مدیریت بیابان (Feb 2018)
Assessment of desertification in east Isfahan using integration MEDALUS model and multi criteria analysis (MCA)
Abstract
Desertification means land degradation in arid, semi-arid and dry sub-humid regions as a result of various factors, including climatic variations and human activities. In this research, the study area with an area of 136 thousand hectares located 20 kilometers far away from east Isfahan was selected. Due to the proximity of this area to Isfahan city and the impact that desertification phenomenon on the city, studying the desertification in this region is of great importance. To assess the current status of desertification, the multi criteria Analysis and MEDALUS model was used. For this purpose, in the first step and based on the local situation, six qualitative criteria, including climate, soil, groundwater, vegetation, soil erosion, desertification management and policy evaluation were considered. These indices have been standardized and quantified based on their effect on desertification in the frame by scoring 100 to 200. The qualitative value of each criterion has been obtained by multiplying the weight of the Analytic Hierarchy Process (AHP) and integration of layers based on the weighted linear combination. Finally, the desertification status map has been acquired through multiplying weight to the layer value of each criterion and integrating layers according to the method of weighted linear combination in Geographic Information System (GIS). According to the results, 35.49% of the area of the region falls in a severe class and 64.5% falls in very severe class of desertification. Besides, the climate criterion with a weight of 0.29 has the greatest impact on the phenomenon of desertification and then it goes to the management and soil criteria with weights of soil 0.23 and 0.21, respectively. Therefore, to assess desertification and executive programs to deal with it in the region, considering these criteria are of great importance.
Keywords
