نتایج جستجو برای: sahand rangelands
تعداد نتایج: 2475 فیلتر نتایج به سال:
Biodiversity in rangelands is decreasing, due to intense utilization for livestock production and conversion of rangeland into cropland; yet the outlook of rangeland biodiversity has not been considered in view of future global demand for food. Here we assess the impact of future livestock production on the global rangelands area and their biodiversity. First we formalized existing knowledge ab...
sahand volcanic-sub-volcanic dome, along with several other magmatic domes in northwest iran and the southern part of tabriz fault show adakitic geochemical characteristics. sahand dome has mainly dacitic composition. the sio2 content and mg number of sahand dome range from 64 to 73 wt% and 27 to 57 respectively. sahand dome can be classified as high silica adakitic (hsa) type. the rocks studie...
abstract a mountain glacier, when it occupies a river valley, immediately begins to change the cross-section and profile of that valley. river valleys in mountain areas tends to have v-shaped profiles. glaciers work to widen as well as deepen their valleys and the typical cross-section of a glacial valley is u-shaped. the u-shaped glacial valley is one of the most characteristic of glacial land...
Rangelands are the most common form of terrain WE PROPOSE A PARADIGM THAT in both the United States (where it accounts for 61% of all land surface) and the world (70% of all land surface). ENHANCES HETEROGENEITY Rangelands consist primarily of native plant communities managed, typically, for livestock production (Holechek et al. INSTEAD OF HOMOGENEITY TO PROMOTE 1998). Because they can embrace ...
Michael P. Brenner,1 Sahand Hormoz,2,3 and Alain Pumir4 1School of Engineering and Applied Sciences and Kavli Institute for Bionano Science and Technology, Harvard University, Cambridge, Massachusetts 02138, USA 2Kavli Institute for Theoretical Physics, University of California, Santa Barbara, Santa Barbara, California 93106, USA 3Division of Biology and Biological Engineering, California Insti...
(2021). Montane rangelands in a changing world. African Journal of Range & Forage Science: Vol. 38, Rangelands Changing World, pp. iii-vi.
Rangelands of China have for centuries provided forage for livestock but now their role in water, soil, and biodiversity conservation is being recognised by Governments and people. However, much of the rangelands has recently degraded anddesertification is nowawidespread problem.The cause of the degradation is over-grazing andover-cultivation. Climate change is exacerbating theproblem.TheChines...
In previous papers we have considered the optimal mix of biodiversity in semi-arid rangelands, focusing on the steady state. This paper addresses the question of conservation in the optimal use of rangelands, where conservation is understood to mean maintenance of the system in a ‘natural’ state. We consider a rangeland that may exist in one of two states. In the ‘natural’ state, its dynamics a...
The evaluation of vegetation covers using conventional methods is difficult over arid areas due to several reasons such as lack of the suitable roads to these regions. Moreover, this task is time-consuming. For these reasons, remote sensing has been considered as an economic alternative for conventional field work. In this study, the feasibility of using IRS images in vegetation cover evaluatio...
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