title: Islands contribute disproportionately high amounts of evolutionary diversity in passerine birds.
abstract: Island systems generally have fewer species than continental areas due to their small size and geographical isolation. Low island diversity reduces the possibility of exportation of island lineages and island systems are not thought to have a major influence on the build-up of continental diversity. However, the view that islands represent the end of the colonization road has recently been challenged and islands do represent the origin of some specific continental lineages. Here we assess the net contribution of island systems to global diversity patterns of passerine birds, using a complete phylogeny (5,949 species), biogeographical regionalization and null-model comparisons. We show that, in contrast to major continental regions, island regions export relatively more evolutionary lineages than would be expected based on current distributional patterns. This result challenges a central paradigm in island biogeography and changes our perception of the relative importance of islands for the build-up of global diversity.
authors.affiliation: Department of Life Sciences, Imperial College London, Silwood Park Campus, Ascot SL5 7PY, UK.|Department of Life Sciences, Natural History Museum, Cromwell Road, London SW7 5BD, UK.
authors.forename: Knud A
authors.initials: KA
authors.lastname: Jønsson
authors.affiliation: Department of Life Sciences, Imperial College London, Silwood Park Campus, Ascot SL5 7PY, UK.
authors.forename: Ben G
authors.initials: BG
authors.lastname: Holt
mesh_terms: D000818:Animals; D044822:Biodiversity; D005075:Biological Evolution; D005843:Geography; D062312:Islands; D046109:Passeriformes; D010802:Phylogeny