Abstract
The short-term effects of plant diversity (number of plant species and species compositions) on aboveground biomass, substrate
inorganic nitrogen (N) concentrations, and substrate solution “effluent” N concentrations were studied in a subsurface verticalflow
constructed wetland (CW). Results showed that (1) the number of plant species increased aboveground biomass (P< 0.05) but
had no effect on the overyielding index DMax; (2) the species compositions and presence of the very productive species (e.g., C.
alternifolius, A. donax) had a positive effect on plant biomass, while negative effects on substrate and substrate solution N
concentrations; (3) substrate nitrate and ammonium concentrations negatively responded to the plant diversity (P< 0.05); (4) the
plant diversity decreased substrate solution nitrate and ammonium concentrations (P< 0.05), suggesting that plant diversity
increased effluent N removal. The results confirmed that plant biomass and N removal were enhanced by plant diversity in a short
time span, and plant diversity could be managed to improve the N removal in a CW at the beginning stage (the second year after
cultivation) for wastewater treatment.