缙云山银木荷（ Schima argentea Pritz.ex Diels）林物种组成与多样性变化

定位研究了25 a来缙云山银木荷林物种组成及多样性在自然演替过程中的动态变化。结果表明，银木荷林维管植物物种由57种（隶属于24科，46属）减少到38种（隶属于19科，26属）。林下草本和层间植物逐渐消失，胸径大于75 cm的乔木层树总胸断面积有所减少。尽管群落物种组成以及多样性发生改变，但是银木荷依然是优势树种，处于林冠层，而林冠亚层的白毛新木姜子、四川山矾、长蕊杜鹃逐渐增多，短刺米槠逐渐减少。群落乔木层4个α多样性指数都呈下降趋势，丰富度指数由298下降为199，Shannon Wiener指数25 a间减小了034，Simpson指数和Pielou指数变化都很小；β多样性分析结果显示，银木荷群落的物种差异很大。研究表明，25 a间群落物种差异显著。揭示缙云山银木荷林自然演替过程中的物种组成和多样性变化规律，可为缙云山保护区及长江流域中上游亚热带常绿阔叶林的银木荷群落的管理提供一定的参考价值。

CHANGES OF SPECIES COMPOSITION AND DIVERSITY OF 〖WTHX〗SCHIMA ARGENTEA〖WTHZ〗 FOREST IN JINYUN MOUNTAIN

We analyzed the dynamics of species composition and diversity change of 〖WTBX〗Schima argentea〖WTBZ〗 forest in Jinyun Mountain during the natural succession for the last two and a half decades,1984 to 2009.The research showed that the number of species had decreased from 57 in 1984 to 39 in 2009 and plants in herbage and liana layer died out gradually.Meanwhile,the breast area of trees in canopy layer in which DBH was longer than 75 cm has fallen.Though the composition and diversity had changed,〖WTBX〗Schima argentea〖WTBZ〗 still dominated the forest.〖WTBX〗Neolitsea aurata〖WTBZ〗 var.〖WTBX〗glauca,Symplocos setchuanensis〖WTBZ〗 and 〖WTBX〗Rhododendron stamineum〖WTBZ〗 had become more and more from 1984 to 2009,but 〖WTBX〗Castanopsis carlesii〖WTBZ〗 var.〖WTBX〗spinulosa〖WTBZ〗 was on the contrary.The four α diversity indices in this community were on the downtrend.Richness index had reduced from 298 in 1984 to 199 in 2009.Shannon Wiener index had reduced by 034 in last 25 years while Simpson index and Pielou index remained almost the same.Besides,the analysis of β diversity and Whittaker index which was 018 also showed that there was a large difference in the 〖WTBX〗Schima argentea〖WTBZ〗 community between 2009 and 1984.In conclusion,the remarkable difference between the two periods of time is of significance for the management of 〖WTBX〗Schima argentea〖WTBZ〗 forest in Jinyun Mountain and the subtropical evergreen broad leaved forest of upper reaches of the Yangtze River.〖