青海高原紫花针茅草原群落数量分类与排序

Quantitative Classification and Ordination of Stipa purpureaSteppe Community in Qinghai Plateau

紫花针茅草原是青藏高原高寒草原中分布面积最大、最重要的群落类型。该文选择青海高原典型紫花针茅草原为研究对象,在大量群落学调查的基础上,采用双向指示种分析(TWINSPAN)和典范对应分析(CCA)等多元数量分析方法研究了青海高原紫花针茅草原群落的数量分类。结果显示:(1)所调查的紫花针茅草原是物种组成相对较简单、菊科和禾本科植物最多、北温带分布的属为主体的草原群落。(2)青海高原紫花针茅草原的90条样带可划分为8个群丛类型:紫花针茅+川青早熟禾群丛、紫花针茅+矮嵩草群丛、紫花针茅+多枝黄芪群丛、紫花针茅+高山嵩草群丛、紫花针茅+二裂委陵菜群丛、紫花针茅+沙生凤毛菊群丛、紫花针茅+弱小火绒草群丛、紫花针茅+梭罗草群丛。(3)影响青海高原紫花针茅草原群丛分布的主要环境因子是空间因子(海拔、经度、纬度)和热量因子(温度),其次是湿润度、降雨量等水分因子。(4)对于紫花针茅草原群落内部的群丛划分,CCA可以补充矫正TWINSPAN等级分划,使分类结果更符合实际生态意义,更清晰地反映群丛类型与环境梯度之间的关系。

Stipa purpurea steppe is the largest area and most important community type of alpine steppe ecosystems in Qinghai-Xizang Plateau.Currently,the number of studies on the S.purpurea steppe classification and ordination is still lacking.In this study,the typical S.purpurea steppe in Qinghai Plateau was selected as subject.Multivariate statistics methods including TWINSPAN（Two-way Indicator Species Analysis） and CCA（Canonical Correspondence Analysis） were used to classify the S.purpurea steppe on the basis of investigating a large number of vegetation communities in this region.The results showed that：（1）The species composition of S.purpurea steppe in the study area is relatively simple.The dominant families of seed plants were Gramineae and Compositae,and the dominant areal types of genera were North temperate type.（2）The 90 transects of S.purpurea steppe in Qinghai Plateau could be merged into 8 main ecological associations：Ass.Stipa purpurea＋Poa indattenuata,Ass.Stipa purpurea＋Kobresia humilis,Ass.Stipa purpurea＋Astragalus polycladus,Ass.Stipa purpurea＋Kobresia pygmaea,Ass.Stipa purpurea＋Potentilla bifurca,Ass.Stipa purpurea＋Saussurea arenaria,Ass.Stipa purpurea＋Leontopodium humilum and Ass.Stipa purpurea＋Kengyilia thoroldia.（3）The major environmental factors influenced the distribution of S.purpurea steppe ecological associations in Qinghai Plateau firstly were space factors（altitude,longitude and latitude） and heat factor（temperature）,then water factors（precipitation,wetness）.（4）For internal ecological association division of S.purpurea steppe community,CCA could complement and correct the TWINSPAN results,make the classification more realistic ecological significance,and reflect more clearly relationship between the associations and environmental gradients.