نتایج جستجو برای: kashaf rood basin
تعداد نتایج: 57243 فیلتر نتایج به سال:
one of the characteristics in iranian model of desertification potential assessment (imdpa) is vegetation. sincevegetation is very important factor in the degradation of land, so some indices were determined for this item in order toevaluate desertification potential of arid, semi arid and arid sub humid areas of iran. the indices included vegetationcondition, exploit and revegetation. to calib...
We investigate the evolutionary history of the wide-ranging Nearctic treefrog Hyla arenicolor through the integration of extensive range-wide sampling, phylogenetic analyses of multilocus genetic data, and divergence dating. Previous phylogeographic studies of this frog documented a potential signature of introgressive hybridization from an ecologically and morphologically divergent sister spec...
1- Introduction Watershed describes an area of land that contains a common set of streams and rivers, which all drain into a single large body of water. For sustainable management of watersheds, soil erosion is a major factor, which accelerates the rate of land degradation and hence influences agricultural productivity, run off movement and sometimes leads flood in the lower basin. Soil is one...
The phenomena of erosion, sediment transport and sedimentations have tremendously destructive effects on environment and hydraulics structures. In general, sediment transportation depends on river discharges, but the proposed equations inherited with large errors. To evaluate the suspended sediment loads and an optimized model on them, in this research, data were collected from some sub-watersh...
s: 30–31.Richter, B.D., Mendelson, M.A. & Master, L.L. (1997a). Threats to imperiled freshwater fauna.Conservation Biology, 11: 1081–1093. Richter, B.D, Baumgartner, J.V., Wigington, R. & Braun, D.P. (1997b). How much water doesa river need? Freshwater Biology, 37: 231–249.Riley, A.L. (1998). Restoring Streams in Cities: a Guide for Planners, Policymakers, and Citizens. Washingt...
Although hypersaline environments pose challenges to life because of the low water content (water activity), many such habitats appear to support eukaryotic microbes. This contribution presents brief reviews of our current knowledge on eukaryotes of water-column haloclines and brines from Deep Hypersaline Anoxic Basins (DHABs) of the Eastern Mediterranean, as well as shallow-water hypersaline m...
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