中文摘要：

应用方差均值比率法、聚块性指数及点格局方法，沿着鄂尔多斯高原从东至西的降水梯度（336～249mm·a^-1），设置5个采样点，对油蒿种群分布格局及其对降水梯度的反应进行了研究．结果表明：随着降水梯度的递减，在小尺度上研究区油蒿种群分布格局表现为由均匀分布向随机分布转变；在大尺度上则表现为由随机分布向聚集分布转变．降雨的减少显著改变了油蒿种群的空间分布格局，在进行生态恢复时需对植物个体进行合理配置．

英文摘要：

Five sites along the precipitation gradient （336-249 mm·a^-1） from east to west in Ordos Plateau were selected to study the spatial distribution pattern of Artemisia ordosica population and its responses to the precipitation gradient by the methods of variance mean ratio, aggregative index, and point pattern analysis. The reduction of precipitation affected the spatial distribution pat- tern of A. ordosica population significantly. With decreasing precipitation gradient, the spatial pattern of A. ordosica population changed from uniform to random in small scale, and from random to clumpy in large scale, suggesting that in the ecological restoration of Ordos Plateau, a rational arrangement of A. ordosica should be made.