中文摘要：

采用多种分析方法探讨放牧对短花针茅荒漠草原建群种与优势种无芒隐子草、碱韭的种群空间分布关系的影响.结果表明：短花针茅＋无芒隐子草＋碱韭群落的景观特征主要由草原的土壤理化性质和种群的固有属性决定.自由放牧导致的空间分布的变异程度为碱韭〉无芒隐子草〉短花针茅.自由放牧对短花针茅和碱韭密度的影响显著,但对无芒隐子草影响不大.随着无芒隐子草密度的增加,自由放牧区短花针茅密度呈现增大趋势,而围封区短花针茅种群密度呈现先增大后减小的趋势;自由放牧区和围封区内短花针茅密度均随碱韭密度的增加而减小.表明植物种群种间关系存在密度效应,在受到外界干扰的情况下,密度效应可能消失;因植物种对或干扰条件不同,植物种间关系可以有多种表现形式.

英文摘要：

The effects of grazing on spatial distribution relationships of constructive species （ Stipa breviflora） and dominant species （Cleistogenes songorica and Allium polyrhizum） in the desert steppe were analyzed by different analysis methods. The results showed that the landscape charac- teristic of S. breviflora ＋ C. songorica ＋ A. polyrhizum community was mainly affected by soil prop- erties and inherent properties of populations. The spatial distribution variability influenced by con- tinuous grazing （CG） was in order of A. polyrhizum 〉 C. songorica 〉 S. breviflora. The influence of CG upon the density of S. breviflora and A. polyrhizum was notable, while little influence upon the density of C. songorica was observed. S. breviflora density increased with the inci＇easing C. songorica density in CG area, whereas it increased firstly and then decreased with the increasing C. songorica density in enclosed area （CK）. S. breviflora density decreased with the increasing A. polyrhizum density in CG and CK area. It was concluded that there was density effect for plant inter- specific relationships which could disappear with the presence of outside interference. Plant inter- specific relationships were multiple with the difference in populations or interference conditions.