Abstract:

To analysis the species composition and species diversity in the different regions from the perspective of germplasm resources, Dactylis glomerata was selected at the altitude from 1800 m to 2200 m on the northern slope of Tianshan mountain. Results showed that the height, density, coverge and aboveground biomass had no significant difference between the eastern and western sections. With the increase of altitude, the D. glomerata dominant position gradually reduced, and the results of species diversity index analysis showed significant differences on distribution of D.glomerata. The α diversity index showed a rise firstly and then a decline trend with altitude increasing. The β diversity index showed that the eastern mountain with altitude from 1800 m to 2200 m had the same habitat and the western mountain with altitude from 1800 m to 2200 m was not all similar. One negative correlation relationship appeared among species diversity, altitude and aboveground biomass. These results could provide the important basis reference to reveal the distribution of species diversity and influencing factors.

Key words: Germplasm resources, Species diversity, Altitude, Aboveground biomass

摘要：

从对种质资源的研究角度出发，选取天山北坡东段与西段海拔1800~2200 m鸭茅（Dactylis glomerata）分布的典型区域，分析不同海拔鸭茅群落的物种组成及物种多样性变化。结果表明：群落高度、密度、盖度及地上生物量方面，天山北坡东段与西段在各海拔之间都存在差异，但无明显的规律性变化。鸭茅种群随海拔的升高，其优势地位逐渐降低；α多样性指数表明，垂直方向上，西段和东段山地均呈现随海拔先升高后降低再升高的趋势，呈现“V”型，水平方向上，两段山地相同海拔处除丰富度Margalef指数和物种丰富度在海拔2000 m呈现出显著性差异外（P<0.05），其他指数均未呈现出显著性的差异。β多样性指数表明，东段海拔1800~2200 m之间，群落相似性极高，共有种较多，生境条件较为一致。西段海拔1800~2200 m之间，共有种较少，生境存在着较大的差别。物种多样性指数与海拔呈现出显著负相关，与群落地上生物量不相关。

关键词: 种质资源, 物种多样性, 海拔, 地上生物量