三江源自然保护区主要森林群落物种多样性研究

Plant Species Diversity of Main Forest Community Types in San Jiangyuan National Nature Reserve

应用典型抽样法研究了三江源自然保护区4个主要森林群落的物种多样性,采用多种测度方法计算了各森林群落的α多样性和β多样性。结果表明:(1)青海云杉林、川西云杉林、紫果云杉林、大果圆柏林内部,3个层片间物种丰富度和物种多样性都表现为草本层>灌木层>乔木层,反映了三江源自然保护区主要林区森林群落层片的物种多样性分布格局;(2)乔木层物种多样性从高到低依次为青海云杉林>紫果云杉林>大果圆柏林>川西云杉林,主要与群落分布的地理位置、海拔等环境因子和建群种生态学特性有关;(3)灌木层物种多样性,分布在阴坡地段的青海云杉林、川西云杉林和紫果云杉林差别不大,但都比分布在阳坡地段的大果圆柏林高,主要与阳坡早春树木生理干旱和放牧有关;(4)草本层物种多样性从高到低的顺序基本与灌木层相反,分布在阳坡的大果圆柏林草本层物种多样性高于分布在阴坡群落中的物种多样性;(5)β多样性表明,紫果云杉林与川西云杉林之间在物种多样性组成方面相似性最大;大果圆柏林和川西云杉林物种组成多样性的相似性位居第二;大果圆柏林和青海云杉林之间的物种多样性相似系数最低,可见,森林群落物种组成相似性程度,首先取决于群落建群种生态幅的宽窄,其次与建群种之间的生态学特性和生物学特性有关。

The characteristics of four main forest community types were analyzed by typical sampling technology, α diversity and β diversity were calculated with various calculation methods. The results showed that ： （ 1 ） In four main forest communities of Picea crassifolia , Picea likiangensis var. balfouriana , Picea purpurea and Sabina tibetica , a di- versity which represented by Shannon-wiener index and Gleason richness index had the highest value in herb layers, the medium in shrub layers and the lowest in tree layers. （2） Among the 4 main forest communities, the ordination order of c~ diversity in tree layers from high to low was that Picea crassifolia community 〉 P. purpurea community 〉 Sabina tlbetica community 〉 P. likiangensis var. balfouriana community. （3） There were no significant difference of species diversity in shrub layers among Picea crassifolia community, P. purpurea community and P. likiangensis var.balfouriana community, which of them distributed in shade slopes, however,Sabina tibetica community distributed in sunny slopes had the lowest species diversity in shrub layers because of grazing disturbance and natural conditions of sunny slopes. （4） Species diversity in herb species of Sabina tibetica community was higher than other communities which distributed in shade slope. （5） Here, β diversity indicated that the similar degree of species composition among communities which was determined by ecological range and biological characteristics of dominant species.