香港灌丛植被的数量分类与环境关系分析

灌丛是香港植被的主要组成部分，2005年1—3月在香港地区(包括香港岛、九龙、新界和大屿山岛)设置样地，利用组平均法(UPGMA)和除趋势对应分析法(DCA)对香港灌丛群落进行聚类和排序分析. 结果表明，灌丛植被可划分为7个群落类型:桃金娘、米碎花、岗松、苏铁蕨、大头茶、山油柑和细齿柃. DCA排序揭示了灌丛群落的分布格局与环境因子的生态关系，DCA排序第1轴反映了灌丛群落所在环境的湿度梯度，排序图的对角线指示出海拔梯度，也反映了温度的变化. 结合物种多样性分析发现，物种多样性指数随海拔的升高而减少，说明水热条件和海拔是制约灌丛植被分布格局的主要因素. 

Quantitative Classification and Analysis of Environmental Variables of Shrub Communities in Hong Kong

Shrub land is an essential component of the vegetations in Hong Kong. A research was carried out in Hong Kong (including Hong Kong Island, Kowloon, New Territories and Lantau Island) from January to March, 2005. Shrub communities from sample plots in these areas were studied. The results from clustering and ordination analysis showed that shrub communities in this area could be classified into 7 types, i.e. Rhodomyrtus tomentosa, Eurya chinensis, Baeckea frutescens, Brainia insignis, Gordonia axillaries, Acronychia pedunculata and Eurya nitida. The result of DCA reflects the relationship between the spatial distribution of vegetation andenvironmental variation. The first of DCA ordination axis indicates the humidity gradient, and the diagonal of the DCA ordination figure reflected the elevation gradient and the variation of temperature as well. The analysis on the speciesdiversity showed that the diversity of species decreases with the increase of elevation. The analysis on the species diversity reflected that the diversity of species decreases with the elevation. These results indicate that humidity and elevation are the main factors that influence the distribution pattern of shrub communities.