藏北双湖地区高寒环境下植物群落格局及其驱动因素

Plant Community Patterns and Driving Factors in High-altitude Cold Environments in the Shuanghu Area of Northern Xizang

为探究藏北羌塘高原双湖地区植物群落组成、群落分布格局及其驱动因素、群落稳定性,本研究以双湖地区为主要研究区域,共设置45个样点进行植被调查,运用灵活聚类法(Beta-flexible clustering)对群落进行数量分类,运用除趋势对应分析(DCA)、典范对应分析(CCA)和对物种丰富度与环境因子进行广义线性回归分析,探讨植物群落格局分布及其与环境的关系。综合群落植物优势种生态位特征、相对资源占有量和生态响应速率分析,探讨群落的稳定性及其发展趋势。结果表明:(1)双湖地区共记录到153个物种,隶属于34科,92属,优势科为菊科、莎草科和十字花科,优势属为薹草属、风毛菊属和棘豆属。(2)聚类分析将植物群落分为紫花针茅群丛、鸡冠茶群丛、弱小火绒草群丛、垫状金露梅群丛和矮生嵩草群丛。(3)水热条件是影响群落结构和物种丰富度格局的重要因素。(4)在当前环境下,鸡冠茶群丛、弱小火绒草群丛和矮生嵩草群丛整体上较为稳定,而紫花针茅群丛和垫状金露梅群丛整体稳定性差,优势物种发展强烈,可能替代其他群落中的建群种。

This study investigated plant community composition,distribution patterns and their driving factors,and stability of plant communities in the Shuanghu area of the Qiangtang Plateau,northern Xizang.Beta-flexible clustering,detrend correspondence analysis(DCA),canonical correspondence analysis(CCA),and generalized linear regression analyses of species richness and environmental factors were employed on 45 sampling points.Additionally,the stability and growing trend of plant communities was assessed based on niche characteristics,relative resource occupancy,and ecological response rate of domi⁃nant species.The results showed that:(1)A total of 153 plant species were documented,belonging to 92 genera and 34 families.Asteraceae,Cyperaceae,and Brassicaceae were the dominant family,while Carex,Saussurea,and Oxytropis were the dominant genera.(2)Beta-flexible clustering identified five dis⁃tinct communities:Stipa purpurea community,Sibbaldianthe bifurca community,Leontopodium pusillum community,Dasiphora dryadanthoides community,Carex alatauensis community.(3)DCA,CCA,and generalized linear regression analyses revealed that hydrothermal conditions were the primary divers of com⁃munity structure,distribution patterns,and species richness.(4)The Stipa purpurea and Dasiphora dry⁃adanthoides communities exhibited signs of instability,with dominant species potentially outcompeting dominants in other communities.Conversely,Sibbaldianthe bifurca,Leontopodium pusillum,and Carex alatauensis associations displayed greater stability,with minimal shifts in dominant species composition.