title: Global patterns and drivers of phylogenetic structure in island floras.
abstract: Islands are ideal for investigating processes that shape species assemblages because they are isolated and have discrete boundaries. Quantifying phylogenetic assemblage structure allows inferences about these processes, in particular dispersal, environmental filtering and in-situ speciation. Here, we link phylogenetic assemblage structure to island characteristics across 393 islands worldwide and 37,041 vascular plant species (representing angiosperms overall, palms and ferns). Physical and bioclimatic factors, especially those impeding colonization and promoting speciation, explained more variation in phylogenetic structure of angiosperms overall (49%) and palms (52%) than of ferns (18%). The relationships showed different or contrasting trends among these major plant groups, consistent with their dispersal- and speciation-related traits and climatic adaptations. Phylogenetic diversity was negatively related to isolation for palms, but unexpectedly it was positively related to isolation for angiosperms overall. This indicates strong dispersal filtering for the predominantly large-seeded, animal-dispersed palm family whereas colonization from biogeographically distinct source pools on remote islands likely drives the phylogenetic structure of angiosperm floras. We show that signatures of dispersal limitation, environmental filtering and in-situ speciation differ markedly among taxonomic groups on islands, which sheds light on the origin of insular plant diversity.
authors.affiliation: 1] Biodiversity, Macroecology &Conservation Biogeography Group, University of Göttingen, 37077 Göttingen, Germany [2] Systemic Conservation Biology, University of Göttingen, 37073 Göttingen, Germany.
authors.forename: Patrick
authors.initials: P
authors.lastname: Weigelt
authors.affiliation: Institute for Biodiversity and Ecosystem Dynamics (IBED), University of Amsterdam, 1090 GE Amsterdam, The Netherlands.
authors.forename: W Daniel
authors.initials: WD
authors.lastname: Kissling
authors.affiliation: Biodiversity, Macroecology &Conservation Biogeography Group, University of Göttingen, 37077 Göttingen, Germany.
authors.forename: Yael
authors.initials: Y
authors.lastname: Kisel
authors.affiliation: Biodiversity and Climate Research Centre (BiK-F) &Senckenberg Gesellschaft für Naturforschung, 60325 Frankfurt, Germany.
authors.forename: Susanne A
authors.initials: SA
authors.lastname: Fritz
authors.affiliation: 1] Institute of Systematic Botany, University of Zurich, 8008 Zurich, Switzerland [2] Department of Biology, University of Turku, 20014 Turku, Finland.
authors.forename: Dirk Nikolaus
authors.initials: DN
authors.lastname: Karger
authors.affiliation: Institute of Systematic Botany, University of Zurich, 8008 Zurich, Switzerland.
authors.forename: Michael
authors.initials: M
authors.lastname: Kessler
authors.affiliation: Department of Biology, University of Turku, 20014 Turku, Finland.
authors.forename: Samuli
authors.initials: S
authors.lastname: Lehtonen
authors.affiliation: Section for Ecoinformatics &Biodiversity, Department of Bioscience, Aarhus University, 8000 Aarhus C, Denmark.
authors.forename: Jens-Christian
authors.initials: JC
authors.lastname: Svenning
authors.affiliation: Biodiversity, Macroecology &Conservation Biogeography Group, University of Göttingen, 37077 Göttingen, Germany.
authors.forename: Holger
authors.initials: H
authors.lastname: Kreft
mesh_terms: D010802:Phylogeny; D010944:Plants / Q000145:classification*