The Community Stability Of Typical Steppe And Desert Steppe In Inner Mongolia

Different succession stages of plant community were selected in two types of grassland in Xilingol league of Inner Mongolia. Using a method of spaces instead of time, we discussed different types of grassland community characteristics in the time-series and the mechanism of community stability, based on plant biomass and soil nutrients for variables. We obtained the following conclusions:1. The typical steppe and the desert steppe in Xilingol league area were divided into five vegetation succession stage which was closely linked to each other. Stipa krylovii and Carex tristachya communities were the key transition types which connected the typical steppe and the desert steppe.2. The stability in different type grassland showed increased trend from population level to functional group level, and then to community level. The variation coefficients of dominant species in different type of grassland community were small and indicated more stable in the community system. At the community functional group level, the perennial grasses top contributor to the community, and showed the most stable type of functional groups.3. Variability of soil nutrients and the ground vegetation were the corresponding relationships. Soil nutrients variability reduced gradually from typical steppe to desert grassland, while the stability presented an increased tendency. In comparison to the community variability, the soil variability presented more stable in the grassland ecosystem.4. Species richness was the key factor which influenced the stability of grassland community. The stability of individual plants increased as the population of individual species richness increased in the community.