桂林岩溶石山“风水林”植物群落数量分类与排序

Classification and Ordination of Fengshui Woods on Karst Hills of Guilin

该研究基于群落学调查,应用TWINSPAN和DCCA方法对桂林岩溶石山"风水林"的植物群落类型进行分类与排序,探讨该地区的植物群落分布规律与环境因子的关系。结果表明:(1)"风水林"乔木层优势种主要有青冈栎、小巴豆、鱼骨木、石山樟、粗糠柴、铁榄、圆叶乌桕、山合欢、檵木和扁片海桐等,灌木层优势种主要有龙须藤、紫凌木、红背山麻杆、皱叶雀梅藤、灰毛崖豆藤、亮叶素馨和疏叶崖豆等,草本层优势种主要有三穗苔草、庐山香科科、野鸡尾和阔叶沿阶草等。(2)TWINSPAN分析结果将"风水林"植物群落的29个样方划分为8个群丛类型,DCCA排序与TWINSPAN分类结果相互验证,揭示了"风水林"不同群丛与环境之间的生态关系。(3)DCCA第一排序轴主要反映坡向的变化规律,即从左到右,坡向由阴坡过渡到阳坡,光照、干热增强,海拔逐渐降低;第二排序轴主要反映坡度和坡位的变化,即从下往上,坡度变陡,坡位由下坡转变为上坡,岩石裸露率升高。(4)坡向和坡度为桂林岩溶石山"风水林"群落结构与分布格局异质化的重要因素。

Based on community investigation on karst hills of Guilin,and used two-way indicator species a- nalysis （TWINSPAN） and detrended canonical correspondence analysis （DCCA） to quantify classification and ordination of Fengshui woods communities on karst hills of Guilin, we explored the relationships be- tween plant communities’ distribution and environmental factors. The results showed as below.（1）domi- nant species of tree layer of Fengshui woods communities are mainly Cyclobalanopsis glauca ,Croton xiao- padou , Canthium dicoccurn , Cinnarnornurn saxatile , Mallotus philippensis , Sinosideroxylon peduncula- turn, Sapiurn rotundi foliurn , Albizia lealleora , Loropetalurn chinense , Pittosporurn planilobum ; Dominant species of shrub layer are mainly Bauhinia charnpionii , Decasperrnurn esquirolii , Alchornea trewioides , Sageretia rugosa ,Millettia cinerea , J asrninurn seguinii , Millettia pulchra ;Dominant species of herbaceous layer are mainly Carex tristachya , Teucriurn pernyi , Onychiurn japonicurn ,Ophiopogon platyphyllus. （2） 29 Fengshui woods plots were classified into 8 different association types. Both TWINSPAN and DCCA made the consistent results. DCCA ordination preferably reflected the ecological relation between the com- munity types and environmental factors. （3）The axis 1 of DCCA mainly reflected the change law of slope aspect. From left to right of the figure of the DCCA ordination, there had the transition of slope aspect from shady slope to south-facing slope,along with the light intensity and dry-hot habitat strengthened,and the altitude gradually reduced. The axis 2 mainly stood for the change of the slope degree and slope position,the slope degree was steeper, and the slope position had the transition from downslope to upslope, along with the rock bare rate increased. （4）The changes of slope aspect and slope degree were the mainly ecologi-cal factors which influenced the heterogeneity of Fengshui woods structure and distribution on karst hills of Guilin.