Phylogenetic relatedness, not geographic origin, shapes traits across ontogenetic stages for common native and exotic plants in subtropical China

Abstract Functional traits, which shift as a plant develops from seed to adult and may be phylogenetically conserved, are widely acknowledged to be associated with exotic species invasion. However, existing studies comparing functional traits between native and invasive species often focus on a single ontogenetic stage, yielding mixed results. It remains unclear whether the functional trait differences and their relationship with invasiveness (e.g. range size) of exotic species remain consistent across ontogenetic stages. In this study, we experimentally compared 18 traits across the seed, early growth and adult stages of 127 native and exotic species from 19 families. These species are common and often co‐occur in the subtropical region of China. We also explored the linkage between these traits, alongside their phylogenetic relatedness with native species and exotic species' range size in China. Our results show that only seed mass differed between native and exotic species. Moreover, the compositions of traits across all stages and the entire lifespan were primarily influenced by phylogenetic relatedness rather than geographic origin. Further, the range size of exotic species in China positively correlated with their mean phylogenetic distance to native species, with no association with individual functional traits or functional distinctiveness. Synthesis . Our results emphasize the importance of comparing functional traits across ontogenetic stages between native and exotic species to improve our understanding of the role of functional traits in shaping plant invasion. Our findings also underscore the pivotal role of phylogenetic relatedness in shaping plant functional traits and the distribution of exotic species in their new ranges.