Region effects and local climate jointly shape the global distribution of sexual systems in woody flowering plants

Abstract. Understanding the evolution and maintenance of plant sexual diversity needs to incorporate both regional processes and local climate factors across large geographic scales. Using data of woody flowering plants from a global set of large-scale forest plots and multinomial logistic regression, we quantified region effects on the proportion of dioecy, monoecy, and hermaphrodite species count and abundance while incorporating evolutionary history and local climate factors. We demonstrated that plants were more likely to be dioecy than monoecy in tropical regions than in temperate regions, supporting the role of colonization processes suggested by Baker’s law in structuring the geographic patterns of plant sexual systems. We further found plants were more likely to be dioecious than monoecious in areas with younger mean species age. Plants were more likely to be hermaphrodite than dioecious in areas with high annual potential evapotranspiration and precipitation seasonality but were more likely to be dioecious than monoecious in areas with high precipitation of driest month. Our results suggest that both regional processes and local climate factors play important roles in shaping the geographic distribution of plant sexual systems, providing a baseline for predicting future changes in forest communities under global change.