Conservation status of Eurasian Otter Lutra lutra in Italy

The southern Italian otter population is considered an ESU, as it is completely isolated from other European populations. The two former disjointed nuclei of this core population are now a unique metapopulationb. Expansion at the edge of this range is proceeding inconstantly with presence/absence varying year by year, especially in Abruzzo and Apulian rivers (Foro, Pescara, Alto Sangro, Candelaro) (Fig. 1). However, despite not all grid cells were resampled over time and sampling designs were not homogeneous and consistent along time and space, all trends are positive (Fig. 2). As to northern Italy, the otter expansion in Austria and Slovenia promoted the return of the species on the eastern Alpine chain since 2011, where its rapid expansion is giving hope for the establishment of a viable population in the short-medium term. Also, a new nucleus on the western part of the Alps was detected in 2020 on the Roya catchmenti across the French border. The Italian Alpine range is also hosting a isolated B-line population in the Ticino river, a population derived from reintroduction of individuals crossbred with L. l. barang. However, a recent study revealed this population is likely unviable and no otter signs have been recorded in the area since 2018 (Fig. 1).