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مهندسی اکوسیستم بیابان - پیاپی 34 (بهار 1401)

نشریه مهندسی اکوسیستم بیابان
پیاپی 34 (بهار 1401)

  • تاریخ انتشار: 1401/05/22
  • تعداد عناوین: 10
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  • محدثه میر، سعیده ملکی*، وحید راهداری صفحات 1-14

    تالاب ها منابع ارزشمندی هستند که به واسطه خدمات اکوسیستمی آن ها، ذی نفعان مختلفی دارند. از آنجا که وابستگی این ذی نفعان به تالاب در مناطق خشک بیشتر است، تغییرات موجودی آب در تالاب اهمیت دوچندان دارد. در این مطالعه با هدف بارزسازی اهمیت احیای تالاب هامون به عنوان تنها منبع آب دشت سیستان، تغییرات این تالاب در ارتباط با ذی نفعان مورد مطالعه قرار گرفت. بدین منظور بر اساس اهمیت هریک از طبقات مورد مطالعه شامل آب، کشاورزی، پوشش گیاهی طبیعی و اراضی بایر، برای ذی نفعان، کاربری ها تفکیک و نقشه کاربری و پوشش اراضی در سال های 1356، 1379، 1394، 1399 با استفاده از تصاویر ماهواره ای تهیه شد. پس از تهیه تصاویر ماهواره ای و طبقه بندی طبقات پوشش اراضی مساحت هرکدام از طبقات تهیه شده، در سال های متفاوت در ارتباط با ذی نفعان مشخص شده مورد بررسی قرار گرفت. پارامترهای اقلیمی دما و بارندگی سالیانه به روش آنومالی بررسی شد. در نهایت نیز تغییرات مساحت طبقات پوشش اراضی، روند تغییرات سطح آب تالاب هامون، و تغییرات پارامترهای اقلیمی در ارتباط با تغییرات سطح طبقات مرتبط با هریک از ذی نفعان تالاب بررسی شد. نتایج نشان می دهد در سال 1356 همه ذی نفعان شرایط مناسبی در منطقه داشته اند. در این سال پتانسیل خیزش خاک کاهش داشته است. سال 1379 به دلیل فقدان منابع آبی، پتانسیل خیزش خاک افزایش و طبقات مورد استفاده ذی نفعان کاهش یافته است. این مطالعه روابط بین حیات اکوسیستم طبیعی و حفظ حیات ذی نفعان را به صورت کمی نشان داد. این نتایج بیانگر لزوم احیای تالاب هامون است زیرا به رغم خشک بودن منطقه، آبگیری تالاب شرایط مناسبی برای زیستمندان منطقه فراهم می کند.

    کلیدواژگان: ذی نفعان، اجتماعی اقتصادی، کشاورزی، خشکسالی، دشت سیستان
  • محمدحسن صادقی روش* صفحات 15-32

    مبارزه با بیابان زایی مستلزم ارزیابی و پایش نوع و شدت تخریب اراضی، تعیین علل تخریب اراضی رخ داده و انتخاب و اعمال اقدامات مناسب برای مقابله با این مشکل است. از طرفی از آنجا که بیابان زایی یک مشکل تکنولوژیکی ساده نیست بلکه یک مسیله اقتصادی اجتماعی پیچیده است که حاصل عملکرد و برهم کنش میان عوامل متعددی است که همیشه در محیط های غیرقطعی و تحت تاثیر شدید قضاوت های مبهم و غیرصریح قرار می گیرند، همواره خلا روشی که بتواند معیارها و راهکارهای مختلف را در نظر بگیرد و از آن میان بر مبنای ساختاری سیستماتیک و دیدگاه گروهی، راه حل های بهینه و قابل استناد را ارایه دهد، مشهود است؛ ازاین رو مقاله حاضر با هدف تلفیق تیوری فازی و روش های تصمیم گیری چندشاخصه به منظور ارزیابی راهبردهای مقابله با بیابان زایی به صورت موردی در دشت یزد- خضرآباد طی سال 1398 تا 1399 شکل گرفت و در این راستا از مدل دیماتل فازی استفاده شد. بر این مبنا در ابتدا با تشکیل ماتریس تصمیم گیری فازی، شدت اثر یا میزان اثرگذاری و اثرپذیری اوزان معیارها و راهبردها برآورد شد و پس از فازی زدایی و تشکیل نمودار علی فازی، راهبردهای نهایی مورد ارزیابی و تحلیل قرار گرفت. بر مبنای نتایج حاصل شده، از دیدگاه مدل ارزیابی دیماتل فازی، راهبرد جلوگیری از تبدیل و تغییر نامناسب کاربری اراضی (18A) با شدت تاثیر و تاثر  (903/0= Di+Ridef) و تعدیل در برداشت از منابع آب زیرزمینی (31A) با شدت تاثیر و تاثر (367/0=Di+Ridef)، تاثیرگذارترین راهبردها به منظور دستیابی به هدف ارزیابی شدند. بنابراین پیشنهاد شد که در طرح های مقابله با بیابان زایی در منطقه مطالعاتی، نتایج به دست آمده مورد توجه قرار گیرد.

    کلیدواژگان: ساختار سلسله مراتبی، تصمیم گیری چندمعیاره، مدل دیمتل فازی، مقایسه زوجی، نمودار علی
  • فاطمه درگاهیان*، مهدی دوستکامیان، سعیده اشرفی صفحات 33-46

    افزایش روزافزون داده های اقلیمی و نیاز به شناخت ویژگی های نواحی اقلیمی، بر پیچیدگی مطالعات اقلیمی افزوده است. استفاده از روش های طبقه بندی چندمتغیره برای تسهیل این پیچیدگی ها ابزاری راهگشاست. در این تحقیق اقلیم حوضه آبریز بیابانی هامون هیرمند با استفاده از 9 پارامتر اقلیمی و به کارگیری روش های تحلیل خوشه ای و تحلیل ممیزی طبقه بندی شد. اعمال تحلیل ممیزی، صحت انجام تحلیل خوشه ای را مورد تایید قرار داده و در بیش از 90% سطح حوضه با نتایج تحلیل خوشه ای منطبق است. اختلاف موجود در نواحی اقلیمی در مرزهای این نواحی بوده و برای رفع این مشکل از احتمال پسین یاخته های مشکوک استفاده و یاخته های مذکور به گروه های واقعی خود منتسب شدند. نتایج حاکی از وجود 5 ناحیه اقلیمی در محدوده مورد مطالعه است: 1. ناحیه بارش متوسط، وزش باد آرام و کم گرد و غبار؛ 2. ناحیه کم بارش، گرم، پرگرد و غبار با وزش باد تند؛ 3. ناحیه بسیار پربارش با دمای کم، کم گرد و غبار با وزش باد آرام؛ 4. ناحیه پربارش با دمای کم و گرد و غبار متوسط؛ 5. ناحیه بسیار کم بارش، بسیار گرم، پرگرد و غبار با وزش باد تند. بررسی تغییرات مساحت نواحی تعیین شده طی سه دهه نشان داد که از سطح نواحی پربارش کاسته شده که حاکی از غلبه شرایط خشکی به سمت دوره های اخیر در حوضه است. افزایش مساحت ناحیه کم بارش- بسیارگرم و پرگرد و غبار با وزش باد تند نشان دهنده پیشروی مناطق گرد و غبارخیز در حوضه است. شناخت و آگاهی نسبت به ویژگی های اقلیمی غالب هر بخش از حوضه برنامه ریزان و تصمیم گیرندگان منطقه ای را در اولویت بندی عملیات اجرایی و سازگاری با شرایط اقلیمی بخش های مختلف این حوضه بیابانی یاری می کند.

    کلیدواژگان: ناحیه اقلیمی، تحلیل خوشه ای، تحلیل ممیزی، حوضه آبریز هامون
  • فاطمه زارعیان*، محمد جعفری، سید اکبر جوادی، علی طویلی صفحات 47-58

    به منظور بررسی اثر سوپرجاذب‎ و دور آبیاری بر عملکرد گیاه اسکنبیل، آزمایشی به صورت فاکتوریل در قالب طرح کاملا تصادفی از اسفندماه 1394 به مدت دو سال در مرکز تحقیقات همزیستی با کویر کاشان انجام شد. در این تحقیق، تاثیر زیولیت در سه سطح (0، 10، 15% وزنی) و سوپرجاذب جیوهوموس در چهارسطح (0، 100، 150،250 گرم در هر چاله) و دور آبیاری (آبیاری معمولی، کم آبیاری)، بر ویژگی های رویشی گیاه اسکنبیل و برخی خصوصیات خاک مورد بررسی قرار گرفت. داده ها بر اساس جدول تجزیه واریانس و برای مقایسه میانگین تیمارها از آزمون مقایسه میانگین دانکن استفاده شد. نتایج نشان داد استفاده از سوپرجاذب درمجموع تاثیر معنی داری بر شاخص‎ های رشدی نهال ها شامل ارتفاع، قطر بزرگ تاج پوشش، قطر کوچک تاج پوشش و قطر یقه در مقایسه با شاهد داشته که بیشترین مقادیر شاخص ها به ترتیب عبارت است از (49، 81/39، 87/10 و0512/0 سانتی متر) و کمترین مقادیر مربوط به تیمار شاهد کم آبیاری می باشد. علاوه بر آن افزودن سوپرجاذب های ذکرشده به خاک باعث کاهش هدایت الکتریکی (39/1 دسی زیمنس بر متر) و وزن مخصوص ظاهری (46/1 گرم بر سانتی متر مکعب) خاک شد. پس از بررسی، بهترین سطح استفاده از سوپرجاذب ها مربوط به 15% وزنی زیولیت و 250 گرم جیوهوموس است. بنابراین با توجه به تاثیر مثبت سوپرجاذب بر ویژگی های مورد بررسی، می تواند گامی موثر در احیای بیولوژیک این مناطق باشد.

    کلیدواژگان: پلیمرهای فراجاذب، خاک، آبیاری، شاخص های رشدی
  • عبدالحمید حاجبی*، محمدامین سلطانی پور صفحات 59-70

    یکی از فاکتورهای مهم در تعیین ظرفیت چرایی مراتع، تعیین ارزش رجحانی گیاهان مرتعی با توجه به نوع دام استفاده کننده از مرتع و تغییرات آن در طول فصل چرا می باشد. در این تحقیق، میزان خوشخوراکی گونه های مرتعی در مرتع سیریک در استان هرمزگان در ماه های فصل چرا (دی تا اردیبهشت) و سال های مختلف (13861389) بررسی شد. برای تعیین میزان خوشخوراکی از روش درصد بهره برداری گونه های گیاهی و تعیین شاخص رجحان استفاده شد. نتایج در قالب طرح آماری اسپیلیت پلات در زمان و طرح پایه بلوک کامل تصادفی در نرم افزار SAS تجزیه و تحلیل گردید و میانگین آماری صفت مورد بررسی با آزمونLSD  مورد مقایسه قرار گرفت. نتایج نشان داد که سال های مورد بررسی فاقد اختلاف معنی دار هستند ولی بین ماه ها و گونه ها تفاوت معنی داری وجود دارد. گونه Cenchrus pennisetoformis با 516/1، بیشترین شاخص رجحان را نشان داد و بعد از آن گونه Cyperus conglumeratus  با 338/1 بود که از نظر آماری تفاوت معنی داری با هم نداشتند. گونه Cenchrus pennisetoformis جزء گونه های نسبتا خوشخوراک (رجحان نسبی)، گونه های Cyperus conglumeratus ، Sphaerocoma aucheri،  Molhtkiopsis ciliata، Panicum turgidum جزء گونه های با خوشخوراکی متوسط (رجحان متوسط) و گونه Heliotropium bacciferum جزء گونه های تقریبا غیرخوش خوراک (اجتناب نسبی) طبقه بندی می شوند.

    کلیدواژگان: شاخص رجحان، خوش خوراکی، مرتع سیریک و استان هرمزگان
  • میترا اسدی، لیلا گلی مختاری*، عطاالله شیرزادی، هیمن شهابی، شهرام بهرامی صفحات 71-86

    تهیه نقشه حساسیت پذیری زمین لغزش اولین گام مهم در ارزیابی خطر زمین لغزش است. هدف اصلی این پژوهش بررسی عملکرد الگوریتم درخت تصمیم متناوب (Alternating Decision Tree) برای مدل سازی حساسیت به زمین لغزش در منطقه یوزیدر تا دگاگا در استان کردستان است. ابتدا نقشه پراکنش زمین لغزش های سطحی با تعداد 175 موقعیت با استفاده از برداشت های میدانی تهیه و به صورت کاملا تصادفی به دو دسته داده مدل سازی (80%: 123 نقطه) و اعتبارسنجی (20%: 52 نقطه) تقسیم شدند. سپس بیست عامل موثر بر وقوع زمین لغزش های سطحی منطقه مورد مطالعه شناسایی شدند. بر اساس شاخص Information Gain Ratio (IGR) سیزده عامل موثر از بین آن ها انتخاب و برای مدل سازی به کار گرفته شدند. عملکرد مدل بر اساس داده های تعلیمی و صحت سنجی با معیارهای آماری حساسیت، شفافیت، صحت، میانگین مجذور ریشه مربعات، سطح زیر منحنی مشخصه عملکرد (AUC) ارزیابی شد. نتایج نشان داد که مدل درخت تصمیم متناوب بر اساس داده های آموزشی و صحت سنجی دارای سطح زیرمنحنی برابر با 665/0 و 677/0 به ترتیب است؛ بنابراین بر اساس نتایج قدرت پیش بینی این مدل متوسط است.

    کلیدواژگان: زمین لغزش های سطحی، الگوریتم درخت تصمیم، پیش بینی مکانی، صحت سنجی، یوزیدر- دگاگا
  • علیرضا دنیایی، امیرپویا صراف* صفحات 87-98

    حفظ اکوسیستم پهنه های آبی به ویژه رودخانه ها در کشورهایی نظیر ایران که در سطح وسیعی دارای اقلیم گرم و خشک بیابانی می باشد از اولویت های هرگونه توسعه به ویژه توسعه پایدار است. هدف از این پژوهش، اولویت بندی اکوسیستمی رودخانه اترک یکی از مهمترین رودخانه های شمال شرق ایران در استان گلستان، شهرستان مراوه تپه با اقلیم گرم و خشک بیایانی است. در این پژوهش از روش آنتروپی شانون برای محاسبه وزن کارکردهای اکوسیستمی رودخانه و تاپسیس بهبودیافته و مدل ارزیابی مبتنی بر فاصله ترکیبی (CODAS) برای اولویتبندی کارکردها استفاده شد، به طوری که داده های پژوهش به صورت پیمایش میدانی، از 149 پرسشنامه که در تابستان و پاییز 1399 توسط ساکنان شهرستان مراوه تپه تکمیل گردید، استخراج شد تا نمایان شود کدام یک از کارکردهای اکوسیستمی رودخانه (تنظیمی، زیستگاهی، تولیدی و اطلاعاتی) دارای اهمیت بیشتری برای ساکنان هستند. تجزیه و تحلیل یافته های وزن دهی کارکردهای اکوسیستمی رودخانه به روش آنتروپی شانون نشان داد که کاکردهای زیستگاهی، تولیدی، اطلاعاتی و تنظیمی بهترتیب با کسب وزنهای 2501/0، 2491/0، 2490/0 و 2478/0، بیشترین وزن را به خود اختصاص داده اند. بر اساس نتایج به دستآمده از اولویتبندی کارکردهای اکوسیستمی با مدلهای تاپسیس بهبودیافته و CODAS، کارکردهای زیستگاهی، تولیدی، تنظیمی و اطلاعاتی در اولویت اول تا چهارم قرار گرفتند. نتایج این پژوهش نشان داد که کارکردهای اکوسیستمی زیستگاهی، تولیدی، تنظیمی و اطلاعاتی به ترتیب برای 41%، 26%، 25% و 8% از شهروندان دارای اولویت اول هستند. لذا پیشنهاد میشود نتایج پژوهش حاضر بهعنوان یک الگو در اختیار طراحان و تصمیمگیران مهندسی رودخانه قرار گیرد تا طرحهایی را در جهت پایداری اکوسیستم رودخانه و کیفیت محیط زیست شهری اجرا کنند.

    کلیدواژگان: رودخانه اترک، کارکردهای اکوسیستمی، مدلهای تصمیمگیری چندمعیاره، مراوه تپه
  • اصغر فرج اللهی*، سید عبدالحسین آرامی، یاسر قاسمی آریان صفحات 99-112

    طرح های بیابان زدایی همواره با هدف حفاظت آب و خاک و توسعه پایدار جوامع محلی طراحی و اجرا شده و ارزیابی اثرات اقتصادی-اجتماعی این طرح ها به منظور بهبود نقاط قوت و شناسایی و رفع چالش ها دارای اهمیت زیادی است. بدین منظور تحقیق حاضر با هدف ارزیابی اثرات اقتصادی-اجتماعی اقدامات بیابان زدایی اجراشده در منطقه جنوب شرق اهواز در استان خوزستان در سال 1400 انجام شد. جامعه آماری شامل دو گروه ساکنان روستایی و کارشناسان آشنا و مرتبط با موضوع مورد مطالعه بودند. 335 نفر روستایی بر اساس فرمول کوکران و تطبیق با جدول کرجسی و مورگان، به عنوان نمونه های مطالعاتی انتخاب و به روش تصادفی در تکمیل پرسشنامه ها مشارکت داشتند. همچنین 26 کارشناس در انجام تحقیق مشارکت کردند. اولویت بندی اثرات اقتصادی و اجتماعی از طریق میانگین رتبه ای و مقایسه دیدگاه ساکنان روستایی و کارشناسان با استفاده از آزمون من وایت نی انجام شد. مطابق نتایج، بهبود وضعیت شغلی و اشتغال زایی با میانگین 20/4 از دیدگاه بهره برداران و حفاظت آب و خاک و کاهش گرد و غبار با میانگین 46/4 از دیدگاه کارشناسان مهم ترین اثرات اجرای طرح های بیابان زدایی بوده است. تفاوت آماری معناداری بین نظرات کارشناسان و روستاییان در خصوص اثرات اقتصادی اجرای طرح ها وجود داشت (05/0P<) اما در خصوص اثرات اجتماعی اجرای طرح های بیابان زدایی، تفاوت معنی داری مشاهده نشد (05/0<P).

    کلیدواژگان: اشتغال زایی، خوزستان، ساکنان روستایی، طرح بیابان زدایی، گرد و غبار، مهاجرت
  • عباسعلی ولی*، هادی زارع پور، حمید قربانی، سید جواد ساداتی نژاد، سید حسن علوی نیا صفحات 113-126

    خشکسالی هواشناسی یکی از بزرگ ترین بلاهای طبیعی است که وجود یک سیستم نظارت موثر برای تحلیل روند خشکسالی و کاهش اثرات آن نیاز ضروری است تا بتوان به کمک آن اقدام موثری برای مدیریت این بحران انجام داد. هدف از این پژوهش، تحلیل روند خشکسالی استان اصفهان با استفاده از داده های بارش ماهانه 10 ایستگاه همدیدی با طول دوره آماری 30 ساله (19902020)، شاخص معیار استاندارد (ZSI) در مقیاس های زمانی متفاوت و آزمون های ناپارامتری من-کندال، پتیت و سن می باشد. درمجموع نتایج آماری برای مقیاس های زمانی متفاوت شاخص ZSI نشان داد که در سطح 5% روند خشکسالی براساس آزمون من-کندال در 58% از ایستگاه ها، بر اساس آزمون پتیت در 81% از ایستگاه ها و بر اساس آزمون سن در 56% از ایستگاه ها روند معنی دار نزولی دارد. بارش ماهانه در هیچ ایستگاهی روند معنی دار ندارد. از تحلیل سری های زمانی در مقیاس های مختلف مشخص شد که سری زمانی های بلندمدت روند تغییرات خشکسالی را بهتر آشکار می کنند. بنابراین با توجه به نتایج روندیابی خشکسالی در استان اصفهان مشخص شد خشکسالی در استان با روند نزولی مواجه است. به نظر می رسد افزایش فراوانی خشکسالی و بروز خشکسالی های شدید بر اکوسیستم منطقه مطالعاتی و در نتیجه آن برخورداری از خدمات اکوسیستم ها تاثیر نامطلوب داشته باشد. در نتیجه، نیاز به سازگاری برای نفی تاثیرات دوره های خشک شدید مکرر در استان وجود دارد.

    کلیدواژگان: استان اصفهان، آزمون پتیت، آزمون سن، آزمون من-کندال، تحلیل روند، خشکسالی، شاخص ZSI
  • حسن علی پور*، علی سلاجقه، علیرضا مقدم نیا، شهرام خلیقی سیگارودی، مجتبی نساجی زواره صفحات 127-141

    یکی از مهم ترین پیامدهای تغییر اقلیم افزایش فراوانی و شدت رویدادهای حدی نظیر سیلاب های مخرب و خشکسالی های گسترده است. بنابراین بررسی رویدادهای حدی بارش و فراوانی آن طی دوره های گذشته و تاثیر تغییر اقلیم بر روند آن طی دوره های آتی ضروری است. در این مطالعه اثر تغییرات اقلیمی آینده بر سیلاب منطقه طرح با مدل CANESM2 بررسی شد. پیش بینی تغییرات اقلیمی تحت سناریوهای RCP2.6 و RCP8.5 و با استفاده از مدل ریزمقیاس نمایی SDSM 4.2.9 انجام شد. به منظور تحلیل فراوانی و شدت سیلاب با استفاده از مدل SMADA مناسب ترین توزیع بر اساس آزمون های RMSE و MSE انتخاب شد. پس از شبیه سازی سیلاب ها با استفاده از مدل HEC-HMS در شرایط تغییر اقلیم فراوانی و شدت سیلاب ها بررسی شد. نتایج نشان داد که دمای حداکثر در طول دوره های (20112055) و (20562100) تحت سناریوهای RCP2.6 و RCP8.5 به ترتیب 02/3، 27/3، 2/ و 47/5 درجه سانتی گراد و دمای حداقل در طول دوره ها و سناریوهای مذکور به ترتیب 62/0، 87/0، 1/1 و 82/2 درجه سانتی گراد افزایش می یابند. بر اساس نتایج حاصل از بارش برای منطقه مورد مطالعه در دوره های آتی روند مشخصی نشان نداد. نتایج نشان داد که توزیع پیرسون نوع سوم دارای کمترین خطا می باشد. فراوانی و شدت سیلاب ها در دوره های آتی افزایشی می باشد به طوری که بیشترین افزایش آن ها در دوره دوم تحت سناریوی RCP8.5 به ترتیب مقدار 68/12 و 76/25 درصد بوده و از دوره بازگشت 2 ساله به 200 ساله بر تعداد دوره هایی که سیلاب های برآوردشده در آن ها نسبت به دوره مشاهداتی بیشتر است، اضافه شده است.

    کلیدواژگان: مدل سازی بارش- رواناب، SDSM، تحلیل فراوانی سیل، حوزه معرف امامه، HEC-HMS
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  • Mohadeseh Mir, Saeedeh Maleki*, Vahid Rahdari Pages 1-14
    Introduction

     Wetlands are valuable water resources that have different stakeholders due to the ecosystem services they provide. Since the dependence of these stakeholders on the wetland is higher in arid and semi-arid areas, changes in water supply in the wetland are more important. Analysis of changes in water resources in relation to wetland stakeholders, in addition, to supporting the life and sustainable management of the ecosystem, is used to address the importance of wetland protection. In this study, to highlight the importance of Hamoun wetland restoration as the only water source in the Sistan plain, the changes of this wetland in relation to stakeholders were investigated. 

    Method

     The land-cover classes were determined based on the importance of each class for the stockholders of the wetland. Then, the land-use/ land-cover map of the wetland in the years 2020, 2015, 2000, 1977 was created using Landsat satellite images. The SVM classification method was used to classify the images and produce the land-use/land-cover maps. The anomaly of the climate variables including mean annual temperature and mean annual precipitation were calculated to show the change in climate variables. The changes in water level of Hamoun wetland, temperature, and annual precipitation in relation to changes in the area of each land-use/land-cover class of each group of stockholders were investigated. 

    Results

     The results of the stakeholder-related classes show that in 1977 all stakeholders had a good condition in this region and the potential for soil erosion has decreased in this year. In natural conditions, the Sistan plain is a suitable area for residents despite locating in an arid area. But in 2000, due to the lack of water resources, the potential for soil eruption has increased the classes used by stakeholders have decreased and the ecosystem services of the wetland were limited. In 2015, the water body was increased in comparison to 2000, and the area of vegetation and agriculture were increased. The area of bare-land was decreased. Based on these results the stockholders had better conditions than 2000. In 2020, the area of the water body was more than 2000 and 2015. The vegetation and agriculture area were increased in this year. Therefore, the condition of life for stockholders was improved. These results show the importance of Hamoun wetland restoration as the only water source in the Sistan plain. As seen, the changes of this wetland affect the well-being of stakeholders.

    Conclusion

     According to the results obtained in 1977, when the temperature and rainfall were better, a higher area of water resources existed. As a result, favorable conditions could be for farmers, livestock, and wildlife. The bare-lands have decreased, thus, the potential for soil erosion in the region has been decreased. In addition, the potential for soil erosion has decreased. Because the soil of the area was covered with water and vegetation. However, in 2000, when the drought occurred, due to the lack of water resources in Hamoun Wetland, the wetland body has changed to bare-lands, and the possibility of soil eruption has increased. In such a situation, because the water body did not exist, the conditions were not suitable for the stakeholders of the region. Especially agriculture, which is the most important occupation of the local people in this area. In case of drought and lack of water resources in Hamoun wetland, the potential of soil erosion increased and, as a result of which dust increases during storms. In addition to economic problems in the region, these factors also endanger the health of local communities. The results showed that after several years of dryness of the bed of Hamoun wetland, with the inundation of the Hamoun in 2020, the level of usable areas for the region's stakeholders has increased. Therefore, the living condition of the people and the wildlife have been improved. Because agriculture and vegetation have expanded, thus the potential for soil erosion has decreased due to the reduction of barren lands. The results of this study show the importance of wetland life in an arid and semi-arid region. With the change of wetland, the level of the lands that are related to each of the groups of users of the wetland also changes. Therefore, rehabilitation and protection of wetland, and water resources management is necessary for sustainable living conditions in the region.

    Keywords: Stockholders, Scio-economic, Agriculture, Drought, Sistan plain
  • Mohammad Hassan Sadeghi Ravesh* Pages 15-32
    Introduction 

    As desertification is growing rapidly, adopting appropriate managerial strategies could help reduce its extension and prevent its development and spread. Otherwise, the loss of resources such as time, energy, etc., would bring about destructive consequences for the efforts made to combat desertification. On the other hand, the process of land desertification results from the interactions between various factors that always operate under uncertain conditions, being strongly influenced by vague and implicit judgments. However, no comprehensive method has been introduced yet to offer operational and reliable solutions for evaluating the strategies used for combating desertification based on a systematic collective fuzzy approach. Therefore, this study sought to combine the fuzzy theory with multi-criteria decision-making methods to evaluate the strategies used in combating desertification, using the Fuzzy DEMATEL method.

    Materials and methods

    The fuzzy DEMATEL technique is a comprehensive method for creating and analyzing a structural model made out of causal relationships between a variety of complex factors under uncertain conditions. Accordingly, after determining the prioritized criteria and strategies via the fuzzy Delphi method and creating a fuzzy mean pair-wise comparison matrix, the matrix was changed to the normalized initial direct-relation matrix  according to equation 1:xij=zijr=lijr,mijr,uijr  (1) Then the mass communication matrix was formed by Eq. 2 (Table 1), showing the relative effect of direct and indirect relationships in a system.T=limk→∞X+X2+…+XK(2) Table (1): Fuzzy Mass Communication Matrix Di     D1 t k1nk-1… t k12 t K11 Tij = D2    t k2nk-1… t k22 t k21 ׃ ׃ ׃ ׃ ׃ Dn t knknk-1… t knk2 t knk1 Rn… R2 R1 Ri tij=lij",mij",uij" In the fuzzy mass communication matrix, the sum line (Di) indicates the extent of that factor's influence on other system's factors and its corresponding sum column (Ri) suggests the intensity of the influence of other system's factors on that factor. Therefore, Di+Ri  determines the total mutual impact of the desired factor and other system's factors on each other, and Di-Ri  shows the extent of each factor's final effect (only the effect) on all other system's factors. Then, the Di+Ri  and Di-Ri  were de-fuzzed according to Eq.3 to facilitate the analysis of the findings. (3)   BNP=lij+uij-lij+mij-lij3  Finally, a causal diagram (cause and effect) including a Cartesian coordinate system was drawn, with its horizontal and vertical axes being graded based on Di+Ridef  and Di-Ridef  values, respectively. Di+Ridef is the total de-fuzzed cause and effect, and Di-Ridef is the extent of the de-fuzzed effect. Moreover, the position of each existing strategy was determined within the system according to a point whose coordinates were (A: Di+Ridef , Di-Ridef). In this system, the points above the horizontal line indicate the effect strategies and vice versa, and the points to the right of the vertical line suggest the cause strategies and vice versa (Fig. 1). Figure (1): The causal diagram and the display of strategies

    Results

    According to the related literature, first, the matrix of the order of criteria's influence on each other, and the matrices of the order of strategies' influence on each other were created in terms of the goal and each criterion, respectively, finding that that the effective strategies differed based on each criterion. Therefore, to select final strategies and grade their impact, the matrix of the order of strategies' influence on each other was formed in terms of total criteria within the group. Table (2): The matrix of the order of influence of strategies on each other in terms of total criteria Di-Ridef Di+Ridef Di-Ri Di+Ri Di    Ri Alternatives -1.252 -0.098 -1.887, -0.956, -0.912 -0.480, -0.31, 0.496 -0.625, -0.633, -0.767 0.145, 0.323, 1.262 A23 1.646 0.903 1.110, 1.515, 2.313 0.406, 0.695, 1.607 0.776, 1.105, 1.942 -0.371, -0.410, -0.335 A18 -1.011 -0.444 -0.548, 1.058, -1.427 -0.075, -0.305, -0.954 -0.421, -0.681, -1.081 0.346, 0.376, 0.127 A33 -0.271 -0.078 -0.186, -0.264, -0.364 0.034, -0.123, -0.145 -0.121, -0.194, -0.209 0.155, 0.070, 0.064 A20 0.889 0.367 0.480, 0.763, 1.421 -0.019, 0.197, 0.922 0.324, 0.480, 1.078 -0.343, -0.283, -0.156 A31 Finally, the causal diagram (cause and effect) was drawn based on Table 2 (Fig. 2) to better interpret the results. Figure (2): The diagram of cause and effect (causal) strategies to combat desertification based on total criteria.

    Discussion and Conclusion 

    According to the study's results, "appropriateness and compatibility with the environment" (C7) with the intensity effect of Di-Ridef=0.874  were the most important criteria based on the Fuzzy DEMATEL perspective, followed by "Destruction of resources, and environmental and human damages" (C16), "Specialized human resources" (C6), "Scientific and technological tools" (C5), and "time”, with their effect intensity  Di-Ridef being 0.802 , -132 , -630, and -0.914, respectively, indicating the experts' concerns for the environmental issues and the existing challenges in terms of the destruction of the environment. Based on the above-mentioned criteria, "preventing inappropriate land-use change" (A18) with the intensity effect of Di+Ridef=0.903  is definitely the most effective strategy to achieve the goal. Moreover, in terms of increasing cause and decreasing effect, other strategies were found to be "Reduction in extracting water from groundwater resources"(A31), " Controlling livestock grazing "(A20), "Developing and restoring the vegetation" (A23), "Changing the irrigation pattern and implementing less water-consuming methods "(A33), whose intensity effect Di+Ridefwas 0.903 , -0.078, -0.098 , and -0.444, respectively . Therefore, it is suggested that the results of this study be considered in the plans devised to control and reduce the consequences of desertification and land restoration in the study area. In fact, the current study's findings enable the managers working in desert areas to use limited facilities and assets available to them to effectively control the desertification process, prevent the loss of national assets, and achieve better results.

    Keywords: Causal Diagram, Fuzzy DEMETAL Method, Hierarchical Structure, Multi-Criteria Decision Making, Pair-wise Comparison
  • Fatemeh Dargahian*, Mehdi Doustkamian, Saeedeh Ashrafi Pages 33-46
    Introduction

    The diversity of climatic elements and their Spatio-temporal behavior make the mixed study of climatic elements a difficult, complex, and time-consuming task. On the other hand, in studies conducted on space in more stations or cells, the complexity and difficulty of the study increases. In such cases, data classification can be helpful. The application of classification methods in climatology has begun since the early twentieth century. The weakness of traditional methods of climatic classification in the presentation of climatic facts led researchers to use multivariate statistical techniques for climatic classification which uses a variety of variables to classify climates. However, computational tools minimize the probability of error in the voluminous, complex, and time-consuming calculations involved in multivariate classification methods.Hamoon Helmand catchment has unique climatic features such as Sistan's 120-day winds and severe dust storms. In different parts of this basin, different climatic parameters have different intensities and weaknesses, leading to the creation of different climatic zones in this catchment area with their own unique conditions. Recognition of these zones and the changes in their area​​ over the last three decades could help planners and decision-makers in the integrated management of the Hamoon Helmand desert watershed.

    Materials and methods

    Considering the small number and high dispersion of synoptic stations that have all the desired climatic parameters of the intended climatic zoning with a suitable statistical period, this study used the relevant data collected by nearby synoptic stations. To conduct climatic zoning of Hamoon catchment, the data concerning the average, minimum, and maximum temperature parameters, average, minimum, and maximum humidity, precipitation, wind, and dust was used for the statistical period 1989 to 2018. Climate analysis and audit analysis methods were also used for climatic zoning of the Hamoon catchment area.Cluster analysis is a widely used method for multivariate data analysis. It is primarily used in situations where the target, i.e., the class classification, is an example of n person (item) with p attribute. In this process, similar people are placed in the same group. In this method which helps identify real groups and reduces the volume of data, classification is done based on similarities or distances.As a multivariate technical analysis, that deals with separating distinct sets of objects (or observations) and assigning new objects (or observations) to previously defined categories, audit analysis ultimately seeks to create a linear combination between variables used for group individuals, turning a complex multivariate problem into a simple mono-variable statistical problem. Since the application of the audit analysis method requires prior knowledge of the number of groups, it can be used to test the clusters obtained from cluster analysis. Therefore, this study used the audit analysis method to test the competence of cluster analysis for grouping.

    Results

    According to the results of climatic analysis on five climatic zones, dendrograms were identified for the Hamoon catchment. To investigate the changes in these areas during three 10-year climate periods, the area of ​​each zone was studied and analyzed based on cluster and audit analyses.The zoning of climatic elements of the first period which was conducted based on cluster analysis indicated that the northern and western parts of the basin were heavily rainy, both of which are low dust areas with a low temperature. Next to this zone, towards the central part of the basin, there was a rainy area with a relatively low temperature and moderate dust. The south of the basin was a low dust area with a moderate rainfall rate. The eastern part of the basin was a very hot and dusty area with a very low rainfall rate, 72.22 days of annual dust, and extreme wind speed. Moreover, the investigation of climatic zoning in the second period showed that the northern part of the basin is a very rainy zone with a significantly lower area than that of the first period. In addition, the precipitation rate was 112.4 mm in this area during the second period which was 54 mm lower than that of the first period.The central part of the basin was located in a dusty area with a low rainfall rate, ranking second in terms of dust and wind speed. The area of this zone (low rainfall) has decreased by 3.8% compared to its area in the first period, with part of it turning into a very low-rainfall area and another part into an area with moderate rainfall. The northern part of the basin is located at a high rainfall area with 153.2 mm annual precipitation, showing a 41 mm increase compared with the second period and a 14 mm reduction compared to the first period. Moreover, the area of ​​this zone has decreased compared to the first and second periods, indicating the movement of the basin towards the mainland.

    Conclusion

    The results obtained from the climatic zoning of the Hamoon catchment area indicated the existence of five climatic zones in the study area: 1. Moderate rainfall area with gentle wind and low dust; 2. A hot, highly dusty, and low rainfall area with strong wind speed; 3-  A highly dusty, low-rainfall area with low temperature -  and moderate wind speed; 4- A high-rainfall, moderately dusty area with low temperature; and 5- A very dusty, very hot, and very low-rainfall area with strong wind speed. The analysis of changes in the area of ​​designated zones during three decades (the study period) in a complete climatic period showed a reduction in the number of rainfall areas and an increase in the number of low rainfall areas, indicating the prevalence of drought conditions in the basin within the recent periods. Therefore, it could be concluded that awareness of the prevailing climatic characteristics of each part of the basin helps regional planners and decision-makers prioritize executive operations and adapt themselves to the climatic conditions of different parts of this desert basin.

    Keywords: Climatic Zone, Cluster Analysis, Audit Analysis, Hamoun Watershed
  • Fatemeh Zareian*, Mohammad Jafari, Sayed Akbar Javadi, Ali Tavil Pages 47-58
    Introduction

    Improving the efficiency of water consumption requires the effective use of modern technologies (Jalili and Jalili, 2011). For instance, as dry and sugar-like substances with the ability to absorb and maintain aqueous solution several times their weight, superabsorbent polymers can increase the plant's height, the stem's diameter, and the leaf length, and lower the plant's water needs by one third compared to the control (Abedi-koupai et al., 2006). Therefore, this study sought to investigate the effect of irrigation periods and different levels of zeolite and Geohumus on a number of Calligonum comosum's growth characteristics under the influence of drought stress and some soil characteristics of the region.

    Materials and methods

    This study investigated the effect of irrigation interval (deficit-irrigation, regular irrigation) on the one hand, and the influence of zeolite mineral and Geohumus superabsorbent at three (0, 10, 15 % by weight) and four levels (0, 100, 150, 250 g per hole), respectively, on the other hand, on the vegetative properties of Calligonum comosum in seedling cultivation (obtained from Forests, Range and Watershed Management Organization of Yazd Province) in the field, and on some soil characteristics in March 2016. Moreover, to evaluate the effect of each factor including the irrigation, type, and level of superabsorbent addition on the studied characteristics, the data were analyzed via SPSS-22 software.

    Discussion

    The study's results indicate significant effects of irrigation treatments and superabsorbent application on the plant's height, large canopy crown's diameter, small crown's diameter, and collar diameter. The highest values ​​in all of the above-mentioned features were obtained for 250 g Geohumus and 15% (w/w) zeolite. The lowest values of vegetative indices were found to belong to the deficit-irrigation control treatment. On the other hand, the reason for decreased plant yield could be attributed to insufficient irrigation as required for the seedlings. Moreover, the application of superabsorbent to the soil dramatically decreased the soil moisture fluctuations around the plant's root, decreasing the stress exerted on the plant during the irrigation or effective rainfall intervals in arid and semi-arid regions where the plant relied on precipitation (Jafarian Lahoeti, 2006). In this regard, some studies have proved that maximizing potential production is one of the main advantages of superabsorbent polymers (Shahriari et al., 2010).The study's results also suggested that the above-mentioned factors increased the root's length and height and dry and wet weights, indicating that the application of superabsorbent polymers in sandy soils can help raise soil moisture storage and, therefore, carry out successful irrigation programs in arid and semi-arid areas. In this regard, Yousefian et al. (2018) investigated the effect of Stockosorb and zeolite on Atriplex lentiformis in the desert areas of Semnan, Iran, showing the effect of treatment on increasing the plant's height, its collar diameter, and its large and small canopy diameters. However, as the amendment material does not have a direct nutritional effect, the growth increase could be attributed to the improvement of the soil's physical condition by the polymers, increasing the root's density and raising the number of secondary roots, as a result of which the roots would have more access to available water and the plant would be less affected by drought stress.Moreover, the study found that using superabsorbent polymers significantly reduced the soil's electrical conductivity (EC), whose highest value was observed in the control treatment. However, the lowest mean value of the soil's electrical conductivity belonged to the application of 250 g Geohumus, which did not show a significant difference compared to 150 g Geohumus. Furthermore, the soil's EC in the sample with 15% zeolite was less than that of the control treatment with a significant difference, which could be attributed to the fact that superabsorbent polymers can absorb and retain a large amount of water, and this high volume of water in the soil leads to the dilution of solute concentration and reduced electrical conductivity (Bal et al., 2010; Doraji et al., 2010). However, if the water volume in the soil is not greater than the limit and does not cause the soil to be saline, it can improve the plant's growth (Banej Shafie et al., 2012), which is consistent with the results found by Doraji et al. (2010), Zanghui Nasab et al. (2013), and Yousefian (2015). Moreover, according to the data analysis performed for soil bulk density, the lowest value was reported for 250 g Geohumus, in which increasing the amount of superabsorbent polymer application decreased the soil's bulk by 5.8%, suggesting that water absorption and superabsorbent re-drying had created empty pores in the soil. Also, it was found that low levels of organic matter decreased the soil's bulk density (Mohammadi Torkashvand et al., 2017), while Zeolite had no significant effect on the soil's bulk density. In this regard, Judy et al (2007), investigated the effect of zeolite, Lika, and Compost on potting soils, concluding that Zeolite had no significant effect on the soil's physical characteristics, including apparent specific weight, which is consistent with the results found by Abrisham (2014).

    Conclusion

    The application of superabsorbent polymer in the present study improved the Calligonum comosum seedling traits. Moreover, the best superabsorbent application rate performed to increase vegetative growth in the region belonged to 250 g Geohumus and 15 wt.% zeolites, and the lowest vegetative growth rate was observed in the control treatment. Therefore, it can be concluded that if the purpose of planting the seedlings in the rangeland is to restore, amend, and maintain the area's soil structure, deficit-irrigation and superabsorbent application are recommended, as they have the ability to absorb nutrients and slowly provide them for the plant. Moreover, in addition to saving the use of fertilizer and reducing costs, deficit irrigation and superabsorbent help the fertilizer to be used in the effective root zone. In fact, using these materials reduces the irrigation costs (that account for about 70% of the total costs) for biological desalination projects. However, choosing superabsorbent polymers made from natural resources, ease of use, the ratio of water absorption, proper life span, price, and environmental impacts are some important considerations to note in this regard.

    Keywords: Superabsorbent, Soil, Irrigation, Growth indices
  • Abdolhamid Hajebi*, Mohammad Amin Soltanipoor Pages 59-70
    Introduction

    Measuring the preferred value of rangeland plants is one of the most important factors in determining rangelands' grazing capacity. The preferential value of rangeland plants is measured based on the type of livestock which uses the rangeland and the changes made in the rangeland during the grazing season. This study sought to investigate the palatability of rangeland plant species within the Sirik rangeland (Hormozgan province) during the grazing season (January to May) of the years 2007-2010.

    Materials and Methods

    The study area was located at sand dunes of Sirik city (Hormozgan province) at 26˚ 39ʹ 12ʺ and 57˚ 4ʹ 26ʺ overlooking the sea. The 30-year ambrothermic curve of the study area showed that the wet and dry seasons lasted one and eleven months, respectively. The average minimum and maximum temperatures of the study area in the coldest and warmest months of the year were found to be 14.36 °C and 33.78 °C, respectively. However, the lowest and highest temperatures in the region were 5.5 and 48.5 °C, respectively, and its average 30-year rainfall rate was 121.8 mm.The region's rangeland type was a mixture of Sphaerocoma aucheri and Cenchrus pennisetoformis. In the study area, seventy plant species from twenty-eight genera were collected and identified, the most important of which were Moltkiopsis Ciliata, Heliotropium bacciferum, Cyperus conglomeratus, and Panicum turgidum. The livestock examined in this study was Tali goat that is bred in Hormozgan, Sistan and Baluchestan, and Bushehr provinces.This study was conducted in Sirik rangeland, Hormozgan province, throughout the grazing season (January to May) for four consecutive years (2007 to 2010). The study area comprised a one-hectare enclosed area located on sand dunes ten kilometers away from Sirik city, overlooking the sea. At the beginning of the grazing season, five similar rootstocks were selected for each species and marked inside and outside the enclosed area.The forage of each rootstock was placed in a separate bag and weighed. Then the consumption percentage was determined for each species. Each species' share in the livestock diet was determined throughout the grazing season by calculating the percentage of production and consumption of species inside and outside the enclosed area. Moreover, the preference index was obtained by dividing the species' share outside the enclosed area by its share inside the area. Finally, preferential value indices were determined according to the classification proposed by Rosiere et al. (1975). The study's results were analyzed in a time-based split-plot statistical design through a complete randomized block design in SAS software, followed by comparing the statistical mean of the studied features with the results of the LSD test.

    Results

    The analysis of the variance of the preferred index showed that there was no significant difference among the studied years. However, a significant difference was found between the months of the study period and between the species examined. The years of the study period were grouped together in one statistical category, and the months of the study period were classified into two statistical categories. The highest value of the preference index was found in March, which was in the same group as January. Cenchrus pennisetoformis showed the highest preference index with the value of 1.516, followed by Cyperus conglumeratus, whose value was reported to be 1.338, both of which were not statistically significant. It was also found that Cenchrus pennisetoformis was a relatively palatable species (relative preference), Cyperus conglumeratus, Sphaerocoma aucheri, Moltkiopsis Ciliata, and Panicum turgidum were moderately palatable species (moderate preference), and Heliotropium bacciferum was identified as almost a non-palatable (relative avoidance) species.

    Discussion and Conclusion

    Cenchrus pennisetoformis was identified as the highest livestock preference in Sirik rangeland, Hormozgan province. According to the classification table proposed by Rosiere et al. (1975), the species is classified as palatable with a preference index of 1.516. Moreover, Cenchrus pennisetoformis was one of the region's low-density and highly consumed species. The second livestock preference in Sirik rangeland was Cyperus conglumeratus, whose preference index was found to be 1.338, representing a boundary between the ratio of good food and average good food. The two species were then grouped together in a statistical category. The third preference rank belonged to Sphaerocoma aucheri with a value of 0.960, which was a highly distributed and consumed species in the region with the highest dense value. It should be noted that this species plays an essential role in Tali goat's nutrition at the end of the grazing season, i.e., April and May, when the annuals are dried up.Other preference indices belonged to Moltkiopsis ciliate and Panicum turgidum, with index values of 0.819 and 0.800, respectively, both of which are classified as moderately palatable species. Moreover, annuals with a preference index of 0.729, including Stipa capensis, Plantago psylium, Erucaria hispanica, Mathiola longipetala, Fagonia bruguieri, Anagalis arvensis, and Medicago polymorpha were among the moderately palatable species. However, it should be noted that at the beginning of the grazing season, the livestock tends to graze those plants that are more than one year old, while at the end of the grazing season, when the grasses are dried up or sowed, the one-year-old plants are less favored by the livestock. Finally, the last preference index belonged to Heliotropium bacciferum with an index of 0.605, which was classified as an almost non-edible species.

    Keywords: Preference Value, Tali Goat, Consumption Percentage, Grazing Behavior
  • Mitra Asadi, Leila Goli Mokhtari*, Ataolah Shirzadi, Himan Shahabi, Shahram Bahrami Pages 71-86
    Introduction

    Iran's mostly mountainous topography, tectonic activity, high seismicity, diverse geological and climatic conditions, population growth-induced pressures on natural resources, and land-use changes in recent decades have created natural conditions for a wide range of landslides. Therefore, it is necessary to take appropriate measures to reduce the damage caused by landslides, identify their prone areas, determine the factors affecting them, and prepare their susceptibility maps. Thus, this study sought to identify the most important factors involved in the occurrence of landslides, and investigate the efficiency of the alternating decision tree models for preparing landslide susceptibility maps in the southwestern part of Kurdistan province (the communication route connecting Yozider to Degaga).

    Materials and methods

    First, a distribution map with 175 landslides and 100 non-landslide locations was identified and classified into a ratio of 80% and 20% for training and model validation, respectively. Thirteen factors derived from topographic, land cover and rainfall data were selected for modeling using the Information Gain Ratio (IGR) technique. Then, the ADT algorithm was used to train and prepare the landslide susceptibility maps. Moreover, statistical criteria were used to evaluate the models for both training and validation datasets. Finally, the model's performance was evaluated in terms of the area under the receiver operating curve (AUC).

    Results

    The highest IGR index values were found to belong to the distance from road, lithology, and road density, respectively. Furthermore, factors such as SPI, curvature, profile curvature, plan curvature, river density, distance from the river, and LS proved to have a negative effect on the modeling results, as zero value was assigned to these indices, which, in turn, led to the creation of noise. On the other hand, final modeling was performed and the 13 remaining factors were removed from the model due to their low impact on shallow landslides in the study area. Then, shallow landslide susceptibility maps were prepared based on the ADT algorithm, using quantile, natural breaks, and geometrical interval methods in the ArcGIS 10.2 environment. Finally, the best method was selected based on the landslides' frequency histogram in each susceptibility class of the maps. The results indicated that the natural breaks method was the best-known method, according to which the landslide susceptibility maps were divided into five classes, including very low susceptibility (VLS), low susceptibility (LS), moderate susceptibility (MS), high susceptibility (HS), and very high susceptibility (VHS).

    Discussion and Conclusion

    The results of IGR-based factor analysis revealed that distance from roads, lithology, and road density had the highest effects on the occurrence of landslides, which could be attributed to the existence of landslide-susceptible formations such as marl and shale, and inappropriate human-set policies including road construction and incorrect cutting off of heels, as road construction provides the grounds for more penetration of water into sensitive soil formations and saturation of these soils under force. Moreover, the soil saturation on slopes under the force of gravity can facilitate the occurrence of landslides in the study area, which is consistent with the results found by Pham et al. (2015, 2016, 2019) who reported that the existence of lithological units susceptible to landslides (i.e., marl and shale) in the middle parts of the slopes played an important role in the occurrence of landslides in such areas, considering the fact that marl and shales layers might act as a lubricant for overlying saturated soils, and, therefore,  facilitate the occurrence of landslides. However, it could be argued that the upper floors and higher altitudes of the area are less susceptible to landslides due to the presence of crystalline and basaltic units that are resistant to any mass movement, especially landslides. As for the land vegetation, it was found that landslides mostly occurred in drylands that were formerly semi-dense and grassland forests, indicating the significant role of forest degradation and land-use change in landslide occurrence.
    The designed models for both the training and validation data were evaluated using the Kappa, TP, specificity, sensitivity, accuracy, and squared statistical measures. Finally, the models' performance was examined through the AUC. Accordingly, the results of model validation showed that the ADT model had a relatively moderate performance with the sub-curve level of 0.665. Furthermore, the sub-curve level of the ADT model was found to be 0.677 for the training data. Finally, the study area was divided into five classes, including the very high, high and moderate, low, and very low sensitivity. It was also found the severity of landslides increased when moving from low-sensitivity classes to the high-sensitivity ones, indicating higher chances for the occurrence of landslides in areas with high sensitivity. Therefore, considering the high influence of the roads in the model proposed in this study, it is suggested that the priority of taking appropriate measures to prevent and/or control landslides be taken into account so that the effect of road construction in the study area could be reduced. Moreover, in cases where future road development operations are considered along the route, principles of road construction and the stability of the slope must be strictly observed.

    Keywords: Decision Tree Algorithm, Shallow Landslide, Spatial Prediction, Validation, Yozidar-Degaga
  • Alireza Donyaii, Amirpouya Sarraf* Pages 87-98
    Introduction

    As the biodiversity of valuable plant and animal species along the riversides –especially the ones located in the arid and semi-arid climate regions- has placed them in the category of sensitive and vulnerable ecosystems, awareness of these natural ecosystem's services could help protect them as much as possible, helping much more citizens benefit from their environmental services. Therefore, classifying different ecosystem services is necessary for identifying main natural ecosystem services, including regulatory, informative, productivity, and habitat services (De Groot et al., 2012). However, although many studies have already investigated issues such as improving the rivers' water quality, improving the riverbanks' landscape, and valuing the rivers' ecosystem services, no study has attempted to prioritize the rivers' ecosystem functions. Therefore, this study sought to do so in one of the Iranian largest rivers, which passes through several towns. In other words, the purpose of this study was to evaluate the function and significance of Atrak River's ecosystem functions as one of the most important northeastern rivers of Iran located in Maraveh Tappeh city, Golestan province, Iran.

    Material and methods

    As one of the most famous waterlogged rivers located in northeastern Iran with an arid and semi-arid climate, the Atrak River was selected to be investigated in this study. Originating from the high lands of Hezar Masjed mountains, the river is considered the fifth largest river in Iran, acting as the basis of economic activities in Golestan province, especially the Maraveh Tappeh city. Passing through different urban and rural areas, the river also connects different surrounding ecosystems that provide the residents of the neighboring cities with a variety of services (Sarraf et al., 2020), making the identification, weighing, and prioritization of the river's ecosystem functions via scientific models a highly important task.There are several methods to weight criteria via multi-criteria decision-making (MCDM) approaches, one of which is the entropy method introduced by Shannon. The method refers to a general measure of uncertainty, playing an important role in information theory. However, in cases such as interval data where the data are nondeterministic, the method must be modified to produce correct results. Therefore, this study used Shannon's entropy method to weigh the river’s ecosystem functions.Although the classical TOPSIS is widely used as a simple, reasonable, and flexibly applied calculation method, it has some shortcomings. For instance, the method could not rank the points in the perpendicular of the positive and negative ideal points. Thus, to overcome the shortcomings of the classical TOPSIS, the Improved TOPSIS has been developed as a new method to solve Multiple Criteria Decision-Making-related problems based on relative entropy. Accordingly, as the CODAS method acts more efficiently in resolving MCDM-related problems (Keshavarz-Gharabaee et al., 2016), the current study used the newest multi-criteria decision-making models (i.e., the Improved TOPSIS and the Combinative Distance-based Assessment (CODAS) approaches) to prioritize the river's functions.The required research data were collected via administering a questionnaire on 149 residents of Maraveh Tappeh in the summer and fall of 2020, asking them their opinion concerning the most important ecosystem functions of the river. Moreover, the Cochran formula was used to estimate the questionnaire's sample size. Also, an information brochure was enclosed with the questionnaire to familiarize the respondents with the Atrak River's ecosystem functions.

    Results and discussion

    According to the results of weighting the river's ecosystem functions with the Shannon entropy method, the weights of habitat, productivity, information, and regulatory functions were found to be 0.2501, 0.2491, 0.2490, and 0.2478, respectively. Moreover, the results of prioritizing the Atrak River's ecosystem functions via the Improved TOPSIS and CODAS models showed that habitat, productivity, regulatory, and information functions ranked first to fourth in terms of priority, respectively. The study's results also showed that the habitat, productivity, regulatory, and information were considered as the most important functions in order of priority for 41%, 26%, 25%, and 8% of the residents, respectively.

    Conclusion

    Considering what was discussed above, it is suggested that the results of the present study be used as a model for designers and decision-makers of river engineering to implement appropriate plans to guarantee the sustainability of the river's ecosystem and the quality of the urban environment. As other studies such as the one carried out by Chaika et al. (2017) on the Florida River Basin have also found that habitat and productivity services are the most important rivers' ecosystem services from the riverbank residents' point of view, it could be argued that providing people, especially villagers and residents of the Atrak riversides, with the means of livelihood is considered as the highest priority. Therefore, preserving aquatic habitats and creating sustainable development in terms of fishing purposes could help fishermen and local stakeholders continue earning their livelihood.

    Keywords: Atrak River, Ecosystem Functions, Maraveh Tappeh, Multi-Criteria Decision Making Models
  • Asghar Farajollahi*, Seyed Abdolhossein Arami, Yaser Ghasemi Aryan Pages 99-112
    Introduction

    Desertification combating projects are usually developed and implemented to protect water and soil and keep sustainable development of local communities. Therefore, evaluating the socio-economic effects of such projects is highly important for identifying and addressing the challenges involved in this regard and perpetuating their positive effects. Thus, this study sought to evaluate the socio-economic effects of the desertification projects and plans implemented in the southeastern region of Ahvaz in 2021.

    Materials and methods

    this study used the documentary method to investigate the theoretical dimensions of the subject and a survey method to collect the required quantitative data. The study's statistical population consisted of two groups of rural residents and experts familiar with the study area. Based on Cochran's formula and matching with Krejcie and Morgan's table, 335 rural residents were selected to participate in the study, using random sampling. Moreover, 26 experts participated in completing the questionnaires and conducting the research. After confirming the questionnaire's validity, Cronbach's alpha coefficient was obtained as 0.86 and 0.83 for rural residents and experts, respectively. On the other hand, the prioritization of the economic and social effects of the projects was performed through the average rankings. Finally, the mean comparison of the viewpoints of rural residents and experts was assessed through a Mann-Whitney test.

    Results

    According to the study's results, improving the employment opportunities and job creation, increasing the price of land in the region, and reducing the migration incentives are ranked first to third in terms of priority from the rural residents' viewpoints with the average values of 4.20, 4.15, and 4.12, respectively, followed by the influence of water and soil protection, dust reduction, and the participation of the local community in the implementation of desertification combating plans and operations, respectively. Moreover, the analysis of the experts' opinions showed that water and soil protection, dust reduction, increases in land prices, improvement of employment opportunities, reduction in migration incentives, and increases in the level of the local and rural communities' trust in goals and programs of executive departments were the most important effects of project implementation in the region with the average values of 4.46, 4.31, 4.19, 4.15 and 4.11, respectively.The mean values of the desertification combating projects were compared between the rural residents' viewpoints and experts' opinions using the Mann-Whitney test, revealing a statistically significant difference between the opinions of rural residents and experts in terms of the effects of water and soil protection and dust reduction, increases in the villagers' revenues, diversification of the villagers' income sources, and strengthening the cooperation and social cohesion among local communities. All of these items had a higher average rank in the experts' viewpoint except for "strengthening the cooperation and social cohesion among local communities. Experts significantly out-evaluated the consequences of the implemented combating desertification projects concerning the water and soil protection, dust reduction, increases in the villagers' revenues, and creation of a variety of new income resources compared to the rural residents. In other items regarding the effects of the projects, no statistically significant difference was found between the viewpoints expressed by residents and experts. As for the economic effects, there was a statistically significant difference between the experts' and rural residents' viewpoints (P<0.05), with the implementation of projects having more significant prominent effects in the experts' view. However, there was no statistically significant difference between the viewpoints offered by experts and residents in terms of the social effects of combating desertification projects (P>0.05).

    Discussion and Conclusion

    According to the viewpoints expressed by both experts and rural residents, water and soil protection, dust reduction, improvement of job opportunities, increases in the price of land in the studied region, and reduction in migration incentives are the most important economic and social consequences of desertification combating projects. Moreover, the viewpoints of experts and rural residents of the region concerning the economic and social consequences of the projects were close to each other and did not differ significantly, indicating their mutual understanding and intellectual proximity of the issue. Therefore, it appears that strengthening such a relationship helps desertification combating projects to be more successful. The results of this study also showed positive and acceptable effects of the projects in the study area. In fact, the implementation of such projects has improved the conditions for the sustainability and activity of rural communities. However, new plans should be developed for improving the welfare status, increasing the revenues, improving the water quality, increasing the production of crops, and increasing horticulture products. On the other hand, attracting the stakeholders' participation by promoting conservation knowledge and culture, using the potentials and capacities of the region, and providing the necessary facilities and financial support in terms of combating desertification goals and measures can help increase the chances for the success of desertification combating projects.

    Keywords: Employment, Khuzestan, Rural Residents, Desertification combating projects, Experts, Dust, Migration
  • Abbas Ali Vali*, Hadi Zarepour, Hamid Ghorbani, Seyed Javad Sadatinejad, Seyed Hassan Alavinia Pages 113-126
    Introduction

    As one of the greatest natural disasters, meteorological drought has traditionally affected human life. Considering the fact that the consequences of drought and its socio-economic damages increase with increasing population, it is necessary to have an effective monitoring system to analyze the drought process and reduce its adverse effects, thereby taking effective measures to manage the crisis.

    Materials and methods

    The study area and data: This study was conducted in Isfahan province, located at latitudes of 30° 43' to 34° 27'N and longitudes of 49° 38' to 55° 32' E with an area of ​​107145 km2 (equivalent to 3.6 percent of the total area of ​​Iran), whose annual precipitation rate is 130 mm which is less than half the country's average rainfall rate and one sixth of the average global rate. This study used 30-year precipitation data collected from 10 meteorological stations and neighboring areas with appropriate statistical quality to investigate the drought indices of the Isfahan province.

    Case Study Indicators

    Trend analysis of precipitation and drought data plays a significant role in the future development and management of water resources. Therefore, this study sought to analyze the trends of meteorological droughts and monthly precipitation rate for the period of 1990-2020 extracted from 10 synoptic stations in Isfahan province, including Ardestan, East Isfahan, Golpaygan, Isfahan, KabootarAbad, Kashan, Khorobianbanak, Naein, Natanz, Shahreza. Moreover, to investigate the variability of the Z-Score Index (ZSI) for different time intervals, the ZSI values of all these stations were calculated at multiple scales of 1, 3, 6, 9, 12, 24 and 48 monthly scales, whose trends were analyzed for all stations by applying the non-parametric Mann–Kendall at 5% significance level. The magnitudes of the trends were also computed and tested using the Sen’s slope estimator method.

    Results and discussion

    It should be noted that the purpose of the Mann-Kendall test is to statistically assess the existence of monotonic upward or downward trend of the intended variable over time. A monotonic upward (downward) trend means that while the variable consistently increases (decreases) over time, the trend may be eighter linear or non-linear.To identify a linear trend, the slope is usually estimated by computing the least squares estimates using linear regression. However, this is only valid when there is no serial correlation. Moreover, the least squares method is very sensitive to outliers. Therefore, as a robust method against those two least square assumptions, non-parametric Sen’s slope estimator was used to analyze ZSI Indices and detect the possible trend. Further trend analysis was also applied to detect possible single change-point using Pettitt’s test, which helped investigate significant abrupt changes in the level of time series at 5% significance level for all stations and different ZSI monthly scales. All statistical analyses were carried out via R statistical software and the facilities of its packages.

    Discussion and Conclusion

    The results of applying Mann–Kendall and Sen’s slope tests based on ZSI Index for 9, 12, 18, 24, and 48-month scales indicated that the drought trend was significantly increasing for all stations out of Esfahan and Shahreza stations. In Isfahan station, the drought trend was significantly decreasing in the 48-month scale, and in Shahreza station, the drought trend was significantly increasing in all time periods. Moreover, the results of Mann–Kendall and Sen’s slope tests for a one-month period revealed a is significantly increasing trend in terms of ZSI Index in Naein and KabootarAbad stations only. Furthermore, applying Mann–Kendall test on monthly precipitation rates of all stations showed an insignificant downward trend.Finally, the results of the Pettitt’s change point test for 9, 12, 18, 24, and 48-month scales indicated the existence of a significant change point in terms of the ZSI Index. However, no change point was observed for all stations' monthly precipitation rates throughout the same periods.In short, considering the ZSI drought index, it could be said about 58% of all stations showed significant downward trend according to the results of the Mann-Kendall test, 56% of all stations showed a significant slope trend according to the Sen's slope test, and 81% of all stations showed a significant change point according to the results of the Pettitt's test. In general, it could be argued that drought trends are better analyzed and displayed in terms of the ZSI index for over six-month periods, and that under six-month scale are unable to produce significant results.Considering what discussed above, it should be reiterated that Isfahan province is facing a water crisis, requiring very urgent water demand management.

    Keywords: Drought, Isfahan Province, Mann-Kendall Test, Pettitt’s Change Point Test, Sen’s Slope Test, Z-Score Index, Trend Analysis
  • Hassan Alipour*, Ali Salajegheh, Alireza Moghaddamnia, Shahram Khalighi, Mojtaba Nassaji Pages 127-141
    Introduction

    As an undeniable environmental phenomenon, climate change can be defined as a reversible change or variability in the average climate and its relevant variables, including the temperature, precipitation, humidity, climate patterns, wind, radiation, etc., which lasts for a long period of time. Located in a special geographical location that suffers from insufficient precipitation, Iran faces inappropriate distribution of rainfall temporally and spatially. On the other hand, the world seems to be facing new challenges in terms of water resources. Moreover, the most important consequence of the change in the hydrological cycle is the tendency toward extreme events ​​such as torrential rains, widespread droughts, and in some cases, regional wetlands. In this regard, it can be said that the frequency and severity of floods are among the terrible or deadly natural disasters brought about by climate change. Therefore, it is necessary to determine the best probability for the distribution of flood discharges, measure the best probability distribution for management and planning in cases where climate change occurs, and finally assess the frequency and severity of floods in Iran.

    Materials and methods

    To analyze the floods' frequency and severity under different climate change scenarios, the minimum and maximum values of precipitation and temperature were measured using the CanESM2 general circulation model under RCP2.6 and RCP8.5 climate change scenarios and the SDSM4.2.9 linear multiple regression downscaling model. Then, the collected precipitation data was processed and analyzed and the flood pattern was simulated for future periods via NetSTORM software (separating the rainfall from the hourly data). Moreover, the HEC-HMS model was used to simulate floods in basic and future periods. Accordingly, the SCS method, the Clark unit hydrograph method, and the Muskingum method were calibrated and evaluated to calculate the infiltration, convert the rainfall to runoff, and rout the river, respectively. Finally, to analyze the floods' frequency and severity, the probabilistic distribution function was fitted for the future periods' baseline data and propagation scenarios using the SMADA software for different statistical distributions (normal, two- and three-parameter log-normal, Pearson type III, Log-Pearson Type III and Gumbel), followed by the selection of the best-fit distribution model based on the RMSE and MSE tests.

    Results

    The results of the climatic model showed that under the RCP2.6 and RCP8.5 scenarios, the maximum temperature rate would increase in 2011-2055-and 2056-2100 by 3.02˚C, 3.27˚C, and 3.2˚C, and 5.47˚C, respectively. Furthermore, the minimum temperature rate would increase in the same periods by 0.62, 0.87, and 1.1 and 2.82 degrees Celsius, respectively. However, the monthly precipitation data did not reveal any specific trend throughout the future periods.The Emamah watershed's data concerning the flood discharge and maximum daily precipitation rate during the study period (1999-2019) were used to select flood and pervasive events. The predicted data were then analyzed under RCP2.6 and RCP8.5 scenarios at five separate periods. Finally, the selected events' data were imported to the HEC-HMS model and simulated. After selecting the flood events with the highest magnitude compared to other events, they were decomposed into one-hour or fewer rainfall events using the NETSTORM model. Then the flood discharge values were calculated ​​for the base and future periods and their probabilistic distribution function was obtained through the SMADA software. Finally, the Pearson type III distribution, the best distribution among normal, two-and three-parameter lognormal, Pearson type 3, Log-Pearson Type 3, and Gamble distributions were selected for each base and future time series using the goodness-of-fit test.According to the results of the best frequency distribution, flood values ​​were estimated with return periods of 2, 10, 25, 50, 100, and 200 years. Moreover, one third of the floods with a 2-year return period witnessed an increase in discharge rate compared to the base period. However, the discharge rate decreased or remained unchanged in floods with other return periods. On the other hand, floods estimated with 10 and 25-year return periods were increased in two-thirds of the periods, the highest increase of which occurred in the second period under the RCP8.5 scenarios by 12.68 and 25.76 percent, respectively. It should also be noted that the highest chances of increase in flood occurrence with a return period of 200 years belonged to the second period by 56.12% increase rate and 10.07 m2 discharge rate under the RCP8.5 scenarios.

    Discussion and Conclusion

    throughout the next hundred years, climate change would experience significant changes in precipitation patterns, leading to the risks of severe floods and droughts. Moreover, the results of the analysis and study of climate change indicated that the temperature increasing trend in the periods under the studied scenarios and that the biggest increase belonged to the RCP8.5 scenarios. It was also found that the temperature rate would increase more in the period 2056-2100 compared to the 2011-2055 period. However, the results of precipitation simulation under the scenarios did not show a definite trend for the future periods, with the precipitation increasing and decreasing in different months of the year. On the other hand, the simulation of basin floods for the future periods and the comparison of peak discharge values within the future and the observation periods indicated a change in the regime of river flood discharges. Accordingly, the maximum discharge rate increased in the constant returns period. Furthermore, the discharge rates significantly increased in the maximum constant flow period with an increase in the return period.

    Keywords: Rainfall- Runoff Modeling, SDSM, Flood Frequency Analysis, Emameh Watershed, HEC-HMS