نتایج جستجو برای: javaherdeh rangelands

تعداد نتایج: 2381  

2011
A. J. Fynn P. Alvarez J. R. Brown C. Kustin M. R. George E. A. Laca C. P. Wong

Rangelands are uncultivated lands that include grasslands, savannahs, steppes, shrub lands, deserts and tundra. The native vegetation on rangelands is predominantly grasses, forbs and shrubs (Kothmann, 1974). Rangelands cover 31 percent of the land surface area of the United States (Havstad et al., 2009), and up to half of the land surface area worldwide (Lund, 2007). Most land areas that are n...

Different land uses have various effects on the changes of soil properties. The purpose of this study was to evaluate the effects of natural forest, needle-leaved plantation and rangelands of central Alborz on new indices of soil quality (i.e. organic matter stratification, carbon management index and soil biological activities). For this purpose, eight samples from organic layer (litter) and m...

Journal: :Environmental Modelling and Software 2006
J. E. Gross R. R. J. McAllister N. Abel D. M. Stafford Smith Yiheyis Maru

Models that seek to guide decisions on policy in rangelands must address the close links between ecological, economic, and social processes, and the adaptation of participants through time. We used an agent-based modeling approach to implement a parsimonious conceptual model of rangelands that includes biophysical processes central to the functioning of rangelands, commercial enterprises, and i...

Journal: :Journal of environmental management 2016
Urs P Kreuter Alan D Iwaasa Gene L Theodori R James Ansley Robert B Jackson Lauchlan H Fraser M Anne Naeth Susan McGillivray Edmundo Garcia Moya

To reduce dependence on foreign oil reserves, there has been a push in North America to develop alternative domestic energy resources. Relatively undeveloped renewable energy resources include biofuels and wind and solar energy, many of which occur predominantly on rangelands. Rangelands are also key areas for natural gas development from shales and tight sand formations. Accordingly, policies ...

Journal: :Proceedings of the National Academy of Sciences of the United States of America 2013
Rob Alkemade Robin S Reid Maurits van den Berg Jan de Leeuw Michel Jeuken

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...

2011
SAMUEL D. FUHLENDORF DAVID M. ENGLE

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 ...

Journal: :African Journal of Range & Forage Science 2021

(2021). Montane rangelands in a changing world. African Journal of Range & Forage Science: Vol. 38, Rangelands Changing World, pp. iii-vi.

Diana Askarizadeh Gholam Ali Heshmati,

To reach the desirable ecosystem management, determining the animal dietselection, which is one of the components of rangeland ecosystem, is important. Therefore, inorder to determine the grazing behavior and diet selection of sheep and goat, the uplandrangeland of northern part of Alborz was selected. In this study, the first weeks of July andAugust of 2009 were chosen for the grazing period o...

2008
J. G. Han Y. J. Zhang C. J. Wang W. M. Bai Y. R. Wang G. D. Han L. H. Li

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...

2004
Charles Perrings Brian Walker

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...

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