Journal Article Research Support, Non-U.S. Gov't Research Support, U.S. Gov't, Non-P.H.S. Soil root traits species coexistence subtropical forest DNA barcoding RLQ analysis RNA, Ribosomal, 16S alternative functional designs biogeography carbon climate change community assembly demography dispersal environmental filtering functional diversity functional traits host selection intraspecific trait variation latitudinal diversity gradients limiting similarity multiple performance peaks net primary productivity niche differentiation niche-neutral continuum null model performance landscapes