Abstract: Due to the food shortage in Shengjin Lake, many wintering water birds would forage the adjacent intermittent wetland, such as paddy and water meadow. In order to understand the impacts of wintering water bird populations on the nutrient input to these intermittent wetlands, two paddies and one water meadow inhabited by wintering tundra swan and bean geese at the west Xiaolu mouth along Shengjin Lake were selected as our study object, with ditches as control (with same water source as paddy and water meadow). During the early, middle and late wintering season of 2016-2017, surface water samples and guanos from these wetlands were collected and analyzed for the concentrations of nitrogen and phosphorus. Meanwhile, the water bird populations were also monitored. The concentrations of total nitrogen (TN) and total phosphorus (TP) in waters from water meadow were significantly higher than those in the control, indicating intense impacts from bean geese populations. In early wintering season, the concentrations of TN and TP in waters from paddy 1 were significantly higher than those in the control, indicating intense impacts from tundra swan populations. In the middle and late wintering season, the concentrations of TN and TP in waters from paddy 1 and paddy 2 showed insignificant differences compared to the control, indicating weak impacts from water birds. Other forms of nitrogen and phosphorus in wetland water samples showed different variations, due to multiple influences such as water bird activities and guano decomposition. Our results indicate that nitrogen and phosphorus status in the intermittent shallow wetlands suffer different impacts from the habitation and feeding of wintering water birds.

Key words: yield, rice-wheat double cropping, resource distribution, resource utilization efficiency