richness index
2.Therefore it may suggest that China silkvine and amur maple be candidate plant species for artificial vegetation construction. The change of plant species richness index (Gleason index and Margalef index), diversity index (Shannon-Wiener index), and Pielou evenness index in herbaceous layer and shrub layer csn be described by a parabolic function: y=at~2+bt+c, but the change of diversity in different layers were asynchronous.
3.The floristic composition structural characteristics of Tiankeng forest communities were analyzed by the importance values of arbor. Species diversity was also analyzed by various kinds of diversity indices, such as the species richness index, Shannon-Wiener index (H), Simpson index (D), PIE and Pielou evenness index (J).
4.The results showed that, in the course of wasteland restoration, the cultivated vegetation grew well; the plant species was increased from 13 to 60, and the richness index, evenness index and diversity index of species was increased significantly; the proportion of annual and biennial herbage in vegetation composition was decreased from 61.5% to 35%, and the vegetation coverage was increased from 18% to 80%.
5.The result suggests that the species richness index ranks as following among 6 stations: Yangma Islet>Drogan-whisker Islet>Moon Bay>Jingouzhai>Jingouzhai Gravel, and Yangma Islet possessed the highest species diversity index, while Jingouzhai the lowest, the order of species diversity index among 6 stations is Yangma Islet>Moon Bay>Drogan-whisker Islet >Jingouzhai>Zhifu Islet>Jingouzhai Gravel, the order of species evenness index is: Moon Bay>Drogan-whisker Islet>Yangma Islet>Jingouzhai>Zhifu Islet>Jingouzhai Gravel.
6.Broad-leaf plants and grasses were the main weeds throughout the growing season,their relative abundance being 27.74%~69.39% and 27.74%~69.39%,respectively. Barnyard grass(Echinochloa crusgalli Beauv.) and Sagittifolia L.were the dominant weed species,their richness index being 0.187 3~0.615 6 and 0.082 5~0.163 3,respectively.
7.The results showed that: (1) In four main forest communities of Picea crassifolia, Picea likiangensis var. balfouriana, Picea purpurea and Sabina tibetica, α diversity 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 a diversity in tree layers from high to low was that Picea crass folia community>P. purpurea community>Sabina tibetica community>P. likiangensis var. balfouriana community. (3) There were no significant difference of species diversity in shrub layers among Picea crassfolia 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.
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。收藏指正
9.The results show that each index has different functions on evaluating the diversity of a phytoplankton community. In general, integrated using of species richness, Margalef index, Fisher α index, Shannon index, Simpson index (1-D form) and Pielou index were fit for analyzing the phytoplankton community. But it should be cautious to use Margalef and Fisher α index in analyzing the phytoplankton community.
