中文摘要：

以宁夏盐池四儿滩湿地为例，以重要值为基础数据，采用丰富度指数、综合多样性指数、均匀度指数对湿地生态系统α多样性沿湿地一干草原梯度变化及样线间的差异进行对比分析，同时进行相关环境因子探讨。结果表明：同一样线内，受土壤含水量、全盐含量和土壤养分等因子影响，多样性指数与丰富度指数、均匀度指数变化趋势一致，交错带最大，其次是旱生带，最小为湿生带。由于受人为活动及地形地貌影响程度的不同，样线间植物α多样性差异较大。南样线的丰富度指数最大，其次为西北样线，西样线最小；多样性指数与均匀度指数变化趋势一致，西北样线最大，西样线次之，南样线最小。

英文摘要：

The vegetable a-diversity in wetland-dry grassland was studied in Siertan wetland, Yanchi County, Ningxia Hui Autonomous Region. Taking the importance value as basic data, this paper use richness index, diversity index and abundances index to analyze the change of plant α-diversity between three strips and three lines in wetland-dry grassland ecosystem and explain main environmental factors. The results showed as follows. Affected by soil moisture content, organic matter, soil salt content, diversity index in ecotone was the biggest, the one in arid grassland strip was in the next place, while that of wetland strip, the smallest. Richness index and evenness index had the same trend as diversity index. Human activity and different landforms had brought the differences between lines. Richness index in the south line was the biggest, the next was in northwest, and the one in west line was the smallest. Diversity index had the same trend as evenness index. They were bigger in the northwest line than in the west line, while the south line had smaller ones than the west line.