海南岛热带草地的数量分类和排序研究

 本文用一些数量分类和排序的方法对海南岛鹦歌岭热带草地进行了分类和排序。所用的方法包括两种多元等级聚合分类——最近邻体法(NN)和最远邻体法(FN)，极点排序(PO)和主分量分析(PCA)排序。结果表明：把19个样地分为三大类型、9个群落，其分布格局与坡度、放牧强度和土壤肥力密切相关。所用的四种方法在热带草地的研究中均有一定的适用性。

A STUDY ON NUMERICAL CLASSIFICATION AND ORDINATION OF TROPICAL GRASSLAND IN HAINAN ISLAND

In this paper, the tropical grassland of the Yinggeling Mountain in Hainan Island was studied using a number of numerical classification and ordination methods, which include two polythetic-hierarchical agglomerative classification (SPSS/PC program)-the nearest neighbour(NN) and the furthest neighbour (FN) methods, the polar ordination (PO) ar principal component analysis (PCA) ordination (MINITAB program). The results show that the 19 plots of grassland studied may be classified into 3 types and 9 plant communities, which are correlative with slope gradient, grazing pressure and soil fertility. It is proved that all the 4 methods are applicable to the study of the tropical grassland. PO is simple and may help clarify those of other methods, PCA and cluster analysis are more objective. PCA and FN are more efficient than PO and NN, and the combination of PCA and cluster analysis can generally produce the most satisfactory result.