中文摘要：

通过野外植被调查,研究了宁夏东部风沙区荒漠草原植物群落组成与结构、物种多样性变化;采用典范对应分析（CCA）对植物群落分布与土壤性状关系进行了分析。结果表明：（1）风沙区荒漠草原物种较为单一,多集中在6~13种;不同群落类型间地上生物量和盖度差异显著;群落内竞争性较弱的物种减少,优势种具有较高的重要值。（2）群落间物种多样性差异显著,但变化趋势并不一致;物种多样性指数与丰富度指数、均匀度指数的相关系数分别为0.975 7和0.880 2,而与优势度指数相关系数为-0.519 8。（3）CCA结果表明,土壤含水率、有机质以及氮磷钾含量较高、容重小时,植物物种相对丰富;对群落分布影响较大的环境因子是土壤水分、容重和土壤有机质,相关系数分别为-0.742 8、0.683 8、0.532 9,物种和群落二者在CCA排序轴相关性较大的土壤因子较为一致。研究认为,宁夏东部风沙区荒漠草原植物优势种在群落中的地位明显,物种丰富度对植物多样性的影响大于均匀度,土壤水分是影响该区草原植物群落分布的决定性环境因子。

英文摘要：

The research of plant species diversity has a great impact on ecological construction.With the vegetation data of field survey,we studied the desert steppe community composition and structure in sandy area of Eastern Ningxia,the vertical variation of species diversity,and canonical correspondence analysis（CCA）the contact between plant community distribution and soil character.The results showed that：（1）the species of desert steppe in sandy area was simple,with only 6-13 species.There was a significant difference between aboveground and coverage in different community types.The weak competitive species in community decreased,and the dominants have higher important value.（2）The species diversity index was significantly different among communities,but the variation tendency was not consistent.The correlation coefficient between diversity index and richness index,evenness index were 0.975 7and 0.880 2,respectively,but the correlation coefficient of dominant index is-0.519 8.（3）In the analysis of CCA,the content of soil moisture,organic matter and NPK were higher.Soil bulk density lower,plant species abundance,relatively;soil moisture,soil bulk density and soil organic matter played a leading role in communitydistribution,the correlation coefficient are-0.742 8、0.683 8、0.532 9,respectively.Species and community both in the axis of CCA about soil factor relevance have a consistency.The results indicated that,the dessert steppe plant in sandy area of eastern Ningxia,dominants have extremely status and roles;the contribution rate of species richness to plant diversity is greater than that of evenness to plant diversity;soil moisture plays a decisive role to plant community distribution in this area.