鄱阳湖越冬季候鸟栖息地面积与水位变化的关系

The Wintering Habitats of Migrant Birds and Their Relationship with Water Level in Poyang Lake,China

本文考虑了候鸟在越冬期的生态习性、食物选择及生境偏好等因素,确定了鄱阳湖候鸟栖息地的划分标准和划分方法。并运用RS和GIS技术,确定了典型年份以及特征水位下候鸟栖息地的面积,同时利用统计方法,分析了栖息地面积及其内部结构与水位之间的关系,并从湿地与候鸟保护的角度,评估了拟建的鄱阳湖水利枢纽工程的水位调控方案对候鸟栖息地可能的影响。结果表明:①鄱阳湖水鸟基本上都分布在莎草草滩、泥滩洼地和水深不超过60cm的浅水区;②在候鸟越冬的不同阶段,鄱阳湖湿地可以提供的候鸟栖息地面积为天然湿地面积的24%-63%,栖息地面积受水位变化的影响较大,冬春季的枯水位,没有对候鸟及其栖息地造成灾难性的影响,但水位在11～12m(吴淞高程)时,可以提供的栖息地面积最大,水位再升高,栖息地面积急剧减小,当水位超过14m(吴淞高程)时,将可能无法维持现有候鸟的栖息需求。

Poyang Lake is the largest lake in China, offering an important stopover site formigratory bird along the East Asian-Australasian Flyway. Lower water levels and longer dryseason persisting in Poyang Lake in recent years would affect such a process. In this context aproject for Poyang lake water-control project is being launched by the local government. Impact ofincreased water level on aquatic organisms, especially on waterfowl, has become a significantissue. The purpose of this study is to investigate the effect of water level changes on migratorybirds. Considering elements of ecological feature, food selection, and habitat preference of migrantbirds during the wintering period, approaches and standards to distinguish bird habitats arepresented. In the meanwhile, 25 scenes of satellite imageries from 2000 to 2008 and long timeseries water level data from 1962 to 2008 were jointly used to classify waterfowl habitats. Therelationship among areas of habitat and water level are analyzed in detail. Effects of the planningPoyang Lake key water-control project on migrant birds and their habitats were comprehensivelyevaluated, with providing measures to conserve wetland and migrant birds. Results indicated that：1） in terms of feeding characteristics, waterfowl can be conceptually divided to six functionalgroups, and the diverse functional groups had a variety of feeding targets. Birds select feeding sitesin accordance with food abundance and accessibility. Most of waterfowls are distributed alongzones with sedge marsh, mudflats, or shallow water less than 60 cm deep; and 2） habitat areassuitable for migrant birds account for roughly one forth to two thirds of the Poyang Lake wetland atdifferent stages in winter. Habitat areas are strongly affected by a changing water level,particularly, more sensitive when the water level is high. Lower water levels in winter and springhad an immaterial effect on birds and their habitats. The habitat area is generally large when thewater level reaches 11 m and 12 m （Wusong elevation）. The habitat areas sharply shrink withwater level rising; In this situation, it is diffcult to find the suitable habitat for birds when waterlevel is higher 14 m （Wusong elevation）.