毛乌素沙地丘间低地植物群落分类与排序

Classification and Ordination Analysis of Plant Communities in Inter-dune Lowland in the Mu Us Sandy Land

为研究植物群落分布格局与环境因子间的相互关系,在群落样方调查的基础上,对毛乌素沙地丘间低地植被复合体的主要植物群落进行TWINSPAN分类和PCA排序,对土壤环境因子进行DCCA排序。结果表明:调查区内53个物种分属21科46属,其中菊科(Compositae,11种)、禾本科(Gramineae,7种)、莎草科(Cyperaceae,7种)、豆科(Leguminosae,5种)、藜科(Chenopodiaceae,4种)等科所含物种数较多,分别占20.8%、13.2%、13.2%、9.4%、7.5%,生活型以多年生草本为主,水分生态类型以中生植物为主。应用TWINSPAN将67个样方划分为17个组,依据《中国植被》的分类原则和系统确定为21个群丛。对PCA排序的第一轴起主要作用的是以北沙柳(Salix psammophila)、假苇拂子茅(Calamagrostis pseudophragmites)和碱茅(Puccinelia distans)为建群种的群落,对第二轴起主要作用的是以寸草苔(Carex duriuscula)为建群种的群落。植物群落分布DCCA排序第一轴主要与地下水位、HCO-3含量负相关,与土壤粗砂粒正相关;第二轴主要与土壤Ca2+、K+和Na+含量正相关,与土壤容重负相关;其中地下水位和土壤Ca2+、K+和Na+含量是环境因子中影响丘间低地植物群落特征和分布的主要因子。

Aiming to well understand the relationship between environmental factors and the structure and distribution pattern of plant communities in inter-dune lowland of the Mu Us Sandy Land,this study took vegetation complex of inter-dune lowland in the Mu Us Sandy Land as research object and made a classification and ordination analysis to plant community using the two-way indicator species analysis（TWINSPAN）and principal component analysis（PCA）,and detrended canonical correspondence analysis（DCCA）to soil environment factors based on field plant community investigation.The results showed that there were 53 plant species which were classified into 21 families and 46 genera.The dominant families were Compositae（11 species）,Gramineae（7 species）,Cyperaceae（7 species）,Leguminosae（5 species）,and Chenopodiaceae（4 species）,which respectively accounted for 20.8%,13.2%,13.2%,9.4% and 7.5% of total species amount.Perennial herbages and mesophyte were the most abundant ecotype.The 67 investigated plant community quadrates were divided into 17 groups by TWINSPAN,and finally determined as 21 associations according to the community characteristics.The PCA analysis showed that the first ordinate axis mainly expressed the communities dominated by Salix psammophila,Calamagrostis pseudophragmites and Puccinellia tenuiflora,and the second ordinate axis mainly expressed the communities dominated by Carex duriuscula.The DCCA ordination indicated that the main ecological factors that affected the distribution of plant associations were ground water level and soil Ca2＋,K＋and Na＋content.Our results will provide scientific basis for reasonable management,utilization and restoration of inter-dune lowland pasture of the Mu Us Sandy Land.