Opposing macroevolutionary and trait-mediated patterns of threat and naturalization in flowering plants

Due to expanding global trade and movement, new plant species are establishing in exotic ranges at increasing rates while the number of native species facing extinction from multiple threats grows. Yet, how species losses and gains globally may together be linked to traits and macroevolutionary processes is poorly understood. Here we show that, adjusting for diversification rate and age, the proportion of threatened species across flowering plant families is negatively related to the proportion of naturalized species. Moreover, naturalization is positively associated with climate variability, short generation time, autonomous seed production, and interspecific hybridization, but negatively with age and diversification; whereas threat is negatively associated with climate variability and hybridization, and positively with biotic pollination, age and diversification. Such a pronounced signature of naturalization and threat across plant families suggests that both trait syndromes have coexisted over deep evolutionary time and that neither strategy is necessarily superior to the other.