西双版纳坝区独生古树附生兰科植物多样性研究

Species Diversity of Epiphytic Orchids on the Isolated Ancient Trees in Lowland Areas of Xishuangbanna

基于实地调查和典范对应分析(CCA),分析西双版纳坝区独生古树上野生附生兰科植物多样性及其与环境关系。调查结果显示,西双版纳坝区独生古树上野生附生兰科植物共计30属59种,占研究区同海拔段(500~1 220 m)已知野生附生兰科植物种数(228种)的25.9%,其中12种(20.3%)属中国红色名录濒危等级。CCA分析结果显示,7个环境因子对坝区独生古树的附生兰物种组成的总效应和净效应均达到极显著水平(P<0.01),按照净效应从大到小排序,依次为:海拔、距居民区距离、年均降雨量、年均温、距天然林块距离、胸径、树高。

Based on the field investigation and the canonical correspondence analysis（ CCA）,the species diversity of epiphytic orchid and its relationship with the environment were analyzed in lowland areas of Xishuangbanna. The results showed that the epiphytic orchids on the isolated ancient trees involved 59 species and 30 genera,accounting for 25. 9 % of the total epiphytic orchids（ 228 species） found in the same altitudinal range（ 500 ~ 1220 m,asl） in Xishuangbanna,among which 20. 3%（ 12 species） belonged to the endangered class（ EN） of the China Biodiversity Red List. The CCA results indicated that both gross effect and net effect of the 7 variables,including height of tree（ HOT）,diameter at breast height（ DBH）, altitude（ ALT）, mean annual temperature（ MAT）, mean annual precipitation（ MAP）,distance to natural forest（ DTF）,and distance to human settlement（ DTS） were extremely significant（ P〈 0. 01）,which ranked in descending order from ALT,DTS,MAP,MAT,DTF,DBH to HOT according to the net effect.