An overview of the natural history of non-indigenous amphibians and reptiles

In his Naturalis Historia (77 AD), Pliny the Elder wrote: “Mirium rerum naturam non solum alia aliis dedisse terris animalia, sed in eodem quoque situ quaedam aliquis locis negasse” [It is a remarkable fact that nature not only assigned different countries to different animals, but that, even in the same country, it denied certain species to particular localities] (book VIII 83). Pliny the Elder, an erudite natural philosopher and encyclopaedist, could not imagine that, as a side-effect of whatwe currently call globalization, an ever increasing number of animals and plants would have beenmoved from one place to another outside their natural range. It is somehow an odd connection that ancient Romans were among the main early actors in fostering the movement of species within the European and Mediterranean regions. Besides several species of mammals and birds introduced for food or hunting, Romans probably also contributed to the movement of reptiles. For example, at that time, pond turtles (i.e. Emys orbicularis Linnaeus) were already kept as pets, as were various land-dwelling tortoises, Testudo Linnaeus spp. Indeed, ancient Romans were not the very first people contributing to the spread of non-indigenous species, because many introductions are known at least since the Neolithic (Kraus 2003), especially in the Mediterranean region (Pleguezuelos 2002). Thus, introductions probably started centuries before Pliny’s time, but certainly since then, a growing number of species has been involved in this global reshuffling. The result is that today about 270 species of amphibians and reptiles are known to exist in countries outside their natural range (Lever 2003) and an unknown number has been subject to other small scale translocations.