Abstract: In order to reveal the hydro environmental factors affecting the community composition of wetland submerged plants, and to approach the possibility of using certain submerged plant species or communities as the direct indicators in detecting hydroenvironment, a field investigation was conducted on nine freshwater wetlands in Beijing. The plant fresh mass, wetland hydrological parameters (flow rate and water depth), and water physical and chemical parameters (transparency, temperature, conductivity, pH, redox potential, total nitrogen, total phosphorus, and chemical oxygen demand) were measured, and DCCA ordination was made. Based on the ordination, and by using two way classification matrix, the fourteen wetland submerged plant species in Beijing were classified into ten groups. According to the comprehensive analysis on the measured variables, the factors affecting the community composition of the wetland submerged plants were flow rate, total nitrogen concentration, chemical oxygen demand, conductivity, and redox potential, among which, flow rate was the key. Different submerged plant communities had indicative significances for the wetland hydro environment. For example, the occurrence of  Myriophyllum spicatum + Potamongeton crispus community was an indicator for severe eutrophication, while that of  Batrachium pekinens community could be regarded as an indicator of better water quality.

Key words: Black soil, Farmyard manure, Microbial biomass, Growth season, Dynamic change