Genetic Variability and Family Relationships in a Reintroduced Osprey (Pandion haliaetus) Population: A Field-Lab Integrated Approach

Abstract

Reintroductions represent an opportunity to restore local biodiversity and reverse the effect of taxa extinction. However, they need feasibility and monitoring plans before and during their implementation to ensure concrete and lasting results. During the 20th century, the osprey (Pandion haliaetus) underwent a severe population decline in many European countries due to direct persecution and coast exploitation. In the 1960s–1970s, it was declared extinct as a breeder in Italy. In 2004, the Maremma Regional Park (Tuscany, central Italy) started a reintroduction project by capturing and releasing, from 2006 to 2010, 33 juvenile Corsican ospreys on the southern coast of Tuscany. The settlement of the first breeding pair in 2011 was the initial sign of the success of the reintroduction project, then further pairs settled from 2011 onward. A total of 81 feather or blood samples were collected for DNA extraction from both translocated (2006–2010) and newborn individuals (2011–2021). Individuals were analyzed at 16 microsatellite loci to verify any changes in genetic variability over time and to set out a protocol for the reconstruction of kinship for conservation and management purposes. We did not observe a reduction in genetic variability between the two sampling periods, although we found a slight sign of the founder effect in the reestablished population. A strong genetic differentiation was observed between this Mediterranean population and an injured osprey from a Northern European population, thus confirming the importance of considering the local genetic pool in any reintroduction project. Monogamous behavior was confirmed by family reconstruction, which allowed the identification of clear kinship relationships. Our findings indirectly inform on the genetic variability of the population during the 16-year period from the start of the project and provide useful insights for its long-term conservation.