Mammals of the Mediterranean islands: homogenisation and the loss of biodiversity

There is possibly no other location in the world which has been so intensively influenced by human activity over a prolonged period as the Mediterranean. Virtually no ecosystems have been left untouched. Since prehistory, the human settlers of the Mediterranean islands brought about a radical turnover between ancient and modern mammalian faunas, introducing a variety of allochthonous continental taxa. The data available for the Mediterranean islands point to endemic mammalian extinction being largely the result of human activities of land clearance and the introduction of allochthonous animals. Today, this fauna is no longer characterised by the majority of the endemic mammals previously reported. It displays virtually the same species composition, being almost exclusively characterised by continental mammals whose appearance on the islands has essentially been influenced by man, and dominated by generalist species. The invasion of ecosystems by exotic taxa is currently viewed as one of the most important causes of the loss of biodiversity. Today, in view of the vulnerability of the insular ecosystems it is critically important to prevent further introductions. But this results in the question of how to treat the allochthonous mammalian populations of certified ancient anthropochorous origin, which instead deserve to be protected and considered in terms of a veritable "cultural heritage". Moreover, their protection and their study can provide an opportunity for testing a range of different evolutionary theories.