麦积山草地植物群落物种多样性及结构相似性特征

Species diversity,community structure similarity of the grassland communities,Maiji mountain

采用标准样地调查法对甘肃省麦积山风景区不同海拔和坡向草地植物群落的数量特征、物种多样性、群落结构与种群习性等特征进行了调查研究。结果表明：臭草（Foeda herba）、冰草（Agropyron）、野燕麦（Avena fatua L）和甘肃羊茅（Gansu fescue）分别为不同海拔的优势种群,优势种与次优势种多为多年生草本植物,且以菊科（Compositae）、禾本科（Gramineae）、豆科（Leguminosae）为主;不同海拔间植物群落相似性系数均在0.50~0.75之间,属于中等相似水平,海拔梯度间群落结构差异小;植物群落密度随海拔升高下降,但差异不显著,群落丰富度指数、多样性指数随海拔升高呈下降趋势,均匀性指数随海拔升高先升高后下降。

The plant community species diversity,community structure similarity at different altitudes and slopes of Maiji mountain grassland in Gansu Province were studied using standard plot survey method.The results showed： Foeda herba,Agropyron,Avena fatua L and Gansu fescue are the dominant species of grassland community in the different altitude,and most belong to Gramineae,Compositae and Leguminosae of Maiji mountain.Anyhow,perennial grass species are the main dominant and sub dominant species.The grassland plant community density declines from lower to higher altitude but has not significant difference in Maiji mountain.With the increasing of altitude,the proportion of richness index and diversity index decrease,evenness index showed first increase then decrease,The similarities were extremely high among different altitude grassland communities with similarity indices from 0.50 to 0.75,the communities structure had not significant difference in different altitude.Grassland plant community had a higher level in diversity,while the slop and altitude had no influence for plant community similarity.