长江口杭州湾鸻形目鸟类群落季节变化和生境选择

在长江口南岸杭州湾北岸滨海滩涂进行了鸻形目鸟类的资源调查,以及鸟类栖息地选择模式分析,2004年3月至2005年1月共统计到鸟类25种,春季优势种为大缤鹬(Calidris tenuirostris)、尖尾缤鹬(Calidris alpine)和红颈滨鹬(Calidris ruficollis);夏季为环颈(Charadrius alexandrinus)、青脚鹬(Tringa nebularia)和蒙古沙(Charadrius mongolus),秋季为环颈、红颈滨鹬和青脚鹬,冬季为黑腹滨鹬(Calidris alpina)、环颈和泽鹬(Tringa stagnatilis),鸟类总体数量呈春季>秋季>冬季>夏季,海堤外(自然滩涂)和堤内(人工湿地)鸟类种数四季大致相等,但鸟类平均密度季节差异显著。通过对样点内鸟类与环境因子进行多元分析,初步总结出堤外滩宽和光滩宽是影响鸟类栖息的最关键因子,海三棱草(Scirpus× mariquete)覆盖比例和潮上坪宽度的影响程度次之。堤内浅水塘比例和裸地比例是影响形目鸟类分布的关键因子,海三棱草覆盖比例也起正向作用。而人类干扰大、芦苇(Phragmites communis)/互花米草(Spartina alternifloral)密植和高水位的区域不利于鸟类利用。

Seasonal change and habitat selection of shorebird community at the south Yangtze River Mouth and north Hangzhou Bay

Coastal regions are important habitats for migratory shorebirds. The aim of the study is to understand the habitat use by the migratory shorebird and to develop a conservation strategy in sustainable-use of wetland and the migrants. From March 2004 to January 2005, we conducted seasonal shorebirds censuses in ten coastal habitats along the south Yangtze River mouth and North Hangzhou Bay, examining the relative seasonal abundance of shorebirds and their spatial distribution simultaneously. A total of 25 species were identified, the seasonal dominant species were Great Knot (Calidris tenuirostris), Sharp-tailed Sandpiper (Calidris alpine) and Red-necked Stint (Calidris ruficollis) in spring; Kentish Plover (Charadrius alexandrinus), Common Greenshank (Tringa nebularia) and Lesser Sand Plover (Charadrius mongolus) in summer; Kentish Plover, Red-necked Stint and Common Greenshank in autumn; Dunlin (Calidris alpine), Kentish Plover and Marsh Sandpiper (Tringa stagnatilis) in winter. These species accounted for more than 85% of all shorebirds counted. The numbers of shorebirds counted were highest in spring and then in autumn, winter and summer consequently. Among the four seasons, there were little significant differences of bird species abundance between the sites outside seawall (natural mudflat) and the sites inside seawall (artificial wetland), but the average density of shorebirds had obvious difference. The habitat-selection analysis of the environmental-factor (outside and inside the seawall) impacting on the shorebird community was made in the ten study sites with Canonical Correspondence Analysis. The study results indicated that: (1) Outside the seawall, total intertidal the widths of intertidal mudflat and bare mudflat were the key factors affecting the shorebirds; the proportion of bulrush (Scirpus×riqueter) covering and supertidal mudflat width had the positive correlation with the bird abundance, the human disturbance and the proportion of reed (Phragmites communis)/smooth cord-grass (Spartina alterniflora) covering had the negative impacts on the bird contribution; (2) Inside the seawall, mudflat with sallow water and the proportion of mudflat were the key factors to increase the bird abundance; the proportion of bulrush covering should benefit to the shorebird appearance. The habitats with heavy human disturbance, dense reed and smooth cord-grass bed or high water table were not good to be used by shorebirds.