ارزیابی آسیب‌پذیری مخاطره‌ی بیابان‌زایی در حوضه‌ی آبریز مند با تاکید بر رهیافت ویکور توسعه‌یافته (e-vikor)

بیابان زایی و تخریب زمین های مستعد کشاورزی در برخی مناطق خشک و نیمه خشک به صورت مخاطره ی طبیعی اکوسیستم های طبیعی و زندگی انسانی را به مخاطره انداخته است. بنابراین، ارزیابی و شناخت مناطق مستعد بیابان زایی ضروری به نظر می رسد. در ایران، به خصوص مناطق جنوبی به علت شرایط آب و هوایی خشک و نیمه خشک جزو مناطق مستعد بیابان زایی محسوب می گردد. این پژوهش با هدف ارزیابی و تحلیل میزان آسیب پذیری بیابان زایی در حوضه ی آبریز مند در سواحل شمالی خلیج فارس انجام شده است. حوضه ی آب ریز رودخانه ی مند در محدوده ی استان بوشهر و جنوب استان فارس قرار دارد. به علت حساسیت و شکنندگی محیط طبیعی در این بخش به شناسایی مناطق مستعد تخریب خاک و بیابان زایی با استفاده از معیارهای جنس زمین، میزان فرسایش (پتانسیل فرسایش آبی)، میزان بارش، شیب، سطوح ارتفاعی، کاربری زمین اقدام شده است. همچنین، سنجش از دور را برای حجم پوشش گیاهی با کمک شاخص ndvi استفاده کردیم. تلفیق معیارها و سرانجام ارزیابی به کمک رهیافت ویکور توسعه یافته (evikor) انجام شده است. نتایج پژوهش نشان می دهد بیش از نیمی از سطح حوضه ی مند در طبقه ی با خطر بیابان زایی متوسط قرار دارد و در صورت تداوم روند فعلی تخریب خاک همه ی این پهنه ها مستعد تبدیل شدن به بیابان را دارند. زوال اکوسیستم های طبیعی و کاهش کیفیت حیات انسانی از پیامدهای چنین روندی خواهد بود.

Vulnerability Assessment of desertification hazard using Extended Vikor E-VIKOR in the Mond watershed

Land degradation in arid, semiarid and subhumid 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 semiarid 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 nearinfrared 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 EVIKOR (VIKOR developed) a method of multicriteria decisionmaking 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 decisionmakers. 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 multicriteria 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 rsquo;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 desertificationcriteriavegetationerosionPrecipitationLanduseGeologySlopeElevation levelsweight(W)0.210.180.150.140.130.110.08 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 desertificationamount vulnerabilitiesArea (ha)Area (in percent)Very low51630011low59890013Average143802530High216867546Very High408251 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.