鄱阳湖南矶湿地国家级自然保护区2种大雁的越冬行为特征及生态位分化

Wintering Behavioral Features and Niche Partition of Two Species of Anseriformes Birds(Anser cygnoide and Anser albifrons) at Nanji Wetland National Nature Reserve,Poyang Lake

2014年12月至2015年3月,对鄱阳湖南矶湿地国家级自然保护区越冬的鸿雁（Anser cygnoides）和白额雁（Anser albifrons）的行为模式和生境选择进行调查。结果显示,鸿雁和白额雁均以静栖和觅食行为为主,鸿雁的静栖行为比例最大,白额雁的觅食行为比例最大;鸿雁的静栖行为比例极显著高于白额雁,觅食行为比例极显著低于白额雁,警戒和游走行为比例低于白额雁。在行为节律上,鸿雁的觅食高峰出现在14：00—15：00,静栖高峰出现在13：00—14：00;白额雁的觅食行为比例在8：00—9：00、11：00—12：00和16：00—17：00这3个时段较高,静栖行为比例在10：00—11：00、12：00—13：00和16：00—17：00这3个时段较高。觅食时间上的＂错峰＂将减轻两者对食物资源的激烈竞争以达到共存。在生境的空间选择上,鸿雁的生境选择和离岸距离生态位宽度均高于白额雁,2种大雁的离岸距离生态位重叠度较大,鸿雁主要选择浅水和泥滩,白额雁主要选择草地,2种大雁对生境的离岸距离均集中选择在〉400~500 m区间。2种大雁生境类型选择的分化避免了离岸距离生态位重叠度较大带来的种间竞争,利于种间共存。2种大雁生境的离岸距离主要选择在〉400~500 m区域,这既利于2个物种避免人为干扰,又可满足自身对食物资源的需求。

During the period from December 2014 to March 2015,Swan geese Anser cygnoide and white-fronted geese Anser albifrons in Nanji Wetland National Nature Reserve,Poyang Lake,Jiangxi Province were studied for their behavior patterns and habitat preferences. Results show that the two species behaved quietly,devoting most of their times to resting and foraging. Swan geese seemed to spend more time in resting and hence less time in foraging than white-fronted geese.Swan geese foraged mainly during the period of 14： 00-15： 00 and rested mainly during the period of 13： 00-14： 00,while white-fronted geese fed mainly during the periods of 8： 00- 9： 00,12： 00- 13： 00 and 16： 00- 17： 00,and rested mainly during the periods of 10： 00-11： 00,12： 00-13： 00 and 16： 00-17： 00. Their different timing of foraging and resting mitigates the competition for food resources between the two species of geese,thus allowing their sympatry. In terms of habitat preference in space,the niche breadth of swan geese for selection of habitat and offshore distance was higher than that of white-fronted geese. The two species of geese overlapped quite much in niche of offshore distance. Swan geese preferred shallow water and mudflat,while white-fronted geese did swampy meadows. Both species preferred to have their habitats400-500 m away from the shore. The differentiation of the two species of geese in habitat selection helps avoid the competition caused by the high niche overlapping in offshore distance,thus favoring their sympatry. The preference of the two species of geese to have their habitats located 400-500 m offshore enables them to escape human disturbance and have enough food resources for survival.