ارزیابی شدت بیابان‏زایی حوزة آبخیز درخت سنجد با استفاده از مدل IMDPA

نوع مقاله : مقاله پژوهشی

نویسندگان

1 دکتری بیابان‏ زدایی، دانشکدة منابع طبیعی دانشگاه تهران

2 استاد دانشکدة منابع طبیعی دانشگاه تهران

چکیده

در این تحقیق از روش ایرانی ارزیابی پتانسیل بیابانی‏زایی اراضی(IMDPA)  برای ارزیابی پتانسیل بیابان‏زایی منطقة درخت سنجد استفاده شد. پس از بررسی‏ها و ارزیابی‏های اولیه، چهار معیار اقلیم، پوشش‏ گیاهی، خاک، زمین‏شناسی و ژئومورفولوژی مهم‌ترین معیارهای مؤثر در بیابان‏زایی این منطقه انتخاب شدند. با استفاده از روش فوق، امتیازات شاخص‏های هر معیار تعیین شد و ارزش آن معیار با محاسبة میانگین هندسی امتیاز شاخص‏های آن محاسبه گردید. سپس، با استفاده از GIS، نقشة شدت بیابان‏زایی منطقه تهیه شد. برای این منظور، لایه‏های رستری معیارهای مذکور روی‏هم‏گذاری و تلفیق شد و میانگین هندسی معیارها محاسبه گردید. در نهایت، با تجزیه و تحلیل نتایج به‌دست‌آمده، به کمک مدل IMDPA نقشة شدت بیابان‏زایی منطقه به‌دست آمد. نتایج حاصل از این ارزیابی نشان می‏دهد که کلاس شدت بیابان‏زایی در 37/0 درصد از منطقه کم، در 80 درصد از منطقه متوسط، و در 63/19 درصد از منطقه شدید است. معیار پوشش گیاهی، با ارزش عددی 05/3، بیشترین تأثیر و معیار زمین‏شناسی، با ارزش عددی 8/1، کمترین تأثیر را در بیابان‏زایی منطقه دارند. همچنین، معیارهای اقلیم و خاک به‌ترتیب، با ارزش عددی 04/2 و 21/2، شدت بیابان‏زایی متوسط را نشان می‏دهند.

کلیدواژه‌ها


عنوان مقاله [English]

Assessment of desertification potential using IMDPA model In Derakhte Senged water shed

نویسندگان [English]

  • Elham alsadat Abrisham 1
  • Sadat Feiznia 2
1 Ph.D. Combating Desertification, University of Tehran, Iran
2 Professor, Faculty of Natural Resources, University of Tehran, Iran The
چکیده [English]

The Derakhte Senged area is located in south of Neishaboor town at Khorasan Razavi province. In this research, desertification intensity of Derakht senged area was evaluated using IMDPA, one of the newest method to Assess desertification potential in arid and semi arid regions of Iran. To evaluate desertification intensity, based on the primary research in this area, 4 criteria were selected including vegetation cover, soil, climate, geology and geomorphology. Each criterion was assessed based on the selected indices which result in qualitative mapping of each criterion cased on geometric mean of the indices. Then, sensitive map of region was extracted using geometric mean of all criteria. By laminate of thematic databases layers and using geometric mean of main criteria intensity map was obtained. The results showed that 0.37 % of study area categorized in low class, 80% was medium and 19.63% involved high class of desertification. Analysis of desertification criteria in this region showed that among study criteria, vegetation cover criteria is a major problem with a geometric average of 3.05 which shows high class, while geology and geomorphology with a weighted average of 1.8, has moderate effect in desertification. Also, climate and soil criteria with a geometric average of 2.04 and 2.21 show medium class desertification.

کلیدواژه‌ها [English]

  • Criteria
  • Derakhte Senged
  • desertification severity
  • IMDPA model
  • index
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