نتایج جستجو برای: vegetation density and type
تعداد نتایج: 17047909 فیلتر نتایج به سال:
Drought as a complex ecosystem crisis can affect vegetation density and health. Iran with an arid and semi-arid climate is exposed to this phenomenon. Therefore, it is necessary to evaluate the effect of drought on vegetation. The purpose of this study is to evaluate the effect of meteorological drought on vegetation dynamics in Iran. In this regard, using MATLAB software, SPEI index with time ...
vegetation cover as the main factor affecting the water erosion plays an important role in preventingsoil loss. to this end, for better understanding the impact of vegetation cover on soil erosion andsediment yield over the major existing geological formations in the summer rangelands of balade inthe mazandaran province, rainfall simulation studies have been carried out using a portable rainfal...
Drought and grazing rangelands play an important role in changing the structure of vegetation and losing the biodiversity of natural ecosystems. In this research, in order to determine the effects of drought and livestock grazing on the vegetation structure of rangelands located in the Nakhab Forest of South Khorasan Province, species abundance, biodiversity, and range condition and trend were ...
primary information about different methods of vegetation sampling is important to researchers to decide about their sampling. in this study we applied five distance methods (closest individual, nearest neighbor, random pairs, point-centered quarter and angle orderd) to estimate plant density in three vegetation types including artemisia sieberi, juncus littoralis and punica granatum in mazanda...
habitat associations of wild sheep, alborz red sheep (ovis orientalis gemelini x ovis orientalis arkali ), in khojir and sorkheh hesar national parks were studied over three seasons (spring, autumn and winter) in 2000. the position of observed maternal groups (including ewe with lamb) and male groups (including rams, barren ewes and juveniles) were determined on topographical maps during the fi...
One of non-forage functions of rangelands vegetation is soil conservation and prevents it from erosion. Water soil erosion has economic, social and environmental implication due to both on-site and off-site effects. So, the objective of this study was to assess the on-site effect of water erosion on conservation function of summer rangelands vegetation, using a combination between economic valu...
Vegetation structure and density affect the dynamics of snow accumulation and ablation. Vegetation also affects our ability to estimate snow-covered area accurately from satellite-based sensors. The objective of this case study is to demonstrate how the angular pattern of reflectance from vegetation over snow can provide information on forest cover density. Imagery from the Multi-angle Imaging ...
مراتع حدود نیمی از خشکی های جهان را در بر دارند و پوشش گیاهی آن در نتیجه تأثیر متقابل محیط و موجودات زنده به وجود آمده است و به عنوان یک اکوسیستم طبیعی مدیریت می شوند. علاوه بر مراتع، راه ها در عصر حاضر نیز از اجزا مهم و زیرساخت های اصلی زندگی نوین و توسعه کشورها به شمار می روند. جاده ها ساخته دست بشر هستند و جوامع گیاهی کنار جاده تحت تأثیر ساخت و ساز قرار دارند. پوشش "رودرال" به مجموعه ای از پ...
چکیده ندارد.
abstract in this study, we synthesized a novel template polymer by using methacrylic acid (mma) as functional monomer, ethylene glycol dimethacrylate(egdma) as cross linker, 2,2-azobisisobutyronitrile (aibn) as initiator and olanzapine as targeted molecule in the presence of chloroform and acetonitrile as solvent. the products have been characterized and confirmed by (chn)elemental analysis,...
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