关键词: 物种多样性, 均匀度, 群落结构, 川西亚高山

Abstract: Based on data from 6 types of forest community within 45 plots, species richness index, evenness index and species diversity index of sub-alpine forest communities in the Jiajinshan mountain were determined and analyzed. The results show ed that the species diversity and evenness of the communities embody a sequential change as Evergreen Broadleaved Forest > Deciduous Broadleaved Forest > Mixed Picea asperata and Pruhus serrulata Forest > Mixed Picea asperata and Betula platyphylla Forest > Mixed Abies fabric and Betula ultilis Forest > Pure Abies fabric Forest. In the sub-apline area, species diversity and evenness decrease gradually as the elevation ascends. The species richness within the herb layer and the shrub layer are similar in that they are significantly higher than that within the tree layer. As for the evenness, shrub layer is similar to the herb layer and both are in a small variation among communities. The evenness of the tree layer varies significantly among different communities. Species diversity index within different layer shows a trend of:herb layer > shrub layer > tree layer. Furthermore, the structure of artificial forests is simpler than that of the natural forests, but their herb species diversity is higher. The number of Phaneropytes in artificial forests is smaller than that of natural forests, but the number of Geophytes and Therophytes is significantly larger. And Phaneropytes dominate natural forests. Accordingly, a suggested management strategy is to maintain proper species diversity in forests so as to optimize the forest structure and to ensure its ecological service.

Key words: species diversity, evenness index, community structure, subalpine of western Sichuan