Distribution of a recolonising species may not reflect habitat suitability alone: the case of the Eurasian otter (Lutra lutra) in southern Italy

摘要: Management of recolonising species needs precise knowledge concerning those environmental parameters that can influence the current distribution at margins their range and potential for further expansion. The otter (Lutra lutra) is one most endangered Italian fauna. After a sharp decline, it has gradually recovered and, present, confined to southern Italy. At boundaries range, two geographic 15 habitat variables on (estimated by 1-year monitoring 18 spraint-sampling stations) was assessed, improve management efficacy. Latitude represented main source variation in spraint-collection data. fact well established central northern areas, whereas western sampling stations showed an unstable river occupancy (the average percentage positive surveys being 94.5 35.8%, respectively; U = 0, P = 0.0014). Secondarily, relative abundance positively associated with degree cover aquatic macrophytes. Our results suggest whole analysed hydrographic network offers suitable otters. Thus we argue discontinuous observed our study area could be consequence decline suffered populations during 1970s 1980s. trend last decades resulted progressive recolonisation empty patches, process still hindered lack connectivity extant populations. findings have implications landscape restoration projects, suggesting provision alone may not sufficient effect some species.