Phylogenetic or functional community dispersions do not translate into demographic benefits or costs

Despite strong theoretical expectations, empirical evidence linking plant community structure to demographic performance remains limited. In this study, we examine how multiple facets of phylogenetic and functional community structure relate to the community-level population growth rate (λ) of Securidaca longepedunculata, a tropical medicinal plant of ecological and conservation importance. To this end, we integrated demographic data with plant community metrics, as well as data on herbivory, harvesting pressure, and environmental data. Using a structural equation modelling framework, we assessed the effects of these variables on λ. Our results show that environmental variables consistently predict herbivory, while different components of phylogenetic structure have contrasting effects on functional diversity and plant-herbivore interactions. Contrary to prevailing assumptions, none of the community structure metrics directly influenced λ, challenging simple biodiversity-demography linkages in plant communities. Collectively, our study offers new insights into how different facets of phylogenetic structure may have contrasting ecological consequences and reveals that that community dispersions do not translate into demographic benefits or costs for S. longepedunculata.