百山祖自然保护区植物群落beta多样性

本文采用植物群落学的典型样方法，研究了百山祖自然保护区森林植物群落beta多样性格局及其维持机制。通过对45个20m?20m标准样地的调查数据进行分析，运用Chao’s群落距离指数衡量该植物群落beta多样性格局，并通过Mantel检验、基于距离矩阵的偏RDA分析和方差分解等方法初步检验和衡量了各环境因子差异（包括群落郁闭度、海拔、坡度、坡向和坡位）和群落空间距离对该区域beta多样性格局的影响。结果显示，该区域内植物群落beta多样性随着群落间综合环境差异或群落空间距离的增加而增大， 但环境差异和群落空间距离只能解释36%左右的beta多样性格局。检验的5个环境因子中，只有群落郁闭度和海拔对百山祖自然保护区植物群落beta多样性有显著影响，并且群落郁闭度对beta多样性的解释度（20.0%）略高于海拔对beta多样性的解释度（18.0%）。群落空间距离对百山祖自然保护区beta多样性的解释度最小（9.0%）。本文展现了百山祖自然保护区内植物群落beta多样性格局及其与群落环境和空间距离的关系，所获得的结果支持生境异质性和扩散限制联合对植物群落beta多样性起作用的假说。

Beta diversity of plant communities in Baishanzu Nature Reserve

In this study, we analyzed the beta diversity pattern of forest plant communities in Baishanzu Nature Reserve by typical quadrat methods. The beta diversity pattern was described by Chao's index based on 45 20m×20m plots in this area. Correlations between the beta diversity and five environmental factors (coverage of tree layer, elevation, slope grade, slope aspect and slope position) and spatial distances of communities were examined by Mantel test, Distance-based Redundancy analysis and ANOVA. The results showed that, beta diversity increased with spatial distance and environmental difference among plots, but only 36% of its variance can be explained by the joint effects of spatial distance and environmental difference. Specifically, only coverage of tree layer and elevation of the local community significantly affected on beta diversity at Baishanzu Nature Reserve. The impact of coverage of tree layer (explained 20.0% variance of the beta diversity) on beta diversity was also slightly larger than that of elevation (18.0%), and evidently lager than spatial distance (only 9.0%). Our study revealed the pattern of beta diversity and its relationship with environment and spatial distance of plant communities in Baishanzu Nature Reserve, and the results supported the joint effect hypothesis of habitat heterogeneity and dispersal limitation on beta diversity.