越冬中华秋沙鸭觅食地选择与取食行为研究

The Chinese Merganser Mergus squamatus belongs to Anatidae of Anseriformes. It is listed in the first category of the nationally protected wildlife species in China and regarded as an endangered species by IUCN. The number of Chinese Mergansers is currently estimated to be 1,000 to 2,499 individuals globally. Jiangxi Province provides the main wintering habitat for this species in China. This project will demonstrate foraging habitat selection and foraging behavior of Chinese Merganser in Fuhe, Xinjiang, Raohe and Xiuhe rivers, Jiangxi Province through three aspects: ① Relationship among foraging habitat selection, environmental factors and potential food resources will be quantified using Principle Component Analysis (PCA), 3S technology and Analysis of Variance (ANOVA); ② Relationship among foraging frequency, foraging time budget and environmental factors: foraging behavioral response of the Chinese Mergansers to the variations of temperature, water depth, day length will be studied by Focal Animal Method; ③ Relationship between diving behavior and environmental factors: The relationship between diving behavior and environmental factors will be demonstrated through recording diving parameters (diving duration, pause duration and diving efficiency). This project can solve some theoretical issues of foraging theories such as the mechanism of foraging habitat selection, foraging time budget and diving foraging. We will also understand the main factors influencing foraging habitat selection and foraging behavior. This information will provide scientifical data for the habitat management and population restoration of Chinese Merganser.

中华秋沙鸭Mergus squamatus属雁形目(Anseriformes)鸭科(Anatidae),国家I级重点保护动物,IUCN将其列为濒危物种。全球数量1,000-2,499只。江西是其重要越冬地。本项目拟在江西四大流域（抚河、信江、饶河和修河）探讨以下3个问题，揭示中华秋沙鸭的越冬觅食地选择和取食行为：①运用主成分和3S技术等揭示觅食地选择与环境因子及潜在食物资源的关系；②取食频次、时间分配等与环境因子的关系：运用焦点动物法记录中华秋沙鸭的取食频次、时间分配等，揭示其取食行为如何响应温度、水深、日照长度的变化；③潜水取食与环境因子的关系：通过记录潜水参数（如潜水和停息持续时间），阐述潜水行为与环境因子的对应关系。通过本项目的完成，理论上阐述一些觅食地选择、取食时间分配、潜水取食的机制问题；实践上弄清中华秋沙鸭的觅食地和取食行为的影响因子，为其栖息地管理和种群恢复提供依据。

中华秋沙鸭Mergus squamatus是国家I级重点保护鸟类，全球数量1,000-2,499只。中华秋沙鸭的越冬生态的研究相对缺乏，不利于其保护措施的制定。江西省中华秋沙鸭种群稳定，是研究其越冬生态的理想场所。本项目利用种群生态和保护生物学的理论重点开展了中华秋沙鸭数量分布、栖息地选择、取食频次和潜水取食的研究。中华秋沙鸭在鄱阳湖五大水系均有分布，部分河段稳定在20只以上，但在浮梁县、宜黄县发现种群减少。中华秋沙鸭的总性比是0.397 （n=790），平均性比是0.43 ± 0.26/群 (n = 148)。中华秋沙鸭活动范围小，越冬期平均日移动距离仅为3100±1313 m，不同月份日移动距离差异不显著，说明中华秋沙鸭生存的适宜生境较少。栖息地的浅滩占比均显著性高于对照样方，表明浅滩是中华秋沙鸭觅食栖息地的重要因素，这是因为浅滩及其周边水体是中华秋沙鸭的休息和觅食场地。中华秋沙鸭觅食栖息地的水流速度、距道路和居民区的距离均显著高于对照样方，表明水和人为干扰对中华秋沙鸭觅食栖息地选择的影响大。河道两岸植被的破坏会导致中华秋沙鸭栖息地的丧失，表明安全因素（隐蔽度）也是其觅食栖息地选择的重要因素。中华秋沙鸭偏好的鱼类包括鲫 Carassius auratus、泥鳅 Misgurnus anguillicaudatus等6种。游泳（117.96±36.80 KJ/day）是中华秋沙鸭昼间能量支出最多的行为，其次是取食（115.60±38.94 KJ/day）。中华秋沙鸭取食频次（9.86±4.42）次/min，主要是头部浸入水中（62.23±36.38）%和潜水取食（26.93±32.75）%，即寻找（头浸入）和捕获（潜水）猎物。头部浸入水中的单次持续时间为（4.11±1.94）s。水流速度对中华秋沙鸭的取食策略有一定影响。平均潜水和暂停持续时间为（18.8±0.1）s和（12.9±0.2）s，潜水效率为（2.297±0.025）。性别、温度、时间、集群大小对中华秋沙鸭的潜水取食均有显著影响。本项目还对中华秋沙鸭共存物种鸳鸯和鄱阳湖区其他水鸟的越冬生态进行了研究。本项目研究成果对中华秋沙鸭保护小区范围的界定、栖息河道的保护与管理具有重要的指导意义，同时也为中华秋沙鸭的生态生物学基础资料的积累及后续更好地保护和规划其栖息地提供科学依据。