杭州湾及钱塘江河口南岸滨海湿地鸟类群落多样性及其对滩涂围垦的响应

Diversity of bird communities in southern Hangzhou Bay and the Qiantang River estuary and their responses to reclamation of intertidal mudflats

为了解杭州湾及钱塘江河口区域围垦过程中多种人工湿地对于鸟类的作用及在快速的土地利用方式转变过程中鸟类的响应过程,2008年11月至2011年9月,作者对上虞曹娥江口至镇海甬江口沿岸滨海湿地鸟类资源进行调查,共记录鸟类16目52科220种,其中候鸟173种,占总数的78.6%,属于国家I、II级重点保护野生动物的24种。对研究区域的8种生境的鸟类群落组成、多样性及相似性进行了比较。结果表明,记录物种数较多的生境依次为芦苇水塘(95种,占总数的43.2%)、海涂林地(93种,占总数的42.3%)、自然潮间带和海涂水库(均为78种,各占总数的35.5%),其他生境的物种数均不少于67种(占总数的30.5%以上);从不同鸟类类群的分布看,82.5%的鸻鹬类分布在自然潮间带,69.2%的雁形目鸟类出现在海涂水库,73.4%的雀形目鸟类分布在海涂林地,海涂林地也是大量鹭鸟的繁殖场所;与自然潮间带相似性系数最高的生境依次为围垦滞留区、海涂水库和芦苇水塘,相似性系数分别为0.56、0.34和0.30;从整体上看,海涂林地和海涂水库的鸟类群落G-F指数最高,自然潮间带最低,但水鸟G-F指数最高的生境类型依次为围垦滞留区、海涂水库和自然潮间带。围垦是目前对杭州湾鸟类动态影响最大的人为干扰活动,适度围垦和合理的垦后土地利用方式可能提高整个区域的鸟类多样性水平。为了有效保护杭州湾鸟类多样性尤其是依赖自然潮间带的鸟类多样性,应加强对滩涂资源的保护与可持续利用;在滩涂围垦过程中应尽量保留足够数量和面积的高潮停歇地;同时,加强对围垦滞留区的水位管理,并注重营造适合鸟类栖息的类型多样的围区人工湿地系统。

Bird communities were surveyed in southem Hangzhou Bay and the Qiantang River estuary from November 2008 to September 2011. A total of 220 bird species belonging to 16 orders and 52 families were recorded, of which, 173 （78.6%） were migrants and 24 were listed as state key protected wildlife grade I or II. The composition and diversity of bird communities in eight habitat types were compared using the G-F index and the Jaccard index. Ninety-five species （43.2%） were observed in the ponds located in Cixi Wetland Centre with common reed （Phragmites australis） marshes, 93 species （42.3%） in the coastal woodland, and 78 species （35.5%） in intertidal mudflats and coastal reservoirs. About 82.5% of the Charadriiformes species were recorded in intertidal mudflats; 69.2% of the Anatidae species in coastal reservoirs, and 73.4% of the Passeriformes species in the coastal woodland which provides the breeding habitat for the Ardeidae birds. Compared with intertidal mudflats, the highest value of the Jaccard index was obtained for bird communities in the newly reclaimed but undeveloped areas （0.56）, followed by coastal reservoirs （0.34） and ponds located in Cixi Wetland Centre with common reed marshes （0.30）. For the whole bird community, the highest value of G-F index was obtained in coastal reservoirs and coastal woodland, whereas the lowest value was recorded in the intertidal mudflats. However, newly reclaimed but undeveloped sites had the highest value of G-F in- dex for the waterbird community, followed by coastal reservoirs and intertidal mudflats. Our results indicate that suitable habitat availability and human disturbance are the main factors influencing the spatial distribu- tion of bird communities in the Hangzhou Bay and the Qiantang River estuary. The most serious human dis- turbance in this region was found to be coastal reclamation. Thus, diversity of local avian communities in the Hangzhou Bay and the Qiantang River estuary could increase if moderate-intensity reclamation and reason- able land use patterns were practiced. Moderate-intensity reclamation is the mode that maintains an intertidal wetland containing a sufficient width of mudflat and upper intertidal zone as well as other important habitat variables for shorebirds and other birds. Local governments should take action to protect the natural wetlands while using them reasonably and efficiently. It is necessary to maintain several main high-tide roosting sites with sufficient areas for shorebirds and other waterbirds. Some appropriate management measures such as controlling water level in newly reclaimed but undeveloped areas should be carried out to increase the avail- ability of suitable habitat for waterbirds. A variety of artificial wetlands should also be constructed to provide potential habitats for waterbirds and other birds after large scale coastal reclamation.