Current climate, isolation and history drive global patterns of tree phylogenetic endemism

Aim: We mapped global patterns of tree phylogenetic endemism (PE) to identify hotspots and test hypotheses about possible drivers. Specifically, we tested hypotheses related to current climate, geographical characteristics and historical conditions, and assessed their relative importance in shaping PE patterns. Location: Global. Time period: We used the present distribution of trees, and predictors covering conditions from the mid-Miocene to present. Major taxa studied: All seed-bearing trees. Methods: We compiled distributions for 58,542 tree species across 463 regions worldwide, matched these to a recent phylogeny of seed plants, and calculated PE for each region. We used a suite of predictor variables describing current climate (e.g. mean annual temperature), geographical characteristics (e.g. isolation) and historical conditions (e.g. tree cover at the last glacial maximum) in a spatial regression model to explain variation in PE. Results: Tree PE was highest on islands, and was hig...