秦岭太白山巴山冷杉天然林群落物种多样性

研究秦岭太白山区域巴山冷杉天然林群落的物种组成、多样性及其对海拔的响应，可为天然林的保护与合理开发利用提供科学依据。采用典型样方调查法，分析巴山冷杉天然林群落各层次的物种组成，计算其重要值、物种多样性指数，并针对天然林物种多样性与其所在海拔因子的关系进行耦合。结果表明，巴山冷杉天然林群落共有123种植物，巴山冷杉为该群落的建群种，重要值高达64.95%,乔木物种构成比较单一；灌木层共有41个物种，其中秦岭箭竹重要值高达32.39%,为灌木层主要优势种；草本层的物种多达77种，呈随机分布，单个物种的优势度不高。群落中各层次物种丰富度为草本层>灌木层>乔木层，均匀度指数、优势度指数和多样性指数均为草本层高于木本层。随着海拔的升高，灌木层的多样性指数变动幅度较大，而草本层多呈平缓上升趋势。物种丰富度在海拔2 500 m处有最大值，均匀度指数、优势度指数、多样性指数均在海拔2 886 m处达到最大值。秦岭太白山巴山冷杉天然林群落的自我更新演替能力较差，呈衰退状态。海拔对林下各层次物种多样性有一定影响，且对灌木层的影响大于草本层。

Species Diversity of Abies fargesii Natural Forest Community in Mt.Taibai of Qinling

To investigate the species composition,diversity and response to altitude gradient of Abies fargesii natural forest community in Mt.Taibai of Qinling,and to provide scientific basis for the protection and reasonable development and utilization of natural forests.Quadrat survey method was adopted to analyze the species composition at different levels in the community,to calculate the important value,species diversity index,and to couple the relationship between species diversity and its altitude.A total of 123 species were found in the community,among which A.fargesii was the constructive species with an importance value of 64.95%,the composition of arbor layer species was relatively simple; there were 41 species in shrub layer,Fargesia qinlingensis was the dominant species with an importance value of 32.39%; 77 species were found in the herb layer,which were randomly distributed,and the dominance of a single species was not high.The species richness was in the order of herb layer>shrub layer>arbor layer.The evenness index,dominance index and diversity index of the herb layer were higher than the woody layer.The species diversity index of all layer of the natural forest was irregular with the altitude pattern.The diversity index of the shrub layer varied greatly with the altitude,while the diversity index of the herb layer showed a gentle upward trend.The species richness of various levels of the natural forest had a maximum at the altitude of 2 500 m,and the evenness index,dominance index,and diversity index reached their maximums at the altitude of 2 886 m.The ability of self-renewal and succession of A.fargesii natural forest community in Mt.Taibai of Qinling was poor,and it was in a state of decline.Altitude had larger influence on shrub layer than on herb layer.