甘肃盐池湾黑颈鹤亚成体夏季生境选择

Habitat Selection of Subadults of Black-necked Crane in Summer in Yanchiwan,Gansu Province,China

开展对亚成体的研究,可以更加全面了解一个物种,进而更有效地开展保护工作。甘肃盐池湾国家级自然保护区是黑颈鹤(Grus nigricollis)成体的重要繁殖地和亚成体的重要栖息地之一。为研究甘肃盐池湾黑颈鹤亚成体生境选择,于2020年7月初至8月中旬在盐池湾党河湿地展开调查,并依据Johnson对生境选择空间尺度的划分,对亚成体活动区内各类型生境和觅食微生境的生境选择进行了研究。通过遥感影像解译和卫星跟踪分别获得各栖息地类型面积以及黑颈鹤的活动位点,利用核密度分析法估计活动区面积并利用Manly研究中的设计Ⅲ来研究活动区内各类型生境选择;通过选取利用样方和对照样方,使用χ2检验、独立样本t检验和Mann-Whitney U检验,对比检验样方数据,进行微生境选择的研究。结果表明,活动区内各类型生境中亚成体选择河流,拒绝戈壁和沼泽化草甸,对沼泽既不选择也不拒绝,而成体选择湖泊,没有利用河流,同时拒绝戈壁、山脉、沼泽化草甸和盐化草甸,对沼泽既不选择也不拒绝;觅食微生境选择中,亚成体选择平均植被盖度为57.07%±4.53%,基质类型为泥炭,基质硬度为中,主要植被黑褐苔草(Carex atrofusca)的微生境栖息,相比成体,亚成体选择的生境基质更硬,距道路距离更近,距房屋、河流、山脉和湖泊距离更远。亚成体的栖息地选择主要受到生境质量、生境资源有限性以及成体选择等因素的影响。在这些因素的影响下,亚成体与成体产生了生态位分离,并在栖息地选择上出现了分化。这种分化对亚成体的生存和成体的繁殖都有益,可以避免种内无效的冲突和竞争,有利于亚成体和成体的适合度增加。保护黑颈鹤的栖息环境需同时考虑到亚成体的选择和生存。

[Objectives]Research on subadults can provide a more comprehensive understanding of a species and a more effective protection work.To adequately protect the Black-necked Crane(Grus nigricollis),a threatened wetland bird on the Tibetan Plateau,according to Johnson's research,we conducted a survey in the Danghe wetland in Yanchiwan(Fig.1)from early July to mid-August 2020 to study the home range and microhabitat scale habitat selection of subadult Black-necked Cranes.[Methods]The kernel density estimation was used to estimate the home range,then home range scale selection was studied using Manly selection ratio design Ⅲ,and the area of each habitat type and the locations of Black-necked Cranes were obtained using remote sensing image interpretation and satellite tracking,respectively.The microhabitat scale selection was performed by selecting utilization and control samples and then comparing the data of samples using the one sample Kolmogorov-Smirnov test,χ^(2) test,independent samples t-test and Mann-Whitney U-test.[Results]In the third-order selection,river(w_(i)=5.12,C_(I) was 2.92﹣7.32)was preferred,lake(w_(i)=0.00)was not being used,gobi(?i=0.16,CI was 0.00﹣0.35)and swamp meadow(w_(i)=0.64,C_(I) was 0.51﹣0.78)were rejected,and swamp(w_(i)=0.83,C_(I) was 0.58﹣1.09)was neither selected nor rejected by subadults(Table 2),and the subadults are wandering around the river(Fig.2).In contrast,adults selected lake(w_(i)=3.11,C_(I) was 1.80﹣4.43)without using river(w_(i)=0.00),while adults rejected gobi(w_(i)=0.05,C_(I) was 0.03﹣0.06),mountain(w_(i)=0.07,C_(I) was 0.01﹣0.14),swamp meadow(w_(i)=0.21,C_(I) was 0.10﹣0.32)and salinization meadow(w_(i)=0.18,C_(I) was 0.01﹣0.35),and neither selected nor rejected swamp(w_(i)=1.22,C_(I) was 0.92﹣1.53)(Table 2).In the microhabitat scale selection,microhabitats with an average vegetation cover of 57.07%±4.53%(Table 3),matrix type of peat(χ^(2)=10.248,df=1,P<0.05),intermediate matrix(χ^(2)=22.483,df=2,P<0.05),and dominant vegetation(χ^(2)=19.419,df=5,P<0.05)of Carex atrofusca were selected by subadults.Harder matrix(χ^(2)=9.875,df=2,P<0.05),closer to road and further from house,river,mountain and lake were the habitats selected by subadults compared to adults(Table 4).[Conclusion]The habitat selection of subadults is mainly affected by factors such as habitat quality,habitat resources limitation and habitat selection of adults.Under the influence of these factors,the separation of ecological niche and the differentiation of habitat selection occurred between subadults and adults.This differentiation is beneficial to both subadult survival and adult reproduction,avoiding ineffective intraspecific conflict and competition,and facilitating increased fitness of subadults and adults.Habitat protection of Black-necked Cranes needs to consider the habitat selection of subadults and their survival.