نتایج جستجو برای: especially in arid and semiarid regions

تعداد نتایج: 21755242  

2014
Guang-Lei Gao Guo-Dong Ding Bin Wu Yu-Qing Zhang Shu-Gao Qin Yuan-Yuan Zhao Yan-Feng Bao Yun-Dong Liu Li Wan Ji-Feng Deng

BACKGROUND Biological soil crusts are common components of desert ecosystem; they cover ground surface and interact with topsoil that contribute to desertification control and degraded land restoration in arid and semiarid regions. METHODOLOGY/PRINCIPAL FINDINGS To distinguish the changes in topsoil affected by biological soil crusts, we compared topsoil properties across three types of succe...

2015
Ashley A. Coble Stephen C. Hart Michael E. Ketterer Gregory S. Newman Andrew L. Kowler

Without exogenous rock-derived nutrient sources, terrestrial ecosystems may eventually regress or reach a terminal steady state, but the degree to which exogenous nutrient sources buffer or slow to a theoretical terminal steady state remains unclear. We used strontium isotope ratios (Sr/Sr) as a tracer and measured Sr/Sr values in aeolian dust, soils, and vegetation across a well-constrained 3M...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه فردوسی مشهد - دانشکده ادبیات و علوم انسانی دکتر علی شریعتی 1391

this ethnographic case study research was carried out in a private school setting in the context of iran. the research tried to explore the analysis and identity construction of a group of learners and teachers along with the content analysis of books on the basis of four types of commodified, political, national and narrative identities. how english language learners and teachers in an informa...

2005
XUBIN ZENG ROBERT E. DICKINSON MICHAEL BARLAGE YONGJIU DAI GUILING WANG KEITH OLESON

In arid and semiarid regions most of the solar radiation penetrates through the canopy and reaches the ground, and hence the turbulent exchange coefficient under canopy Cs becomes important. The use of a constant Cs that is only appropriate for thick canopies is found to be primarily responsible for the excessive warm bias of around 10 K in monthly mean ground temperature over these regions in ...

The aim of this paper is to project extreme precipitation events in an arid and a semiarid station. In order to project climate change based on general circulation models (GCMs), we have applied LARS-WG[1] downscaling tool. This stochastic weather generator down-scaled the climate of two synoptic stations using HADCM3 model and A2 emission scenario for 2040. We extracted extreme precipitation e...

Journal: :Ecological applications : a publication of the Ecological Society of America 2008
K David Hambright Tamar Zohary Werner Eckert Steven S Schwartz Claire L Schelske Kathleen R Laird Peter R Leavitt

Exploitation of freshwater resources is having catastrophic effects on the ecological dynamics, stability, and quality of those water resources on a global scale, especially in arid and semiarid regions. Lake Kinneret, Israel (the Biblical Sea of Galilee), the only major natural freshwater lake in the Middle East, has been transformed functionally into a reservoir over the course of approximate...

Journal: :تحقیقات آب و خاک ایران 0
علیرضا راهب دانشگاه تهران احمد حیدری دانشگاه تهران شهلا محمودی دانشگاه تهران

soil genesis and evolution studies are based on well understanding of geochemical processes involved in pedogenic processes and formation of soil. parent materials are main factors controlling soil properties in arid and semiarid regions. in this study, physicochemical and geochemical properties of 6 selected soil profiles developed on basalt rocks along arid (eshtehard), semiarid (qazvin) and ...

2003
Mitchel P. McClaran

The International Arid Lands Consortium (IALC) was established in 1990 to promote research, education, and training activities related to the development, management, and reclamation of arid and semiarid lands in the Southwestern United States, the Middle East, and elsewhere in the world. The Consortium supports the ecological sustainability and environmentally sound stewardship of these lands ...

Persian gazelle, Gazella subgutturosa, exists throughout arid and semiarid regions of Iran and has a key role in these frail ecosystems. Habitat degradation and population decline has placed it on the list of vulnerable species in 2008. The phylogenetic relationships of three Persian gazelle populations in the central part of Iran (i.e. Ghamishlou National Park and Wildlife Refuge, Mouteh Wildl...

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