Land degradation in arid, semi-arid and sub-humid areas, leads to desertification and land degradation is a concept that refers to any reduction of soil potentials. In Iran, that 85 percent of its area is classified in arid and semi-arid climates, and one percent per annum growth rate of desertification and its increasing trends, finding ways to evaluate this phenomenon and its causes in the form of models seems essential. In Iran, especially southern areas due to their arid climatic conditions, are considered to be areas prone to desertification. This study aims to evaluate and analyze the vulnerability of desertification in the Mond watershed located in the northern coast of the Persian Gulf.

In order to evaluate the potentials of desertification in the Mond watershed, geological, the erosion (water erosion potential), rainfall, slope, elevation levels and land use maps are used. To identify vegetation cover conditions Landsat ETM + sensor data and normalized vegetation index (NDVI) are used.

Where in reflected in the near-infrared band (Band 4, Landsat ETM+) and the reflection in the visible band (band 3 sensor ETM+) respectively. Overlaps and combines the above criteria is done using E-VIKOR (VIKOR developed) a method of multi-criteria decision-making models (MCDM). This method is based on a compromise plan proposed in the compromise solution is justified determines solutions that are as close to the ideal solution and has been created through special credit decision-makers. VIKOR use linear approach normal. The normal value in VIKOR is not related method unit of measure. Also standardization effective indicators of desertification has been done using a linear scale.

In this study, the ANP method (Analytical Network Process) was used for weighting criteria. Analysis method Network, is one of the popular methods of multi-criteria decision problems. This method complex relationship between and among the elements of the decision by replacing hierarchical network structure considers. Table 1 shows the weights of the effective criteria in desertification. In this study 7 criteria are used that results show criteria’s of climate and vegetation, have the most effective measures in the area of desertification and erosion (water and wind) have the least amount of importance in the region.



Table 1: weight criteria of effectivein desertification





criteria


vegetation


erosion


Precipitation


Landuse


Geology


Slope


Elevation levels




weight(W)


0.21


0.18


0.15


0.14


0.13


0.11


0.08







After mapping the effective indicators in evaluating desertification separately, Standardization of maps, weighting the index, To obtain amount and , Finally, the amount of , was produced Zoning map of desertification that in it Mond watershed in the province Bushehr in terms of desertification is divided into five ratio and the area is provided in Table 2.



Table 1: Percentage and area zone of desertification





amount vulnerabilities


Area (ha)


Area (in percent)




Very low


516300


11




low


598900


13




Average


1438025


30




High


2168675


46




Very High


40825


1









Studies show that more than half of the Mond basin have on the surface with average risk of desertification and In the continuation of the current trend of soil degradation, desertification prone zones and will be reduced all lead to the deterioration of the natural ecosystems and human life quality.