Plants show strong zonation patterns in wetlands. Nevertheless, the mechanisms determining these patterns remain unclear. In the present study, growth and morphological responses to a water level gradient [-20 cm (i.e., water level 20 cm below soil surface), -10 cm, 0 cm, 10 cm, 20 cm] were compared between a higher elevation plant (Imperata cylindrica) and a lower elevation plant (Carex brevicuspis) in the Dongting Lake wetlands of China. The aboveground, belowground, and total biomass were greater at -10 cm than at any other water level for bot