ارزیابی وضعیت بیابان‌زایی حوضۀ آبخیز جازموریان با استفاده از مدل‌های Esas و Imdpa

اکوسیستم شکنندۀ مناطق بیابانی نیازمند تدوین برنامه های مدیریتی مناسب به منظور حفاظت پایدار از منابع آن است. اولین گام برای توسعۀ پایدار اکوسیستم های بیابانی ارزیابی خطر و سپس تدوین برنامۀ مدیریت مناطق بیابانی است. ازاین رو در این تحقیق به منظور ارزیابی وضعیت بیابان زایی حوضۀ جازموریان، از دو مدل esas و imdpa استفاده شد. بنابراین مدل imdpa با استفاده از 5 معیار و مدل esas نیز به کمک 3 معیار خاک، پوشش گیاهی و اقلیم مورد ارزیابی قرار گرفتند. در نهایت، نقشۀ وضعیت بیابان زایی برای منطقۀ مورد مطالعه با استفاده از دو مدل به دست آمد. نتایج مدل imdpa نشان داد که حوضۀ جازموریان از سه کلاس i، ii و iii بیابان زایی تشکیل شده که کلاس بیابان زایی با شدت کم با 52.22درصد از سطح منطقه، بیشترین مساحت را به خود اختصاص داده است. همچنین 19.46درصد از منطقه نیز در کلاس بیابان زایی شدید قرار دارد. بر اساس مدل esas حوضۀ جازموریان به چهار کلاس (بی اثر، بالقوه، شکننده و بحرانی) و هفت زیرکلاس (n، p، f1، f2، f3، c1، c2) تقسیم شد. از بین کلاس های نامبرده، زیرکلاس شکنندۀ متوسط (f2) با 29.68درصد بیشترین سطح منطقه را به خود اختصاص داد. معیارهای خاک و پوشش گیاهی در هر دو مدل imdpa و esas، موثرترین معیارهای بیابان زایی منطقۀ جازموریان معرفی شدند. در نهایت، کلاس بندی مناسب مدل esas باعث شده است روند مناسبی از کلاس وضعیت بیابان زایی در حوضۀ جازموریان مشخص شود و می توان آن را به عنوان مدل برتر برای ارائۀ برنامه های مناسب مدیریتی مورد استفاده قرار داد.

Assessment of The Jaz_Murian Desertification Hazard Using ESAs and IMDPA Models

Extended abstract Introduction: Desertification, the process of land degradation in arid semiarid and sub humid areas, is one of the most complex environmental and socioeconomical threatening events. Global desertification has serious implications for biodiversity, environmental safety, poverty eradication, socioeconomic stability and sustainable development around the world. The most suitable method for determining the severity of desertification hazard is the use of empirical models. To evaluate desertification, various studies have been carried out both inside and outside the country, which has led to the provision of many regional models, including ESAs and IMDPA models. In the Jaz_Murian basin, the presence of natural constraints along with the lack of suitable economic and cultural infrastructures has led to excessive utilization of natural resources and has exacerbated secondary problems such as migration and poverty.In addition, in recent years, the Jaz_Murian wetland has been wrecked and the desertification signs are intensifying in the region, so that the studied area has been identified as one of the centers of refuge in Iran. Therefore, the purpose of this study is to use IMDPA and ESAs desertification hazard models to assess the hazard of desertification. Research Methodology: The studied area is located in Kerman and Sistan and Baluchestan provinces with coordinates 33 26 to 36 29 north latitudes and 16 56 to 26 61 east and 69374 square kilometers. In this study, according to Jaz_Murian province conditions, studies of two ESAs and IMDPA models were used to assess the hazard of desertification.Five criteria were used to assess the hazard using the IMDPA model. Each criterion consists of indicators that according to its effect on desertification and according to the region conditions, weighted from 1 to 4. Finally, based on the average of the indicators, a map of each criterion was obtained.Based on the weighted average of the criteria map, the IMDPA model for the desertification hazard map was prepared for Jaz_murian. The ESAs model also uses a mathematical method similar to that of IMDPA. In the ESA model, three soil criteria, vegetation and climate were used. The range of scores for model indicators is 1 to 2. Finally, desertification hazard maps were obtained using two models.Here Q1 is indicative of water and climate components, Q2 the geology and geomorphology, Q3 the ground cover and geomorphology and Q4 the societal aspect. Results: Geomorphic facies were used to assess the hazard of desertification using IMDPA and ESAs desertification models. The Jaz_murian area consists of twelve facies; the upper facies of the highest mountains with the highest 1837679.51 hectares (26.3%) were Jaz_Murian.Desertification models were evaluated in each of the geomorphic facies and finally the desertification hazard class was obtained for each facies.The results of the study of the hazard map of desertification with the IMDPA model showed that Jaz_Murian province consists of three classes I, II and III of desertification, with the lowest class with 52.22% of the area's area has the highest area. 19.46 percent of the area is in severe desertification. Based on the ESA model, the Jaz_Murian area was divided into four classes (No effect, potential, fragile and critical) and seven subclasses (N, P, F1, F2, F3, C1, C2). Among the classes, the subclass F2 (29.68%) of the region had the highest surface area. Discussion and conclusion: The results of this study showed that, based on the IMDPA model, the majority of the study area (52.22 percent) is at low risk class (I). The ESAs model also divides the area into four classes of desertification risk that the fragile class having the largest area. Soil and vegetation criteria in both IMDPA and ESAs are the most effective factors in desertification of Jaz_murian area.Flood plain units have been identified as the most critical part of the region due to heavy clay, clay and drainage, with the highest ESAI (ESAI = 1. 53), which requires more attention.The sand dune workshop with a value of 1.52 is next due to the depth of the soil and the lack of vegetation, and requires management arrangements in this area.The results of the two models show that the ESAs model is efficient in the Jaz_Murian area versus the IMDPA model. Finally, it is suggested using ESA model to propose appropriate management plans to control desertification.