金沙江流域干热河谷草地群落物种数量及多样性特征

选择金沙江干流及支流小江干热河谷典型草地,采用标准样地调查法,对其上游、中游、下游以及支流干热河谷草地植物群落数量特征、物种特性、以及物种丰富度、多样性、均匀度等特征等开展研究,结果表明,①金沙江干热河谷草地植物群落密度自上游至下游显著增加（F=5.226;P≤0.01）。金沙江干流河谷内植物分布受经向的影响较大,纬向对河谷内植物群落影响较小,河谷间影响较大。草地植物群落中扭黄茅（Heteropogon contortus）种群在数量上占优势,同时扭黄茅种群密度沿着河谷走向逐渐增加,但在群落中的比例逐渐降低。②金沙江干流及支流小江东川干热河谷草地植物群落以禾本科（Gramineae）、豆科（Leguminosae）、莎草科（Cyperaceae）、菊科（Compositae）为主。③金沙江干热河谷草地植物群落丰富度分析发现,群落丰富度指数自上游至下游逐渐降低。Simpson多样性指数、Shannon-Wiener多样性指数及Peilow均匀性指数自上游至下游逐渐升高。

The species quantitative & diversity characteristic of grassland community in hot-dry valley of Jinsha River

This study was conducted to investigate the quantitative features,species characteristics,the richness,diversity and evenness characteristics of typical grassland community in the hot-dry valley along Jinsha River and Xiaojiang River,a tributary of Jinsha River.The results show that： ① The grassland plant community density increases significantly from upper to lower Jinsha River hot-dry valley （F=5.226;P≤0.01）.While the longitude change shows more influence on the plant distribution in the hot-dry valley of the main stream of Jinsha River,the latitude shows less influence on the plant community in the valley,but more between valleys.Heteropogon contortus （Poaceae） is dominated in quantity in the grassland community,and the population density of that increases gradually along the valley trend,yet the proportion in the community decreases gradually.② The grassland community in the hot-dry valley of Jinsha River is determined by Gramineae,Leguminosae,Cyperaceae,and Compositae.③ By analyzing the richness of the grassland community,the community richness index decrease gradually from upper to lower Jinsha River.Besides,Simpson,Shannon-Wiener diversity index and Peilow evenness index increase gradually.