projected on past scenarios using fossil data to crosscheck the validity of the climatic explanation for the selective extirpations. Palaeobotanical proxies and the hypsodonty of mammals were used to reconstruct the humidity pattern of the last million years in the studied area. The climate of the Italian Peninsula during the Last Glacial Maximum was proved herein to be unsuitable for many reptile taxa, which persisted in this area until the Early or Late Pleistocene, whereas they survived till the present day in the Iberian and/or Balkans peninsulas. On the contrary, all the proxies agree that Italy was comparably more humid than the other peninsulas during the Pliocene and Pleistocene, therefore allowing the prolonged survival of amphibian taxa (including the still living Salamandrina and Speleomantes), which became extinct or extirpated elsewhere in Europe. An intensification of the conservation efforts concerning amphibians, particularly sensitive to the global climate change, is recommended in the Italian Peninsula, which acted as an amphibian refugium for Europe due to its peculiar climatic history.