Hazard Assessment of Desertification Using the New Model of Proposed MEDALUS

An increasing trend of natural resources degradation threatens human life dramatically. Desertification process is the main sign of land degradation. The principal aim of this research was an assessment of potential hazard of desertification using the MEDALUS model in the study of Golsara Torbat Heydarieh area in the province of Khorasan Razavi. The MEDALUS model was evaluated based on 5 key factors, namely: soil quality, climate quality, vegetation quality, management quality and trend of desertification (suggested factors). The quality of each factor was evaluated using the geometric mean of its indices. The desertification intensity map was prepared based on the geometric mean of all 5 key factors. In the Golsara region, 3 fragile classes (F1, F2, F3) and 1 potential class (P) and 1 non affected class (N) were evaluated. The MEDALUS model was modified by of adding a trend factor in which 3 other steps were revised. 1. After preparation the desertification intensity map based on the MEDALUS model, a new map of desertification intensity of the study area was prepared based on 4 classes of low to very severe situations showing 66% of the study area was under a moderate potential of desertification. 2. By upgrading the map of current productivity to potential productivity the current state of desertification that wasn’t considered in the MEDALUS model was run showing 60% of the study area was under a severe state of desertification. 3. Based on the map of current productivity to potential productivity, a new classification involving two main classes of potential risk and actual risk were defined for the desertification intensity map of revised the MEDALUS model. According to the final revised map of desertification in the Golsara region, 93.4% of the area was classified as the main class of actual risk and 6.6% as the main class of potential risk. These results point to the inefficiency of the current the MEDALUS model in the study area without considering the current degradation status parameter; therefore, we recommend the use of the modified model.