青海湖鸟岛沙地植物群落物种多样性研究

根据野外样地调查资料，采用丰富度指数、物种多样性指数和均匀度指数对青海湖乌岛沙地植物群落的多样性进行了研究，并用相关分析研究了多样性指数间的关系，结果表明：①鸟岛7个主要沙地群落间的植物多样性差异很大，分布于固定沙丘上的赖草、甘青铁线莲等群落均具有较高的丰富度指数、多样性指数，而西伯利亚要、藏虫实等分布在流动沙丘上的群落则最小，但均匀度指数最高。②从流动沙丘到固定沙丘阶段的变化过程中，丰富度指数、Shannon-Wiener指数和Simpson指数的变化趋势基本一致，而均匀度指数则呈相反趋势，半固定沙丘是这一变化的重要转折点。②物种在各沙地类型中出现频率的多样性指数差异很大，特有种多样性指数在固定沙丘中最高，占主导地位，而在流动沙丘阶段，普通种的物种多样性指数最高。④植物生活型上各沙丘类型上的物种多样性指数均以多年生草本为最高，其次为一年生草本，而且从流动沙丘至固定沙丘阶段呈递增变化。⑤丰富度指数与多样性指数、均匀度指数之间存在极显著的相关性。

Sand Plant Community Diversity on the Bird Island of Qinghai Lake

Based on the data investigated from the field, one richness index, two species diversity indices and two evenness indices were used to analyze the vegetation on the Bird Island of Qinghai Lake. In addition,relationships among these indices were studied by correlation analysis. There are some results: (1) The species diversity was much different between the seven main sand plant communities. Those distributed on fixed sand dunes had higher richness and diversity indices, such as \%Leymus secalinus\% and \%Clematis tangutic\%; indices of \%Polygonum sibiricum\% and \%Corispermum tibeticum\% on shifting sand dunes were the lowest,while the evenness indices were the highest.(2) In the gradient from shifting to fixed sand dune,the changing tendency of the richness index, Shannon\|Wiener index and Simpson index showed almost the same,but the evenness indices showed the contrary tendency and semifixed sand dune was an important turning point.(3) The species frequent diversities on different sand dunes were different. Special species dominated on fixed sand dunes,the Shannon\|Wiener index and Simpson index were the highest. But on shifting sand dunes,the common species diversity indices were the highest. (4) For all dune types the species diversity indices of perennial plants were the highest,those of annual plants were at the second,they increased from shifting sand dune stage to fixed stage. (5) There was very near correlation between the richness and species diversity indices or evenness indices.