نتایج جستجو برای: arid rangeland

تعداد نتایج: 21136  

Journal: :مرتع و آبخیزداری 0
سعیده ابراهیمی ازندریانی سیدحمیدرضا صادقی

recognition of rangeland species with the maximum efficiency and the minimum water usage is very important, since major parts of rangelands in iran are located in arid and semiarid climate. in addition, the rangeland improvement and management on the basis of transpiration rate of rangeland species in different climatic conditions has great importance. the goal of this research is comparison an...

Journal: :مرتع و آبخیزداری 0
طاهره صادقی شاهرخت کارشناس ارشد مرتع داری، دانشگاه فردوسی مشهد محمد جنگجو دانشیار گروه مرتع و آبخیزداری دانشکده منابع طبیعی و محیط زیست، دانشگاه فردوسی مشهد منصور مصداقی استاد مدعو، دانشکده منابع طبیعی و محیط زیست دانشگاه فردوسی مشهد

rangeland shrubs may provide mechanical facilitation on their understory plants, by protecting themagainst the livestock grazing. however, such a facilitation effect may vary depending on the rangelandutilization rate. in a field research, mechanical facilitation of rangeland shrubs was compared in ahighly grazed, a moderately grazed and an enclosure site; in an arid rangeland, kakhak, gonabad,...

Journal: :Remote Sensing 2017
Anne Schucknecht Michele Meroni François Kayitakire Amadou Boureima

Livestock plays an important economic role in Niger, especially in the semi-arid regions, while being highly vulnerable as a result of the large inter-annual variability of precipitation and, hence, rangeland production. This study aims to support effective rangeland management by developing an approach for mapping rangeland biomass production. The observed spatiotemporal variability of biomass...

2006
JIAGUO QI

Understanding landscape conversion is vital for assessing the impacts of ecological and anthropogenic disturbances at regional and global scales. Since rangelands cover nearly half of the global land surface, and because a large part of rangelands is located in semi-arid ecosystems, they serve as critical land cover types for determining regional biodiversity, global biogeochemical cycles, and ...

2005
Ian A. Simpson Amanda M. Thomson Jennifer L. Brown

The introduction of domestic livestock particularly sheep and rangeland grazing by Norse settlers to Faroe during the 9th century has generally been described as a major pressure on a sensitive landscape, leading to rapid and widespread vegetation change and contributing to land degradation. This view has, however, been developed without consideration of Norse grazing management practices which...

2010
Sujith Ravi Paolo D’Odorico Travis E. Huxman Scott L. Collins

Shrub encroachment in arid and semiarid rangelands, a worldwide phenomenon, results in a heterogeneous landscape characterized by a mosaic of nutrient-depleted barren soil bordered by nutrient-enriched shrubby areas known as ‘‘fertile islands.’’ Even though shrub encroachment is considered as a major contributor to rangeland degradation, little is known about mechanisms favoring the reversibili...

2003
MS. Moran A. F. Rahman J. C. Washburne DC. Goodrich M. A. Weltz

The Penman-Monteith equation is useful for computing evaporation rates of uniform surfaces, such as dense vegetation or bare soil. This equation becomes less useful for evaluation of evaporation rates at the regional scale, where surfaces are generally characterized by a patchy combination of vegetation and soil. This is particularly true in the arid and semi-arid regions of the world. The appr...

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