Source pools and disharmony of the world's island floras

摘要: Island disharmony refers to the biased representation of higher taxa on islands compared their mainland source regions and represents a central concept in island biology. Here, we develop generalizable framework for approximating these conduct first global assessment its underlying drivers. We compiled vascular plant species lists 178 oceanic 735 regions. Using data only, modelled turnover as function environmental geographic distance predicted proportion shared between each region. then quantified over- or under-representation families individual (representational disharmony) by contrasting observed number against null model random colonization from pool, analysed effects six family-level functional traits resulting measure. Furthermore, aggregated values representational per characterize overall taxonomic bias given flora (compositional disharmony), this second measure four biogeographical variables. Our results indicate considerable variation both within among families. Examples generally over-represented include Urticaceae, Convolvulaceae almost all pteridophyte Other such Asteraceae Orchidaceae were under-represented, with local peaks over-representation known radiation hotspots. Abiotic pollination lack dispersal specialization most strongly associated an insular families, whereas other showed minor effects. With respect compositional disharmony, large, high-elevation tended have disharmonic floras. provide important insights into taxon- island-specific drivers disharmony. The proposed allows overcoming limitations previous approaches provides quantitative basis incorporating phylogenetic future studies