Global patterns and drivers of phylogenetic structure in island floras

• Published in: Scientific reports Vol. 5; no. 1; p. 12213
• Main Authors: Weigelt, Patrick, Daniel Kissling, W., Kisel, Yael, Fritz, Susanne A., Karger, Dirk Nikolaus, Kessler, Michael, Lehtonen, Samuli, Svenning, Jens-Christian, Kreft, Holger
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 22.07.2015; Nature Publishing Group
• Subjects: 631/158/670; 631/158/851; 631/158/852; 631/181/759; Adaptation; Angiosperms; Bioclimatology; Climate adaptation; Colonization; Dispersal; Ferns; Humanities and Social Sciences; Islands; multidisciplinary; Phylogenetics; Phylogeny; Plant diversity; Plant species; Plants - classification; Science; Speciation
• DOI: 10.1038/srep12213
• ISSN: 2045-2322

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.