川西亚高山森林群落物种多样性与群落结构研究

采用多样性指数、丰富度指数和均匀度指数对川西亚高山6种典型森林群落物种多样性和群落结构进行研究,结果表明:①各类型森林群落物种多样性指数表现为常绿、落叶阔叶林>云杉冷杉混交林、云杉白桦混交林、冷杉糙皮桦林>冷杉纯林;②在海拔800～3150m范围内,各类森林群落物种多样性指数及均匀度指数随着海拔升高而降低;③植物生长型与群落多样性指数的关系表现为灌木层与草本层物种丰富度指数相近且明显高于乔木层,物种多样性指数则表现出草本层>灌木层>乔木层的规律;④从群落起源看,人工林群落上层结构比天然林群落简单,且人工林群落中草本层的物种多样性指数显著高于其他层次;⑤人工林群落高位芽植物明显少于天然林群落,地下芽植物和一年生草本植物则高于天然林群落;在天然林群落中高位芽植物在生活型谱中占绝对优势;⑥在森林经营中,应根据生境特点调控亚高山森林群落结构,丰富物种多样性,促进群落结构优化;同时,减少对天然林群落的人为扰动,保护生物多样性,从而充分发挥其生态服务功能。

A Study on Community Structure and Species Diversity of Subalpine Forests in Western Sichuan

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 showed 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.