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1 - نتایج وجودی جواب برای یک مدل واکنشی - انتشاری با تابع وزن نامحدود و رشد لجستیکی
صالح شاکری قاسم علیزاده افروزیدر این مقاله، با استفاده از روش جواب‌های بالایی و پایینی، یکی از روش های انالیز غیر خطی به بررسی وجود جواب‌های مثبت برای یک معادله‌ی واکنشی- انتشاری با شرایط مرزی دیریکله تحت شرایطی مناسب می‌پردازیم همچنین پویایی جمعیت ماهی با شکار طبیعی و برداشت ثابت محصول را تشریح می أکثردر این مقاله، با استفاده از روش جواب‌های بالایی و پایینی، یکی از روش های انالیز غیر خطی به بررسی وجود جواب‌های مثبت برای یک معادله‌ی واکنشی- انتشاری با شرایط مرزی دیریکله تحت شرایطی مناسب می‌پردازیم همچنین پویایی جمعیت ماهی با شکار طبیعی و برداشت ثابت محصول را تشریح میکند. در سطوح بالای تراکم پوشش گیاهی، این پارامتر به حد نهایی cمیل میکند زیرا جمعیت چراکننده ثابت است. در اینجا فرض می‌شود که اکوسیستم از لحاظ فضایی همگن است و تراکم پوشش گیاهی ثابت است که البته هر دوی این فرض‌ها برای سیستم‌های چرای مدیریت شده معتبر هستند. این مدل همچنین برای تشریح پویایی جمعیت ماهی ها نیز اعمال شده است .هدف این مقاله یافتن شرایط مناسب برای پارامترهای موجود بکار رفته در مساله برای وجود جواب می باشد. این مدل جمعیتی چریدن یک تعداد ثابت علف خوار را روی گونه های در حال رشد لجستیکی توصیف می کند.شکل کلی تابع لجستیکی دارای این ویژگی است که در ان تابع سرانه نرخ رشد نزولی است.(فرمول) در اینجا p جمعیت rنرخ رشد جمعیت و Kثابتی مثبت هستند [21]. اما برخی اکوسیستم ها وجود دارند که در انها سرانه نرخ رشد میتواند در یک تراکم مثبت به نقطه اوج برسد این اثر" الی"نامیده میشوداین میتواند به خاطر کمبود جفت گیری ,عدم گرده افشانی موثر,ازدیاد شکارچی, ویا تراکم از این ها باشد ما دراین مقاله بحث خود را تنها به مدل های لجستیک محدود میکنیم. تفاصيل المقالة -
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2 - بررسی تاثیر قرق بر ویژگی های پوشش گیاهی مراتع رزبند استان قم
سید مهدی ادنانی علیرضا افتخاری پرویز غلامی حسین توکلی نکو عباس پورمیدانیبررسی تغییرات پوشش گیاهی مراتع در فواصل زمانی معین و آگاهی از روند وضعیت آن، یکی از موارد مهم برای برنامه‌ریزی و اعمال مدیریت صحیح بهرهبرداری از مراتع است. تحقیق حاضر به منظور بررسی روند تغییرات برخی ویژگی های پوشش گیاهی در مراتع چرا شده و قرق در منطقه رزبند استان أکثربررسی تغییرات پوشش گیاهی مراتع در فواصل زمانی معین و آگاهی از روند وضعیت آن، یکی از موارد مهم برای برنامه‌ریزی و اعمال مدیریت صحیح بهرهبرداری از مراتع است. تحقیق حاضر به منظور بررسی روند تغییرات برخی ویژگی های پوشش گیاهی در مراتع چرا شده و قرق در منطقه رزبند استان قم صورت پذیرفت. اندازه‌گیری پوشش گیاهی در قالب ترانسکت‌های جفتی با فاصله 10 متر از هم انجام شد. هر جفت ترانسکت شامل ۲۰ پلات بود. پلات ها به ابعاد 1×1 متر به فاصله 3 متر از هم و به تعداد 10 عدد بر روی هر ترانسکت قرار گرفت. در نهایت تعداد 240 پلات (120 پلات در داخل و 120 پلات در خارج قرق) مورد ارزیابی قرار گرفت. آنالیز داده ها به وسیله نرم افزار SPSS و بررسی تنوع و غنای گونه ای با استفاده از نرم افزار PAST صورت پذیرفت. از مجموع 8 تیره گیاهی، تعداد 6 تیره دارای اختلاف معنی داری در داخل و خارج قرق بود. انجام قرق در منطقه مورد مطالعه باعث افزایش معنی دار پوشش تاجی فرم های رویشی بوته ای و پهن برگان علفی گردید، درحالی که فرم رویشی گندمیان اختلاف معنی داری نداشت. فرم های زیستی کاموفیت ، همی کریپتوفیت و تروفیت و نیز گونه های گیاهی با کلاس خوشخوراکی I و III پاسخ معنی دار و مثبت به انجام قرق نشان دادند. آزمون t برای شاخص های تنوع و غنای گونه ای نشان داد، شاخص تنوع سیمپسون و شانون وینر و نیز شاخص غنای مارگالف دارای تفاوت معنی دار می باشد. این امر در حالی است که شاخص غنای منهینیک و شاخص یکنواختی تفاوت معنی داری در داخل و خارج قرق نداشت. همچنین آنالیز RDA به منظور بررسی تاثیر قرق بر کل گونه های گیاهی موجود در پلات ها نشان داد قرق بر پوشش گیاهی اثر معنی دار داشته است (29/66 = F، 0/001 = P). نتایج این تحقیق بیانگر این مطلب بود که قرق کوتاه مدت می تواند شرایط را برای بازسازی و تجدید شادابی گونه هایی نظیر Bufonia macrocarpa و Artemisia sieberi در مراتع مناطق خشک مانند رزبند قم فراهم سازد. تفاصيل المقالة -
حرية الوصول المقاله
3 - تحلیل مهمترین تخلفات در عرصه‌های طبیعی بوم‌سازگان زاگرس، شهرستان گیلان‌غرب
محسن جوانمیری پور ندا محمدخانی گیلانی علی رستمیجوامع محلی به طور مستقیم با عرصه‌های طبیعی وابسته بوده و اکوسیستم را تحت تاثیر قرار می دهند. هدف از انجام این بررسی شناخت دقیق مهمترین تخلفات موثر در تخریب منابع طبیعی با استفاده از پرونده های حقوقی منابع طبیعی بود. برای انجام این مطالعه، از پرونده‌های حقوقی سالهای أکثرجوامع محلی به طور مستقیم با عرصه‌های طبیعی وابسته بوده و اکوسیستم را تحت تاثیر قرار می دهند. هدف از انجام این بررسی شناخت دقیق مهمترین تخلفات موثر در تخریب منابع طبیعی با استفاده از پرونده های حقوقی منابع طبیعی بود. برای انجام این مطالعه، از پرونده‌های حقوقی سالهای 1385 تا 1395 در بایگانی اداره منابع طبیعی و آبخیزداری شهرستان گیلان غرب برای روستاهای چله، گواور و گورسفید استفاده شد. با مطالعه پرونده‌ها، نوع تخلف و میزان آن ثبت و مواد قانونی از فصل ششم قانون حفاظت و بهرهبرداری از جنگل‌ها و مراتع کشور مصوب سال 1346 مورد بررسی قرار گرفت. در تحقیق حاضر به‌منظور ارزیابی تخلفات حوزه منابع طبیعی، از شیوه توصیفی- تحلیلی در قالب روش تحلیل محتوی کمّی استفاده شد. نتایج نشان داد بیشترین پرونده جرایم مربوط به آتش‌سوزی (211 پرونده) بود، درحالی که فراوانی قطع نهال و درخت به ترتیب برابر با 77 و 66 مورد بودند. فراوانی قطع نهال و درخت در طی زمان مورد مطالعه نشان داد بیشترین فراوانی تخلف مذکور در سال 1387 رخ داده بود که میزان آن به ترتیب برابر با 1624 و 1505 اصله نهال و درخت بودند. فراوانی موارد وقوع آتش سوزی نشان داد روند آن افزایشی بوده و بیشترین میزان آن در سال 1395 رخ داده است که برابر با 31 مورد بوده است. در سه روستای مورد مطالعه به تفکیک نیز فراوانی قطع نهال و درخت نسبت به سایر انواع تخلف بیشتر بود. نتایج آنالیز آماری برای بررسی معنی‌دار بودن اختلاف بین میانگین تخلفات حاکی از آن بود که سه روستا با هم فاقد اختلاف معنی‌دار بودند، درحالی که فراوانی قطع نهال و درخت دارای اختلاف معنی‌دار میباشد. همچنین در روستاهای گورسفید و چله، گواور و چله از لحاظ تعداد آتش‌سوزی تفاوت معنی‌داری وجود دارد اما روستاهای گورسفید و گواور اختلاف معنی‌داری با هم نداشتند. همچنین دام غیرمجاز و تعداد موارد آتش‌سوزی در بین روستاها دارای اختلاف معنی‌داری بودند. به طور کلی با نتایج به دست آمده، وجود انواع تخلفات از قبیل آتش سوزی، دام غیرمجاز، قطع درخت و نهال و قاچاق چوب، هیزم و ذغال در روستاهای مورد مطالعه اثبات گردید که در طی زمان منجر به تخریب طبیعت منطقه گردیده است. بنابراین با توان‌افزایی و استفاده از آموزش جوامع محلی و فرهنگ‌سازی در استفاده از مواهب طبیعی و همچنین اعمال قوانین سختگیرانه برای متخلفان می‌توان در این زمینه اقدامات موثری انجام داد. تفاصيل المقالة -
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4 - نقش حفاظت بر ویژگی‌های کمی و کیفی گونه آوری (Quercus macranthera C. A. Mey) در جنگل‌های رودبار استان گیلان
علی نقی صدیقی چافجیری ایرج حسن زاد ناورودی کامبیز طاهری آبکنار حسن پوربابائیزمینه و هدف: گونه اوری در ارتفاعات فوقانی مناطق جنگلی در شمال ایران گسترش دارد و در حفظ خاک و نفوذ آب نقش مؤثری را ایفا می کند. بزرگ ترین مشکل در این مناطق چرای دام و حضور جنگل نشینان است. هدف از این پژوهش، بررسی نقش حفاظت بر ویژگی های کمی و کیفی گونه اوری در جنگل های ر أکثرزمینه و هدف: گونه اوری در ارتفاعات فوقانی مناطق جنگلی در شمال ایران گسترش دارد و در حفظ خاک و نفوذ آب نقش مؤثری را ایفا می کند. بزرگ ترین مشکل در این مناطق چرای دام و حضور جنگل نشینان است. هدف از این پژوهش، بررسی نقش حفاظت بر ویژگی های کمی و کیفی گونه اوری در جنگل های رودبار استان گیلان بود. روش بررسی: در مجموع 40 قطعه نمونه 1000 متر مربعی (20 قطعه نمونه در منطقه حفاظت شده و 20 قطعه نمونه در منطقه حفاظت نشده) به روش تصادفی- سیستماتیک و با استفاده از شبکه آماربرداری 100 × 100 متر در خرداد 1394 برداشت شدند. در هر قطعه تعداد و نوع گونه های درختی و درختچه ای و همچنین قطر برابر سینه، ارتفاع گیاه، وضعیت تاج و کیفیت تنه پایه های اوری اندازه گیری شدند. همچنین، به منظور بررسی وضعیت زادآوری از یک میکروپلات 100 متر مربعی در مرکز هر قطعه نمونه استفاده شد. یافته ها: نتایج نشان داد که تعداد درختان در هکتار، میانگین قطر برابر سینه، مجموع سطح مقطع برابر سینه، ارتفاع درختان، حجم و زادآوری گونه اوری در منطقه حفاظت شده به صورت معنی داری بیش تر از منطقه حفاظت نشده است. سایر گونه های درختی اختلافی بین دو منطقه نداشتند. تراکم گونه های درختچه ای آلوچه (Pronus spinosa)، ولیک (Crataeogus microphylla) و زرشک (Berberis integgerima) در منطقه حفاظت نشده به طور معنی داری بیشتر از منطقه حفاظت شده بود. همچنین، کیفیت تاج و تنه پایه های اوری نیز در منطقه حفاظت شده بهتر از منطقه تخریب شده بود. بررسی طبقات قطری در مثلث ساختار نشان داد که منطقه حفاظت شده در بخش جنگل نامنظم و منطقه تخریب یافته در بخش منظم شده در کم قطر-میان قطر قرار دارد. بحث و نتیجه گیری: با توجه به اینکه درختان اوری نقش مهمی در بخش های فوقانی جنگل دارند، حفظ این گونه ارزش مند و تداوم برنامه های خروج دام و جنگل نشینان از رویشگاه های طبیعی آن ضروری به نظر می رسد. تفاصيل المقالة -
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5 - مقایسه شاخص‌های تنوع و یکنواختی گونه‌ای در شدت‌های مختلف چرای دام در مراتع دامنه‌های جنوب شرقی سبلان
رباب باقریان کیومرث سفیدی فرشاد کیوان بهجو علی اشرف سلطانی بهزاد بهتریزمینه و هدف : ارزیابی تنوع و یکنواختی گونه‌ای به درک صحیحِ کارکرد اکوسیستم، حفظ و نگهداری ذخایر ژنی، بررسی و کنترل تغییرات محیطی، و موفقیت یا عدم موفقیت برنامه‌های مدیریت منابع طبیعی کمک میکند. چرای بی رویه و بدون برنامه‌ی دام یکی از شایع‌ترین و شاید مهمترین عامل تخری أکثرزمینه و هدف : ارزیابی تنوع و یکنواختی گونه‌ای به درک صحیحِ کارکرد اکوسیستم، حفظ و نگهداری ذخایر ژنی، بررسی و کنترل تغییرات محیطی، و موفقیت یا عدم موفقیت برنامه‌های مدیریت منابع طبیعی کمک میکند. چرای بی رویه و بدون برنامه‌ی دام یکی از شایع‌ترین و شاید مهمترین عامل تخریب مراتع و کاهش تنوع و یکنواختی گونه‌ای است. روش بررسی : به منظور بررسی اثر شدت‌های مختلف چرایی بر تنوع و یکنواختی گونه‌ای در مراتع دامنه‌های جنوب شرقی سبلان، سه رویشگاه دارای مدیریت‌هایی چرایی متفاوت شامل چرای سبک، متوسط و شدید انتخاب و با استفاده از پلاتهای یک متر مربعی در طول سه ترانسکت 200متری اقدام به نمونه‌برداری از پوشش گیاهی شد. در هر پلات، فهرست گونههای موجود، درصد تاج پوشش و تعداد افراد هر گونه یادداشت شد. شاخص‌های تنوع سیمپسون، شانون و بریلئون و شاخص یکنواختی کامارگو، سیمپسون و اسمیت- ویلسون محاسبه گردید. یافته‌ها : نتایج نشان داد که منطقه با شدت چرای متوسط تا سبک بیش ترین میزان تنوع و یکنواختی را نسبت به منطقه با شدت چرای سنگین دارد. که نشان گر شرایط مساعد برای استقرار گونههای متعدد است. بحث و نتیجه‌گیری: با توجه به تأثیر معنی‌دار شدت چرا بر شاخص‌های تنوع و غنا لازم است مدیران بخش مرتع با کنترل شدت چرا از طریق شیوه‌های مدیریتی در جهت حفظ تنوع موجود در اکوسیستم‌های مرتعی عمل کنند. بنابراین کافی است که بهرهبرداری بر مبنای چرای متوسط را هدف مدیریت قرار داد و مناطق با چرای شدید را به شرایط چرای متوسط رساند تا به تدریج گونههای مرغوب و خوش خوراک جایگزین گونه های خشبی و نامرغوب شوند. تفاصيل المقالة -
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6 - بررسی تغییرات فصلی تولید و مصرف گونه Agropyron trichophorum در مراتع ییلاقی استان لرستان
رضا سیاه منصور مرتضی اکبرزادهزمینه و هدف: وابستگی ما به گیاهان برای ادامه حیات آنقدر شدید است که بهره برداری و مدیریت آن علوم خاصی را به خود اختصاص داده است. یکی از گونه های کلیدی مراتع گونهtrichophorum Agropyron است. آگاهی از اطلاعات اکولوژیکی آن اهمیت ویژه ای دارد. مطالعه حاضر با هدف تعیین تغییرا أکثرزمینه و هدف: وابستگی ما به گیاهان برای ادامه حیات آنقدر شدید است که بهره برداری و مدیریت آن علوم خاصی را به خود اختصاص داده است. یکی از گونه های کلیدی مراتع گونهtrichophorum Agropyron است. آگاهی از اطلاعات اکولوژیکی آن اهمیت ویژه ای دارد. مطالعه حاضر با هدف تعیین تغییرات فصلی تولید و مصرف گونه Agropyron trichophorum در مراتع ییلاقی استان لرستان انجام گرفته است. روش بررسی: در این تحقیق تولید در داخل قطعه محصور و مصرف در خارج آن (شاهد)، در سالهای 1386 تا 1389 بررسی شد. هرساله تعداد 50 پایه متوسط از گونه در آغاز فصل رویش مشخص شده و 5 پایه متوسط در ابتدای فصل به ازای هر ماه از فصل چرا در داخل قطعه قرق و 5 پایه مشابه در خارج قرق انتخاب و در هر ماه از فصل چرا قطع و توزین شد. داده‌ها در نرم افزارMSTATC تجزیه و مقایسه میانگین با آزمون چند دامنه دانکن انجام پذیرفت. یافته ها: اختلاف میانگین های اثر سال، ماه و اثر متقابل سال× ماه از نظر آماری معنی‌دار است (01/0P < ). تفاوت تولید در سال های مختلف زیاد بود، به‌طوری‌که علوفه تولید شده در سال کم تولید حدود 42% علوفه تولید شده در سال پر تولید بود. به‌طور متوسط هر ساله حدود 80 % از تولید این گونه در طول فصل چرا مورد استفاده دام قرار گرفت که در سال های بررسی بین حدود 75 تا 87 % در نوسان بود. بحث و نتیجه گیری: تولید در خرداد ماه که نتیجه متابولیسم گیاه در نیمه دوم اردیبهشت و نیمه اول خرداد است، بیشتر بوده و در تیر و مرداد کاهش می‌یابد. در کل این گونه به‌طور متوسط 4/149 کیلوگرم در هکتار علوفه تولید میکند که 8/119 کیلوگرم در هکتار (2/80 %) آن مصرف می‌شود. در تیر و مرداد فشار چرا به پس چر مزارع منتقل شد، این امر به واسطه وجود علوفه در اراضی نزدیک روستا همچنین افزایش دما و کاهش منابع آب در مرتع میباشد. تفاصيل المقالة -
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7 - تاثیر شدت‌های مختلف چرایی بر تنوع و ترکیب پوشش گیاهی مراتع نیمه خشک (مطالعه موردی: مراتع محمدآباد، جیرفت)
احسان کمالی مسکونی بهزاد عادلی ایرج امیریز زمینه و هدف: آگاهی از فشارهای محیطی مخرب بر اکوسیستم که باعث تخریب زیستگاه ها و بیوم ها و در نتیجه کاهش تنوع گونه ای می گردد، ضروری است. یکی از فشارهای مخرب فیزیکی بر عرصه مرتع که باعث کاهش تنوع و از بین رفتن عناصر گیاهی حساس می گردد، چرای مفرط می باشد. هدف از انجام أکثرز زمینه و هدف: آگاهی از فشارهای محیطی مخرب بر اکوسیستم که باعث تخریب زیستگاه ها و بیوم ها و در نتیجه کاهش تنوع گونه ای می گردد، ضروری است. یکی از فشارهای مخرب فیزیکی بر عرصه مرتع که باعث کاهش تنوع و از بین رفتن عناصر گیاهی حساس می گردد، چرای مفرط می باشد. هدف از انجام این تحقیق بررسی اثر شدت های مختلف چرایی بر تنوع و غنای گونه ای در مراتع نیمه خشک بخش محمد آباد، شهرستان جیرفت، استان کرمان بوده است. روش بررسی:به منظور بررسی اثر شدت های مختلف چرایی بر تنوع و غنای گونه ای سه رویشگاه متفاوت قرق، چرای متوسط و چرایشدید انتخاب و با استفاده از 90 پلات 4 متر مربعی در طول 18 ترانسکت اقدام به نمونه برداری گردید. در داخل هر قاب، فهرست گونه های موجود، درصد تاج پوشش و تعداد افراد هر گونه یادداشت شد. برای ارزیابی شاخص های تنوع و غنا، شاخص های غنای مارگالف و منهینگ و شاخص های تنوع سیمپسون، شانون-واینر، N0 هیل و N1 هیل محاسبه گردید. تجزیه و تحلیل داده ها در نرم افزار SPSS انجام شد و مقایسه شاخص های مختلف تنوع و غنا بین مناطق با شدت های چرایی مختلف توسط آزمون توکی صورت پذیرفت. یافته ها: نتایج حاصل از محاسبه شاخص غنای مارگالف نشان داد که بین تمامی عرصه های چرایی از نظر آماری اختلاف معنی داری وجوددارد. از طرف دیگر بین مناطق مختلف چرایی از نظر شاخص غنای منهینگ اختلاف معنی داری وجود ندارد. نتایج حاصل از محاسبه شاخص های تنوع، در هر چهار شاخص سیمپسون، شانون-واینر، N0هیل و N1 هیل نشان دادند که بین تمامی عرصه های چرایی اختلاف معنی داری وجود دارد. بحث و نتیجه‌گیری: به طور کلی در منطقه مورد مطالعه شاخص های تنوع و غنای گونه ای به دلیل میزان بارندگی کم منطقه و قرارگیری در ناحیه نیمه خشک نسبتاً پایین است. بنابراین به علت حساس و شکننده بودن این نوع مراتع در بهره برداری از آن ها باید توجه بیش تری داشت تا از تخریب بیش تر جلوگیری شده و ترکیب گیاهی نیز اصلاح گردد. تفاصيل المقالة -
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8 - فنولوژی گونههای Ferula ovinia و Poa bulbosa و بهترین زمان ورود و خروج دام در مرتع گوراب اصفهان
مریم غلامی مصطفی سعیدفرزمینه و هدف: مطالعه فنولوژی یکی از عوامل مهم و اساسی در اعمال مدیریت جهت بهره برداری بهینه از پوشش گیاهی است. گونه های مرتعی Ferulaovinia وPoabulbosaاز نظر علوفه ای و مرتعی و همچنین جلوگیری از فرسایش خاک از اهمیت خاصی برخوردار هستند. این تحقیق به منظور تعیین زمان مناسب أکثرزمینه و هدف: مطالعه فنولوژی یکی از عوامل مهم و اساسی در اعمال مدیریت جهت بهره برداری بهینه از پوشش گیاهی است. گونه های مرتعی Ferulaovinia وPoabulbosaاز نظر علوفه ای و مرتعی و همچنین جلوگیری از فرسایش خاک از اهمیت خاصی برخوردار هستند. این تحقیق به منظور تعیین زمان مناسب ورود و خروج دام از مرتع، درسایت گوراب اصفهان در 35 کیلومتری غرب شهرستان فریدونشهر به مدت 4 سال (1395-1392) شده است. روش بررسی: در این تحقیق ده پایه انتخاب و اطلاعات مربوط به مراحل فنولوژی برای هر پایه در مقاطع زمانی 7 روزه در مرحله رویشی و 15 روزه در مرحله زایشی اندازه گیری و در فرم ویژه ای ثبت گردید. هم زمان آمار هواشناسی روزانه از ایستگاه هواشناسی مستقر در محل اجرای طرح برداشت شد. یافته ها: رشد رویشی گونه ovinia Ferulaاز اواخر اسفند آغاز و تا اواسط خرداد ادامه یافت. دوره گلدهی اوایل خرداد آغاز و تا اواخر خرداد به طول انجامید. مرحله رسیدن بذر از اواسط خرداد آغاز و تا اواخر تیر کامل شد. در گونه Poabulbosaرشد رویشی از اواخر اسفند شروع و تا اواسط خرداد ادامه داشت. دوره گل دهی از اوایل خرداد شروع و تا اواسط خرداد ادامه یافت. مرحله رسیدن بذر از اواسط خرداد شروع و تا اوایل تیر به پایان رسید. بحث و نتیجه گیری: نتایج نشان داد که با توجه به رفتار گونه های مورد مطالعه در بروز پدیده های زیستی در سال های مختلف مطالعه این امکان فراهم شده است که رفتار گیاهان را با تغییرات رطوبتی و دما در شرایط مختلف بررسی کنیم. بهترین زمان و ورود و خروج باید براساس نحوه بروز پدیده های زیستی در گونه ی Poa bulbosa تنظیم شود که در این صورت براساس مطالعات انجام یافته بهترین زمان می تواند در آخر اردیبهشت و اوایل خرداد باشد و زمان خروج دام به علت وجود پایه های خشک شده به ویژه در گونه ی Ferula ovina که در زمان خشک شدن (شروع تابستان) مورد استفاده دام قرار می گیرد، می تواند تا اواسط شهریور (مشروط بر رعایت تعداد دام مبتنی بر ظرفیت مرتع)، ادامه یابد. تفاصيل المقالة -
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9 - بررسی اثر کپه‌کاری و قرق بر خصوصیات خاک مراتع (مطالعه موردی: مراتع دارانی علیا، شهرستان تویسرکان، استان همدان)
مریم احمدوند داود اخضریزمینه و هدف: امروزه نگرانی‌‌های مرتبط با افزایش دام و اثرات مخرب آن از جمله فشرده‌‌سای خاک، تخریب خاک و فرسایش و آلودگی آب وجود دارد. یکی از راههای رایج جهت احیای مراتع و بازیابی توان آنها کاشت گونههای مرتعی مناسب و سپس قرق میباشد. روش بررسی: برای انجام این پژوهش 10 أکثرزمینه و هدف: امروزه نگرانی‌‌های مرتبط با افزایش دام و اثرات مخرب آن از جمله فشرده‌‌سای خاک، تخریب خاک و فرسایش و آلودگی آب وجود دارد. یکی از راههای رایج جهت احیای مراتع و بازیابی توان آنها کاشت گونههای مرتعی مناسب و سپس قرق میباشد. روش بررسی: برای انجام این پژوهش 10 ترانسکت 100 متری به شیوهای که هر ترانسکت با ترانسکت قبلی 50 متر فاصله داشته باشد در نظر گرفته شد. در طول هر ترانسکت 10 پلات 1 در 1 تعیین و در هر پلات یک نمونه 100 گرمی خاک از 3 عمق 0-10، 10-20 و 20-30 سانتی‌متری برداشت گردید. به طور مشابه، به همین تعداد نمونه و مانند منطقه قرق و کپه‌کاری، در عرصه مجاوری که کپه‌کاری نشده و بهعنوان منطقه شاهد در نظر گرفته شده بود، نیز نمونه برداری انجام گردید. نمونه‌ها جهت اندازه‌گیری جرم مخصوص ظاهری، محتوی رطوبت خاک، pH، EC، نیتروژن کل، فسفر کل و کربن آلی خاک به آزمایشگاه منتقل گردیدند. سپس با استفاده از تجزیه واریانس یک‌طرفه در سطح احتمال 05/0 مورد بررسی قرار گرفتند. یافته‌ها: نتایج نشان داد در منطقه چرا شده جرم مخصوص ظاهری، EC، نیتروژن کل، فسفر کل و کربن آلی خاک در سطح معناداری 5 درصد بیشتر از منطقه قرق و کپه‌کاری بوده است اما رطوبت خاک و pH خاک در دو منطقه در هیچ سطحی تفاوت معناداری نداشتند. بحث و نتیجه‌گیری: جرم مخصوص ظاهری با اعمال چرا و لگدکوبی بر اثر فشرده شدن خاک افزایش می‌یابد. هدایت الکتریکی منطقه قرق شده نیز به دلیل افزایش پوشش گیاهی و کاهش تبخیر و تعرق در منطقه قرق کمتر از منطقه چرا شده بود. افزایش میزان نیتروژن، فسفر و کربن آلی خاک در منطقه چرا احتمالا به دلیل جذب آن¬هاتوسط ریشه گونههای گیاهی و برگشت این مواد از طریق فضولات دام‌های موجود به لایه‌های سطحی خاک مربوط میباشد. تفاصيل المقالة -
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10 - بررسی تأثیر قرق بر پتانسیل ترسیب کربن در مراتع قشلاقی سرخکلای ساری
عاطفه خانلری رضا تمرتاش محمدرضا طاطیانمراتع حاوی بیش از یک سوم ذخایر کربن زیست کره خاکی هستند که قادرند دی اکسید کربن اتمسفر را از طریق پوشش گیاهی جذب کرده و در بافت های گیاهی و سپس خاک تجمع و رسوب دهند. چرای دام از پوشش گیاهی به عنوان یک عامل انسانی می تواند در میزان این جذب اثر داشته باشد. لذا در این پژوه أکثرمراتع حاوی بیش از یک سوم ذخایر کربن زیست کره خاکی هستند که قادرند دی اکسید کربن اتمسفر را از طریق پوشش گیاهی جذب کرده و در بافت های گیاهی و سپس خاک تجمع و رسوب دهند. چرای دام از پوشش گیاهی به عنوان یک عامل انسانی می تواند در میزان این جذب اثر داشته باشد. لذا در این پژوهش تأثیر چرا بر میزان ترسیب کربن در مراتع قشلاقی قرق و غیرقرق سرخکلای شهرستان ساری مورد مطالعه قرار گرفته است. پس از تعیین تیپ گیاهی و شناسایی گونه غالب (Hordeum glaucum Steud) نمونه برداری از پوشش گیاهی با روش تصادفی- سیستماتیک با استفاده از 20 پلات یک متر مربعی انجام گردید. سپس زیتوده بالای سطح زمین شامل اندام هوایی و همچنین زیتوده ریشه گیاهان با اندازه گیری مستقیم تعیین شد. با توزین نمونه ها، درصد ماده خشک برای هر یک از بخش ها محاسبه گردید. همزمان با نمونه برداری پوشش گیاهی، نمونه برداری از خاک از دو عمق 0-15 و 15-30 با توجه به مرز تفکیک افق سطحی و زیرین در منطقه انجام شد. درصد کربن آلی نمونه های گیاهی و درصد کربن آلی خاک در آزمایشگاه به دست آمد. همچنین سایر خصوصیات خاک شامل وزن مخصوص ظاهری، بافت خاک، کربنات کلسیم، هدایت الکتریکی و واکنش خاک تعیین شد. در نهایت داده های به دست آمده از دو منطقه قرق و تحت چرا، با استفاده از آزمون تی مستقل در نرم افزار SPSS 16 مورد تجزیه و تحلیل آماری قرار گرفت. نتایج نشان داد که چرا موجب کاهش معنی دار ترسیب کربن از اندام هوایی به زیرزمینی در هر دو منطقه تحت چرا و قرق گردیده است (p≤0/01). در حالی که با وجود کاهش میزان ترسیب کربن خاک از منطقه قرق به غیرقرق، تفاوت معنی داری بین آن ها در عمق اول و دوم خاک مشاهده نشد. همچنین نتایج نشان داد که سهم خاک در میزان ترسیب بسیار بیش تر از گیاه بوده و به ترتیب 97 و 99% از میزان کربن موجود در منطقه قرق و غیرقرق را به خود اختصاص داده است. تفاصيل المقالة -
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11 - قابلیت دستورالعمل طبقه‌بندی شایستگی مرتع برای چرای گوسفند (مطالعه موردی: مراتع کوهستانی امام‌کندی ارومیه)
جواد معتمدی حسین ارزانی اسماعیل شیدای کرکجتعیین شایستگی مرتع با استفاده از شرایط محدود کننده روش فائو، به لحاظ تعدد عوامل و اینکه در برخی از موارد نیاز به عملیات آزمایشگاهی و تهیه نقشه دارد، زمان بر بوده و امکان قابلیت کاربرد آن توسط تمامی کارشناسان، وجود ندارد. از اینرو دستورالعمل طبقه بندی شایستگی مرتع برای أکثرتعیین شایستگی مرتع با استفاده از شرایط محدود کننده روش فائو، به لحاظ تعدد عوامل و اینکه در برخی از موارد نیاز به عملیات آزمایشگاهی و تهیه نقشه دارد، زمان بر بوده و امکان قابلیت کاربرد آن توسط تمامی کارشناسان، وجود ندارد. از اینرو دستورالعمل طبقه بندی شایستگی مرتع برای چرای انواع دام در مناطق مختلف آب و هوایی، از طرف دفتر فنی مرتع پیشنهاد شد. بر اساس دستورالعمل پیشنهادی، شایستگی مرتع برای چرای انواع دام، از تلفیق سه معیار پوشش گیاهی (20 امتیاز)، آب (15 امتیاز) و فرسایش خاک (15 امتیاز) حاصل می شود. جهت ارزیابی قابلیت دستورالعمل ذکر شده در منطقه نیمه خشک، پژوهش حاضر در فصل رویش سال 1396 در مراتع کوهستانی امام کندی ارومیه انجام و نتایج حاصل از تعیین شایستگی تیپ های گیاهی بر مبنای دستورالعمل پیشنهادی با نتایج حاصل از روش شرایط محدود کننده فائو، توسط آزمون غیرپارامتری ویلکاکسون، مورد مقایسه قرار گرفت. نتایج نشان داد که در روش شرایط محدود کننده فائو، در 83 درصد موارد، معیار تولید علوفه، در 46 درصد، معیار حساسیت خاک به فرسایش، در 11 درصد، معیار منابع آب، به عنوان معیارهای کاهش دهنده شایستگی تیپ های گیاهی می باشند. ولی در دستورالعمل پیشنهادی، تنها حساسیت خاک به فرسایش، سبب کاهش امتیاز شاخص ها و در نتیجه، طبقات شایستگی شده است. نتایج نشان داد که تفاوت معنی داری بین دو روش از نظر طبقات شایستگی نهایی وجود ندارد (P≤0.05)، و بیش از 85 درصد از مراتع منطقه، در دو روش به صورت یکسان طبقه بندی شدند. بنابراین دستورالعمل پیشنهادی، قادر به شناسایی و تفکیک مناطق مستعد و غیرمستعد از نظر چرای گوسفند می باشد و کارایی آن در مقایسه با روش شرایط محدود کننده فائو، با توجه به صرفه جویی در هزینه و سادگی، قابل توجه است. این دستورالعمل، کارشناسان را قادر خواهد ساخت که در هنگام تهیه طرح های مرتعداری چند منظوره (تلفیقی)، با روشی ساده و کاربردی در عرصه، به تناسب استفاده از مراتع جهت چرای دام پی ببرند. تفاصيل المقالة -
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12 - بررسی اکولوژیکی تغییرات وضعیت مرتع و ارتباط آن با گونه های سمی
کوروش خلعتبری محمدحسن جوری حمیدرضا محرابیتغییرات شدید ساختار بهره برداری از مراتع باعث دگرگونی پوشش گیاهی مراتع شده است که هجوم گونه های سمی در مناطق عاری از پوشش گیاهان بومی بعنوان نمادی از این تغییرات مطرح است. آگاهی از درجات وضعیت مراتع باعث اتخاذ تصمیم درست مدیریت بهره برداری از مراتع می گردد. به منظور برر أکثرتغییرات شدید ساختار بهره برداری از مراتع باعث دگرگونی پوشش گیاهی مراتع شده است که هجوم گونه های سمی در مناطق عاری از پوشش گیاهان بومی بعنوان نمادی از این تغییرات مطرح است. آگاهی از درجات وضعیت مراتع باعث اتخاذ تصمیم درست مدیریت بهره برداری از مراتع می گردد. به منظور بررسی روند این تغییرات و ارتباط آن با حضور گونه های سمی، مراتع جواهرده رامسر تحت سه تیمار قرق بلندمدت (30 سال)، کوتاه مدت (7 سال) و منطقه چرایی انتخاب شد. به کمک پیمایش صحرایی اقدام به جمع آوری گونه ها و شناسایی آنها توسط منابع معتبر شد. تعدادی پلات به روش تصادفی در هر سایت به منظور تعیین وضعیت و گرایش انداخته شد. وضعیت مرتع به روش شش فاکتوره و گرایش نیز با استفاده از روش ترازوی گرایش تعیین شد. همچنین به منظور تعیین میزان مصرف گونه های سمی توسط دام، از روش شمارش لقمه استفاده شد. نتایج نشان داده است که در این منطقه 133 گونه متعلق 19 تیره و 56 جنس حضور دارند. همچنین با توجه به وضعیت خوب (قرق بلندمدت)، متوسط (قرق 7 ساله) و ضعیف (تحت چرا)، 39 گونه بصورت سمی بوده است. 46 گونه مورد مصرف دام قرار گرفت که از بین آنها 15 گونه دارای خاصیت سمی بوده اند. بنابراین مطالعه روند وضعیت مرتع در منطقه نشان داده است که در مواقعی که فشار چرایی شدید می گردد و یا اینکه مراتع تحت چرای مداوم قرار دارند، گونه های بومی عرصه را به نفع گونه های مهاجم (که اکثرا غیرخوشخوراک و سمی هستند) خالی می کنند. اما بعضی از گونه های سمی بومی نیز وجود دارند که با توجه به خاستگاه اکولوژیک خود، عرصه عاری از گونه های خوشخوراک را تحت اشغال خود درمی آورند. تفاصيل المقالة -
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13 - بررسی تاثیر قرق بر میزان ترسیب کربن و صفات فیزیکی و شیمیایی خاک در مراتع نیمه‌استپ استان چهارمحال و بختیاری
مهدی مرادی شاهقریه پژمان طهماسبیچکیده: اکوسیستم های گیاهی کره خاکی سرویس ها و خدمات متفاوتی را ارائه می دهند، با توجه به شرایط حال حاضر کره زمین و آلودگی بیش از حد اتمسفر یکی از مهم ترین خدمات جوامع گیاهی ترسیب کربن در طولانی مدت در درون خاک می باشد. در مطالعه حاضر هدف بررسی تاثیر قرق بر میزان ترسیب أکثرچکیده: اکوسیستم های گیاهی کره خاکی سرویس ها و خدمات متفاوتی را ارائه می دهند، با توجه به شرایط حال حاضر کره زمین و آلودگی بیش از حد اتمسفر یکی از مهم ترین خدمات جوامع گیاهی ترسیب کربن در طولانی مدت در درون خاک می باشد. در مطالعه حاضر هدف بررسی تاثیر قرق بر میزان ترسیب کربن و خصوصیات فیزیکی و شیمیایی خاک در مراتع نیمه استپی استان چهارمحال و بختیاری می باشد. در هر منطقه(قرق و غیر قرق) هفت سایت همگن از لحاظ شرایط محیطی انتخاب و نمونه برداری از پوشش گیاهی و خاک درون آن انجام گردید. نمونه بردای پوشش گیاهی با استقرار ترانسکت و نصب پلاتهای چهار مترمربعی صورت گرفت و برداشت نمونه خاک تا عمق 30 سانتی متری در هر پلات در هر سایت نمونه برداری انجام شد. زیتوده هوایی و لاشبرگ در هر پلات جمع آوری و توزین گردید. نتایج حاصل از تجزیه و تحلیل داده ها نشان داد که میزان زیتوده هوایی، کربن خاک و کل کربن ترسیب شده در اکوسیستم در مراتع نیمه استپ گندمی به ترتیب با 99/1 t/ha، 75/51 t/ha و02/53 t/ha بصورت معنی داری بیشتر از مراتع نیمه استپ بوته زار برآورد گردید. میزان زیتوده هوایی، کربن زیتوده هوایی، درصد پوشش و کربن خاک منطقه نیمه استپ گندمی به ترتیب با 99/1 t/ha، 95/0 t/ha، 91/67% و 8/540 t/ha بیشتر از منطقه نیمه استپ بوته زار می باشد. همچنین نتایج نشان داد میانگین ترسیب کربن کل و خاک در هر دو منطقه مورد مطالعه در تیمار قرق تفاوت آماری معنی داری با تیمار غیرقرق دارد. تفاصيل المقالة -
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14 - Impact of an Agroforestry System on Grazing, Ruminating, and Resting Behaviors of Dairy Cows
آ.آ. اُلیوال اف.ب. آرایوجو ت.آ. دلوالِ جی.آ.سی. اُسوریو م. کامپانا جی.پی.جی دِ مورایسThe present study aimed to evaluate the effects of agroforestry system on the feeding behavior of dairy cows in the Brazilian Amazon region. Nineteen cross breed dairy cows (14.0±3.30 kg/d of milk yield and 450±40.1 kg body weight) were used. The following أکثرThe present study aimed to evaluate the effects of agroforestry system on the feeding behavior of dairy cows in the Brazilian Amazon region. Nineteen cross breed dairy cows (14.0±3.30 kg/d of milk yield and 450±40.1 kg body weight) were used. The following treatments were evaluated: A) animals were maintained in opened pasture of Brachiaria brizantha during all the day; B) animals were kept in forage peanuts (Arachis pintoi) during the morning (between 07:00 and 1200 h) and in muvuca, a type of agroforestry arrangement, afternoon (between 12:00 and 23:00 h); and C) animals were maintained in forage peanuts during the morning (between 07:00 and 11:00 h) and in opened pasture of Brachiaria brizantha during the afternoon (between 12:00 and 23:00 h). Behaviors of grazing, ruminating, and resting was monitored every ten minutes, and the hourly index was analyzed as repeated measures in a 3 × 3 latin square design study. Between 07:00 and 09:00 h, animals maintained in opened pasture showed higher grazing and lower ruminating index than those animals kept in forage peanuts. During the hottest period of the day, animals maintained in opened pasture showed a higher grazing index. Animals of A and C treatments showed a higher grazing index than those of B treatment, between 15:00 and 17:00 h. Animals maintained in muvuca had increased grazing index, resulting in lower ruminating and resting, at the end of the day. As a whole, the agroforestry system stabilizes the grazing and ruminating index and increases the grazing index during the hottest period of the day. تفاصيل المقالة -
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15 - Increased Fecal Ethanol and Methanol Concentration in Dairy Heifers after Grazing
H. Sato T. KurosawaTo clarify fermentative alterations in the large intestine (hindgut) during grazing, fecal alcohol and volatile fatty acids (VFAs) concentrations were evaluated in 30 dairy heifers. The heifers were kept in pasture growing mixed grass herbage from spring (mid May) until أکثرTo clarify fermentative alterations in the large intestine (hindgut) during grazing, fecal alcohol and volatile fatty acids (VFAs) concentrations were evaluated in 30 dairy heifers. The heifers were kept in pasture growing mixed grass herbage from spring (mid May) until October, and their rectal feces were collected periodically. Concentrations of ethanol, methanol and isopropanol were increased in runny feces at early stage of grazing, but gradually decreased thereafter, despite the fact that ethanol remained at a high level until early October. Fecal VFA concentration was barely influenced at early grazing stage; however, it showed marked decrease thereafter. Hindgut exposure of increased nutrients which escaped upper tract digestion might promote active alcoholic fermentation in the colon of the heifers, particularly during early grazing period when runny defecation happens frequently. تفاصيل المقالة -
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16 - Sward Factors Influence on Pasture Dry Matter Intake of Grazing Dairy Cows: A Review
آ.ال. روکا فرناندز آ. گنزالو ردریگوئزSuccessful pasture-based milk production systems pivot on balancing dairy cows’ feed requirements with seasonal and annual fluctuations in pasture production. In order to maximise cow production from grazing dairy systems, it is necessary to reach an efficient uti أکثرSuccessful pasture-based milk production systems pivot on balancing dairy cows’ feed requirements with seasonal and annual fluctuations in pasture production. In order to maximise cow production from grazing dairy systems, it is necessary to reach an efficient utilization of grazed grass for feeding cows and the development of appropriate grazing management systems designed to maximize daily pasture dry matter intake (PDMI) per cow and per hectare, while maintaining high sward quality over the grazing season by keeping high pasture levels of crude protein, water soluble carbohydrates and digestibility of organic matter and low levels of acid and neutral detergent fibers in the swards. To maximize PDMI, cows need to consume plants that have characteristics that allow rapid consumption and lead to fast rates of passage through the rumen. This review considers the role of sward factors which affect the short-term feed budget of cows at pasture and, therefore, condition cow feed requirements at grazing and influence on PDMI. Furthermore, it highlights the relevance that havefor the development of pasture-based milk production systems the study of the species of grasses and / or legumes that integrate the pastures, the changes on sward structure, the seasonality in grass production, the pasture chemical constituents, the sward botanical composition, the grass feeding value, the digestibility of pastures, the intensity of sward defoliation, and the importance of sward height and herbage mass in relation to maximizing PDMI. The amount of herbage consumed is the major determinant of cow production but it is yet one of the most difficult aspects of forage quality to predict. In this review, three methods for PDMI calculation are presented as faecal output/diet digestibility method, sward difference method and the grazing-behaviour method. Also, three equations for PDMI estimation are described considering different sward and animal variables. تفاصيل المقالة -
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17 - The opinion of respondents about the effects of Grazing on Tabar (Ipomaea kordofana) on animal health and milk characteristics in Gezira State, Sudan
Mohamed HashimAbstract The objective of the experiment was the opinion of respondent about effects of Grazing on Tabar plant on animal health and milk characteristic in Gezira State, Sudan. This the questionnaire was conducted in two localities of Gezira state where Tabar plant was أکثرAbstract The objective of the experiment was the opinion of respondent about effects of Grazing on Tabar plant on animal health and milk characteristic in Gezira State, Sudan. This the questionnaire was conducted in two localities of Gezira state where Tabar plant was cultivated. This included, South Gezira locality and Greater Wad Madani Locality. The questionnaire was distributed randomly to 50 animal owners who already have experience with grazing of Bt-CCR, in each of the two localities. Revealed that the results of increase in milk production, the color of milk ,the taste of milk , There is an impact on animal health, Symptoms of feeding on Tabar plant, Quick coagulation of milk , presence of diarrhea and increased frequency of affected animals by Tabar plant grazing was significantly different (p< 0.001) higher in no effect of Grazing on Tabar plant . It is recommended that, further studies are required for recommending of the optimum level of inclusion of Tabar plant in ruminant diets. تفاصيل المقالة -
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18 - بررسی تغییرات زمانی-مکانی نسبت‌زی توده فیتوپلانکتون/ زئوپلانکتون در سواحل ایرانی حوزه جنوبی دریای خزر
حسن نصراله زاده ساروی آسیه مخلوق مژگان روشن طبری فرشته اسلامیفشارهای آنتروپوژنیک و یوترفیکاسیون به ساختار و عملکرد تجمع های پلانکتونی و نیز نسبت زی توده فیتوپلانکتون به زئوپلانکتون (BPhyt/BZp) دراکوسیستم آسیب می رسانند. در این مقاله تغییرات نسبت BPhyt/BZp بعنوان یکی از اثرهای فشارهای آنتروپوژنیک بر شبکه غذایی دریای خزر مورد بررسی أکثرفشارهای آنتروپوژنیک و یوترفیکاسیون به ساختار و عملکرد تجمع های پلانکتونی و نیز نسبت زی توده فیتوپلانکتون به زئوپلانکتون (BPhyt/BZp) دراکوسیستم آسیب می رسانند. در این مقاله تغییرات نسبت BPhyt/BZp بعنوان یکی از اثرهای فشارهای آنتروپوژنیک بر شبکه غذایی دریای خزر مورد بررسی قرار گرفته است. این مطالعه بصورت فصلی بر روی نمونه های بدست آمده در 8 نیم خط در حوزه جنوبی دریای خزر در سال 1388 انجام گرفته است. نتایج نشان داد که نه تنها جمعیت، بلکه ترکیب گونه‌ای نیز اثر زیادی در تغییرات نسبت BPhyt/BZp داشته است. به طوری که در تابستان با افزایش شدید جمعیت گونه های سبک وزن از سیانوباکتریا نسبت BPhyt/BZp (4)کاهش یافت در حالی که در زمستان با افزایش گونه های زنجیره ای از باسیلاریوفیتا نسبت BPhyt/BZp (11)افزایش نشان داد. اما از نظر مکانی در طی سال اگر چه منطقه غربی دارای میزان کمتری از نسبت فوق بود ولی تفاوت چندانی با منطقه شرقی و مرکزی نداشته است. مقایسه نسبت های بدست آمده در سال 1388 با سال های 1374 و 1375 (دوره های ثبات اکوسیستم) به ترتیب بیانگر 3 و 7 برابر افزایش بوده است. نتیجه اینکه، افزایش میزان این شاخص به همراه دیگر شواهد از قبیل افزایش شاخص تنوع گونه‌ای شانون در فیتوپلانکتون و کاهش آن در زئوپلانکتون بیانگر نامناسب بودن فرایند مصرف (چرا) و انتقال انرژی از فیتوپلانکتون به زئوپلانکتون است. تفاصيل المقالة -
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19 - Using SWAT Model to Investigate the Impact of Rangeland Management Practices on Water Conservation (Case Study: Gorganroud Watershed, Golestan, Iran)
Mohadeseh Zadsar Mojgansadat AzimiHydrological response of a watershed is a comprehensive symbol of environmental conditions and characteristics of the basin. Vegetation is one of the main factors in water resources status, erosion, and sediment of a watershed. Rangelands of Golestan province, Iran due أکثرHydrological response of a watershed is a comprehensive symbol of environmental conditions and characteristics of the basin. Vegetation is one of the main factors in water resources status, erosion, and sediment of a watershed. Rangelands of Golestan province, Iran due to the geographical location, climate, and destruction of these resources as well as drastic land use changes from forests, and rangelands to agricultural lands have a high potential of run-off. Therefore, in the present study in order to determine the best management of the rangelands, we developed a rangeland improvement model using the Soil and Water Assessment Tool (SWAT) in the Gorganroud Watershed, Golestan, Iran. Calibration and validation of model were performed using Sequential Uncertainty Fitting Program (SUFI-2) in the eco-hydrological model of SWAT. Simulating the run-off in the studied hydrometric stations, the results showed that this model performed well for the study area (P-factor 0.6-0.9; R-factor 0.85-1.5). As well, four range improvement scenarios (mechanical, biological, biomechanical and livestock grazing management) were defined in this study. On average, by applying mechanical, biological, biomechanical, and grazing management scenarios, runoff was reduced to 13.5%, 11%, 20.7% and 12.5%, respectivelyin comparison with the actual runoff. According to the obtained results, the biomechanical scenario was identified as the best one in reducing the runoff and water conserve in poor and moderate rangelands. تفاصيل المقالة -
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20 - Determining the Preference Value of Perennial Grasses Using Preference Index and Sheep Grazing Time Methods in Grasslands of the Middle Alborz, Iran
Saeed Rashvand Hassan Yeganeh Fazel AmiriPreference value means livestock preference to eat some plants relative to other plants or species. Accordingly, by studying the preference values, the range managers could determine the rangelands grazing capacity to achieve the optimum performance of livestock and to أکثرPreference value means livestock preference to eat some plants relative to other plants or species. Accordingly, by studying the preference values, the range managers could determine the rangelands grazing capacity to achieve the optimum performance of livestock and to guarantee the stability of rangeland ecosystem. The objective of this study was to determine the preference value of perennial grasses using two methods of preference index (species feeding frequency) and sheep grazing time (feeding time recording) in a semi-steppe rangeland in the middle Alborz Mountains of Iran during four consecutive years (2010-2013). The collected data were tested for normality and then, analyzed by the software of SAS9.1. The means comparisons were made using the Duncan method. Results showed that sheep preferred five grass species (Bromus tomentellus, Festuca ovina, Dactylis glomerata, Agropyron intermedium, and Agropyron trichophorum) in the rangeland. There were significant differences between species and years for grazing time method; however, there were no significant differences for preference index. Also, there were significant differences between months within years for both methods. Results showed that A. trichophorum with the average value of 13.8% grazing time was ranked as the first species followed by D. glomerata with the average value of 11.1% as the second one (Grazing time method). There were no significant differences between A. trichophorum, B. tomentellus, D. glomerata and F. ovina regarding the preference index with the average values of 0.57, 0.75, 0.70 and 0.56, respectively. Overall, the results indicated that grazing time percent method in semiarid rangelands gives more realistic results as compared to the preference index method because of the concrete and tangible results. تفاصيل المقالة -
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21 - The Effects of Deferred Grazing System on Vegetation Parameters in Semi-Arid Rangelands (Case Study: Jashlubar, Semnan, Iran)
Mojgansadat Azimi Moslem MozafariRangeland management plan is one of the major means of management and utilization of rangelands in Iran. The formulation of these plans for the rangeland users should be studied from the ecological and socio-economic points of view. One of the main envisaged activities أکثرRangeland management plan is one of the major means of management and utilization of rangelands in Iran. The formulation of these plans for the rangeland users should be studied from the ecological and socio-economic points of view. One of the main envisaged activities in almost all the management plans is the grazing system. An experiment was used to study the effects of three deferred grazing systems (15, 30, 45 days delay) and control treatment (Non- grazed) on vegetation parameters in semi-arid rangelands of Jashlubar in Semnan province. The experiment was conducted using a completely randomized block design (RCBD) with three replications over 6 years (2006-2011). In each experimental unit, data from three life forms of vegetation (shrub, forbs and grasses) were collected along a 30 m transect within ten fixed quadrates (0.5 × 0.6 m2) appropriate to vegetation sizes. In addition, forage productions of two life forms (forbs and grasses) were collected over 5 years. Data were analyzed using SAS software and means comparison was made based on Duncan’s method. The results showed the significant effects of deferred grazing systems on the growth of shrubs in terms of canopy cover. However, there were no significant differences between treatments for canopy cover percent of forbs and grasses. The lowest shrub canopy cover was obtained in 45-day delay of grazing. There were also significant effects of deferred grazing systems (15, 30 and 45 days delay) on forage production of both forbs and grasses (P<0.05). Result of means comparison showed that the best delay time for the rangeland utilization of this area considering the annual precipitation is the 15-day delay with the highest forage production for forbs and grasses and the highest cover percent for shrubs. تفاصيل المقالة -
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22 - Importance of Black Locust (Robinia pseudoacacia) Foliage in the Extension of the Grazing Season and in the Reduction of Damages Caused by Climate Change (a Review)
Andras Halasz Marta Bajnok Agnes Suli Edit Mikone Tamas SchieszlForest grazing of cattle, horse and sheep is allowed under certain strict regulations. Black locust forests have major importance amongst domestic forestry (Central Europe), as their habitat are situated on less productive sand soils. In most cases there are no other op أکثرForest grazing of cattle, horse and sheep is allowed under certain strict regulations. Black locust forests have major importance amongst domestic forestry (Central Europe), as their habitat are situated on less productive sand soils. In most cases there are no other option than setting trees next to the grazing areas. Black Locust (Robinia pseudoacacia) leaves and the herbage of Gramineae amongst the trees provide excellent supplemental feed at the beginning and in the last period of grazing season. It can be well integrated into rotational grazing system, thus grazing season can be prolonged with two months. Digestibility of black locust is significantly lower than alfalfa because of its high lignin content. The protein level however is remarkably high (20%) during spring. Despite its lower feeding value it is still a considerable forage due to its role as rumen filling feed, and also because other valuable plants also available during forest grazing. Black locust trees contain poisonous compounds in the crust. Such compounds are robiine and fazine. Diverse rangelands with clump act major role in healthy grassland ecosystems. Foliage provides basic forage and shade at once. Ground water usage of trees also discussed as they might be competitors of the basic grassland association. تفاصيل المقالة -
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23 - Investigating Vegetation of Mowed and Grazed Areas in Tamdere Village Alpine Pastures in Turkey
Yavuz Karakuş Metin DeveciActivities of transhumance ongoing have been mostly carried out in alpine pastures for centuries in Turkey. These pastures used unconsciously have faced to the danger of extinction. In order to implement improvement plans in the mentioned areas, qualitative and quantita أکثرActivities of transhumance ongoing have been mostly carried out in alpine pastures for centuries in Turkey. These pastures used unconsciously have faced to the danger of extinction. In order to implement improvement plans in the mentioned areas, qualitative and quantitative characteristics of pastures should be determined. This study was conducted in the mowed and grazed pastures in alpine zones in Anatolia, Turkey in 2013 and 2016. In the study, botanical compositions, quality degree, condition and healthy of areas, hay yield, grazing capacity and basal plant coverage of the pastures were investigated. Loop method was used for vegetation measurements concerning the blooming time of commanding plant species. According to the results obtained from the research, 146 taxa were identified involving 8 endemic from 30 families. In the mowed pastures, the average values of botanical composition were found as 31.61% grasses, 18.65% legumes and 49.74% other plant families and in the grazed pastures, the average of composition was estimated as 37.75% grasses, 14.25% legumes and 49.00% other plant families. Botanical compositions of grasses (P≤0.01), legumes (P≤0.05) and other families (P≤0.05) were significantly different among the areas. Although all of the studied pastures were in the healthy quality degree and conditions (P≤0.05) and danger of erosion has not been seen, quality of forage and grazing is not adequate in the study areas. Hay yield was given as 2869 kg ha-1(P≤0.01) in the mowed areas and 1912 kg ha-1 (P≤0.01) in the grazed areas. Grazing capacities in the mowed and grazing pastures were identified as 9.37 (P≤0.01) and 6.87(P≤0.01) animal unit ha-1, respectively and it was detected that the examined pastures were grazed over their capacity. According to situation of vegetation, it can be said that climax vegetation of pastures was perished and the management measures should be planned for grazing capacity. Pasture breeding studies should be paid attention. In addition, weed control, top seeding and fertilizing should be conducted. تفاصيل المقالة -
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24 - Determining Timely Entry and Exit of Livestock in Rangelands Using Bromus tomentellus Phenological Stages (Case Study: Goorab Rangeland of Isfahan)
Maryam Gholami Mostafa SaeedfarIn the rangelands of Iran, the lack of appropriate grazing management is one of the major problems ultimately leading to untimely and excessive grazing intensity of forage. Accordingly, most of the rangelands show a retrogression trend and poor conditions. In forage spe أکثرIn the rangelands of Iran, the lack of appropriate grazing management is one of the major problems ultimately leading to untimely and excessive grazing intensity of forage. Accordingly, most of the rangelands show a retrogression trend and poor conditions. In forage species, phenological stage is one of the most important criteria for range management. Bromus tomentellus species is an important range species for forage production controlling soil erosion. In order todeterminethetimely entry and exit of livestock in rangelands based on phenological stages of B. tomentellus, this study was conducted in Goorab rangeland, Fereydoun Shahr, Iran during four years (2007-2010). In this research, ten plant bases of B. tomentellus were selected and their phonological stages were recorded in a 7-day interval period. At the same time, meteorological data were collected from meteorological station adjacent to the study site. According to the occurrence of biological phenomena in the different years of study (wet conditions in 2007, severe droughts in 2008 and normal years in 2009 and 2010) and also based on plant growth stage in the 4 year study, it was concluded that 30th April and 31th May were suggested as the best time for livestock to enter and exit from the rangeland, respectively. تفاصيل المقالة -
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25 - Overgrazing is a Critical Factor Affecting Plant Diversity in Nowa-Mountain Rangeland, West of Iran
Saeed Mahmoudi Mahmud Khoramivafa Moslem Hadidi Nastaran Jalilian AliReza BagheriIn western Iran, mountainous rangelands provide significant resources for livestock productions. Many ecosystems that are of high environmental and economic value are threatened by climate change and social economic pressures. This is especially important for semi-arid أکثرIn western Iran, mountainous rangelands provide significant resources for livestock productions. Many ecosystems that are of high environmental and economic value are threatened by climate change and social economic pressures. This is especially important for semi-arid rangelands, which have a multifunctional system. Quantifying the direct and indirect effects of grazing disturbance on plant biodiversity in the semi-arid mountainous rangelands can provide sight into the appropriate measures to restore degraded rangelands and conserve biodiversity. Here, the effects of different levels of grazing intensity (Light Grazing (LG), Moderate Grazing (MG), and Heavy Grazing (HG)) on plant biodiversity were examined in Nava-mountain rangeland in Kermanshah Province, Western Iran, in 2016. The results showed that increasing grazing intensity led to a decrease in species richness, Margalef's richness index, and Shannon-Wiener index (p <0.05). Stepwise regression analysis was used to investigate the effect of grazing intensity as (independent variables) on species diversity and richness as (dependent variable). The estimates parameter were significant (p <0.01) for species richness, Margalef's richness and Shannon-Wiener indices in the different levels of grazing intensity. In overall, grazing intensity explained 47%, 47% and 50% of the variation for species richness, Margalef's richness, and Shannon-Wiener indices, respectively. In addition, species richness and diversity were affected in response to grazing disturbance intensity and reducing grazing pressure can contribute to maintaining relatively high species diversity in Nowa-mountain rangeland. تفاصيل المقالة -
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26 - Variation of Plant Functional Groups along Livestock Grazing Gradient in Semi-steppe Rangelands (Case Study: Tangsayad Rangelands of Chaharmahal Bakhtiari Province, Iran)
Elham Bani Hashemi Pejman Tahmasebi Kohyani Esmaeel AsadiAssessment and monitoring of rangeland in different grazing managements seems necessary to manage rangelands. The plant functional groups can be used as appropriate responders for rangelands condition and management. Therefore, this study was performedand aimed to deter أکثرAssessment and monitoring of rangeland in different grazing managements seems necessary to manage rangelands. The plant functional groups can be used as appropriate responders for rangelands condition and management. Therefore, this study was performedand aimed to determine the most important traits that are influenced by rangeland variation and management. In order to this, three areas along a grazing gradient including national parks, protected area and free grazing were selected inTangsayad rangelands of Chaharmahal Bakhtiari Province, Iran in 2015. A 100 m transect was established randomly in each site and within it five plots of 4 m2 area at 20 m intervals along transects were determined systematically. Plant species were identified and vegetation cover was recorded in each plot. The number and size of plots and transects were determined regarding to semi-arid rangeland sampling guidelines as well as the dimension of dominant plant species in plant community. Finally, some traits as leaf dimension, plant biomass and cover of species were measured. The results showed that the traits such as leaf length, leaf width, leaf area and leaf weight, grass growth forms and life forms of Hemicryptophyes and Geophytes had significant differences at least in one of three grazing managements sites (P<0/05). Also Principal Component Analyses (PCA) showed that traits as yield, overall weight of plants and perennial plants had high correlation with the first component and the traits such as leaf length, leaf width, leaf area, Hemicryptophyes had also high correlation with the second component. In general conclusion; leaf traits as leaf length, leaf width, leaf area and leaf weight, grass growth form, Hemicryptophytes and Geophytes life forms were introduced as good indicators for assessing and monitoring of grazing management. تفاصيل المقالة -
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27 - Soil Organic Carbon Content and Stocks in Relation to Grazing Management in Semi-Arid Grasslands of Kenya
Hillary Rotich Richard Onwonga Judith Mbau Oscar KoechRangelands cover approximately 85% of Kenya’s land mass and is a major resource for livestock farming with a considerable potential to mitigate climate change, yet these lands are stressed differently by various management. Our study aimed at determining the influ أکثرRangelands cover approximately 85% of Kenya’s land mass and is a major resource for livestock farming with a considerable potential to mitigate climate change, yet these lands are stressed differently by various management. Our study aimed at determining the influence of grazing management systems (rotational, continuous and ungrazed) on soil organic carbon stocks in Yoani ranch located in the southern rangelands of Kenya (2016). This research was conducted on a commercial grazing ranch, a section of it was converted from continuous grazing into rotational grazing and has been under rotational grazing for 11 years during the time the research was conducted. Within the same ranch, there was a section with similar geomorphology and soils as the rotationally grazed which was not converted and has been continuously grazed for over 30 years to represent the continuous grazing system. The ungrazed area consists of an abandon section of the ranch for more than 30 years due to a deep gully which was formed by gully erosion creating an isolated area inaccessible by livestock. Soil samples were taken up to a depth of 1.2m, at an interval of 0-10, 10-20 cm, 20-30 cm, 30-60 cm, 60-90 cm and 90-120 cm. The difference between soil sampling depths is because the upper layer between 0-30 cm is more dynamic with respect to soil microbial activities which can be influenced by grazing as compared to the deeper depths along the soil profile. The ungrazed site recorded significantly (P<0.5) higher soil organic carbon concentrations than rotational and continuously grazed sites for all soil layers up to 1.2m depth. The rotationally grazed site had higher soil organic carbon concentrations across depths compared to continuously grazing system which was attributed to grazing management effects. تفاصيل المقالة -
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28 - Vegetation Dynamics in Relation to Grazing Management Practices in Semi-arid Grazing Lands of Makueni County, Kenya
Hillary Kipngetich Rotich Judith Symbua Mbau Richard Onwonga Oscar Kipchirchir KoechLivestock grazing practices in rangelands are being recognized as management tool for environmental protection and increased livestock productivity. Continuous grazing has been largely reported to reduce pasture productivity and increase environmental degradation. Rotat أکثرLivestock grazing practices in rangelands are being recognized as management tool for environmental protection and increased livestock productivity. Continuous grazing has been largely reported to reduce pasture productivity and increase environmental degradation. Rotational grazing is an alternative to continuous grazing and is considered to reduce negative environmental effects and provide quality pastures and browse ensuring availability of quality feed for animals while conserving the environment. This study was conducted in a semi-arid grassland in the south eastern rangelands of Kenya which is primarily used for cattle production to establish how grazing management system affects herbaceous biomass yield, cover, plant species richness and diversity (in 2016). Quadrat method was used to collect vegetation samples. In each plot, a 100 m2 sub- plot was demarcated and five 1×1m quadrats laid out. A quadrat was placed at each of the four corners of the 100m2 plot and the 5th quadrant placed at the center of the plot. Herbaceous biomass production was significantly higher (p≤0.05) in rotationally grazed areas compared to both continually grazed and ungrazed areas with average values of 7037, 2478 and 2390 Kgha-1 respectively. Similar trend was obtained for vegetation cover. Vegetation cover of herbaceous plants was significantly higher under rotationally grazed areas compared to both continually grazed and ungrazed areas with average values of 55, 37 and 27%, respectively. There was no significant difference for plant species richness and diversities and between the three sampling blocks. However, the highest values of both latter traits were obtained in rotationally grazed areas, followed by continually and ungrazed areas. Improved biomass yields and high species diversity in rotation grazed areas was largely attributed to the flexibility in the management in which grazing frequency, durations and the rest periods are efficiently controlled compared to continuous grazing areas. This study concludes that rotation grazing allows flexibility of animal utilization of pastures resulting to enhanced soil water retention, increased species diversity; richness and vegetation cover which increase biomass yields. تفاصيل المقالة -
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29 - Projected Changes in Soil Organic Carbon Stocks over a 50-Year Period under Different Grazing Management Systems in Semi-Arid Grasslands of Kenya
Hillary Rotich Richard Onwonga Oscar Koech Judith MbauRangeland cover approximately 85% of Kenya’s land mass and is a major resource for livestock farming with a considerable potential to mitigate climate change, yet these lands are stressed differently by various management. Our study aimed at predicting the long-te أکثرRangeland cover approximately 85% of Kenya’s land mass and is a major resource for livestock farming with a considerable potential to mitigate climate change, yet these lands are stressed differently by various management. Our study aimed at predicting the long-term changes in Soil Organic Carbon (SOC) in grazing lands of Kenya under different grazing management systems (rotational, continuous and ungrazed), for a 50-year period using RothC 26.3. This research was conducted on a commercial grazing ranch which practices the two grazing management systems. Soil samples were collected at the depths of 0-10, 10-20 and 20-30 cm for the determination of soil organic carbon concentrations and bulk densities, results were later used for running the RothC model. The predicted results showed that the rate of SOC stock [t/ha] was higher under rotational grazing system in comparison to ungrazed and continual grazing system for the modelling period of 2015-2064. In the absence of grazing, the system was predicted to accumulate 19.22 Mg C ha-1 of SOC at the rate of 0.369 Mg C ha-1yr-1, whereas rotational grazing system was predicted to accumulate 30.46 Mg C ha-1 at the rate of 0.61 Mg C ha-1yr-1. The continual grazing management system resulted in the accrual of 18.49 Mg C ha-1 at the rate of 0.37 Mg C ha-1 yr-1 over 50 years. Thus, rotationally grazing management system have the potential of accumulating soil organic carbon in semi-arid grasslands. تفاصيل المقالة -
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30 - Resting Impact on Vegetation Cover of Fescue-Forbs Rangeland in Mongolia
Otgontuya Lkhagvajav Lkhagvajav Namdag Munkhbat ChimedThe rangeland in the Khangai mountain region in Mongolia has degraded for the last decades mainly because of overgrazing and climate change. Livestock production is important part of the economy and is based on natural rangeland. In this research we seek to elucidate th أکثرThe rangeland in the Khangai mountain region in Mongolia has degraded for the last decades mainly because of overgrazing and climate change. Livestock production is important part of the economy and is based on natural rangeland. In this research we seek to elucidate the influence of five years (2004-2009) of protection from grazing on vegetation cover of different degradation levels of Fescue-forbs rangelands in Khangai mountain region of Mongolia. In the beginning of the study grasses dominated within the slightly degraded site, especially Agropyron cristatum and Koeleria macrantha. Forbs dominated within the moderately degraded site, mainly Artemisia frigida and A. commutata and within the heavily degraded site sedge species dominated, mainly Carex duriuscula. The climate was fluctuated during the study period that affected the plant growth and vegetation cover. When looked at variation of total vegetation cover among years within un-grazed and grazed sites there had been fluctuation among years. The total vegetation cover was significantly different (P<0.001) among years at all degradation levels. The total vegetation cover was 18-22% higher in un-grazed site of slightly degraded site, 8-10% in un-grazed site of moderately degraded, 39-58% in un-grazed site of heavily degraded site in 2005 to 2006. The total vegetation cover was higher (P<0.05) at un-grazed sites than grazed fir many years. The vegetation cover was lower at all sites in 2007 through 2009. It was depending on drought and accumulation of litter cover. Grasses and forbs had improved in un-grazed site of slightly and heavily degraded sites. تفاصيل المقالة -
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31 - Forage Loss Valuation under Traditional Pastoralism in Arid to Semiarid Rangelands of Iran
Azam Khosravi Mashizi Mohsen SharafatmandradEconomic valuation of rangelands is one of the best methods for conservation goals. A study was conducted to assess the economic value of forage loss under the two main forms of traditional pastoralism i.e. sedentary pastoralism and nomadism in historic grazing semiarid أکثرEconomic valuation of rangelands is one of the best methods for conservation goals. A study was conducted to assess the economic value of forage loss under the two main forms of traditional pastoralism i.e. sedentary pastoralism and nomadism in historic grazing semiarid rangelands in Khabr National Park, Kerman province, Iran in 2019. Forage production was measured by clip-and-weigh method and forage quality was assessed using Crude Protein (CP) and Acid Detergent Fibre (ADF) indices. The replacement cost method was used for forage valuation and Total Digestible Nutrients (TDN) was used as the principal character of forage value. Forage production was decreased by 65% and 78% under nomadism and sedentary pastoralism respectively as compared to exclosure. Assessing species distribution along grazing gradient, using Detrended Correspondence Analysis (DCA), showed that forage quality decreased as grazing intensity increased due to plant composition change. Lathyrus annuus and annual grasses were the highest and lowest value forage, respectively. The forage values for exclosure area, near exclosure area and near village and pastoral tent were 75 $, 20-25 $ and 6-10 $.ha-1.year-1, respectively, indicating 65 to 92% reduction in the forage value in traditional pastoralism forms than to exclosure area. Therefore, there was priority to perform appropriate grazing systems such as rest rotational grazing to improve the condition of historic grazing lands and pastoral’s income. تفاصيل المقالة -
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32 - Livestock Production at the Nexus of Resources Competition and Ethnoreligious Cynicism in Nigeria–Implicative Analysis on Food Security
Akeem SikiruNigeria is one of the most malnourished and hunger ridden in the league of developing countries; according to reports of Food and Agricultural Organization (FAO) of United Nations estimated daily animal protein intake for developing countries averaged at 4.5 g/head/day أکثرNigeria is one of the most malnourished and hunger ridden in the league of developing countries; according to reports of Food and Agricultural Organization (FAO) of United Nations estimated daily animal protein intake for developing countries averaged at 4.5 g/head/day at the beginning of this century which has hardly risen to 10 g/head/day into the second decade of the century in Nigeria. This calls for an increase in the supply of animal protein to address the poor intake, but Nigeria’s animal protein supply depends on pastoral livestock production on extensive natural grassland. This production system is under challenges of climate and poor production techniques; hence government effort towards improvement via the establishment of grazing reserves is a way out. Therefore, this paper discusses Nigerian livestock production, climate change effects on Nigeria livestock production and its social implications, including food insecurity. We also consider sources of ethnoreligious violence linked to livestock production in Nigeria, grazing reserve bills (proposed legislation) in Nigeria the proponents, the opponents and what are the pitfalls the rationale for modification and re-introduction of grazing reserves bill in Nigeria and the potential of some models such as the Taylor Grazing Reserve Act of the United States of America. تفاصيل المقالة -
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33 - Economic Value of Morocco Oued Beht Watershed Rangeland Habitats in terms of Forage Production
Ismaili Hassana Elasri Bouchra Ghazi Souad Ziri Rabea Brhadda NajibaRangelands represent a potential resource with a high socio-economic value. This value remains unmonetarized and therefore, not taken into account in public policies, which does not reflect the real value of this Ecosystem Services (ES) and negatively affects the sustai أکثرRangelands represent a potential resource with a high socio-economic value. This value remains unmonetarized and therefore, not taken into account in public policies, which does not reflect the real value of this Ecosystem Services (ES) and negatively affects the sustainable management of rangelands. This study was carried out in 2019; it aims to estimate the economic value of the supply service of the rangelands and to demonstrate its place in the local economy. The result reflects the socio-economic importance of this service, offering an average of 22.65 million forage units (FU/year= 1 kg barely grain), with the gross economic value of 6.79 million USD/year. The study also illustrates the degree of pressure on these pastoral ecosystems, represented by high overgrazing rates and negative net economic value. The comparison between the supply and demand of forage units shows an average cost of degradation of 760 USD /ha in forests and 209 USD/ha out of forests, which negatively affects the sustainable management of these resources. To this end, the strategies adopted must respond to all environmental and socio-economic challenges, based on the preservation of the fragile environment to benefit the socio-economic development of local populations. These strategies must give users a sense of responsibility in the process of setting up, monitoring, and eventually adapting the management systems practiced. تفاصيل المقالة -
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34 - Effects of Intermediate-Term Grazing Rest on the Vegetation Characteristics of Steppe Rangelands
Naser Baghestani Mohammadtaghi Zare Ehsan Zandi Sedighe ZarekiaThe effects of grazing rest on rangelands are different in different climates and knowledge of these effects is necessary to apply correct management. For this purpose, this study was carried out on the percent vegetation cover (PVC) and forage production (FP) of range أکثرThe effects of grazing rest on rangelands are different in different climates and knowledge of these effects is necessary to apply correct management. For this purpose, this study was carried out on the percent vegetation cover (PVC) and forage production (FP) of range species at the Nir Range Research Station in Yazd province as a model of steppe rangelands of Iran. In the study area, different grazing intensities were applied until the end of the grazing season of 2006 and from then on, the whole area was under exclusion. PVC and FP were measured in each of the experimental plots once in May 2007 and again seven years later in May 2014. The results of vegetation data analysis in 2007 showed that the heavy grazing intensity applied in the past caused the reduced PVC and FP of two desirable species i.e. Salsola rigida and Stipa barbata as well as increased PVC and FP of Launaea acanthodes and increased forage production of Scariola orientalis as undesirable species. The results of vegetation data analysis in 2014 showed that the lowest PVC and FP of S.rigida was recorded in the experimental plots under heavy grazing intensity. In other experimental plots, there was no significant difference in PVC and FP of this species (p>0.05). There was no significant difference between PVC and FP of other species and total species in different experimental plots (p>0.05). Thus, during the 7-year rest period, although the negative effect of grazing on S.barbata is resolved, it remains on S.rigida and the resulting degradation is not completely compensated during this period and needs more time. Therefore, S.barbata showed better resistance to grazing as compared with S.rigida. According to the results, if steppe rangelands are grazed heavily in the short-term, intermediate-term grazing rest could improve the vegetation to the previous state. تفاصيل المقالة -
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35 - Determination and Comparison of Preference Value for Five Halophyte Species in the Marginal Rangeland of Salt Lake in Aran and Bidgol Region, Kshan, Iran
Reza Dehghani BidgoliSince the halophytes species have an important role in such ecosystem balance and they have been grazed by livestock as supplementary forage, the awareness of livestock's desire to grazing and their preference values of these species is of high priority. Regardless of t أکثرSince the halophytes species have an important role in such ecosystem balance and they have been grazed by livestock as supplementary forage, the awareness of livestock's desire to grazing and their preference values of these species is of high priority. Regardless of the importance of halophyte species in the livestock feeding in Iran, there is less published research on the livestock grazing from these species. In present study, the preference value of the five halophyte species (Seidlitzia rosmarinus, Salsola crassa, Aeluropus littoralis, Suada fruticosa and Anabasis setifera) was determined using preference index and timing methods in the marginal rangelands of Aran and Bidgol salt lake, Kashan, Iran in 2013-2016 during the grazing season. The preference values of these halophytes spices were assessed using Whittaker and Niering method. In the timing method, the animal grazing for 20 minutes was filmed for 1 to 2 hours after the flock arrival to the rangeland, and the grazing time of each species was recorded. According to the results of the analysis of variance, the species effect was significant for both grazing time and preference index (p<0.01). The results of the mean comparison showed that the Aeluropus littoralis with average values of 0.636 and 10.1 had a higher preference index and grazing time by livestock than that for other halophyte species, respectively. Also, in terms of livestock behavior for both factors, the highest grazing time was observed in October followed by November. The results of the species by grazing season interaction effect showed that the Salsola crassa and Aeluropus littoralis had higher preference indices for grazing whereas Seidlitzia rosmarinus and Aeluropus littoralis had longer times of grazing. According to the results of this research, the timing method was introduced as an appropriate method to determine the preference values of halophyte species in the studied area. تفاصيل المقالة -
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36 - The Response of Topsoil Properties and Nitrogen Transformation to Land Cover in a Semi-arid Rangeland (Case Study: Kojur Rangeland in Mazandaran Province, Iran)
Nastaran Armat Ghasem Ali Dianati Tilaki Yahya KoochThe role of different plant covers (i.e. Artemisia aucheri Boiss, Cousinia commutate Bunge and Agropyron longiaristatum Boiss) in topsoil properties and Nitrogen transformation is less known under semi-arid mountains. The main objective of this research was to study the أکثرThe role of different plant covers (i.e. Artemisia aucheri Boiss, Cousinia commutate Bunge and Agropyron longiaristatum Boiss) in topsoil properties and Nitrogen transformation is less known under semi-arid mountains. The main objective of this research was to study the effect of land covers on topsoil properties and nitrogen transformation. The study was carried out for investigating the soil properties of Grazing Exclusion (GE), Grazed Rangeland (GR) and Rainfed Agriculture (RA) in Kojur, Mazandaran province, Iran. Thirty-six 1m2 plots were set at three treatments to sample the dominant plant species. Soil samples were then taken from the central part of each plot sample in an area of 20×20 cm and depth of 20 cm. Our findings demonstrated that the carbon (C) content of plant materials did not differ for studied land covers whereas GR and RA had higher N content (1.48 and 1.41%, respectively) and lower C/N ratio (13.33 and 14.45%, respectively). In the GE, N concentration of soil (with 0.34%) was 1.5 times more than that in GR and RA (0.20 and 0.21%, respectively). Soil nitrification and N mineralization rates were significantly higher in the GE (0.33 and 0.28 mg kg−1d−1 respectively) as compared to the RA (0.15 and 0.08 mg kg−1d−1 respectively) and GR (0.01 and 0.04 mg kg−1d−1 respectively). There were no significant differences among land covers for bulk density, available K, microbial respiration, and ammonification rates. According to the results, grazing exclusion with presence of grass species increases the organic C contents, total N, and eventually, N mineralization which totally leads to improved soil quality in these regions. تفاصيل المقالة -
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37 - Effect of Environmental Traits and Grazing Intensities on Plant Community Distribution (Case Study: Saral Rangelands, Iran)
Bahram Gholinejad Hamed Jonaidi JafariUnderstanding ecological processes is a prerequisite for the management of rangelands; therefore, recognition of the relationship between environmental factors and vegetation is very important. The present research aims to investigate environmental and management factor أکثرUnderstanding ecological processes is a prerequisite for the management of rangelands; therefore, recognition of the relationship between environmental factors and vegetation is very important. The present research aims to investigate environmental and management factors affecting rangeland vegetation distribution in Saral rangelands of Kurdistan province, Iran, in 2017. Sampling was done in eight vegetation types along four 300 m transects. Fifteen 1m2 plots established along each transect in 20 m distances. Ten soil samples along transects were taken according to the plants root depth in the average depth 0-50 cm in 10 profiles within each vegetation type. Various environmental factors such as topographic factors (slope, aspect, and elevation), soil physical properties (depths, soil texture, gravel, and saturation moisture) and various chemical factors such as acidity, electrical conductivity, lime, gypsum, nitrogen, phosphor, and potassium were measured and grazing intensity considered and measured as managerial factor. The collected data were subjected to Principal Component Analysis (PCA) and the important factors affecting plant community distribution were determined. According to the results, first and second components account for 39.29% and 26.28% of community distribution, respectively. The results showed that among various environmental and grazing factors affecting plant distribution, soil texture, soil depth, grazing intensity, elevation, potassium and gravel had the most significant effects on present plant community distribution in studied rangeland. Silt, gravel and grazing intensity play important roles in the spatial distribution of vegetation communities, respectively. تفاصيل المقالة -
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38 - Effectiveness of Range Management Plans in Middle Zagros Region from Viewpoint of Rangeland Experts
Mehrdad Baharvandi Nourollah Abdi Abbas Ahmadi Hamid Toranjzar Saeed GholamrezaiAssessment of Range Management Plans (RMP) enables policy makers and governmental planners to understand their impact from different environmental, social, human, and economic aspects in order to improve future planning. The purpose of the present study was to explore t أکثرAssessment of Range Management Plans (RMP) enables policy makers and governmental planners to understand their impact from different environmental, social, human, and economic aspects in order to improve future planning. The purpose of the present study was to explore the effective variables on RMP in Middle Zagros Mountain in Lorestan, Ilam, Kurdistan, and Kermanshah provinces, Iran in 2018. Data were collected using a structured interview technique and questionnaires (N=140) prepared in 6 sections and filled by rangeland experts of local offices of natural resources in four provinces. Seven factors were asked about weaknesses of range plans and 6 factors were asked for strengths of the plans. Result of the logistic unit (Logit regression) showed that the variables of lack of government credits (p≤0.01) and lack of continuous monitoring on the proper implementation of the project (p≤ 0.10) were negative while the variables of users’ participation in the implementation of RMP (p≤ 0.01) and specifying customary system for herders (p≤ 0.01), controlling herders’ grazing license (p≤ 0.10), the rate of acceptance of the rural municipality, Implementation of modifying and rehabilitation operations, establishing livestock and rangeland balance (p≤ 0.05), Intersection cooperation between the involved institutions and departments (p≤0.01) and rural council the range management projects (p≤ 0.05) were positively significant from the perspective of the experts. Also, 47% of experts were against renting rangeland to nomadic and non-rural nomad herders. They also suggested the implementation of RMP could be done in the divided rangelands rather than common form. In sum, the available projects and plans in the region under study area were not efficient due to technical, social, and economic problems. Hence, they need to be reviewed in this regard. It should be attempted to take into consideration the technical, social, and economic issues more seriously while preparing new projects. تفاصيل المقالة -
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39 - Determination of Allowable Use and Grazing Tolerance of <i>Picris strigosa</i> (Case Study: Blooman rangelands, Lorestan Province, Iran)
Reza Siahmansour Ataollah Ebrahimi Reza Chamanpira Ehsan Zandiesfahan Parvin RamakPicris strigosa is a valuable forage species in mountainous rangelands of Lorestan province, Iran, which produces suitable forage for sheep grazing. The aim of this study was to determine the allowable use and grazing tolerance of this species. For this purpose, 50 indi أکثرPicris strigosa is a valuable forage species in mountainous rangelands of Lorestan province, Iran, which produces suitable forage for sheep grazing. The aim of this study was to determine the allowable use and grazing tolerance of this species. For this purpose, 50 individuals of P. strigosa were selected in its typical habitat and marked for monitoring after applying four levels of harvesting intensities including control (0%), 25, 50, and 75% of the annual production during 2007–2011. Treatments were investigated by clipping and weighing method every month from May to July in vegetation period. The results showed a significant difference in terms of forage production between treatments (P≤0.01). The highest and lowest forage production with average values of 42.45g and 15.23 g per plant were obtained in 0% harvesting rate (control) and 75% intensity rate, respectively. In other words, harvesting higher than 50% coupled with early grazing (April and May, in accordance with the local pattern and research method of this article) weakens the individuals. Continuation of this process also increases the mortality of the individuals (death of 30% of the stands at a harvest intensity rate of 75%). Due to the sensitivity of the species to early grazing, it was recommended that for such a dominant species, livestock should enter the pasture in early June. Maximum forage production in control and the fast reduction in forage production of 75% treatment emphasize that overgrazing of this species would completely eliminate it from the field. It was concluded that P. strigosa is sensitive to grazing and its sensitivity should be considered in rangeland management plans. تفاصيل المقالة -
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40 - Ecology, Ethnobotany, and Conservation Status of Browse Vegetation from Cholistan Rangelands of Pakistan
Muhammad Abdullah Muhammad Rafay Muhammad Farooq Azhar Malik Muhammad YousafThe browse vegetation of the Cholistan rangelands is diminishing with the passage of time due to climatic extremities, overgrazing, and human exploitation. Therefore, this study was planned to collect the baseline data about ecology, ethnobotany, and conservation status أکثرThe browse vegetation of the Cholistan rangelands is diminishing with the passage of time due to climatic extremities, overgrazing, and human exploitation. Therefore, this study was planned to collect the baseline data about ecology, ethnobotany, and conservation status of browses. A semi-structured questionnaire was designed to record information of plant species from nomadic peoples (85 males, 05 female) and by ecological observations during field visits. In this study, a total of 25 browse species belonging to 17 genera and 12 families were documented, however family status showed that Chenopodiaceae and Mimosaceae were most dominant families. In these rangelands three-soil microhabitats sandunal, interdunal and clayey saline were noted, and each have different species structure and composition. According to life span and life form, all identified species were found as perennials and phanerophytes, respectively. Leaf spectra of Raunkiaerian approach revealed that leptopylls dominated study area, which is an indicator of arid conditions. Phenological observations revealed two flowering seasons, first season was from February to April and second was from September to November, both were associated to winter and monsoon rains, respectively. Further ethnobotanical observations have divided species into four categories based on their uses i.e. firewood, timber wood, forage and medicinal. The peoples of this area depend on local plants and different parts of plants (bark, leaves, shoots, roots) were used for different treatments. Out of total species, 24 species were observed to have forage value that shows potential of this area as rangeland whereas based on grazing response, maximum number of species (40%) were noted as decreasers. According to conservation status, most of browse species have become threatened followed by endangered, vulnerable, least concerned, and critically endangered, respectively. Results showed current status and potential of browses to apply quick conservation measures with suggestion of further floral investigation in Cholistan rangelands. تفاصيل المقالة -
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41 - Effects of Grazing Management on Greenhouse Gas Emissions in Southern Rangelands of Kenya
Hillary Rotich Oscar Koech Richard Onwonga Judith MbauRangelands ecosystems play a critical role in regulating the emission and uptake of the most important Greenhouse Gases (GHGs) such as CO2, CH4, and N2O. However, the effects of grazing management on GHG fluxes in the semi-arid lands of East Africa remain unclear. The p أکثرRangelands ecosystems play a critical role in regulating the emission and uptake of the most important Greenhouse Gases (GHGs) such as CO2, CH4, and N2O. However, the effects of grazing management on GHG fluxes in the semi-arid lands of East Africa remain unclear. The present study compared the effects of three grazing systems on cumulative CO2, CH4, and N2O fluxes in the semi-arid grazing land ecosystem in Yohani ranch Makueni County, Kenya. The study followed a pseudo-replication design in which there were three treatments: 1) Continual grazed, 2) rotational grazed and 3) and ungrazed. Greenhouse gas samples were collected using the static chamber method for a period of three months covering the dry and wet season as well as a transition period. Cumulative soil CO2 fluxes were highest in continual grazing system (2357±123.9 kg ha-1 3 months), followed by rotational grazing (1285±123.9 kg ha-1 3 months) and lowest in the ungrazed (1241±143 CO2 kg ha-1 3 months), respectively. The three month cumulative N2O and CH4 fluxes were also highest in continual grazing and lowest in ungrazed site 677.9±130.1, 208.6±127.3 and 162.2±150.3 (g ha-1 3 months) and CH4, 232.7±126.6, 173.1±126.6 and 80±46.2 (g ha-1 3 months) respectively. The results suggest that the continual livestock grazing system increases emissions of GHGs compared to rotational grazing. تفاصيل المقالة -
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42 - Nomads’ Perceptions on Nomadic Rangeland Management in Two Provinces of Iran (An Application of Grounded Theory)
Ali Mohebbi Rosemary Black Zahra Farzizadeh Mahdi Ramezani Rostam KhalifehzadehIn Iran, rangeland management is based on grazing licenses that were introduced in 1963. Following the nationalization of the country's forests and rangelands, the Iranian Government began approving grazing licenses to eligible users. However, evidence suggests that thi أکثرIn Iran, rangeland management is based on grazing licenses that were introduced in 1963. Following the nationalization of the country's forests and rangelands, the Iranian Government began approving grazing licenses to eligible users. However, evidence suggests that this strategy was not effective in utilization and improvement of the rangelands. This study aimed to answer the question, from the nomads’ perceptions, whether the grazing licenses in the optimal rangelands management have been effective or not? The study location was the territory of the Bakhtiari pastoral nomads, who were engaged in animal husbandry in Chaharmahal & Bakhtiari and Khuzestan provinces, Iran. Data were collected using the grounded theory technique and semi-structured interview. The sampling method was purposeful and theoretical and data collection continued until theoretical saturation was reached. Content analysis was used to identify categories. Data were analyzed using open, axial and selective coding. Findings showed that six key categorizes emerged from the data: i) Grazing management is necessary to improve rangeland condition ii) the need for strict implementation of the license rules, iii) The number of livestock on the grazing license must be sustainable, iv) The problem of presence of urban dwellers with livestock grazing licenses and some real herders without grazing licenses, v) Nomads should protect natural resources, and the Government should support them, vi) the current system of livestock grazing licenses is not sustainable in balancing between livestock number and rangeland production. The central category was, "Inefficiency of animal grazing license in creating balances between livestock and pasture"; as a result, the creation of jobs for surplus herders in outside of pastures was introduced as an important strategy to solve the problem. The findings suggest a new management regime needed to achieve a balance between grazing and rangeland management. تفاصيل المقالة -
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43 - Impact of Deferment on Grassland Condition and Diet Quality of Cattle under a Short-Duration Grazing System
Raul Tacuna Enrique Flores Roberto DistelRest and deferred rotation grazing treatments have proven to be effective tools that improve range condition, but little is known about their effect on range animal’s diets. The purpose of the present research was to evaluate the impact of deferment in a short-dur أکثرRest and deferred rotation grazing treatments have proven to be effective tools that improve range condition, but little is known about their effect on range animal’s diets. The purpose of the present research was to evaluate the impact of deferment in a short-duration grazing on vegetation and diet quality of heifer in a context of a Puna grassland ecosystem. The study was conducted under a completely randomized factorial design, where treatments resulted from the combination of two grazing systems (shorth duration grazing with and without deferment) evaluated over three years. Forage yield (4.9 vs. 4.5 Tm DM/ha/year) and range condition (55.5 vs. 50.7 %) improved with deferment. Conversely, diet quality was negatively affected (P<0.05) as result of deferment as evidenced by a lower in vitro digestibility of dry matter (40.6 vs. 45.5 %), a higher neutral detergent fiber content (79.0 vs. 74.6 %) and also a lower crude protein content (10.0 vs. 11.4%). The results revealed that deferred grazing improves range condition and forage yield of Puna grasslands when managed under a shorth duration grazing scheme; however, at the cost of reducing the quality of the diet selected by heifers. When combined with short-duration grazing, deferment improved range condition and increased forage yield at the expense of diet quality, although, with no failure to meet the minimum recommended protein level for bacteria ruminal function. تفاصيل المقالة -
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44 - Determination of Rangeland Grazing Suitability Model by GIS (Case Study: Sarab Sefid Basin, Lorestan, Iran)
Ali AriapourLivestock grazing in unsuitable land has increasingly grown in most part of rangelands of Iran due to population growth. It causes many irreparable damages such as soil erosion, water loss, and wealth loss. Therefore, it is important to identify the best suitable land f أکثرLivestock grazing in unsuitable land has increasingly grown in most part of rangelands of Iran due to population growth. It causes many irreparable damages such as soil erosion, water loss, and wealth loss. Therefore, it is important to identify the best suitable land for livestock grazing. Land suitability for livestock grazing affects by many ecosystem components but due to time and funding restrictions, the most important and feasible elements were investigated. This paper adapted the schematic model based on the concepts presented by the FAO suitability analysis for livestock grazing in Sarab Sefid Borujerd rangeland of Iran. Significant needed factors to livestock grazing such as forage; soil and water which were in sub-models were determined and incorporated into the final model of rangeland grazing suitability. Some important maps include such as: DEM, slope, aspect, range condition, range trend, forage, soil erosion, water sources used as input data. Three sub models including water accessibility, forage production and erosion sensitivity were considered. The most adaptation of Suitability occurs for class (Good) S1, (Medium) S2, (Poor) S3 and (Non-suitable) N respectively using Geographic Information Systems (GIS). First of all, the complete raster layers valued and ranked by FAO method for each factor then integrated by overlays intersected command. Results show that according to 16 types of vegetation cover there was no each of them in S1 class, 3088.75 ha S2, 1892.63 ha S3 and 882.85 ha were N class. Also result determined that there is no limitation of water resource in total rangeland and the most and main important factors effect on suitability are soil erosion and slope due to mountainous area. According to the field data and comparing with the study data it can/is possible to conclude GIS technique is fast and accurate to monitoring and determining of suit abilities of rangelands. تفاصيل المقالة -
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45 - Changes in Species Diversity and Functional Diversity of Vegetation under Different Grazing Intensities in Changizchal Rangelands, Mazandaran Province, Iran
Mansoureh Kargar Majid Sadeghinia Sara FarazmandDifferent indices of functional diversity as: functional richness (FRic), functional evenness (FEve) and functional divergence (FDiv), could help to understanding of the relationship between plant diversity and ecosystem function. Therefore, this study was aimed to eval أکثرDifferent indices of functional diversity as: functional richness (FRic), functional evenness (FEve) and functional divergence (FDiv), could help to understanding of the relationship between plant diversity and ecosystem function. Therefore, this study was aimed to evaluate changes in species diversity and functional diversity of vegetation under different grazing intensities in relation to soil physic-chemical properties in Changizchal rangelands, Mazandaran province, Iran. During the spring and summer of 2014. Three functional traits including Specific Leaf Area (SLA), Vegetation Height (VH), and Leaf Dry Matter Content (LDMC) were measured in three grazing intensities (low, moderate and high). Taxonomic diversity was quantified using several indices including Species richness (S), Shannon (H), Evenness (E) and Simpson (D). In addition, functional diversity was quantified using single trait-based (FDvar) and multi trait-based indices (functional richness (FRic), functional divergence (FDiv), and functional evenness (FEve). The result showed that functional richness and species richness increased at moderate grazing. Similarly, the higher values of FDvar of the SLA were observed in a moderate grazing. Whereas, the FDvar of VH values significantly increased in light grazing. The low grazing induced increase in the FDive and FEve coupled with decreasing soil organic carbon (P<0.05). The FDvar for SLA had a positive relationship with soil N and P in low grazing. Stable grazing on Changizchal rangelands tends to increase competition for soil N and P, resulting in an increase in the functional richness in grazed plant communities. The present study highlights the potential importance of low to moderate grazing intensities in mediating and reducing competition between plants for nutrient resources. تفاصيل المقالة -
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46 - Evaluation of Seeds and Pods Variation of 5 Annual Medic Medicago Spp.
Masoomeh Izadpanah Ali Ashraf JafariMedicago spp. is the most important forage crop in many regions of the world.Annual medics have distinct advantages over perennial Medicago. These species have fastergrowth rate in cultivation year, higher crude protein percentage, tolerance to pests and morevigorous se أکثرMedicago spp. is the most important forage crop in many regions of the world.Annual medics have distinct advantages over perennial Medicago. These species have fastergrowth rate in cultivation year, higher crude protein percentage, tolerance to pests and morevigorous seedlings. Morphological and physical aspects of pod and seeds of annual medicsplay a major role in the tolerance of the plants to over grazing and establishing in differenttype of rangelands i.e., plants with small seeds can establish better in heavy grazed rangelands,spiny pods establish better in dense compact clay soil, hard seeds increase seed bank of thesoil and maintain the pasture for the next years. In order to study the variation in seeds andpods morphological traits of five annual Medicago spp. seeds of 50 accessions of M. rigidula,M. polymorpha, M. orbicularis, M. radiata and M. minima, provided from natural resourcesgene bank of Iran, were sown in pots. Data were collected for size of the seeds, spins andpods, number of seeds per pod, levels of hardseededness and elevation of the seed origin.Results showed that M. rigidula 1000-seed weight had the most variation. Largest seeds were17 times bigger than the smallest one in this species. M. polymorpha showed the mostvariation in the elevation of seed origin (upper=2280 m, lower=5 m above sea level). M.radiata showed the most variation in the amount of hard seeds. M. rigidula showed the leastamount of hard seeds (mean=59.93). M. radiata had the largest pods. M. radiata and M.orbicularis showed the highest variation in pod size. M. polymorpha showed the highestvariation of spine length. The correlation between 1000-seed weight and the elevation of seedorigin was positive and significant for M. polymorpha and negative and significant for M.orbicularis. Based on Ward clustering method, the five species were grouped into two clustersin a dendrogram. First cluster included M. minima and M. polymorpha and the second clusterincluded M. rigidula, M. orbicularis, and M. radiata. This result indicated that it may possibleof interspecific hybridization between species of the same cluster. تفاصيل المقالة -
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47 - Assessment of the Effects of Overgrazing on the Soil Physical Characteristic and Vegetation Cover Changes in Rangelands of Hosainabad in Kurdistan Province, Iran
H. Azarnivand A. Farajollahi E. Bandak H. PouzeshSoil physical properties have an important role on vegetation growththrough affecting the development of root system. The aim of this study was toinvestigate the trampling effect of livestock grazing on soil physical properties andvegetation cover changes. The experimen أکثرSoil physical properties have an important role on vegetation growththrough affecting the development of root system. The aim of this study was toinvestigate the trampling effect of livestock grazing on soil physical properties andvegetation cover changes. The experiment was conducted on three range conditionsites (Reference, Key and Critical area) with ten frequencies in HosseinabadeKudistan in 2009. Soil physical characteristics consist of humidity, bulk density,porosity and aggregate stability index. In this study remarked soil cover changes inthree mentioned regions. The results showed that soil moisture reduced fromreference to critical area. Soil bulk density was the lowest in reference area and thehighest in critical area. Reference site had the highest soil porosity while the soilporosity reduced in critical area. However, as the density of grazing increased, soilbulk density increased and soil moisture, soil porosity, aggregate stability index andvegetation cover percent decreased. Bare soil percentage was the highest in criticalregion. According to the results of this research, the grazing seems caused to majorchanges in the physical properties of the topsoil. Since the region has highecological potential, if the intensity of grazing would be in a moderate level, theregion soil will be able to compensate the negative aspects of livestock trampling. تفاصيل المقالة -
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48 - Studying the sffects of Grazing Capacity and Rangeland Conditions on Occurrence of Landslide in Subalpine Grassland (Case Study: Rangeland of Masoleh Watershed)
Mona Fakhre Ghazi Mohammad Hasan Jouri Vahid GholamiSubalpine rangeland as a rara avis ecosystem is very important because ofecological features. Consistency and resistance of this ecosystem is so frangible and itsnatural equilibrium is instable due to the effects of biotic and abiotic factors. The landslideas one of neg أکثرSubalpine rangeland as a rara avis ecosystem is very important because ofecological features. Consistency and resistance of this ecosystem is so frangible and itsnatural equilibrium is instable due to the effects of biotic and abiotic factors. The landslideas one of negative consequences in upland area is seen in Masoleh watershed (north ofIran). This study has investigated the roles of biotic factors playing in the occurrence of thelandslides in Masoleh rangeland. Hence, two sites such as exclosure and grazing areaswere analyzed and compared. The plot size was 1m² and totally, 128 plots were obtainedby minimal area method and statistical formula approach, respectively. The rangelandconditions were measured by six-factor method. Clipping and weighing method was usedto determine the grazing capacity. In order to do the landslide zonation, the landslide indexwas employed. Results showed that there were significant differences between speciesdensities and soil conservation factors in both exclosure and grazing areas. There might bemore than 1.2 overstocking in the grazing area. The rangeland conditions‟ classes anddistance from fold, effective biotic factors, geologic formation, soil texture and effectiveabiotic factors were the most influential factors on the landslide occurrence in subalpineecosystem of Masoleh. Regarding results of current research, the exclosure can protect thesoil from the landslide through increasing the perennial and endemic species. Decreasinglivestock and regulating the animal entrance and egress to reach the suitable circumstancesof vegetation covers and pull up the landslide occurrence are recommended in this area. تفاصيل المقالة -
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49 - Effects of Enclosure, Rest-delayed and Continuous Grazing Treatments on Production Rate and Vegetation Cover of SadrAbad Nodoushan of Yazd Pastures A.
A. MirjaliliIn this investigation, the effects of enclosure, restal delayed grazing andcontinued grazing treatments on the production rate and vegetation cover were studied.Study area was SadrAbad pasture. After selecting three bands (1+1+1=3 hectare area) asthree treatments in the أکثرIn this investigation, the effects of enclosure, restal delayed grazing andcontinued grazing treatments on the production rate and vegetation cover were studied.Study area was SadrAbad pasture. After selecting three bands (1+1+1=3 hectare area) asthree treatments in the restricted and non restricted area, they were transected to threetransects. Then plots (1×2m2 ) were selected to measure the production rate with clippingand weight method and vegetation cover was determined. The data were analyzed usingDuncan test in completely randomized block design. As the results showed, the productionand vegetation cover percentage in enclosure area, the restal delayed grazing and continuedgrazing had significant differences(p<0.01). تفاصيل المقالة -
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50 - Plant Species and Functional Types’ Diversity in Relation to Grazing in Arid and Semi-arid Rangelands, Khabr National Park, Iran
Mohsen Sharafatmandrad Adel Sepehry Hossein BaraniIn arid and semi-arid rangelands, grazing as one of the natural or human induced processes has direct and indirect effects on structure and dynamics of plant community and ecosystems. A study was done to analyze the effects of grazing on plant species diversity and Plan أکثرIn arid and semi-arid rangelands, grazing as one of the natural or human induced processes has direct and indirect effects on structure and dynamics of plant community and ecosystems. A study was done to analyze the effects of grazing on plant species diversity and Plant Functional Types‘ (PFTs) diversity of arid and semi-arid rangelands. We analyzed plant richness and diversity data from 75 sampling plots located in five bioclimatic zones of Khabr National Park containing a total of 73 plant species. Ward's hierarchical clustering was then used to cluster all plant species into eight PFTs according to the chosen traits. For each site, grazing intensity was estimated in three classes (low grazing, medium and high grazing intensities). We found that as grazing intensity increased, total species richness and diversity were decreased. Considering PFTs as total showed the same pattern for species; however, each PFT diversity and richness didn‘t display a significant different response to grazing. Looking at each PFT relative cover change in different grazing intensities showed that PFT1 and PFT8 were grazing sensitivities while PFT6 and PFT7 benefited from grazing and their relative cover increased consistently in response to the increased grazing intensity. PFT3 and PFT4 had the highest relative cover rates in moderately grazed areas. PFT2 and PFT5 had a complicated response to grazing and their relative cover was the minimum at moderately grazed sits. This finding may imply that grazing has completely negative impacts on the community structure and it seems that it reduces plant species and functional types‘ diversity and richness. It can be also concluded that the analyses on PFTs level possibly give more insight into the grazing response of plant community in arid and semi-arid rangelands than those on species level but there is a need for further studies. تفاصيل المقالة -
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51 - Relationships Among Forage and Litter Production in Three Grazing Intensities in Nodooshan Rangeland (Yazd, Iran)
E. Fakhimi M. Mesdaghi Gh.A. Dianati Tilaki M. TavanGrazing management plays an important role in the continuous and economicutilization of pastures. Proper grazing management is a main factor for the accumulation ofplant litter which reduces soil erosion and increase the soil permeability to keep moremoisture in the soi أکثرGrazing management plays an important role in the continuous and economicutilization of pastures. Proper grazing management is a main factor for the accumulation ofplant litter which reduces soil erosion and increase the soil permeability to keep moremoisture in the soil. In current study, the effect of three different grazing intensities (low,moderate and high) along with the grazing gradient on the forage production rate and plantlitter percentage was investigated on Nodooshan steppe pastures of Yazd, Iran. A randomizedcomplete block with three replications was used to compare three grazing methods. Data forforage production and litter percent were collected from a 2m2 quadrate in each plot. Theresults showed significant differences among grazing systems for both traits (P<0.05). Theresults showed that low grazing had the highest forage production. The regression equationbetween forage production and litter percentage were logarithmic in both moderate and highgrazing intensities. For low grazing intensity, the relationships between two traits showedquadratic egression and therefore, it was concluded that moderate grazing intensity was thebest in terms of both forge and litter production. تفاصيل المقالة -
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52 - The Study of Preference Values of Forage Species and Grazing Behavior of Tali Goat in Chabahar Rangelands of Iran
Parvaneh Ashouri Sanjabi Mohammad Fayaz Niloufar Zare Ahmad Gharanjik Hassan Yeganeh Shahram AfroughehIn recent years, studying the dietary preferences and livestock grazing behaviorhas attracted lots of attention due to manage and improve the efficiency of rangelands. So,in this study the foraging behavior and diet selection of Tali goat was investigated in theChabahar أکثرIn recent years, studying the dietary preferences and livestock grazing behaviorhas attracted lots of attention due to manage and improve the efficiency of rangelands. So,in this study the foraging behavior and diet selection of Tali goat was investigated in theChabahar Rangeland during 2008-2010. Data were collected and analyzed for speeds oflivestock, covered distance, time of grazing, resting, and walking for months of grazing(February to May) as replications over 3 years. To determine the preference value, timerecorder method was used. Time of grazing of specific plant species by livestock wasmonthly recorded and analyzed, across February to April. Results showed that Launaeamucronata species of annual broad-leaved had the highest preference value while twospecies of Sporobolus arabicus and Lotononis platycarpos had the lowest ones. All themeasured parameters of grazing behavior had no significant differences during the studiedyears. The resting time rates of various months had significant differences. Accordingly,the highest resting time rate could be attributed to May whereas this rate was likely to bereduced during February, March and April. The result of the study will therefore be usefulin planning a grazing strategy and determination of carrying capacity for livestock grazingin the studied rangelands. Also the findings help us in rehabilitate Chabahar rangelands,with palatably species for the Tali goats. تفاصيل المقالة -
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53 - Determining Rangeland Suitability for Sheep Grazing Using GIS (Case Study: Sadegh Abad Watershed, Kermanshah Province, Iran)
Erfan Rostami Hamidreza Mehrabe Mehdi FarahpourAbstract. Rangelands are mainly used for grazing the livestock in Iran, it is essential to specify grazing suitability of rangelands in each region of country, so that it may improve the management policies and approaches for planning and designing current and future pl أکثرAbstract. Rangelands are mainly used for grazing the livestock in Iran, it is essential to specify grazing suitability of rangelands in each region of country, so that it may improve the management policies and approaches for planning and designing current and future plans. The aim of this research was to determine the rangeland suitability for sheep grazing in the watershed of Sadegh Abad, Kermanshah Province, Iran. Three sub-models namely forage production model, water siutablity model (quantity, quality and distance of water resources) and erosion sensibility which formed the components of the final studied model. EPM procedure for erosion sensitivity and FAO method for land capability evaluation were employed. Furthermore, combining information layers was done by means of ArcGIS9.3 software. For forage production suitability, the effective factors as allowable limit of exploitation, having access to forage and physical conditions were considered. Our findings indicated two separate classes including low suitability (S3) and non-suitability (N) with the contributions of 68.65 and 31.34% rangeland area, respectively. Low suitability was due to soil erosion sensitivity and limited standard exploitation of forage. In some regions, distance to water resources and high slope of grazinig land caused the decrease of grazing suitability. Considering the grazing capacity and applying the correction programs in rangelands can affect the increase of range suitability for grazing sheep. Using GIS may lead to the increase in accuracy and speed of implementing plans. تفاصيل المقالة -
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54 - Application of New Techniques to Monitor Livestock Grazing Distribution by GPS and GIS
Mehdi Farahpour Alireza Naseri Mohamasreza Najibzaadeh Mohamad Fayaz Mahmod MoallemiRange management needs information on distribution of livestock. The better the distribution of the livestock, the more uniform the use of the rangeland. This study was conducted to record the path of the herd steering by the shepherd. A GPS was attached to a three year أکثرRange management needs information on distribution of livestock. The better the distribution of the livestock, the more uniform the use of the rangeland. This study was conducted to record the path of the herd steering by the shepherd. A GPS was attached to a three year old ewe which was moving with the flock. The path of flock movement was recorded for three years on a monthly basis during the grazing season. Results showed that the path was not changing within the years. On the contrary, the pattern of monthly movements showed variation. Area at the vicinity of the watering point and the sheep pen, as a sign of overgrazing for those areas, was used every day. Calculation of the grazed area showed that almost half of the range was used and the other half was left ungrazed. The map and attribute data such as speed of the movement and timing of the daily orbit could help the range manager to find a way out of over grazing problem. تفاصيل المقالة -
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55 - Comparison between Some Vegetation Traits and Bioindicators in Two Grazing and Exclosure Areas (Case Study: Sorkhe-Graz and Valikbon Rangelands)
Soode Miarrostami Mohammad Hasan JouriOvergrazing, via harvesting of forage species and decrease the other herbs, is of progressive factors in biodiversity destroying. In order to investigate the animal grazing impacts on changing of plant structure and diversity, we selected the comparison between this eff أکثرOvergrazing, via harvesting of forage species and decrease the other herbs, is of progressive factors in biodiversity destroying. In order to investigate the animal grazing impacts on changing of plant structure and diversity, we selected the comparison between this effect with exclosure area, and proving of the excluded area effects on plant diversity; two sites of Kojour rangeland, Mazandran province, Iran. Four transects, 50 m were systematic-accidentally established on two different aspects including along of slope (two transects) and staple on steep slope side. Cover percentage was recorded by 10 plots 1m2 in each transect. Rangeland condition and trend was determined by 6-factor and Trending Balance methods, respectively. Diversity indices in each area, by analysing of vegetation parameters, were calculated using PAST software. Vegetation traits and bioindicators were analysed by independent T-test using SPSS software. The result showed that percentages of all life-forms in rangeland were different between the exclosure and grazing areas, especially, grasses and forbs were meaningfully remarked. Regarding to bioindicators, diversity-Shannon index and richness-Menhinick index values were higher in the exclosure area than open area (P<0.01). Dominance index in grazing area was significantly higher than exclosure area (P<0.05). Evenness index, however, has not punctual difference in both areas. تفاصيل المقالة -
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56 - Grazing Response of Topsoil Characteristics in Temperate Rangelands of Kashmir, Himalaya
T. H. Jaweed P. G. Saptarshi S. W. GaikwadThe superficial strata of ground have been perennially exposed to the action of natural agents such as heat, cold and water. However, grazing agent was not different from them when soils were investigated from temperate rangelands of Kashmir and caused the soil compacti أکثرThe superficial strata of ground have been perennially exposed to the action of natural agents such as heat, cold and water. However, grazing agent was not different from them when soils were investigated from temperate rangelands of Kashmir and caused the soil compaction, soil structure degradation and loss of soil organic C and C/N ratio. Soils from three grazing intensities were investigated for physio-chemical parameters. The results showed that soil bulk density was the lowest in Low Grazed (LG) areas and critical in Highly Grazed (HG) areas. The results revealed that C storage in 0–10 cm of soil layers was decreased linearly with the increase of stocking rates. However, total soil nitrogen content in HG is 1.26 times more than LG. Therefore, grazing is responsible for major changes in the physical and chemical properties of the topsoil which may further cause the spatial heterogeneity followed by regional ecological problems. تفاصيل المقالة -
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57 - Multivariate Statistical Method for Assessing Livestock Grazing Effects on Soil and Vegetation in Steppe Rangelands (Case Study: Steppe Rangelands of Saveh)
Sedigheh Zare Kia Hossein Arzani Mohammad Jafari Seyyed Akbar Javadi Ali Ashraf JafariThis study aims to assess the effect of grazing intensity on vegetation structure, soil nutrient concentrations and soil physical properties. The study was carried out in steppe rangelands of Saveh, Markazi province, Iran. Four sites with four grazing intensities includ أکثرThis study aims to assess the effect of grazing intensity on vegetation structure, soil nutrient concentrations and soil physical properties. The study was carried out in steppe rangelands of Saveh, Markazi province, Iran. Four sites with four grazing intensities including very high, high, moderate and non-grazed with the same ecological conditions were selected. To study various vegetation and soil parameters in each range site, a reference area was selected. Then, sampling was performed by randomized systematic method in reference areas. Vegetation characteristics, soil physical properties, bulk density, infiltration rate, soil texture and chemical constituents including nitrogen, phosphorus, potassium, pH, EC and organic carbon were measured. Principal component analysis was performed on a dataset with 22 variables to determine the effect of grazing intensity on vegetation structure and soil properties. Results indicated that the first three axes explained the total variation. The variables of potassium, phosphorous, bulk density, class I, class II, clay, field capacity, infiltration, Peganum harmala, Salsola laricina, Artemisia sieberi and perennial forbs had significant correlations with the first axes and explained a 74.27% variation. For the second components, silt, sand and perennial grasses were more important traits and explained a 15.5% variation. In non-grazed and moderate grazed sites, there were more canopy cover of both Artemisia sieberi and Salsola laricina, and for high grazing sites, there were plants of class III such as Noaea mucronata and Peganum harmala. The grazing intensity was associated with lower values of infiltration, clay percent and field capacity and higher values of bulk density, potassium, phosphorous and sand percent. Therefore, vegetation structure and soil properties were changed by the interaction between grazing intensity, soil properties and vegetation structure. The results suggested that excluding grazing livestock on the arid steppes has a great potential to restore vegetation and soil. Therefore, it must be encouraged as an alternative to stop further degradation and to combat desertification in arid and semi arid ecosystems. تفاصيل المقالة -
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58 - بررسی تغییرات میزان بیوماس گونه های Bromus tomentellus و Festuca ovina (مطالعه موردی: مناطق کوهستانی الموت قزوین)
سعید رشوند حسن یگانهبدون شناخت خصوصیات تولیدی گیاهان و مقدار مصرف علوفه یک مرتع در طول دوره چرا، برنامه ریزی و مدیریت صحیح مرتع و دام مقدور نمی باشد. لذا به منظور میزان تغییرات تولید و مصرف دو گونه گندمی مهم در مراتع نیمه استپی بادامستان زنجان بررسی شد. این تحقیق در 4 سال انجام گرفت و هر أکثربدون شناخت خصوصیات تولیدی گیاهان و مقدار مصرف علوفه یک مرتع در طول دوره چرا، برنامه ریزی و مدیریت صحیح مرتع و دام مقدور نمی باشد. لذا به منظور میزان تغییرات تولید و مصرف دو گونه گندمی مهم در مراتع نیمه استپی بادامستان زنجان بررسی شد. این تحقیق در 4 سال انجام گرفت و هر ساله پایه های یکسان در داخل قرق و پایه های یکسان در خارج قرق از گونه های Festuca ovina و Bromus tomentellus به منظور بررسی تغییرات تولید و مصرف انتخاب شد. در هر ماه از فصل چرا، تولید و مصرف علوفه تعداد 5 پایه از هر یک از گونه های مورد بررسی برداشت و به تفکیک در پاکت‌های جداگانه به آزمایشگاه منتقل و پس از خشک شدن در هوای آزاد، اختلاف وزن علوفه خشک در داخل و خارج قرق، مبنای محاسبات علوفه تولید شده و مصرف شده در سایت قرار گرفت. داده‌های حاصل از سال 1386 تا سال 1389 مورد تجزیه واریانس مرکب در قالب طرح کاملا تصادفی قرار گرفت. نتایج آنالیز واریانس گونههای مورد مطالعه نشان داد که اختلاف معنی‌داری در سطح 1 و 5 درصد در بین سال‌ها و ماه‌های آماربرداری از نظر میزان علوفه تولیدی وجود دارد و از نظر میزان مصرف گونه‌ها هم به غیر از اثر متقابل ماه در سال برای 2 گونه اثرات سال و ماه معنی دار است. درصد مصرف گونه‌ها نسبت به هم و زمان اوج مصرف گونه‌ها در بین ماه‌های مورد بهرهبرداری شبیه به هم بود. تفاصيل المقالة -
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59 - اثر شدت چرای دام بر پوشش گیاهی و خاک در فواصل مختلف کانون بحرانی روستا (مطالعه موردی: روستای پنجالو، مغان)
سحر غفاری اردوان قربانی کلام الله ارجمند علی تیمورزاده آزاد کاکه ممی سیما جعفریبه منظور بررسی اثر شدت‌های مختلف چرایی (سبک، متوسط و سنگین) در میزان تخریب مرتع، در سطح یک تیپ گیاهی با شرایط اکولوژیکی تقریباً یکسان، شاخص‌های پوشش گیاهی و خصوصیات خاک در مراتع روستای پنجالو در استان اردبیل مورد بررسی قرار گرفت. در هر محل نمونه‌برداری سه ترانسکت، و در أکثربه منظور بررسی اثر شدت‌های مختلف چرایی (سبک، متوسط و سنگین) در میزان تخریب مرتع، در سطح یک تیپ گیاهی با شرایط اکولوژیکی تقریباً یکسان، شاخص‌های پوشش گیاهی و خصوصیات خاک در مراتع روستای پنجالو در استان اردبیل مورد بررسی قرار گرفت. در هر محل نمونه‌برداری سه ترانسکت، و در هر ترانسکت 10 پلات یک مترمربعی مستقر شد. در هر پلات پارامترهای تراکم، تولید کل، درصد تاج پوشش، لاشبرگ، خاک لخت و سنگ و سنگریزه ثبت شد. نمونه‌برداری خاک از عمق 0 تا 30 سانتی‌متری انجام شد. اندازه‌گیری پارامترهای خاک شامل اسیدیته، هدایت‌الکتریکی، پتاسیم، آهک، فسفر، نیتروژن و کربن‌آلی انجام شد. برای بررسی اثر شدت چرا بر کلیه ویژگی‌های اندازه‌گیری شده از آزمون تجزیه واریانس و از آزمون دانکن برای مقایسه میانگین‌ها و گروه‌بندی آنها استفاده شد. نتایج نشان داد بیشترین مقدار تولید و درصد تاج پوشش در چرای سبک (61/129 گرم در متر مربع و 41/87 درصد) و کمترین در چرای سنگین (91/71 گرم در متر مربع و 25 درصد) بود. بیشترین درصد خاک لخت و سنگ و سنگریزه در چرای سنگین (63/65 و 31/5 درصد) و کمترین در سطح چرای سبک (05/10 و 0 درصد) مشاهده شد. بیشترین مقدار تنوع و غنا در شدت چرای متوسط (85/0 و 28/2) و کمترین مربوط به چرای سنگین (79/0 و 08/2) است. نتایج نشان داد با افزایش شدت چرا مقادیر هدایت‌الکتریکی، فسفر و آهک افزایش یافت (01/0>P). بیشترین مقادیر اسیدیته (82/7) و پتاسیم (96/3) در چرای متوسط و بیشترین مقدار کربن‌آلی (60/1) در چرای سنگین مشاهده شد. تفاصيل المقالة
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