Abstract: In September-November 2008 and March-May 2009, an investigation was made on the spatiotemporal patterns of shorebirds during their migration period at Sheyang estuary of Yancheng Nature Reserve. A total of 22 shorebird species were recorded, all found in spring and 13 of them found in autumn. The dominant species in spring were Dunlin (Calidris alpina) and Red-necked stint (C. ruficollis), and those in autumn were Dunlin, Red-necked stint, and Kentish plover (Charadrius alexandrinus). The shorebirds number was obviously greater in spring than in autumn, with a ratio about 3:1. The shorebirds were mostly at natural mudflat, also at artificial wetland (aquaculture ponds), and most of them inhabited there. No significant differences were observed in the species number of the shorebirds among six habitats in the two seasons, but the density of the shorebirds had significant differences among the habitats. The density of dominant species Dunlin had significant differences among the habitats in the two seasons, while the density of Red-ecked stint had not. The density of Kentish plover had significant differences among the habitats in autumn. The Shannon-Wiener index of the shorebirds showed significant differences among the habitats in spring, but not in autumn.

Key words: Soil moisture regime, Boron, Oilseed rape, Utilization efficiency