近年来乌梁素海疣鼻天鹅种群数量变化及原因分析

为查清内蒙古乌梁素海湖泊湿地疣鼻天鹅(Cygnus olor)繁殖期和秋季迁徙前期种群数量,2014至2017年采用路线统计法和样点统计法对其进行精确计数统计,结合近十余年来的文献数据和监测记录,探讨了种群数量的变化及原因。结果显示,2015至2017年春季繁殖成鸟数量依次为84只、92只、80只,基本稳定;2014至2017年,秋季种群数量依次为411只、302只、281只、153只,逐年减少;近几年适宜繁殖地和觅食地面积不断缩小、天敌偷袭、捡蛋和投毒等因素影响亚成鸟和幼鸟的生存。根据文献和保护区监测数据,1996至2004年种群数量逐年增多,与自然保护区的建立、严禁捡蛋和没收猎枪有关,而2005至2013年因干旱缺水、水域被开发利用、芦苇(Phragmites australis)和宽叶香蒲(Typhalatifolia)面积扩增、水质恶化、富营养化加重等原因种群数量下降。研究表明,近几年乌梁素海被过度开发利用,人为干扰频繁,影响疣鼻天鹅正常繁殖栖息;栖息地的科学管理和严禁捡蛋及投毒行为,对该种群的生存及增长至关重要。

Population Variation and Its Causes of Mute Swan in the Wuliangsuhai Lake in Recent Years

We made population census on the Mute Swan (Cygnus olor) during the breeding season and pre-migration period in the Wuliangsuhai Lake from 2014 to 2017 by line transects and point counts methods (Fig. 1), compared with data and records in past decades, and analyzed the causes of the changes of the populations. The breeding adults in springs of 2015 to 2017 remained basically stable, with the number of 84, 92, and 80 individuals, however, the autumn population of 2014 to 2017 declined year by year, with the number of 411, 302, 281, and 153 individuals respectively (Table 1), possibly because that the reduction of suitable breeding and feeding habitat, predation, egg collecting by local people and poisoning factors have affected the survival of sub-adults and juveniles in recent years. From 1996 to 2004, the number of Mute Swan populations increased as the establishment of the nature reserves, with hunting and egg-collecting being forbidden. From 2005 to 2013, the number of populations declined due to drought and water shortage, development and utilization of waters, expansion of reed (Phragmites australis) and broad leaf cattail (Typha latifolia), deterioration of water quality, and increased eutrophication. The research showed that the Wuliangsuhai Lake has been overexploited and utilized, and frequent human interference affecting the breeding of Mute Swan in recent years. Scientific management on the habitats and more strictly control of egg collecting and poisoning are essential to the survival and population growth of Mute Swan.