نتایج جستجو برای: vegetation density and type

تعداد نتایج: 17047909  

Journal: :مرتع و آبخیزداری 0
سیده زهره میردیلمی شناخت مهم ترین تغییر در مؤلفه های کمّی و کیفی پوشش گیاهی بر اثر قرق مراتع دشت کالپوش با استفاده از آنالیز چندمتغیره اسماعیل شیدایی کرکج دانشجوی دکتری علوم مرتع، دانشگاه علوم کشاورزی و منابع طبیعی گرگان موسی اکبرلو دانشیار گروه مرتع داری دانشگاه علوم کشاورزی و منابع طبیعی گرگان

considering the importance of vegetation changes and awareness of its destruction or improvement trends in programming and its proper managing of utilization, this study was conducted in order to survey the effects of grazing on the qualitative and quantitative components of vegetation (including life form, growth form, palatability class, plant families and species diversity) and recognition t...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه مازندران - دانشکده علوم انسانی و اجتماعی 1388

abstract the present study was conducted to examine the effect of proficiency on students interaction while carrying out the grammar-based task(s) in collaboration. in particular, the study examines whether the level of proficiency affects the learners’ focus of attention to grammatical and lexical features. the study takes a further step and examines whether there is any difference in the use...

2015
Rodrigo Marciente Paulo Estefano D. Bobrowiec William E. Magnusson Danilo Russo

Vegetation clutter is a limiting factor for bats that forage near ground level, and may determine the distribution of species and guilds. However, many studies that evaluated the effects of vegetation clutter on bats have used qualitative descriptions rather than direct measurements of vegetation density. Moreover, few studies have evaluated the effect of vegetation clutter on a regional scale....

Journal: :Environmental management 2012
K W Davies J D Bates A M Nafus

Fires in mountain big sagebrush [Artemisia tridentata spp. vaseyana (Rydb.) Beetle] plant communities historically shifted dominance from woody to herbaceous vegetation. However, fire return intervals have lengthened with European settlement, and sagebrush dominance has increased at the expense of herbaceous vegetation in some plant communities. Management actions may be needed to decrease sage...

2007
Elizabeth A. Allen Robert S. Nowak

As pinyon–juniper (specifically, Pinus monophylla and Juniperus osteosperma) woodlands in the western United States increase in distribution and density, understory growth declines and the occurrence of crown fires increases, leaving mountainsides open to both soil erosion and invasion by exotic species. We examined if the loss in understory cover that occurred with increasing tree cover was re...

2014
Raúl Ochoa-Hueso Daniel de la Puente Ranea José Luis Viejo

Butterfly community and single species based approaches were taken to establish conservation priorities within a nature reserve in Central Spain. In this study, patch type (sclerophyllous, halophilous, or disturbed), potential herbaceous nectar availability, potential woody plant nectar availability, total nectar availability, and two approximations to plant diversity (herbaceous and woody plan...

2016
Lie Xiao Guo-Bin Liu Sha Xue

Soil microbial communities are very sensitive to changes in land use and are often used as indicators of soil fertility. We evaluated the microbial communities in the soils of four types of vegetation (cropland (CP), natural grassland (NG), broadleaf forest (BF) and coniferous forest (CF)) at depths of 0–10 and 10–20 cm on the Loess Plateau in China using phospholipid fatty acid (PLFA) profilin...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه تربیت معلم تهران - دانشکده علوم 1372

in this study reference as one of the five cohesive devices in the achievement of textuality in english and persian narrative/descripitive written texts is focused on and analysed . to do so , the theoretical framework elaborated by halliday and hasan (1976) and its version adapted by the writer to match the sub-types of reference in farsi are applied to the analysis of reference in english and...

ستوده, احد, شجاعی, مهین, عظیم‌زاده, حمیدرضا, کیانی, بهمن,

To investigate the relationship between slope, aspect and elevation and quantitative characteristics of plant species, totally 125 sampling plots were selected in a block systematic design. In each sampling, plot presence, number, height, diameter at breast height (for trees) or root collar (for shrubs) and crown diameters were measured and recorded. Also, we recorded vegetation type according ...

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