Journal of Rangeland
مرتع
مرتع
Agriculture
http://rangelandsrm.ir
1
admin
2008-0891
2676-5039
fa
jalali
1401
8
1
gregorian
2022
11
1
16
3
online
1
fulltext
fa
پیشبینی شاخصهای تنوع گونهای گیاهان با مدل خطی تعمیم یافته (GLM) و مدل درخت رگرسیون تقویت شده (BRT) در مراتع شرق استان مازندران
Prediction of Plant Species Boibiversity using Generalized Linear Model (GLM) and Boosted Regression Tree (BRT) in Eastern Rangelands of Mazandaran
تخصصي
Special
پژوهشي
Research
<span style="font-size:11pt"><span style="line-height:115%"><span style="direction:rtl"><span style="unicode-bidi:embed"><span style="font-family:Calibri,sans-serif"><b><span lang="FA" style="font-size:12.0pt"><span style="line-height:115%"><span b="" nazanin="" style="font-family:"><span style="color:black">چکیده</span></span></span></span></b></span></span></span></span></span><br>
<span style="font-size:11pt"><span style="line-height:normal"><span style="direction:rtl"><span style="unicode-bidi:embed"><span style="font-family:Calibri,sans-serif"><b><span b="" nazanin="" style="font-family:"><span style="color:black">سابقه و هدف:</span></span></b> <span b="" nazanin="" style="font-family:"><span style="color:black">پیش</span></span><span dir="LTR" style="color:black">­</span><span b="" nazanin="" style="font-family:"><span style="color:black">بینی الگوهای غنا و تنوع زیستی برای ایجاد استراتژیهای حفاظت از تنوع تحت تغییرات محیطی منطقه­ای و جهانی مورد استفاده هستند لذا، مطالعه آنها به مدیریت مراتع کمک خواهد کرد. </span></span><span lang="FA" style="font-size:12.0pt"><span b="" nazanin="" style="font-family:"><span style="color:black">از آنجایی که مدلسازی پراکنش گونههای گیاهی</span></span></span> <span lang="FA" style="font-size:12.0pt"><span b="" nazanin="" style="font-family:"><span style="color:black">میتواند</span></span></span> <span lang="FA" style="font-size:12.0pt"><span b="" nazanin="" style="font-family:"><span style="color:black">اطلاعات</span></span></span> <span lang="FA" style="font-size:12.0pt"><span b="" nazanin="" style="font-family:"><span style="color:black">کاربردی</span></span></span> <span lang="FA" style="font-size:12.0pt"><span b="" nazanin="" style="font-family:"><span style="color:black">و با</span></span></span> <span lang="FA" style="font-size:12.0pt"><span b="" nazanin="" style="font-family:"><span style="color:black">اهمیتی</span></span></span> <span lang="FA" style="font-size:12.0pt"><span b="" nazanin="" style="font-family:"><span style="color:black">در</span></span></span> <span lang="FA" style="font-size:12.0pt"><span b="" nazanin="" style="font-family:"><span style="color:black">راستای</span></span></span> <span lang="FA" style="font-size:12.0pt"><span b="" nazanin="" style="font-family:"><span style="color:black">شناسایی</span></span></span> <span lang="FA" style="font-size:12.0pt"><span b="" nazanin="" style="font-family:"><span style="color:black">و</span></span></span> <span lang="FA" style="font-size:12.0pt"><span b="" nazanin="" style="font-family:"><span style="color:black">معرفی</span></span></span> <span lang="FA" style="font-size:12.0pt"><span b="" nazanin="" style="font-family:"><span style="color:black">زیستگاه</span></span></span><span dir="LTR" style="font-size:12.0pt"><span style="color:black">­</span></span><span lang="FA" style="font-size:12.0pt"><span b="" nazanin="" style="font-family:"><span style="color:black">های</span></span></span> <span lang="FA" style="font-size:12.0pt"><span b="" nazanin="" style="font-family:"><span style="color:black">بالقوه</span></span></span> <span lang="FA" style="font-size:12.0pt"><span b="" nazanin="" style="font-family:"><span style="color:black">گونههای گیاهی</span></span></span> <span lang="FA" style="font-size:12.0pt"><span b="" nazanin="" style="font-family:"><span style="color:black">ارائه</span></span></span> <span lang="FA" style="font-size:12.0pt"><span b="" nazanin="" style="font-family:"><span style="color:black">نماید و هم­چنین مطالعات کمی در زمینهی مدلسازی غنای گونهای با کمک متغیرهای محیطی در ایران صورت گرفته است، بنابراین مطالعه مدلسازی غنای گونه­ای در مدیریت پوشش گیاهی مراتع دارای اهمیت و ضرورت است که هدف تحقیق حاضر است.</span></span></span><span b="" nazanin="" style="font-family:"><span style="color:black"></span></span></span></span></span></span></span><br>
<span style="font-size:11pt"><span style="line-height:normal"><span style="direction:rtl"><span style="unicode-bidi:embed"><span style="font-family:Calibri,sans-serif"><b><span b="" nazanin="" style="font-family:"><span style="color:black">مواد و روش­ها:</span></span></b><span b="" nazanin="" style="font-family:"><span style="color:black"> چنین بررسی در مراتع سرخ گریوه</span></span> <span b="" nazanin="" style="font-family:"><span style="color:black">منطقه</span></span> <span b="" nazanin="" style="font-family:"><span style="color:black">هزار</span></span> <span b="" nazanin="" style="font-family:"><span style="color:black">جریب بهشهر با مساحت 2620 هکتار انجام شد. برای</span></span> <span b="" nazanin="" style="font-family:"><span style="color:black">نمونهبرداری</span></span> <span b="" nazanin="" style="font-family:"><span style="color:black">از</span></span> <span b="" nazanin="" style="font-family:"><span style="color:black">پوشش</span></span> <span b="" nazanin="" style="font-family:"><span style="color:black">گیاهی</span></span> <span b="" nazanin="" style="font-family:"><span style="color:black">و</span></span> <span b="" nazanin="" style="font-family:"><span style="color:black">خاک</span></span> <span b="" nazanin="" style="font-family:"><span style="color:black">از</span></span> <span b="" nazanin="" style="font-family:"><span style="color:black">روش</span></span> <span b="" nazanin="" style="font-family:"><span style="color:black">طبقهبندی</span></span> <span b="" nazanin="" style="font-family:"><span style="color:black">تصادفی-سیستماتیک</span></span> <span b="" nazanin="" style="font-family:"><span style="color:black">استفاده</span></span> <span b="" nazanin="" style="font-family:"><span style="color:black">شد. در مجموع 260 پلات یک متر مربعی در منطقه مستقر گردید. در</span></span> <span b="" nazanin="" style="font-family:"><span style="color:black">هر</span></span> <span b="" nazanin="" style="font-family:"><span style="color:black">پلات</span></span> <span b="" nazanin="" style="font-family:"><span style="color:black">لیست</span></span> <span b="" nazanin="" style="font-family:"><span style="color:black">گونهها، درصد</span></span> <span b="" nazanin="" style="font-family:"><span style="color:black">پوشش گونهها، درصد لاشبرگ، سنگ و سنگریزه و تعداد گونه یادداشت گردید. سه نمونه خاک از عمق 30-0 سانتیمتری در طول هر ترانسکت برداشت و در آزمایشگاه برخی ویژگی­های فیزیکی و شیمیایی اندازه­گیری شدند. متغیرهای فیزیوگرافی </span></span> <span b="" nazanin="" style="font-family:"><span style="color:black">در</span></span> <span b="" nazanin="" style="font-family:"><span style="color:black">نرم</span></span> <span b="" nazanin="" style="font-family:"><span style="color:black">افزار</span></span> <span dir="LTR" style="font-size:10.0pt"><span new="" roman="" style="font-family:" times=""><span style="color:black">Arc GIS</span></span></span> <span b="" nazanin="" style="font-family:"><span style="color:black">تعیین شدند. متغیرهای اقلیمی برای دوره آماری 15 ساله (1995-2010) جمع­آوری شدند. متغیر­های اقلیمی پیش­بینی­گر در این تحقیق شامل رطوبت نسبی سالانه، میانگین دمای سالانه و میانگین بارندگی سالانه بودند. ویژگی­های فیزیکی و شیمیایی خاک نیز شامل درصد رطوبت، شن، رس و سیلت، </span></span><span dir="LTR" style="font-size:10.0pt"><span new="" roman="" style="font-family:" times=""><span style="color:black">pH</span></span></span><span b="" nazanin="" style="font-family:"><span style="color:black">، </span></span><span dir="LTR" style="font-size:10.0pt"><span new="" roman="" style="font-family:" times=""><span style="color:black">EC</span></span></span><span b="" nazanin="" style="font-family:"><span style="color:black">، کربن آلی، نیتروژن، فسفر و پتاسیم استفاده شد.</span></span> <span b="" nazanin="" style="font-family:"><span style="color:black">پیش بینی شاخص­های تنوع گونهای</span></span> <span b="" nazanin="" style="font-family:"><span style="color:black">گیاهان</span></span> <span b="" nazanin="" style="font-family:"><span style="color:black">با دو روش</span></span><span arial="" style="font-family:">: </span><span b="" nazanin="" style="font-family:"><span style="color:black">مدل­ خطی تعمیم یافته (</span></span><span dir="LTR" style="font-size:10.0pt"><span new="" roman="" style="font-family:" times=""><span style="color:black">GLM</span></span></span><span b="" nazanin="" style="font-family:"><span style="color:black">)، مدل­ درخت رگرسیون تقویت شده (</span></span><span dir="LTR" style="font-size:10.0pt"><span new="" roman="" style="font-family:" times=""><span style="color:black">BRT</span></span></span><span b="" nazanin="" style="font-family:"><span style="color:black">)، انجام پذیرفت</span></span><span lang="FA" style="font-size:12.0pt"><span b="" nazanin="" style="font-family:">. <span style="color:black">آنالیز اهمیت متغیرهای محیطی برای مدل </span></span></span><span dir="LTR" style="font-size:10.0pt"><span new="" roman="" style="font-family:" times=""><span style="color:black">GLM</span></span></span> <span lang="FA" style="font-size:12.0pt"><span b="" nazanin="" style="font-family:"><span style="color:black">و مدل </span></span></span><span dir="LTR" style="font-size:10.0pt"><span new="" roman="" style="font-family:" times=""><span style="color:black">BRT</span></span></span> <span lang="FA" style="font-size:12.0pt"><span b="" nazanin="" style="font-family:"><span style="color:black">در بسته </span></span></span><span dir="LTR" style="font-size:10.0pt"><span new="" roman="" style="font-family:" times=""><span style="color:black">biomode2</span></span></span> <span lang="FA" style="font-size:12.0pt"><span b="" nazanin="" style="font-family:"><span style="color:black">انجام ­شدند. برای</span></span></span> <span lang="FA" style="font-size:12.0pt"><span b="" nazanin="" style="font-family:"><span style="color:black">ارزیابی مدل­ها از ضریب</span></span></span> <span lang="FA" style="font-size:12.0pt"><span b="" nazanin="" style="font-family:"><span style="color:black">تبیین </span></span></span><span dir="LTR" style="font-size:10.0pt"><span new="" roman="" style="font-family:" times=""><span style="color:black">R<sup>2</sup></span></span></span> <span lang="FA" style="font-size:12.0pt"><span b="" nazanin="" style="font-family:"><span style="color:black">و </span></span></span><span dir="LTR" style="font-size:10.0pt"><span new="" roman="" style="font-family:" times=""><span style="color:black">RMSE</span></span></span> <span lang="FA" style="font-size:12.0pt"><span b="" nazanin="" style="font-family:"><span style="color:black">استفاده شد.</span></span></span><span lang="FA" style="font-size:12.0pt"><span b="" nazanin="" style="font-family:"><span style="color:black"> برای مقایسه عملکرد دو مدل از معیار سطح زیر منحنی (</span></span></span><span dir="LTR" style="font-size:10.0pt"><span new="" roman="" style="font-family:" times=""><span style="color:black">AUC</span></span></span><span lang="FA" style="font-size:12.0pt"><span b="" nazanin="" style="font-family:"><span style="color:black">) استفاده شد.</span></span></span><span lang="FA" style="font-size:12.0pt"><span b="" nazanin="" style="font-family:"><span style="color:black"></span></span></span></span></span></span></span></span><br>
<span style="font-size:11pt"><span style="line-height:normal"><span style="tab-stops:294.55pt"><span style="direction:rtl"><span style="unicode-bidi:embed"><span style="font-family:Calibri,sans-serif"><b><span b="" nazanin="" style="font-family:"><span style="color:black">نتایج</span></span></b><span b="" nazanin="" style="font-family:"><span style="color:black">: نتایج مدل </span></span> <span dir="LTR" style="font-size:10.0pt"><span new="" roman="" style="font-family:" times=""><span style="color:black">GLM</span></span></span><span b="" nazanin="" style="font-family:"><span style="color:black">نشان داد به ترتیب ارتفاع، سیلت، میانگین بارندگی سالانه، نیتروژن و میانگین رطوبت سالیانه موثرترین عوامل محیطی تاثیرگذار بر غنای گونه­ای بودند. هم چنین در مدل </span></span><span dir="LTR" style="font-size:10.0pt"><span new="" roman="" style="font-family:" times=""><span style="color:black">BRT</span></span></span> <span b="" nazanin="" style="font-family:"><span style="color:black">نتایج بیانگر این مطلب است که به ترتیب متغیرهای ارتفاع، اسیدیته خاک، میانگین رطوبت سالانه و رس بیشترین اهمیت را در غنای گونه­ای دارند. نتایج مدل</span></span> <span dir="LTR" style="font-size:10.0pt"><span new="" roman="" style="font-family:" times=""><span style="color:black">GLM</span></span></span> <span b="" nazanin="" style="font-family:"><span style="color:black">نشان</span></span> <span b="" nazanin="" style="font-family:"><span style="color:black">داد</span></span> <span b="" nazanin="" style="font-family:"><span style="color:black">که</span></span> <span b="" nazanin="" style="font-family:"><span style="color:black">از</span></span> <span b="" nazanin="" style="font-family:"><span style="color:black">بین</span></span> <span b="" nazanin="" style="font-family:"><span style="color:black">شاخصهای</span></span> <span b="" nazanin="" style="font-family:"><span style="color:black">غنا و تنوع گونهای، بالاترین</span></span> <span dir="LTR" style="font-size:10.0pt"><span new="" roman="" style="font-family:" times=""><span style="color:black">R<sup>2</sup></span></span></span> <span b="" nazanin="" style="font-family:"><span style="color:black">مربوط</span></span> <span b="" nazanin="" style="font-family:"><span style="color:black">به</span></span> <span b="" nazanin="" style="font-family:"><span style="color:black">شاخص</span></span> <span b="" nazanin="" style="font-family:"><span style="color:black">غنا به مقدار</span></span> <span b="" nazanin="" style="font-family:"><span style="color:black">33/0</span></span> <span b="" nazanin="" style="font-family:"><span style="color:black">بوده است.</span></span> <span b="" nazanin="" style="font-family:"><span style="color:black">همچنین</span></span> <span b="" nazanin="" style="font-family:"><span style="color:black">مهمترین</span></span> <span b="" nazanin="" style="font-family:"><span style="color:black">متغیرهای</span></span> <span b="" nazanin="" style="font-family:"><span style="color:black">تأثیرگذار</span></span> <span b="" nazanin="" style="font-family:"><span style="color:black">بر</span></span> <span b="" nazanin="" style="font-family:"><span style="color:black">این</span></span> <span b="" nazanin="" style="font-family:"><span style="color:black">شاخص نیتروژن، اسیدیته، هدایت الکتریکی، بارندگی، رطوبت بودند نتایج مدل</span></span> <span dir="LTR" style="font-size:10.0pt"><span new="" roman="" style="font-family:" times=""><span style="color:black">BRT</span></span></span> <span b="" nazanin="" style="font-family:"><span style="color:black">نشان</span></span> <span b="" nazanin="" style="font-family:"><span style="color:black">داد</span></span> <span b="" nazanin="" style="font-family:"><span style="color:black">که</span></span> <span b="" nazanin="" style="font-family:"><span style="color:black">از</span></span> <span b="" nazanin="" style="font-family:"><span style="color:black">بین</span></span> <span b="" nazanin="" style="font-family:"><span style="color:black">شاخصهای</span></span> <span b="" nazanin="" style="font-family:"><span style="color:black">بررسی شده بالاترین</span></span> <span dir="LTR" style="font-size:10.0pt"><span new="" roman="" style="font-family:" times=""><span style="color:black">R<sup>2</sup></span></span></span> <span b="" nazanin="" style="font-family:"><span style="color:black">مربوط</span></span> <span b="" nazanin="" style="font-family:"><span style="color:black">به</span></span> <span b="" nazanin="" style="font-family:"><span style="color:black">شاخص تنوع </span></span> <span b="" nazanin="" style="font-family:"><span style="color:black">شانون به میزان</span></span> <span b="" nazanin="" style="font-family:"><span style="color:black">37/0</span></span> <span b="" nazanin="" style="font-family:"><span style="color:black">بود.</span></span> <span b="" nazanin="" style="font-family:"><span style="color:black">همچنین</span></span> <span b="" nazanin="" style="font-family:"><span style="color:black">مهمترین</span></span> <span b="" nazanin="" style="font-family:"><span style="color:black">متغیرهای</span></span> <span b="" nazanin="" style="font-family:"><span style="color:black">تأثیرگذار</span></span> <span b="" nazanin="" style="font-family:"><span style="color:black">بر</span></span> <span b="" nazanin="" style="font-family:"><span style="color:black">این</span></span> <span b="" nazanin="" style="font-family:"><span style="color:black">شاخص نیتروژن، ارتفاع، درصد رس و رطوبت بودند. در</span></span> <span b="" nazanin="" style="font-family:"><span style="color:black">مجموع</span></span> <span b="" nazanin="" style="font-family:"><span style="color:black">با</span></span> <span b="" nazanin="" style="font-family:"><span style="color:black">توجه</span></span> <span b="" nazanin="" style="font-family:"><span style="color:black">به</span></span> <span b="" nazanin="" style="font-family:"><span style="color:black">نتایج</span></span> <span b="" nazanin="" style="font-family:"><span style="color:black">به</span></span> <span b="" nazanin="" style="font-family:"><span style="color:black">دست</span></span> <span b="" nazanin="" style="font-family:"><span style="color:black">آمده</span></span> <span b="" nazanin="" style="font-family:"><span style="color:black">از</span></span> <span b="" nazanin="" style="font-family:"><span style="color:black">پژوهش</span></span> <span b="" nazanin="" style="font-family:"><span style="color:black">حاضر</span></span> <span b="" nazanin="" style="font-family:"><span style="color:black">اینطور بر می­آید که پارامترهای محیطی تاثیرگذار بر غنا توسط مدل </span></span><span dir="LTR" style="font-size:10.0pt"><span new="" roman="" style="font-family:" times=""><span style="color:black">GLM</span></span></span><span b="" nazanin="" style="font-family:"><span style="color:black">، شامل ارتفاع، میانگین بارندگی سالانه، میانگین رطوبت سالیانه، نیتروژن و سیلت و توسط مدل </span></span><span dir="LTR" style="font-size:10.0pt"><span new="" roman="" style="font-family:" times=""><span style="color:black">BRT</span></span></span><span b="" nazanin="" style="font-family:"><span style="color:black">، شامل ارتفاع، رطوبت سالیانه، اسیدیته و رس بودند. نتایج ارزیابی دو مدل نشان داد که سطح زیر منحنی (</span></span><span dir="LTR" style="font-size:10.0pt"><span new="" roman="" style="font-family:" times=""><span style="color:black">AUC</span></span></span><span b="" nazanin="" style="font-family:"><span style="color:black">) مدل </span></span><span dir="LTR" style="font-size:10.0pt"><span new="" roman="" style="font-family:" times=""><span style="color:black">GLM</span></span></span> <span b="" nazanin="" style="font-family:"><span style="color:black">61/0 و مدل </span></span><span dir="LTR" style="font-size:10.0pt"><span new="" roman="" style="font-family:" times=""><span style="color:black">BRT</span></span></span> <span b="" nazanin="" style="font-family:"><span style="color:black">72/0 بود که نشان می­دهد مدل </span></span><span dir="LTR" style="font-size:10.0pt"><span new="" roman="" style="font-family:" times=""><span style="color:black">BRT</span></span></span> <span b="" nazanin="" style="font-family:"><span style="color:black">عملکرد بهتری در مدلسازی غنای گونه­ای در منطقه داشته است.</span></span></span></span></span></span></span></span><br>
<span style="font-size:11pt"><span style="line-height:normal"><span style="direction:rtl"><span style="unicode-bidi:embed"><span style="font-family:Calibri,sans-serif"><span b="" nazanin="" style="font-family:"><span style="color:black">نتیجه گیری: در این تحقیق نتایج بیانگر این مطلب بود که مدل­های مطالعه شده در یک مقیاس کوچک به خوبی جواب داده و با استفاده از مدلسازی می توان عوامل محیطی اثر گذار بر تنوع زیستی را تعیین نمود. پیشنهاد می­گردد که مدیران مراتع از نتایج تحقیق حاضر و تحقیقات مشابه استفاده کنند و برای عوامل محیطی تاثیرگذار بر پراکنش و غنای گونه­ای اهمیت ویژه­ای قائل شوند.</span></span></span></span></span></span></span>
<span style="font-size:11pt"><span style="unicode-bidi:embed"><span style="line-height:115%"><span calibri="" style="font-family:"><b><span new="" roman="" style="font-family:" times="">Background and objectives</span></b><b><span style="font-size:10.5pt"><span style="line-height:115%"><span style="font-family:" timesnewroman="">:</span></span></span></b><span style="font-size:12.0pt"><span style="line-height:115%"><span new="" roman="" style="font-family:" times=""><span style="color:black"> Prediction of species richness and diversity patterns are used to develop conservation strategies for biodiversity under regional and global environmental changes. </span></span></span></span><span style="font-size:12.0pt"><span style="line-height:115%"><span new="" roman="" style="font-family:" times=""><span style="color:black">Since modeling the distribution of plant species can provide useful and important information about identifying and introducing potential habitats of plant species, and also few studies have been done in the field of modeling species richness using environmental variables in Iran, so the study of modeling Species richness is important and necessary in the management of vegetation, which is the aim of this research </span></span></span></span><span style="font-size:12.0pt"><span style="line-height:115%"><span new="" roman="" style="font-family:" times=""><span style="color:black">to help rangeland management</span></span></span></span><span style="font-size:12.0pt"><span style="line-height:115%"><span new="" roman="" style="font-family:" times=""><span style="color:black">.</span></span></span></span></span></span></span></span><br>
<span style="font-size:11pt"><span style="unicode-bidi:embed"><span style="line-height:115%"><span calibri="" style="font-family:"><b><span new="" roman="" style="font-family:" times="">Methodology</span></b><b><span style="font-size:9.5pt"><span style="line-height:115%"><span style="font-family:" timesnewroman="">:</span></span></span></b><span style="font-size:12.0pt"><span style="line-height:115%"><span new="" roman="" style="font-family:" times=""><span style="color:black"> This study was conducted in the Sorkh Grieve rangeland with an area of 2620 ha. vegetation and soil sample were taken via random-systematic stratification method. On each slope a transect with a length of 100 meters of was established in the direction of the height gradient and 10 plots were placed along it. Totally 260 plots of 1 m<sup>2</sup> were used. In each plot, the list of species, percentage of species cover, and percentage of litter, rocks and number of species were recorded. Three soil samples were taken from a depth of 0-30 cm along each transect and some physical and chemical properties were measured in the laboratory. Physiographic variables were determined in Arc GIS software. Climatic factors were collected for a period of 15 years.</span></span></span></span> <span style="font-size:12.0pt"><span style="line-height:115%"><span new="" roman="" style="font-family:" times=""><span style="color:black">Predictive climate variables in this research included annual relative humidity, average annual temperature, and average annual rainfall. The physical and chemical characteristics of the soil such as the percentage of moisture, sand, clay, silt, pH, EC, organic carbon, nitrogen, phosphorus, and potassium were measured. Prediction of species diversity indices of plants was done with two methods: generalized linear model (GLM) and, enhanced regression tree model (BRT). Analysis of the importance of environmental variables for GLM and BRT models was done in the biomode2 package. R<sup>2</sup> and RMSE coefficient of explanation were used to evaluate the models. The area under the curve (AUC) criterion was used to compare the performance of these models. </span></span></span></span></span></span></span></span><br>
<span style="font-size:11pt"><span style="unicode-bidi:embed"><span style="line-height:115%"><span calibri="" style="font-family:"><b><span new="" roman="" style="font-family:" times="">Results</span></b><b><span style="font-size:10.5pt"><span style="line-height:115%"><span style="font-family:" timesnewroman="">:</span></span></span></b><span style="font-size:12.0pt"><span style="line-height:115%"><span new="" roman="" style="font-family:" times=""><span style="color:black"> The results of the GLM model showed that altitude, silt, average annual rainfall, nitrogen, and average annual humidity were the most effective environmental factors affecting species richness, respectively. The BRT model results show that the variables of height, soil acidity, average annual humidity, and clay are the most important in species richness, respectively. The results of the GLM model showed that among the richness and species diversity indices, the highest R<sup>2</sup> related to the richness index was 0.33. Also, the most important variables affecting this index were nitrogen, acidity, electrical conductivity, rainfall, and humidity. The results of the BRT model showed that among the examined indices, the highest R<sup>2</sup> was related to the Shannon diversity index of 0.37. Also, the most important variables affecting this nitrogen index were altitude, clay percentage. and humidity. In general and according to the results, it appears that the environmental parameters affecting richness by the GLM model include altitude, average annual rainfall, average annual humidity, nitrogen, and silt</span></span></span></span><span style="font-size:12.0pt"><span style="line-height:115%"><span new="" roman="" style="font-family:" times="">. For the BRT model were altitude, annual humidity, acidity and clay. The evaluation results of the <span style="color:black">two models showed that the area under the curve (AUC) of the GLM model was 0.61 and the BRT model was 0.72, which shows that the BRT model performed better in modeling species richness in the region.</span></span></span></span></span></span></span></span><br>
<span style="font-size:11pt"><span style="unicode-bidi:embed"><span style="line-height:115%"><span calibri="" style="font-family:"><b><span new="" roman="" style="font-family:" times="">Conclusion:</span></b><span style="font-size:12.0pt"><span style="line-height:115%"><span new="" roman="" style="font-family:" times=""><span style="color:black"> The result of this research provides good information about the distribution of plant species and affecting environmental factors on their diversity and richness.</span></span></span></span> <span style="font-size:12.0pt"><span style="line-height:115%"><span new="" roman="" style="font-family:" times=""><span style="color:black">It is suggested that rangeland managers use the results of this research as well as similar research and give spatial importance to the environmental factors affecting the distribution and richness of species.</span></span></span></span></span></span></span></span><br>
پراکنش گونهای, ارتفاع از سطح دریا, خاک, اقلیم, مدلسازی.
Species distribution, Altitude, Soil, Climate, Modeling.
468
480
http://rangelandsrm.ir/browse.php?a_code=A-10-107-8&slc_lang=fa&sid=1
Mandana
Mohamadi
ماندانا
محمدی
mandana_mohmdi@yahoo.com
100319475328460014929
100319475328460014929
No
Department of Range Management, Faculty of Natural Resources, Sari Agricultural Sciences and Natural Resources University, Sari
گروه مرتعداری، دانشکده منابع طبیعی، دانشگاه علوم کشاورزی و منابع طبیعی ساری، ساری
Zeinab
Jafarian
زینب
جعفریان
z.jafarian@sanru.ac.ir
100319475328460014930
100319475328460014930
Yes
Department of Range Management, Faculty of Natural Resources, Sari Agricultural Sciences and Natural Resources University, Sari
گروه مرتعداری، دانشکده منابع طبیعی، دانشگاه علوم کشاورزی و منابع طبیعی ساری، ساری
Reza
Tamartash
رضا
تمرتاش
reza_tamartash@yahoo.com
100319475328460014931
100319475328460014931
No
Department of Range Management, Faculty of Natural Resources, Sari Agricultural Sciences and Natural Resources University, Sari
گروه مرتعداری، دانشکده منابع طبیعی، دانشگاه علوم کشاورزی و منابع طبیعی ساری، ساری
منصوره
کارگر
Saha_kargar@yahoo.com+
100319475328460014932
100319475328460014932
No
Natural resources and watershed management administration of Alborz province, Karaj
اداره کل منابع طبیعی و آبخیزداری استان البرز، کرج