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

Abstract

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