Community dissimilarity of angiosperm trees reveals deep‐time diversification across tropical and temperate forests

Question To better understand the influence of deep-time diversification on extant plant communities, we assessed how community dissimilarity increases with spatial and climatic distances at multiple taxonomic ranks (species, genus, family, order) in angiosperm trees. We tested prediction that dissimilarity–distance relationship should change across depending different biogeographical regions reflecting geohistories geographical settings. Location Global. Methods Using a data set plot-based surveys globe (861 plots), compiled composition matrix comprising 21,455 species, 2,741 genera, 240 families, 57 orders. then calculated Sørensen's pairwise (βsor), its turnover (βsim) nestedness (βsne) components, among plots within seven regions. Finally, modeled relationships between biotic dissimilarities spatial/climatic each rank, compared them Results βsor βsim increased increasing distance all regions: was dominant general, while βsne showed relatively high contributions to total temperate historically unstable conditions. The βsim-distance curve more saturated smaller scales tropics than In curves became flatter higher (order or family), exception Africa, North America, Australia, pointing region-specific constraints. Conclusions Compositional generally shaped through abrupt species along gradients. importance component suggests historical dispersal filters related extinction/colonization may play important roles. Region-specific changes components suggest differential imprints over deep evolutionary time shaping diversity patterns region.