浅水通江湖泊越冬水鸟取食集团对食物资源变化的时空和功能响应机制研究

The lakes in the middle and lower Yangtze River flood plain are important habitats for wintering waterbirds on the East Asian-Australian flyway. Increasingly habitat degenerations are resulted from the anthrologic and natural disturbances. The food resources for waterbirds in the lakes are faced with depletion. It's urgent to shed light into the mechanism of the responses of waterbirds to the habitat variation. In this proposal, we will survey the wintering waterbirds and their habitats based on remote sensing,hydroacoustics,reomte monitoring,conduct the study of spatial and functional ecology about wintering waterbirds,including the population patterns,foraging guild structure, and the niche breath relative to the food resources,so as to understand the support mechanism of waterbird communities wintering in the middle and small shallow river-connected lakes in the Anhui Yangtze River flood plain. This study is aimed to have a light into: a) the effects of aquatic vegetation,especially surbmeged vegetation and benthic invertebrates on the distribution patterns of waterbirds; b) the characateristcs of resource partitioning and niche shifts, tempo-spatial responses of guild structure to food resources, and the support mechanism of wintering waterbird communities; c) the effects of the variation of food resources on foraging behaviors and carrying captivity, and the functional response to the food supply. The studies about the functional and spatial ecology of the wintering waterbirds are helpful for us to have profound understanding for the impacts of the anthrologic disturbances on wintering waterbirds, so as to take effective conservation steps for these birds.

长江中下游湖泊是东亚-澳大利亚迁徙水鸟的重要越冬聚集区，由于人为扰动影响，越冬水鸟生境不断退化，食物资源逐渐丧失，亟待加强水鸟对湿地退化响应机制研究。本项目以安徽沿江中小型浅水通江湖泊为研究区域，通过越冬水鸟种群和生境调查、取食行为观测等途径，借助遥感影像解译、水文声学探测和远程监测等技术手段，进行越冬水鸟种群动态及其生境变化、取食集团结构和生态位宽度、取食行为特征分析，开展越冬水鸟取食集团空间和功能的整合生态学研究。旨在：1）阐明水鸟种群时空动态和水生植被和底栖动物资源变化的关系；2) 阐明越冬水鸟资源分割和生态位分化特征,探讨水鸟取食集团结构对食物资源变化的空间和功能响应，揭示群落的维持机制；3) 阐明食物资源变化对越冬水鸟觅食活动和种群容纳量的影响，探讨越冬水鸟取食活动对食物资源配置的功能响应机制。本项目对于深入理解湖泊变化对越冬水鸟的生态影响，制订有效的湖泊管理措施具有积极意义。

长江中下游浅水通江湖泊是东亚-澳大利亚迁徙水鸟的重要越冬地，受围网养殖和水位控制影响，越冬水鸟食物资源减少，适宜栖息地不断丧失，亟待加强水鸟对湿地变化响应机制研究。本项目以安徽沿江中小型浅水通江湖泊为研究区域，通过越冬水鸟种群和生境调查、行为观测等途径，借助遥感影和地理信息技术手段，开展越冬水鸟种群动态及其生境变化、群落和取食集团结构、取食行为特征研究，探讨越冬水鸟群落的维持机制。结果表明，升金湖、菜子湖和武昌湖是越冬水鸟数量超2万只水鸟重要聚集地。沉水植被的退化是导致小天鹅、针尾鸭等浅水取食集团和鸿雁等挖掘集团水鸟数量锐减的主要原因，苔草滩面积增大使得啄取集团如豆雁、白额雁和小白额雁等草食性雁类数量明显增加；湖区大面积渔塘转变为水稻田，使部分鸭类丧失了适宜的觅食地，但为白头鹤、豆雁、白额雁等水鸟提供了替代生境。水鸟通过选择适宜觅食斑块适应湖泊水位变化。底栖动物性食物的种类组成和分布存在生境差异，导致鸻鹬类空间分布的差异性。食物资源的丰富度增加减少越冬小天鹅的觅食时间，人为活动的干扰使小天鹅的觅食活动时间分配的相应降低，警戒行为时间和能量消耗分配的增加，导致小天鹅放弃觅食生境。越冬鸭类通过增加觅食时间和警戒时间以适应食物资源丰富但干扰较大的人工湿地，面积和水深是选择人工湿地栖息有决定因素。白额雁越冬初期觅食生境主要是草滩，中期主要是稻田，后期重新回到草滩生境，当食物资源量减少时，白额雁采取增加觅食行为时间以及提高觅食速率的觅食策略。浅水和泥滩生境是东方白鹳较高利用的觅食生境，水深对觅食活动有关键作用。围网拆除后，人为干扰降低，食物资源可获得性提高，东方白鹳越冬数量增多，觅食地点的范围扩大。本项目对于深入理解湖泊变化对越冬水鸟的生态影响，制订有效的湖泊管理措施具有积极意义。