Population survey of European beaver (Castor fiber Linnaeus, 1758) in the western Iberian Peninsula: insights from camera trapping and non-invasive genetics

Le résumé fourni par la source

The numerous reintroductions of European beaver (Castor fiber) over the last two centuries have played an important role in the recovery of the species across most of its native range, despite many of these efforts have not been official. In the Iberian Peninsula, where beaver was extinct for several centuries, this species was illegally released in 2003 in the north-eastern region and, since then, the species has increased its distribution along the Ebro basin. Two decades later, in 2022, new evidences of the species were reported in the Douro River basin (Salamanca, Spain), close to the Portuguese border and apparently resulting from another illegal release. Herein, we present the results of a beaver population survey in two sites of this new area in the Douro basin, using sign surveys, direct observations, camera trapping and genetic non-invasive sampling. We confirmed the presence of a minimum of 10 individuals in two tributaries of the Douro River, including two family groups with reproduction in 2023 and a potential third one. Genetic analyses of a non-invasive sample (hair) using mitochondrial DNA control region suggest that the individuals belong to the European beaver species, specifically to the western clade (subspecies C. fiber albicus-galliae-fiber). The findings of this work provide relevant information on the current status of European beaver in a transboundary area of western Iberia, contributing to support management actions that should target population monitoring, public awareness and ecological modelling to predict their future distribution.

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