不同林龄桉树林下植被结构与物种多样性

依据野外样方调查数据，对广东省德庆县三叉顶自然保护区不同林龄桉树林下植被作了研究，用Margale丰富度指数、Simpson优势度指数、Shannon—Wiener指数、Pielou均匀度指数分析其物种组成与结构。结果表明：三叉顶自然保护区1年生桉树林共记录维管束植物52科94属113种，3年生桉树林共记录维管束植物56科99属121种，林下植被优势种是盐肤木、山苍子、广东蛇葡萄、断肠草、买麻藤、鬼灯笼、芒、芒萁等；1年生和3年生桉树林各样地的各项多样性指标差别不大；3年生桉树林物种多样性指数总的来说比1年生桉树林的物种多样性指数大，说明桉树人工林的物种多样性指数有随着林龄增加而增大的趋势。

Vegetation Structure and Species Diversity in Eucalypt \=Understory at Different Stand Age

Based on the field survey of Sanchading Nature Reserve in Deqing,Guangdong province,the paper analyzed it′s species′ constitution and structure by using Margale richness index,Simpson dominance index,Shannon-Wiener index,Pielou evenness index.The result shows that,there are 52 families 94 genus 113 species in annual growth Eucalypt,56 families 99 genus 121 species in the triennial Eucalypt,the dominant species of undergrowth are Rhus chinensis Mill.,Litsea cubeba(Lour.)Pers.,Ampelopsis cantoniensis(Hook.et Arn.) Planch,Gelsemium elegans(Gardn.et Champ.) Benth.,Clerodendrum fortunatum L.,Miscanthus sinensis Anderss,Dicranopteris dichotoma(Thunb.) Bernh.etc.There are no significant differentiation between the annual growth Eucalypt and the triennial Eucalypt in their each diversity index;the species diversity index of triennial Eucalypt is bigger than the annual growth Eucalypt on the whole,which indicates that the species diversity index of Eucalyptus plantation has a increasing trend with the increase of stand age.