[Responses of spatial distribution pattern of Artemisia ordosica population to the precipitation gradient on Ordos Plateau].

Five sites along the precipitation gradient (336-249 mm x 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 pattern 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.