星斗山木本植物多样性沿海拔的格局

The altitude pattern of woody plant diversity of Xingdoushan

以星斗山11个样方的调查资料为基础,应用物种重要值、物种丰富度、α多样性和β多样性指标,对星斗山木本植物群落结构及多样性空间分布特征进行了研究,同时也作为验证Rapoport理论的一个案列。结果表明:星斗山自然保护区群落以多优种群落为主,群落重要值大于15的优势种主要有杉木、楠木、水青树、鹅耳栎及青冈等;该地区群落外貌随着海拔高度的升高表现出一定规律性;随着海拔升高,物种α多样性及丰富度呈现减小趋势,同时β多样性亦减小,验证了Rapoport理论;不同坡向物种多样性存在差异,Simpson指数以东坡、东北坡最高,其次是西坡,北坡最低;同一群落灌木层物种多样性均高于乔木层。

The woody plant species richness,community diversity and spatial distribution features were analyzed based on sampling plots in Xingdoushan Nature Reserve,Hubei,China. The research also took Rapoport＇s altitude rule as a case study. Results showed that the forests in Xingdoushan consisted of multi-species dominant communities. The trees whose importance values were more than 15included Cunninghamia lanceolata,Phoebe zhennan,Tetracentron sinense,and Cyclobalanopsis glauca. The physiognomy of the community changed with elevations. The α diversity,presented by the Simpson and Shannon-Weiner indices,decreased for both the tree and shrub layers with increasing altitude. The β diversity,which was indicated by the Cody index,declined with increasing altitude.These patterns supported Rapoport＇s altitude rule. Furthermore,the species diversity was significantly different among aspects. The Simpson index was the highest in the east and northeast aspect,followed by west,and the lowest in north aspect. The species diversity of shrub layer was higher than the tree layer at same forest community due to environment differences in canopy layers.