classification of desertification intensity using esas model in niyatak region (sistan, iran)

desertification is the consequence of series of processes in which climate change and human activities are more important factors than others. arid and semi-arid areas have occupied most parts of iran. sistan region is one of arid areas of iran where wind erosion is an important factor of land degradation and soil deterioration. for classification of desertification intensity, several methods have been proposed so far. esas model is on of the best and recent methodologies introduced by the european commission in 1999 and evaluated by most of european as well as middle eastern countries. esas has more advantageous than other methods because of its accuracy, particular weighing of layers, use of geographical information systems in overlaying of maps, use of geometric mean over arithmetic one or sum in computing indices and final desertification map. the method was chosen to monitor desertification in the study area. the factors which affect on desertification were evaluated based on the related tables. according to the conditions of the study area, it was found that four factors including vegetation cover, soil, climate and land use management are the most important desertification factors. the results showed that climate play vital role in land degradation and desertification. based on the results of it is found that the study area has critical conditions. it includes high critical (c3), moderate critical (c2) and low critical (c1) classes of desertification which cover 68%, less than 1% and 31% of the region, respectively.