Plant species diversity dynamics in Dinghu Mountain forests
鼎湖山植物物种多样性动态

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.