【摘要】 从生物多样性保护原则出发，物种多样性应是评价防护林综合效益的重要指标之一。本文采用Ｗｅｉｂｕｌ分布模型分析建溪流域防护林乔木层、灌木层的种－多度关系，用多种公式计算防护林各层次的物种多样性并与我国暖温带落叶阔叶林的物种多样性相比较，得出以下结论：１）该流域防护林乔木层的种－多度关系符合Ｗｅｉｂｕｌ分布模型，说明个体数量较多的乔木仅限于少数几种主要的树种，群落的均匀度相对较小；２）该流域防护林主要群落内乔木层、灌木层和草本层的丰富度、均匀度和总多样性指数都较我国暖温带落叶阔叶林相对应的指数高。更多还原

【Abstract】 According to the principle of biodiversity conservation, the species diversity should be regarded as an important target of synthetical benefit of the shelter forests. The authors analyzed the species abundance of tree layer and shrub layer of the shelter forest using the model of the Weibull distribution, and calculated the species diversity for each layer by means of various formulas and compared with that of the deciduous broad leaved forests in North China. The results were as follows:(1)in the valley the species abundance relationship fitted with the Weibull distribution model, suggesting that those trees with the greatest number of individuals were only restricted in a few species and evenness indices was small;(2)its richness indices, evenness indices and species diversity indices were higher than those of the deciduous broad leaved forests.更多还原