Format: ORAL

Shogo Ikari1, Takayuki Shiono1, Kubota Yasuhiro1

1 Faculty of Science, University of the Ryukyus, JPN

We focused on the impact of paleoclimate changes on large-scale taxonomic sorting related to geography; specifically, how cooler and warmer climatic conditions  affect  the  distance-dependency  of  beta  diversity. Using a dataset of Cenozoic fossil assemblages of  angiosperm  woody  plants  (7,468  data  points;  310  genera in 95 families) in the Japanese portion of the East  Asian  archipelago  (except  Ryukyu  islands),  we  modeled  the  distance-dependency  of  genus  turnover  (pairwise  compositional  dissimilarity)  through  the  Oligocene, Miocene, Pliocene, Pleistocene, Last Glacial Period, Holocene, and present day. The genus turnover of angiosperm woody plants was significantly correlated with geographical and climatic distance only in the Last Glacial  Period,  Holocene,  and  present  day.  During  the  Oligocene to Pliocene, the warmer periods, genus turnover was  mostly  independent  of  geographical  distance.  Spatial/climatic distance-dependent turnover under colder environments involved a climate-induced sorting process to spatially diversify woody-plant assemblages across  the  archipelago.  Moreover,  the  predominance  of distant-independent turnover suggested the effect of dispersal release under warmer, stable climates. Our findings suggest that future tropicalization in temperate habitats could promote geographical homogenization of biodiversity patterns.