准噶尔盆地南缘荒漠绿洲区主要物种的生态位分析

Niche Characteristics of Main Natural Vegetation in the Southern Margin of the Junggar Basin

以新疆准噶尔盆地南缘石河子绿洲区为例,采用Levins生态位宽度指数和Cowell生态位相似性计测方法,对该区域所分布的7个主要植物种,分别从群落梯度和土壤水分维、土壤盐分维、土壤有机质维、土壤全氮维四种生态因子方面对其生态位分化进行定量分析。结果表明:在群落梯度上,自然植物种的生态位大小依次为柽柳>角果藜>猪毛菜>花花柴>地白蒿>沙大戟>小叶碱蓬。在单一资源轴上,生态位的土壤盐分维最大,说明该区域多为耐盐植物。综合资源维和群落维,柽柳的生态位最大,其次是角果藜、猪毛菜,为优势种,其余为非优势种。生态位较宽的柽柳与角果藜、柽柳与猪毛菜、角果藜与猪毛菜的生态位相似性比例在4种资源维上均较大(>0.5),而生态位较小的物种与其它物种间的生态位相似性比例较小,说明柽柳、角果藜、猪毛菜3种优势植物的在利用土壤资源维上有相似性。单一生态因子上物种间的生态位相似性比例分析的结果表明,在土壤盐分梯度上物种间的生态位相似性比例较大,说明该区自然植物种在盐分资源梯度上生态分化较小,物种的耐盐性较强。

This paper took Shihezi oasis as a case to analyze the niche differentiation of 7 main species on the southern margin of the Junggar Basin in Xinjiang.The Levins niche breadth index and Corwell proportional similarity Index were emploied to qunatify community gradients and 4 ecological factors（soil moisture,soil salinity,soil organic matter and soil total nitrogen） of the nature species.Results showed that the niche breadth order of the 7 species was Tamarix hispidaCeratocarpus arenariusSalsola collinaKarelinia caspicaSeriphidium terraealbaeChrozophora sabulosaSuaeda microphylla on level of community dimension.On level of resource dimension,soil salinity with the widest niche breadth of 4 ecological factors,which indicated salt-endurance vegetation in this area.On level of resources and community dimension,Tamarix hispida occupied the widest niche,next was Ceratocarpus arenarius and Salsola collina.They were the dominant of 7 species,and with most niche similarity with each other on 4 ecological factors（0.5）,while narrow niche species with low niche similarity were find for other species.Vegetation with more niche similarity on level of soil salinity indicated high potential of salt-tolerance species in the study area.