Abstract: Based on field investigations in and remote-sensing images of the Yangtze Estuary in 1980, 1990, 2000 and 2010, and taking references of reports from international and domestic literature about potentials of wetlands, similar to those in the Yangtze Estuary in vegetation and meteorology, of removing nutrient substances, such as N and P, in the waterbody, the potentials of the tidal wetlands in the Yangtze Estuary were assessed and their changes predicted. Results show that along with the expansion of land and total wetland and changes in wetland landscape triggered by poldering, N removing potential of the tidal wetlands at the Yangtze Estuarine increased from 710.53~4 039.37 t in 1980 to 5 137.68-9 305.83 t in 2010, and P removing potential did from 64.62~408.55 t in 1980 to 886.45-1 228.08 t in 2010. In the past 30 years, N removal potential of the three dominant salt marsh vegetation outside the dike increased by 800-1 100 t, and P removal potential did by about 60-70 t. But their contribution to the total N and P removal dropped by 44-71 and 62-84 percentage point, respectively, especially Scirpus and Phragmites communities, whose contributions to the total N and P removal followed a steady downward trend. In contrast, the contribution from Spartina alterniflora, an exotic species, increased from 0% to 0% to 17%-24% and 10%-19%, respectively. The assessment may provide some scientific basis for improving water quality and protecting water sources and wetlands in the Yangtze Eestuary.

Key words: nitrogen, phosphorus, removal capacity, ecosystem function, Yangtze Eestuary wetland