Plant species diversity dynamics in Dinghu Mountain forests

Abstract

For long2term study , t hree plots were established in a pine forest , a pine and broad2leaved mixed forest and an evergreen broad2leaved forest respectively in Dinghu Mountain Biosp here Reserve in 1982. The first forest was subject to human disturbance before t he plot was set up and t he ot hers have been protected well. In t his paper , t he plant species dynamics were studied and analyzed , based on two surveys to t he t hree plots in 1982 and 1994. The results showed t hat order of plant species diversity is broad2leaved forest > mixed forest > pine forest . For trees(DB H > 2. 5) ,species diversity and evenness indices increased from 1982 to 1994 in all t he t hree forests. The differences between two surveys are significant except t he broad2leaved forest . Be2 cause t hey are developing on advance succession under protection. As for t he understory , on contrast , bot h di2 versity and evenness indices decreased except in t he broad2leaved forest . The species richness and individual changes correspond well wit h t he diversity indexes changs. The species composition changes following succes2 sion rule. The canopies become closer when t he pine forest develops to mixed forest and t he later develops to broad2leaved forest . Thus more shade2tolerant species invade and some sun2loving ( shade2intolerant) species exit . The study supports t hat human disturbance would decrease plant species diversity and conservation would restore or increase it .