冬季水鸟对崇明东滩水产养殖塘的利用

自然湿地的丧失和退化给依赖湿地生存的水鸟带来了严重威胁,人工湿地作为水鸟栖息地的功能日益受到关注.水产养殖塘是人工湿地的重要类型之一.通过研究崇明东滩水产养殖塘冬季水鸟群落组成及其栖息地特征,发现大面积养殖塘比小面积养殖塘吸引更多种类和更高密度的水鸟.养殖塘在放水前水位较高时吸引更多游禽栖息,而在放水后水位较低时吸引更多涉禽;在放水过程中,养殖塘中水鸟的种类最多,密度最大.另外,在放水的不同时期,不同的环境因子对水鸟群落的影响不同:放水之前,养殖塘水面面积和平均水深是水鸟种类和数量的主要影响因子,其中游禽种类和数量受水面面积影响较大,涉禽种类和数量受平均水深影响较大;放水过程中,裸地面积、芦苇面积、干扰程度、平均水深和水深变异对水鸟、游禽和涉禽的种类和数量起主要作用;放水之后,水深变异对水鸟种类和数量的影响较大,而影响游禽种类和数量的主要因子是水面面积,影响涉禽种类和数量的主要因子是水深变异.研究表明,通过对影响水鸟栖息地利用的主要因子的有效管理,养殖塘在提供经济效益的同时也能为水鸟提供适宜的栖息地.

Waterbird use of aquacultural ponds in winter at Chongming Dongtan

With increasing loss and degradation of natural wetlands on which waterbirds depend, artificial wetlands as alternative habitats for waterbirds receive more and more attention. Aquacultural ponds are one of the types of artificial wetlands. In this study, we investigated waterbirds and habitat properties of aquacultural ponds at Chongming Dongtan in the Yangtze River estuary. Our results indicated that large ponds supported a greater number of species and higher bird density than the small ones. More natatores were found in ponds before drawdown when the water level was high. In contrast, more grallatores were recorded in ponds after drawdown when the water level was low. Waterbird species number and individual density in ponds were higher during drawdown than those before and after drawdown. Importance of different habitat variables to waterbird communities varied among different phases of management. Before drawdown, area of water body and average water depth of the ponds had significant effects on the species number and abundance of all waterbirds; and the species number and abundance of natatores and grallatores were affected respectively by the area of water body and the average water depth. During drawdown, area of substrate and of reeds, human disturbance, average water depth and variation of water depth had significant effects on the species number and abundance of all waterbirds, natatores and grallatores. After drawdown, variation of water depth had significant effects on the species number and abundance of all waterbirds and grallatores, while natatores were greatly affected by the area of water body. Our results suggest that with effective management of these habitat variables, aquacultural ponds can not only provide economic benefits for the locals but also serve as the habitats for waterbirds.