Functional Traits as Predictors of Global Dominance and Prevalence in Herbaceous Plants

ABSTRACT Aim Understanding why some plant species are abundant or widely distributed is a long‐standing aim of plant ecology. This research investigated whether the position of herbaceous plant species within the plant economics spectrum (aboveground and belowground) and along the mycorrhizal collaboration gradient could explain their local abundance, geographic occupancy, and global abundance. Location Global. Methods We used two published sources of global plant community data (sPlotOpen and the global biodiversity initiative facility; GBIF) to determine whether the local abundance, geographic occupancy, and global abundance of herbaceous plant species can be explained by their above‐ and belowground traits and estimates of mycorrhizal dependence and flexibility. Results Both above‐ and belowground traits were only weakly associated with local abundance, while geographic occupancy was associated with small plant size and traits indicating fast return on investment in aboveground tissues. Geographic occupancy was also related to belowground traits, being positively associated with specific root length and negatively associated with root diameter, and weakly positively associated with mycorrhizal flexibility. The traits associated with global abundance largely mirrored those associated with occupancy. Main Conclusions Our analysis suggests that the local success of herbaceous plants is context‐specific and there are no universal traits globally underlying high local abundance. By contrast, geographic occupancy aligns strongly with belowground traits, including specific root length and root diameter. The wide success of fine‐rooted species may be related to nutrient enrichment during biogeographic history and in recent increasingly anthropogenic conditions.