نتایج جستجو برای: diversity of vegetation density
تعداد نتایج: 21214870 فیلتر نتایج به سال:
The impact of large herbivores on ecosystems before modern human activities is an open question in ecology and conservation. For Europe, the controversial wood-pasture hypothesis posits that grazing by wild large herbivores supported a dynamic mosaic of vegetation structures at the landscape scale under temperate conditions before agriculture. The contrasting position suggests that European tem...
Vegetation in any landscape reflects its health condition. Monitoring land use change and land cover plays a key role in environmental planning and management. Mazandaran province has always been considered by tourists due to its high tourism potential and consequently the vegetation, especially the forest, has been damaged. In this study, vegetation Contiguity and integrity in Mazandaran using...
بررسی تنوع ژنتیکی ژنوتیپهای بومی پیاز ایرانی در مقایسه با انواع خارجی چکیده: برنامه های اصلاحی گیاهان بر اساس تنوع و انتخاب صفات برتر کمی و کیفی صورت می گیرد. لذا، ارزیابی تنوع ژنتیکی، اولین مرحله در برنامه های اصلاحی است. در این راستا، استفاده از روش های جدید مطالعهی تنوع ژنتیکی ضروری به نظر می رسد. در این بررسی تعیین تنوع ژنتیکی سیزده ژنوتیپ پیاز ایرانی در مقایسه با دو ژنوتیپ خارجی با است...
Remote sensing and aerial photography are means of exploring, studying and estimating vegetation variables such as species frequency and density in forests and rangelands. Common remote sensing images usually offer general information about vegetation parameters. For detailed information about vegetation (e.g. estimation of vegetation density and/or frequency), larger scale images are needed. T...
Pteridium aquilinum is known as an invasive species in different ecosystems of the world. The spread of this species is increasing in the north of Iran particularly outside of forest ecosystems. In this study, the amount and composition of soil seed banks in the dense pathes of Pteridium were investigated in summer rangelands of Bandpay in the south of Babol city in Mazandaran province, Iran...
This study aimed to investigate the effects of the fire products treatments (heat, smoke and ash) on the density, species diversity, growth form and the life form of the soil seed bank in the semi-steppe rangelands of the Karsanak region in Chaharmahal and Bakhtiari Province. For this purpose, soil samples were collected from the studied region and fire products treatments were applied to them...
Based on the importance and role of species diversity and richness as ameasurement of the health of an ecosystem; studying of their components can lead toevaluate the health condition of rangeland. This research was carried out in a part ofhighland mountainous rangeland of Mount Alborz Range in Iran. Diversity and richnesswere assessed as an ecosystem health indicator. The study area was locate...
The objective of this study was to quantify the effects of protection on herbaceous species composition, total plant cover, dry matter, plant density, floristic richness and diversity. Characteristics of vegetation under continued grazing and protected area for 10 and 65 years were examined in a degraded arid environment in South Tunisia. Our results show that protection enhances significantly ...
Introduction: Students with specific language impairment (SLI) have many difficulties in producing coherent written texts The goal of this study was to investigate and compare the management of cohesion in the written production of individuals with SLI and their normal peers in terms of density and diversity of connectives, the density of punctuation marks (periods and commas) and density and d...
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