江西大岗山低海拔常绿阔叶林物种组成与群落结构特征

The characteristic of species composition and community structure of low-altitude evergreen broad-leaved forest in Dagang Mountain, Jiangxi Province

以江西大岗山生态站低海拔常绿阔叶林乔木层为研究对象,在样地调查的基础上,开展了物种组成、空间分布、生物多样性和群落结构的研究。结果表明:1)样地植株密度为1667株·hm-2,来自于22科34属41种,个体数最多的为樟科、壳斗科和山茶科,其个体占样地内总个体数的52.49%,各物种在环境因素、干扰因素与生物学特性相互影响下,在空间上呈现规律性分布;2)Simpson指数、Shannon指数、Pielou均匀度指数和Menhinick丰富度指数分别为0.896、2.674、0.725和0.978,生物多样性指数低于亚热带其他地区常绿阔叶林;3)整个样地植株树高阶和径阶均呈现近似倒"J"型分布,表现为典型的异龄林结构,说明群落结构较为稳定,但就每个物种而言,树高阶和径阶具有多种分布形式,如在径阶分布方面,刨花楠(Machilus pauhoi)为类似泊松分布,而丝栗栲(Castanopsis fargesii)则为多峰分布;4)群落处于近顶极群落阶段,建群种为丝栗栲、刨花楠和山矾(Symplocos sumuntia),从树高阶分布和径阶分布上看,三者具有稳定的种群结构,有利于整个群落的稳定发展。本研究有助于认识多物种组成在演替过程中资源竞争变化规律,为探讨森林群落演替过程及其维持机制和生态系统服务功能提升提供了科学依据。

We investigated species composition,spatial distribution,biodiversity,and community structure of tree layer in an evergreen broad-leaved forest at low elevation in Dagang Mountain Ecological Station in Jiangxi Province.The results showed that:(1)Plant density was 1667 individuals·hm-2 and there were 22 families,34 genera and 41 species.Lauraceae,Fagaceae and Theaceae were most abundant,accounting for 52.49%of the total abundance.In addition,each species had a regular spatial distribution under the influence of environmental factors,disturbance factors and biological characteristics.(2)Simpson index,Shannon index,Pielou evenness index and Menhinick richness index were 0.896,2.674,0.725 and 0.978,respectively,which were lower than other evergreen broad-leaved forests in subtropical regions.(3)The height and diameter classes of trees showed an inverted"J"type distribution,which represented a typical heterogeneous forest structure and a relatively stable community structure.For each species,the height class and diameter class of trees had several distribution forms.For example,diameter distribution of Machilus pauhoi followed Poisson distribution,while Castanopsis fargesii followed multi-peak distribution.(4)This community was in the near climax community stage,with constructive species of C.fargesii,M.pauhoi and Symplocos sumuntia.In terms of tree height class and diameter class distribution,these three species had stable population structure,which was beneficial to the stable development of the whole community.Our results were helpful for understanding the variation of resource competition in the succession process of multi-species composition,providing scientific support for exploring forest community succession and its maintenance mechanism and the enhancement of ecosystem services.