Individual-level interactions with neighbors and the surrounding environment are key factors influencing performance that ultimately structure and maintain the diversity of tropical plant communities. However, discerning the main drivers of individual performance and how they are linked to individual phenotypic variation within communities remains unknown. We address these outstanding challenges by utilizing an unprecedented dataset containing individual-level demographic and functional trait data for tropical tree seedlings to quantify the influence of trait dissimilarity among neighbors and individual trait variation on survival and growth.
The results show traits associated with resource acquisition do not explain observed negative density dependence occurring in seedling communities. However, irrespective of the trait dissimilarity among neighbors, individuals with relatively larger investments in leaf allocation are able to attain higher growth rates. Combined, these results indicate that focal individual trait values govern seedling growth, but the functional traits of neighbors related to resource acquisition do not influence focal individual growth rates or observed negative density dependence thereby also suggesting a strong role for shared host-specific pests in tropical tree communities.