Evaluation of Desertification Intensity with Using of ״Iranian Model for Desertification Potential Assessment״ in the Marghzar of Shahrekord,S

Abstract

Desertification could be traced back to one or many factors. Thus, to cope with such a phenomenon, there exists a need for a profound understanding of the processes and the causes. The study area of the current paper is the extent of Shahrekord's Marghzar as an important case amongst the important ones of the province. In order to evaluate the roots of desertification in the area, the Iranian model of desertification potential assessment (IMDPA) was used. Three criteria included are water resources status, soil and vegetation. These criteria were scored against the defined set of scores provided in the tables. According to the fact that in the model, each criterion is summed up by applying geometric average of the indices, the final map of the corresponding criterion was prepared by superimposing all the maps of the indices. Next, the criteria were combined by applying geometric average and the final map was created. Based on the criteria, the severity of desertification in the region according to the IMDPA model is 1.61 which falls into the medium class. Results indicate that the vegetation utilization and water table drawdown indices, as the two most influential indices, are averaged around 4 and 3.23, respectively. The vegetation index acts as the most critical case defining the lion share of the desertification severity of the area. Of the total area, 3.1% is classified as low and 96.9% as medium severity classes. From the major causes of desertification in the region, one could point out to over utilization of the rangelands and intense livestock grazing which have imposed a downgrading force over the vegetation cover. Of the rest, over withdrawal from the underground reservoirs and the multiplicity of wells could be mentioned. These latter causes have the Marghzar dried and water tables drawn