Investigating the puzzling genetic structure of mallard populations (Anas platyrhynchos L.) in Italy

The mallard (Anas platyrhynchos L.), the most abundant waterfowl species, is an important migratory component of the Holartic fauna. In Europe, massive numbers of farm-reared mallards of unknown genetic origin are released into the wild for hunting and in urban areas for ornamental purposes. Human manipulations have caused shifts in range, influenced migration propensity, led to behavioural modifications and altered the genetics of this duck species. With the aim to contribute to knowledge on the genetic consequences of large-scale game releases of mallards in southern Europe, we analysed the relationship among 245 individuals (wild and captive-bred) from eight localities in central and northern Italian regions and four from North America, by using nine microsatellite loci. In most Italian sites, a large admixture of mallard strains were observed, whereas significant genetic differentiation levels were found between urban and wild populations and among the wild population from North America and all European populations.