长江口滩涂围垦后水鸟群落结构的变化——以南汇东滩为例

近年来长江口滩涂湿地高强度的促淤围垦对生物多样性保育造成了严重影响。本研究于2006至2010年在南汇东滩进行了水鸟调查，研究围垦后堤内环境的快速演替过程对水鸟的群落结构的影响。通过分析鸻鹬类、雁鸭类和鹭类三类主要水鸟类群，结果表明鸻鹬类的总数呈严重下降趋势（ANOVA, p=0.009），而雁鸭类和鹭类总数在上升（ANOVA，p=0.015；p=0.00）；在种类数量方面，鸻鹬类和雁鸭类差异不显著（ANOVA，p=0.597；p=0.523），鹭类种类数变化极显著（ANOVA ,p=0.00）。同时，通过对水鸟的栖息地选择因子偏好的分析， 发现滩涂减少是鸻鹬类减少的主要因素，而大型鱼塘和芦苇增加是雁鸭类和鹭类增加的重要原因。为此我们提出相应海岸带湿地管理建议。

Change of waterbird community structure after the intertidal mudflat reclamation in theYangtze River Mouth: a case study of NanHui Dongtan area

Recently, the intensive coastal engineerings in Yangtze River Mouth have put a serious influence on biodiversity conservation. In this region, some coastal engineerings like intertidal mudflat reclamation were undertaken in many sites. The engineering of reclamation is to build a seawall on the intertidal mudflat to stop tidal wave flowing into the enclosed area. With the disappearance of tidal wave, a series of environmental succession took place which made the environment inside seawall evolve to the terrestrial type in a short period. In addition to anthropogenic effects, these formal coastal wetlands were transformed into other forms of artificial wetlands, including rice paddies, fishing ponds, salt work, reservoirs and irrigations. In order to know whether waterbirds adapted to the great changes of environment and how the intertidal mudflat reclamation influencedthe structure of waterbirds, we carried out the waterbirds survey in Nanhui Dongtan coastal area of Yangtze River Mouth from 2006 to 2010. The waterbirds was divided into three groups: shorebirds(Charadriiforms), waterfowls(Anseriformes) and egrets and herons(Anseriformes). We recorded 45 species of shorebirds, 24 of waterfowls and 15 of egrets and herons. And the dominant species were Red-necked Stint(Calidris ruficollis) in shorebirds group, Eurasian Wigeon (Anas falcate), Falcated Duck(Anas penelope) in waterfowls group, Little Egret(Egretta garzetta) and Cattle Egret(Bubulcus ibis) in egrets and herons group. The study results indicted that the shorebirds abundance declined quickly after reclamation (ANOVA, p=0.009) and waterfowls and egrets including herons increased steadily (ANOVA, p=0.015; p=0.00). However, the species diversities of shorebirds and waterfowls did not appear a significant change (ANOVA, p=0.645; p=0.523) while the species diversity of egrets and herons increases significantly (ANOVA, p=0.00). The traditional reclamation way mainly destroyed natural intertidal mudflat that provides rich food resources for shorebirds forging. The loss of prefer habitat led to the sharp decrease of shorebirds abundance. But, this way might do good to waterfowls and egrets and herons. At the same time, some important species like Whistling Swan (Cygnus Cygnus bewickii) and Bean Goose (Anser cygnoides) were not observed in 2009. We also investigated the occurrence frequency of representative species in different habitats from the large scale. The waterbirds habitats were classified into five types: deep water, shallow water, vegetation, mudflat and dry land. After analyzing waterbirds habitat selection and environmental factors impacting their selection with cluster analysis, we can find out the following significant correspondences between waterbirds and the key factors: the shorebirds abundance declined due to the loss of mudflat, and waterfowls, egrets and herons increased as large fish ponds with reed bed were formed after the reclamation. The recommendations about management coastal wetlands in this area have been made in our research: 1. Human disturbance should be reduced, particularly, the resident building should be avoided to develop in the surround area and tourism activity should be controlled properly; 2. Prefer habitats for shorebirds should be resorted since this area is one of the important staging sites for migratory shorebirds, and we recommend encouraging local community to develop rice paddies or ecological fish ponds rather than intensive ones to preserve some bare mudflats for shorebirds.