中文摘要：

在内蒙古短花针茅（Stipabreviflora）草原分布区选择赛汉、化德、准格尔3个典型样地，在各样地沿坡面设置3条样线进行植被调查和土壤分析，并采用聚类分析、二项式检验、差异显著性检验、典范对应分析、Pearson~N关性分析等一系列统计学方法，探讨了坡位对植被格局的影响及土壤效应。结果表明：（1）坡位导致缓丘上部坡面和下部坡面植被类型明显分异，且以群落复合体的形式出现，上部坡面发育的是该区气候顶级群落，下部坡面发育的为地形群落；（2）坡位影响了物种沿坡面的分布格局，主要体现在建群种及部分优势种上；（3）坡位导致上部坡面和下部坡面生产力的差异，且下部坡面的生产力高于上部坡面，形成2个不同的功能区域；（4）坡位通过地貌过程和起伏变化，外加风蚀、水蚀影响，严蕈改变了表层_十（尤其是0—5cm）的土壤特征，从而在极小的范围内形成了非常明显的生境异质性，提供了多样化的生存环境，为局域范围内生物多样性的形成与维持提供了一种重要机制；（5）坡位导致植被分异的土壤效应主要是表层土（尤其是0-5cm）土壤机械组成的差异，生产力沿坡面的分异主要来源于土壤含水量。开展坡位对植被分布格局的影响将为植被分类、植被制图学科的发展提供理论依据，并为植被资源的合理规划和利用以及开展植被保护与各种生态恢复工程提供科学依据和现实指导意义。

英文摘要：

Aims Spatial pattern of vegetation is determined by a variety of environmental factors on different scales. The influence of landform on vegetation pattern is receiving growing attention. This study examined the influence of slope location on vegetation pattern in Inner Mongolia grassland to provide a scientific basis for vegetation classi- fication, vegetation mapping, rational utilization and ecosystem restoration and reconstruction. Methods In each of three typical sites in Stipa breviflora grassland, we established three parallel line transects of unequal length and placed 0.5 m × 0.5 m herb plots at 2-m intervals along each line. Vegetation and soil were sur- veyed for each plot. Cluster analysis, binomial test, significant difference test, canonical correspondence analysis and Pearson correlation analysis were used to analyze the influence of slope location on vegetation pattern and soil effects. Important findings Vegetation types were clearly differentiated between upper and lower slopes, with a climatic climax community on the upper slope and a terrain community on the lower slope. Slope locations affected the species distribution pattern along the slope, mainly in species composition and some dominant species. The pro- ductivity of the lower slope is higher than that of the higher slope, and two different functional areas had formed. The character of the surface soil （especially 0-5 cm） was largest difference between upper and lower slope. Vari- ous geomorphic processes resulted in great habitat heterogeneity in a very small region. It provides an important mechanism for formation and maintenance of biological diversity at the local scale. Mechanical compositiondifference of surface soil （especially 0-5 cm） affected vegetation pattern, and soil moisture affected the productivity difference along the slope.