八大公山自然保护区珙桐群落结构与物种多样性研究

为了掌握八大公山自然保护区珙桐群落的现状，采用样方法对湖南省八大公山自然保护区珙桐群落的物种组成、群落结构和物种多样性进行分析。结果表明，在4000 m2的样地内共有维管束植物73科132属160种，植物区系组成以北温带分布最多，达37属，占25.87%。其次是东亚热带，共23属，占16.08%。珙桐群落区系的温带成分所占比例大于热带成分，其种类组成具有亚热带向温带过渡的特征。群落垂直结构可分为乔木层、灌木层、草本层和层间植物。乔木层及灌木层不发达，草本层较发达。群落根据Raunkiaer生活型谱划分以高位芽植物占优势(42.8%)，与其他亚热带常绿落叶林生活型谱各项比率相近似。种群丰富度、Shannon-Wiener指数、Simpson指数均表现出相同的趋势，为草本层>灌木层>乔木层。而均匀度指数为草本层>乔木层>灌木层。八大公山自然保护区珙桐种群种类组成具有亚热带向温带过渡的特征，群落处于中期稳定生长期与衰退期之间，未达到一个稳定状态。

Community structure and species diversity of Davidia involucrate in Badagongshan National Nature Reserve

To research the Davidia involucrate community situation in Badagongshan Nature Reserve,Hunan Province,using the sample plot method to analyze the floristic composition,structure,physiognomy and species diversity of Davidia involucrate community in Badagongshan Nature Reserve,Hunan Province,by field investigation of a 4000 m 2 plot.The results showed that there were 160 vascular plant species in the community belonging to 73 families and 132 genera.The largest composition of Davidia involucrata community was the North Temperate Zone Plants,reached to 25.87% （37 genera）.Then was east Asia,about 16.08% （23 genera）.The community vertical structure was simple,which composed of tree layer,shrub layer,herb layer and interlayer plant.Herb layer was better than tree layer and shrub layer.In term of life form,42.8% was phanerophytes and was similar to that in subtropical evergreen and deciduous forest.The Richness index,Simpson dominance index,Shannon-Wiener index had similar trend,with herb layer〉shrub layer〉tree layer in the community.But Pielou evenness index was herb layer 〉tree layer 〉shrub layer.The species component of Davidia involucrate community had the typical transition characteristics that from the subtropics to the temperate zone.The community growth situation between metaphase normal growth and decline stage,and had not yet developed into its climax.