Radiocarbon evidence for the presence of mice on Madeira Island (North Atlantic) one millennium ago

Abstract

Owing to the catastrophic extinction events that occurred following theHolocene arrival of alien species, extant oceanic island biotas are a mixture ofrecently incorporated alien fauna and remnants of the original fauna. Knowl-edge of the Late Quaternary pristine island faunas and a reliable chronologyof the earliest presence of alien species on each archipelago are critical in under-standing the magnitude and tempo of Quaternary island extinctions. Until now,two successive waves of human arrivals have been identified in the NorthAtlantic Macaronesian archipelagos (Azores, Madeira, Selvagens, Canary andCape Verde Islands): ‘aboriginal’, which is limited to the Canary Islandsaround two millennia ago, and ‘colonial’, from the fourteenth centuryonwards.New surveys in Ponta de Sa ̃oLourenc ̧o (Madeira Island) have allowed us toobtain and date ancient bones of mice. The date obtained (1033+28 BP) docu-ments the earliest evidence for the presence of mice on the island. This dateextends the time frame in which the most significant ecological changesoccurred on the island. It also suggests that humans could have reachedMadeira before 1036 cal AD, around four centuries before Portugal officiallytook possession of the island.