The Balearic herpetofauna: a species update and a review on the evidence

Abstract

Here, we update the current list of amphibian and reptile fauna present in the Balearic Islands, probably the most outstanding case in the Mediterranean and of the most in the world where massive species introduction is in conflict with the survivorship of highly restricted endemic taxa. Resulting of a long term evolution in insularity, endemic herpetofauna was already decimated during the Pleistocene but, after the human colonisation of the archipelago, the introduction of alien species, passive or deliberate, has been provoking new extinctions and range retractions in the native herpetofauna. Such process is not interrupted but has even intensified during the last years. The current species list is composed by five amphibians (one native) and 21 reptiles (2 native). A critical review of the evidence on extinctions and introductions is provided together with the conservation implications. Compared to the last review (Mayol, 1985) six new reptile species are now naturalised or are in process of naturalization, colubrid snakes constituting the most conflicting element due to their predator role.