The masked invader strikes again: The conquest of Italy by the Northern raccoon

The Northern raccoon Procyon lotor is a species native to North and Central America, but alien populations have established in Europe, several Caribbean islands, Azerbaijan, Uzbekistan and Japan, being introduced for fur farming, hunting, or as pets/attraction in animal parks. In the introduced range, raccoons may impact on breeding birds and amphibians, exert crop damages and transmit pathologies to wild species and humans. The species has been introduced also in Italy, where the only known reproductive population is observed since 2004 in Lombardy, along the Adda river. We reconstructed the current distribution range of the Northern raccoon in Italy, collecting information from scientific papers, articles in newspapers and books, as well from experts and local reporters. A total of 53 occurrence points were collected from observation sites. Since 2008, records from Lombardy increased, and sporadic observations were reported from seven other regions. A complete lack of records from the Northernmost provinces of Lombardy (Varese, Como and Sondrio) suggests that the only Italian population does not derive from a range expansion from Switzerland, but it should be considered as an independent, new introduction. Accidental observations of single individuals possibly escaped from captivity are often ignored, and only few animals were removed from the wild. An analysis of the potential distribution of the species was performed in a species distribution modeling framework (MaxEnt). A global model was built up considering the occurrences of reproductive populations from the native range and introduced areas in Europe and Japan and then projected to Italy. The model suggested a good suitability for the plains in Central-Northern Italy and a very low suitability of the Alpine region, thus providing support to the hypothesis that the Italian population did not derive from dispersal from Switzerland. If escapes or releases of raccoons will continue, there is a risk that the species could colonize other areas, making its containment more difficult.