Quantitative assessment of desertification status using MEDALUS model and GIS (Case study: Shamil Plain - Hormozgan province)

Desertification is a major problem in many parts of the world. Nowadays different methods are used to assess and map desertification. One of these methods is Medalus. In this study، the desertification severity of Shamil Plain in the northeastern of Bandar Abbas was evaluated using Medalus model. This area is one of the major agricultural areas in the Hormozgan province. For this purpose، four criteria (climate، soil، vegetation، and management) and regional groundwater، an effective criterion on the process of desertification were selected. Indicators for each criterion are defined in the model Medalus. Indicators for each criterion were prepared using geographic information systems with software ArcGIS®9. 3. These indicators were ranked according to Medalus model. The geometric mean was then calculated and map was produced for each criteria. Desertification status map of the study area was finally prepared using the geometric mean criteria. Results showed that 68. 27%، 30. 07%، and 1. 02% of study area are located in critical regions (C)، (B)، and (A) respectively; and 0. 67% of the regions is located in fragile class (C). Besides climate was determined as the most inappropriate criteria and vegetation quality was measured as the most appropriate criteria.