沅水下游中华秋沙鸭越冬种群的数量和分布变化

Changes in Overwintering Population and Distribution of Scaly-sided Merganser(Mergus squamatus)in the Lower Reach of the Yuan River

掌握濒危水鸟的种群数量和分布动态对于湿地生物多样性保护和生态系统维护极为重要。于2011年至2023年期间,在沅水下游,进行了多次中华秋沙鸭(Mergus squamatus)越冬种群数量和分布动态调查。研究结果显示,与2011年至2012年越冬季相比,2022年至2023年越冬季,沅水下游区域中华秋沙鸭越冬数量由66只增加至119只,沅水主干流的中华秋沙鸭最大数量从37只增加至62只,其主要栖息地从凌津滩水电站大坝下游至桃源水电站大坝之间的38 km长的河段转移至桃源水电站大坝下游9 km长的河段;在沅水下游区域水库中分布的中华秋沙鸭数量由2012年1月的29只增加到2023年1月的59只,在竹园水库中分布的中华秋沙鸭数量的增长幅度最为显著;越冬中华秋沙鸭在沅水主干流分布的变化可能与桃源水电站建设导致的上游水位抬升、栖息地淹没有关;越冬中华秋沙鸭数量增加可能与2014年后水利工程建设减少、长江十年禁渔以及分布集中便于观察有关,沅水下游区域水库所处的乡镇人口流失、人为干扰减少可能是在水库中越冬的华秋沙鸭种群增加的原因之一。

Population and distribution dynamics of endangered waterbirds is essential for the conservation of wetland biodiversity and ecosystem maintenance.This study systematically monitored the wintering population and distribution dynamics of the Scaly-sided Merganser(Mergus squamatus)in the lower reach of Yuan River from 2011 to 2023.The results showed that from 2011/2012 to 2022/2023,the wintering population of Scaly-sided Merganser in the lower reach of the Yuan River increased from 66 to 119.Specifically,the maximum number in the main stream increased from 37 to 62,with the main habitat changing from the 38 km river section between the Lingjintan hydropower station dam and the Taoyuan hydropower station dam to the 9 km downstream river section of the Taoyuan hydropower station dam.The number of Scaly-sided Merganser in reservoirs in the lower reach of Yuan River increased from 29 in January 2012 to 59 in January 2023,with the most significant increase observed in the Zhuyuan Reservoir.Changes of the distribution of Scaly-sided Merganser in the main stream of the Yuan River may be related to the upstream water level rising due to the construction of the Taoyuan hydropower station,potentially leading to habitat loss.The increase in population may be attributed to the finalization of water project construction after 2014,the ten-year fishing ban on the Yangtze River,and easier observation due to a more concentrated distribution.The population increase of Scaly-sided Merganser in reservoirs in the lower reach of the Yuan River may be partially attributed to the depopulation and reduced human disturbance in towns where the reservoirs are located.