海南岛霸王岭热带山地常绿林和热带山顶矮林群落特征

Community characteristics of tropical montane evergreen forest and tropical montane dwarf forest in Bawangling National Nature Reserve on Hainan Island,South China

热带山地常绿林和热带山顶矮林均属于热带云雾林。为了揭示其群落结构和物种多样性特征,在海南岛霸王岭热带山地常绿林和热带山顶矮林分别设置8个和10个2,500m2样方,调查所有DBH≥1cm的乔木、灌木和藤本植株。结果显示:(1)热带山地常绿林幼树(1cm≤DBH<5cm)和小树(5cm≤DBH<10cm)的平均密度显著小于热带山顶矮林,而成年树(DBH≥10cm)平均密度无显著差异;前者小树和成年树的平均胸径显著大于后者,而幼树平均胸径显著小于后者;前者所有径级植株的平均高度显著大于后者;(2)两森林类型优势种不同,但优势科和优势属相似,S?rensen物种相似性指数为0.71;(3)逻辑斯蒂模型是拟合两森林类型种-面积关系的最优模型;热带山地常绿林物种丰富度观测值及根据刀切法和抽样法估计的物种丰富度值都比热带山顶矮林高。综合分析表明,热带山地常绿林和热带山顶矮林群落植株密度、胸径、高度和物种多样性差异较大。

Both tropical montane evergreen forest（TMEF） and tropical montane dwarf forest（TMDF） are typical tropical cloud forests on Hainan Island.To compare community structure and species diversity between these two forest types,we established eight and ten plots（each with 2,500 m2 in area） in TMEF and TMDF,respectively,in Bawangling National Nature Reserve on Hainan Island,South China.We investigated each individual plant with diameter at breast height（DBH） ≥1 cm including trees,shrubs and lianas,and found that the mean density of saplings（1 cm≤DBH 5 cm） and small trees（5 cm≤DBH 10 cm） was lower in TMEF than TMDF,while there were no differences in density of adult trees（DBH≥10 cm） between the two forest types.TMEF had higher mean DBH of small trees and adult trees,but lower mean DBH of saplings than TMDF.Mean height of saplings,small trees and adult trees was higher in TMEF than TMDF.The dominant species differed between these two forest types,but dominant family,dominant genera and overall species compositions were similar,with a S？rensen similarity index value of 0.71.Compared with the power and exponential curves,the logistic curve was the optimal model approximating the species-area relation within the two forest types.The observed species richness values,as well as the values predicted by 1st order Jackknife estimator,2nd order Jackknife estimator and bootstrap estimator,were higher in TMEF than TMDF.Our results highlight the differences in community structure and species diversity between TMEF and TMDF,which likely resulting from differences in mechanisms maintaining the structure and diversity of these two types of forest communities.