Studying the sffects of Grazing Capacity and Rangeland Conditions on Occurrence of Landslide in Subalpine Grassland (Case Study: Rangeland of Masoleh Watershed)

Subalpine rangeland as a rara avis ecosystem is very important because of ecological features. Consistency and resistance of this ecosystem is so frangible and its natural equilibrium is instable due to the effects of biotic and abiotic factors. The landslide as one of negative consequences in upland area is seen in Masoleh watershed (north of Iran). This study has investigated the roles of biotic factors playing in the occurrence of the landslides in Masoleh rangeland. Hence, two sites such as exclosure and grazing areas were analyzed and compared. The plot size was 1m² and totally, 128 plots were obtained by minimal area method and statistical formula approach, respectively. The rangeland conditions were measured by six-factor method. Clipping and weighing method was used to determine the grazing capacity. In order to do the landslide zonation, the landslide index was employed. Results showed that there were significant differences between species densities and soil conservation factors in both exclosure and grazing areas. There might be more than 1.2 overstocking in the grazing area. The rangeland conditions‟ classes and distance from fold, effective biotic factors, geologic formation, soil texture and effective abiotic factors were the most influential factors on the landslide occurrence in subalpine ecosystem of Masoleh. Regarding results of current research, the exclosure can protect the soil from the landslide through increasing the perennial and endemic species. Decreasing livestock and regulating the animal entrance and egress to reach the suitable circumstances of vegetation covers and pull up the landslide occurrence are recommended in this area.