Abstract: According to the natural distribution of Reaumuria. soongorica in desert regions of Inner Mongolia, we selected four typical vegetation belt (transitional zone from desert steppe to steppificated desert, steppificated desert zone, transitional zone from steppificated desert to typical desert and typical desert zone) from east to west as the sampling plots. Based on field investigation of the R. soongorica population, according to different levels classified by plant volume, the spatial pattern of the R. soongorica populations was studied by using point pattern analysis. The results showed that:with the aggravating drought degree, the population density of R. soongorica decreased; the population model changed from growing to mature or senescent type; the population pattern changed from aggregated distribution to random distribution; the R. soongorica populations clumped in smaller scales; regular distribution occurred in typical desert zone. Spatial associations of different R. soongorica population classes had strong spatial heterogeneity and scale heterogeneity. With the aggravating drought and desertification degree, the internal ecology mutually beneficial relationship of the R. Soongorica population was weaken; even an unfavorable internal ecology relationship appeared in typical desert zone. In desert regions of Inner Mongolia, the community composition of R. soongorica was simple, especially in typical desert zone, the community composition of R. soongorica was simple composed by itself. The community of R. soongorica in desert regions of Inner Mongolia was special and fragile.

Key words: Reaumuria soongorica, population age structure, spatial distribution pattern, spatial association