College of Urban and Environmental Science Tianjin Normal University Tianjin 300387 China;
College of Environmental Science and Engineering Nankai University Tianjin 300071 China;
College of Environmental Science and Engineering Nankai University Tianjin 300071 China;
College of Environmental Science and Engineering Nankai University Tianjin 300071 China;
EMERGY analysis; sustainability; wetland ecosystem; indicators;