Generation of raptor diversity in Europe: linking speciation with climate changes and the ability to migrate

Abstract

AbstractAimEurope should be considered as a diversity hotspot for diurnal raptors, but just during the breeding season, as it holds the higher proportion of transcontinental migratory species of any landmass, and the area becomes depleted during the winter period. This study will test the hypothesis that the high diversification of the raptor assemblage in Europe is a recent event, occurring mainly during the Quaternary, and that closely related species sharing the same trophic niches can only coexist in sympatry during the breeding period, when food availability is higher.LocationContinental Europe.TaxonDiurnal birds of prey (Accipitriformes and Falconiformes).MethodsA consensus molecular phylogeny for the 38 regular breeding species of raptors in Europe was obtained from BirdTree. For the same species, a trophic niche cluster dendrogram was constructed. Size and migratory strategy were introduced in the resulting phylogeny, where trophic groups were also identified.ResultsA total of 16 trophic groups were identified. Multispecific trophic groups tended to be composed of reciprocal sister species, while monospecific groups (only three) were composed of highly specialized species. According to time calibrated phylogenies, the speciation events took place during the glacial cycles of the Quaternary period in a majority of cases. During the non-breeding season, the smaller species in every trophic group migrate to sub-Saharan Africa, whereas larger species are either non-migratory or perform shorter migrations within Europe and/or northern Africa.Main conclusionsThis investigation illustrates how the rich assemblage of diurnal birds of prey in Europe, more diverse and more migratory than the North American assemblage at equivalent latitudes, has emerged recently due to the multiplication of look-alike species with similar trophic ecologies, mainly in climate refugia during cold periods. In the non-breeding season, when shared food resources are limited, smaller species migrate to Africa and alleviate competition.