Abstract: With Duguitala Township in the north part of Hangjin County as an example,this paper studied the spatial distribution pattern of natural vegetation along moisture gradient at the north edge of Ordos Plateau.The results showed that based on TWINSPAN classification,the communities were dominated by mesophytes and xerophytes,and there were some halophytes in some quadrats.The similarity indices of neighboring quadrats could reflect the mosaic pattern of different type communities,and thus,the diversity and complexity of communities along this gradient,which could be reconfirmed by DCA ordination.The CCA ordination for quadrats and geomorphological factors indicated that in this transitional region,the formation of vegetation’s spatial distribution pattern was determined by moisture gradient,while the latter was controlled not by the distance from the main course of the Yellow River but by the change of micro-geomorphology.In the land exploitation of this region,relatively stable geo-morphological units should be taken into consideration,and large scale land exploitation through surface leveling should be avoided if shelterbelt measures and drainage and desalinizeation system were defective.This study would be helpful to the protection of natural vegetation and the integrated development of agriculture and animal husbandry.

Key words: Geostatistics, Soil nutrients, Spatial variability, GIS, Scale, Isotropic