Global patterns and drivers of phylogenetic structure in island floras

Abstract

<p> <b>Islands are ideal for investigating processes that shape species assemblages because they are isolated &nbsp;and have discrete boundaries. Quantifying phylogenetic assemblage structure allows inferences in-situ speciation. Here, we link phylogenetic assemblage structure to island characteristics across 393 islands worldwide &nbsp;and 37,041 vascular plant species (representing angiosperms overall, palms and ferns). Physical and &nbsp;bioclimatic factors, especially those impeding colonization and promoting speciation, explained &nbsp;more &nbsp;variation &nbsp;in &nbsp;phylogenetic &nbsp;structure &nbsp;of &nbsp;angiosperms &nbsp;overall &nbsp;(49%) &nbsp;and &nbsp;palms &nbsp;(52%) &nbsp;than &nbsp;of &nbsp;ferns consistent with their dispersal- and speciation-related traits and climatic adaptations. Phylogenetic &nbsp;diversity was negatively related to isolation for palms, but unexpectedly it was positively related large-seeded, animal-dispersed palm family whereas colonization from biogeographically distinct in-situ among taxonomic groups on islands, which sheds light on the origin of insular plant diversity.</b></p>