نتایج جستجو برای: semi arid environment

تعداد نتایج: 659440  

2016
Yuting Yang Huade Guan Okke Batelaan Tim R. McVicar Di Long Shilong Piao Wei Liang Bing Liu Zhao Jin Craig T. Simmons

Drought is an intermittent disturbance of the water cycle that profoundly affects the terrestrial carbon cycle. However, the response of the coupled water and carbon cycles to drought and the underlying mechanisms remain unclear. Here we provide the first global synthesis of the drought effect on ecosystem water use efficiency (WUE = gross primary production (GPP)/evapotranspiration (ET)). Usin...

Journal: :Remote Sensing 2017
Ran Goldblatt Alexis Rivera Ballesteros Jennifer Burney

Semi-arid ecosystems play a key role in global agricultural production, seasonal carbon cycle dynamics, and longer-run climate change. Because semi-arid landscapes are heterogeneous and often sparsely vegetated, repeated and large-scale ecosystem assessments of these regions have to date been impossible. Here, we assess the potential of high-spatial resolution visible band imagery for semi-arid...

2016
Yao Zhang Xiangming Xiao Luis Guanter Sha Zhou Philippe Ciais Joanna Joiner Stephen Sitch Xiaocui Wu Julia Nabel Jinwei Dong Etsushi Kato Atul K. Jain Andy Wiltshire Benjamin D. Stocker

Carbon uptake by terrestrial ecosystems is increasing along with the rising of atmospheric CO2 concentration. Embedded in this trend, recent studies suggested that the interannual variability (IAV) of global carbon fluxes may be dominated by semi-arid ecosystems, but the underlying mechanisms of this high variability in these specific regions are not well known. Here we derive an ensemble of gr...

Journal: :desert 2015
amir reza keshtkar

knowledge about low flow statistics is essential for effective water resource planning and management in ungauged orpoorly gauged catchment areas, especially in arid and semi-arid regions such as iran. we employed a data set of 20 riverflow time-series from the iranian central plateau river basin, iran to evaluate the low-flow series using several frequencyanalysis methods and compared the resu...

Journal: :journal of rangeland science 2014
mohsen sharafatmandrad adel sepehry hossein barani

in arid and semi-arid rangelands, grazing as one of the natural or human induced processes has direct and indirect effects on structure and dynamics of plant community and ecosystems. a study was done to analyze the effects of grazing on plant species diversity and plant functional types‘ (pfts) diversity of arid and semi-arid rangelands. we analyzed plant richness and diversity data from 75 sa...

Journal: :journal of rangeland science 2011
nasrin kolahchi mohsen mohseni saravi ali tavili mohammad jafari ghasem assadian

at the beginning of twenty-first century, the water crisis in the priority policy andmanagement is inside and outside of the country as principle thoroughly human, social,economic and political rulers of the country is considered abundant. the world bank hasannounced that during 1960 and 2025, water resources in middle east, from 3430 m3 for theeach person in year reach to 667 m3 because of pop...

Journal: :journal of rangeland science 2012
sedigheh zare kia hossein arzani mohammad jafari seyyed akbar javadi ali ashraf jafari

this study aims to assess the effect of grazing intensity on vegetation structure, soil nutrient concentrations and soil physical properties. the study was carried out in steppe rangelands of saveh, markazi province, iran. four sites with four grazing intensities including very high, high, moderate and non-grazed with the same ecological conditions were selected. to study various vegetation and...

A. Abubakar M.M. Mikailu, N. Muhammad S. Altine U.M. Chafe

The study was conducted to determine the effect of varying protein levels and preservation method on external egg qualities of Japanese quails. A total of 180 birds were randomly allotted into three dietary treatments in a completely randomized design (CRD) replicated six times. A factorial arrangement of 3 × 4 × 4 which involves 3 protein levels (15, 20 and 25% crude protein), 4 storage method...

2003
S. Tabeni R. A. Ojeda

Loss of species richness and reduced abundance have been the main responses to perturbations of smalland medium-sized mammals in arid and semi-arid areas. Nonetheless, some mammal species whose habitat requirements are met in disturbed patches may benefit from structural changes in the environment brought about by perturbations. In desert areas of Argentina different mammal responses are attrib...

Journal: :CoRR 2017
Nicolas Rey Michele Volpi Stéphane Joost Devis Tuia

This is the pre-acceptance version, to read the final version published in Remote Sensing of Environment, please go to: 10.1016/j.rse.2017.08.026. Unmanned aerial vehicles (UAVs) offer new opportunities for wildlife monitoring, with several advantages over traditional field-based methods. They have readily been used to count birds, marine mammals and large herbivores in different environments, ...

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