توسعه گیاهان بومی یکی از راهکارهای احیاء مراتع تخریب شده می باشد. گاوزبان خارک دار (Anchusa strigosa) یکی از گونه های مرتعی شهرستان دزفول و گونه ای دارویی و صادراتی است. با توجه به تخریب این‌گونه، تحت تأثیر چرای مفرط و تخریب مراتع، می توان با ملاحظه خواهش های اکولوژیکی گونه مذکور، اقدام به توسعه رویشگاهی آن نمود. هدف از این تحقیق تعیین رویشگاه بالقوه برای توسعه گونه گاوزبان خارک دار با توجه به معیارهای اقلیمی، خاکی و توپوگرافی با استفاده از سامانه های اطلاعات جغرافیایی و تحلیل سلسله مراتبی می‌باشد. برای این منظور در سال 1394 از داده های مکانی حضور گونه به عنوان مکان های بالفعل برای رویش استفاده شد. بخشی از اطلاعات رویشگاهی این‌گونه با استفاده از مطالعات زمینی و برداشت نقاط حضور آن استخراج شد. بدین ترتیب که ابتدا نقشه نقطه ای مناطق حضور بر اساس بازدید میدانی تهیه و سپس اطلاعات بیوفیزیکی رویشگاه های فعلی استخراج شد. جهت تکمیل اطلاعات فوق، خواهش های اکولوژیک گونه مذکور استخراج و با اطلاعات زمینی تلفیق شد. نقشه شش معیار در محیط ArcGIS®10.1 تهیه، طبقه بندی و استانداردسازی شد. ازآنجاکه وزن لایه های مذکور یکسان نیست، جهت اولویت‌بندی مناطق مستعد رویشگاهی از فرآیند تحلیل سلسله مراتبی جهت وزن دهی استفاده شد. نتایج این تحقیق نشان داد از کل مساحت 3/464547 هکتاری منطقه، 31 درصد رویشگاه خوب، 38 درصد رویشگاه متوسط، 7 درصد جزء رویشگاه های ضعیف تا خیلی ضعیف می باشد. درواقع مقدار مساحت مناطق رویشگاهی مناسب برای رشد و استقرار این‌گونه 2/349909 هکتار است. همچنین از نتایج تحقیق استنباط می شود که بارندگی بیشترین وزن و شیب کمترین وزن را دارد که نشان داد که معیار بارندگی مهم‌ترین و شیب بی اهمیت ترین برای رشد این‌گونه است. پرونده مقاله

Assessing and monitoring rangelands in arid regions are important and essential tasks in order to manage the desired regions. Nowadays, satellite images are used as an approximately economical and fast way to study the vegetation in a variety of scales. This research aims to estimate the coverage percent using the digital data given by ETM+ Landsat satellite. In late May and early June 2018, the vegetation was measured in Ardakan plain, Yazd province, Iran. Information was obtained by 320 plots in 40 transects and also, the satellite images in terms of sampling time were downloaded and processed in USGS website. 16 indices involving NDVI, NIR, MSI, SS, IR1, MIRV1, NVI, TVI, RAI, SAVI, LWC, PD322, PD321, PD312, PD311 and IR2 were estimated. Through estimating the indices and extracting the values in order to conduct index-based predictions, six data mining models of Artificial Neural Network (ANN), the K Nearest Neighbor (KNN), Gaussian Process (GP), Linear Regression (LR), Support Vector Machine (SVM) and Decision Tree (DT M5) have been applied. Model assessment results indicated high vegetation estimate efficiency based on the indices but the model KNN with Root Mean Square Error (RMSE= 2.520) and Coefficient of determination (R2= 0.94) and (RMSE= 2.872 and R2= 0.96) had the highest accuracy in the training and data sets, respectively. As well, to determine the weight and importance of parameters, and to estimate the coverage percent, the weighing process were conducted based on support vector machine. Weighing results indicated that the KNN model and the Simple Subtraction (SS) index had higher weight and importance in terms of vegetation percent. پرونده مقاله

Pollinators that feed on insect-pollinated plants have an important role in the food chain. Because pollinator insects have the potential to raise the value of agricultural crops and are very helpful in the nitrogen stabilization and the prevention of pest invasions. The present study mainly investigated the contribution of three services of insect pollination in rangeland along with the valuation of the services. In the study, to calculate the share of each service, cutting and weighing methods (for forage production) and engineering economics methods (replacement cost and Transfer of Benefits) were used to calculate the economic value in 2017. These services include increased yield of agricultural supply, upgraded nitrogen fixation by nitrogen fixing plants in rangelands, and reduction of plant pests and diseases by pollinator insects. Each service value was anticipated to be 15.31%, 48.9% and 35.78% of the overall of insect pollination, respectively. Besides, the extent of pollinator insects services value per hectare and the whole rangeland ecosystem was 62.37$ and 649096.5$, respectively. Consequently, following the outcome of the present study, preservation of insect pollination services is considerable to sustain and keep food security, sustainable agricultural development, sustainable employment, and protection of natural, environmental ecosystems and the environment, especially rangelands. Thus, insect pollinator services were regarded significant by policy makers and managers. پرونده مقاله

Different 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. پرونده مقاله