鼎湖山植物物种多样性动态

鼎湖山自然保护区于1982年分别在针叶林、针阔叶混交林和常绿阔叶林内建立了3个永久样地。样地建立前，针叶林常受到人类的干扰，其它2种一直受到较好的保护。本文植物物种动态的研究和分析基于对3个样地在1982年和1994年的两次调查。结果表明,物种多样性的顺序是阔叶林＞混交林＞针叶林。就乔木（DBH>2.5cm）而言，3个样地的物种多样性和均匀度指数从1982年至1994年都已增长。除阔叶林外，两次调查的结果差别很大，这是因为在保护之下它们正产生进展演替。至于林下层植物则正好相反，除阔叶林外，针阔叶混交林和常绿阔叶林的多样性及均匀度指数均下降。物种的丰富度和个体数的变化同多样性指数变化一致。物种的组成变化符合演替规律，随着针叶林发展成为混交林，混交林发展成为阔叶林，其林冠变得较为密集，因而有更多的耐阴植物侵入，而一些喜光（不耐阴的）种消失。研究结果表明，人类的干扰将降低植物的物种多样性，而保护将使物种多样性得到恢复和提高。

Plant species diversity dynamics in Dinghu Mountain forests

For long term study, three plots were established in a pine forest, a pine and broad leaved mixed forest and an evergreen broad leaved forest respectively in Dinghu Mountain Biosphere Reserve in 1982. The first forest was subject to human disturbance before the plot was set up and the others have been protected well. In this paper, the plant species dynamics were studied and analyzed, based on two surveys to the three plots in 1982 and 1994. The results showed that order of plant species diversity is broad leaved forest>mixed forest>pine forest. For trees(DBH>2.5),species diversity and evenness indices increased from 1982 to 1994 in all the three forests. The differences between two surveys are significant except the broad leaved forest. Because they are developing on advance succession under protection. As for the understory, on contrast, both diversity and evenness indices decreased except in the broad leaved forest. The species richness and individual changes correspond well with the diversity indexes changs. The species composition changes following succession rule. The canopies become closer when the pine forest develops to mixed forest and the later develops to broad leaved forest. Thus more shade tolerant species invade and some sun loving(shade intolerant) species exit. The study supports that human disturbance would decrease plant species diversity and conservation would restore or increase it.