甘肃敦煌西湖荒漠-湿地植物群落物种多样性特征研究

Species Diversity Characteristics of Plant Community in Xihu Desert Wetland of Dunhuang,Gansu Province

基于375个样方和150条样线的调查,对甘肃敦煌西湖荒漠-湿地生态系统植物群落物种多样性进行了研究。结果表明:①区内共记录植物26种,分属16科24属,芦苇(Phragmites australis)、多枝柽柳(Tamarix ramosissima)和胡杨(Populus euphratica)为绝对优势种,苏枸杞(Lycium ruthenicum)、疏叶骆驼刺(Alhagi sparsifolia)和胀果甘草(Glycyrrhiza inflata)为主要伴生种,其平均重要值依次为0.4728、0.4563、0.4342、0.2908、0.2594和0.2455。植物群落分多枝柽柳群落、胡杨群落、胀果甘草群落、疏叶骆驼刺群落、多枝柽柳沙包群落、苏枸杞群落、芦苇沼泽群落和芦苇群落8个类型。②植物群落物种多样性指数偏低(0.784～1.379),多枝柽柳群落、胡杨群落和芦苇群落物种多样性指数最大(1.379、1.266和1.194),群落之间差异显著(P<0.05);疏叶骆驼刺群落和苏枸杞群落次之(1.154、1.077),胀果甘草群落、芦苇沼泽和多枝柽柳沙包群落最低(0.919、0.881、0.784),各群落之间不存在显著差异。③灌(乔)木层是敦煌西湖植被主要层次,灌(乔)木层物种多样性指数(0.549～1.077)大于草本层(0.052～1.038)。④物种多样性指标H′、D、J和Ma随海拔梯度增加基本均显下降趋势,而指数C变化趋势则相反,表现为上升,均匀度指数变化幅度不显著。⑤物种多样性指标H′、D、J和Ma随经纬度升高变化趋势基本一致,均表现为先下降,后上升,再下降,而优势度指数C变化趋势则相反。

The plant species diversity in Xihu desert wetland of dunhuang,Gansu province has been studied based on the surveying of 375 sampling plots and 150 sampling transects.Results showed that：（1） 26 species belonging to16 families,24 genera were recorded in the area.Phragmites communis,Tamarix ramosissima and Populus euphratica are dominant species,Lycium ruthenicum,Alhagi sparsifolia and Glycyrrhiza inflata are main associated species,and their average importance values are 0.4728,0.4563,0.4342,0.2908,0.2594 and 0.2455 respectively.The plant communities are composed of 8 types,including Tamarix ramosissima community,Populus euphratica community,Glycyrrhiza inflate community,Alhagi sparsifolia community,Tamarixramosissim community,Lycium ruthenicum community,Phragmitescommunis community and Phragmites communis community.（2） The plant community species diversity indexes are generally low（0.784-1.379）,in which the species diversity indexes of Tamarix ramosissima community,Populus euphratica community and Phragmitescommunis community are larger（1.379,1.266 and 1.194）,the species diversity indexes of Alhagi sparsifolia community and Lycium ruthenicum community are second（1.154 and 1.077）,and the species diversity indexes of Glycyrrhiza inflate community,Phragmites communis community and Tamarixramosissima community are lower（0.919,0.881 and 0.784）.（3） Shrub and tree are main vegetation layers in Xihu desert wetland ecosystem,and the species diversity indexes of shrub and tree（0.549-1.077） are larger than that of the herb layer（0.052-1.038）.（4） The species diversity indexes such as Shannon-Wiener diversity,Simpson diversity,Simpson superiority and Margalef richness significantly decrease with the increase of elevation,while the Simpson superiority value shows an opposite trend,the change of evenness index is not significant.（5） With change of horizontal sites,the Shannon-Wiener diversity,Simpson diversity,Simpson superiority and Margalef richness show similar trend,being decreased at first at relatively low-longitude and low-latitude sampling area and then increased at relatively low-longitude and high-latitude sampling area,and decrease at last at relatively high-longitude and high-latitude sampling area,but the change trend of the Simpson superiority value shows an opposite trend.