نتایج جستجو برای: arid
تعداد نتایج: 18687 فیلتر نتایج به سال:
Current global changes are putting both biodiversity and the processes that depend on it at risk. This is especially true for semi-arid regions and the flagship groups that inhabit them, such as amphibians and reptiles. Semi-arid regions are often thought to have lower biodiversity and thus have been overlooked, resulting in the underestimation of their biological richness. Therefore, the aim o...
the purpose of this study was to evaluate the species-environment relationships in arid and semi-arid rangelandsof nodushan, yazd. the plant species cover and the environmental variables were measured at 9 sites. soil sampleswere taken for measurement of 12 attributes in 0-10 cm and 10-80 cm layers. vegetation was classified using twowayindicator species analysis (twinspan). data was analyzed u...
The riotion of “cottipittatiotial crcgtitig ” focuses oti the tiiinierous ~ * a y s in which coniputatiotial niedia tilay be used to expand the expressive range of traditional editcational crufts. One itnportant dimension of this approach involves a close re-examination of titi issue often taketi f o r grtitited iti educational technologytinniely, the desigri and use of I/O devices. The next de...
Climate change may significantly affect the hydrological cycle and water resource management, especially in arid and semi-arid regions. In this paper, output from the Providing Regional Climates for Impacts Studies (PRECIS) regional climate model were used in conjunction with the Soil and Water Assessment Tool (SWAT) to analyse the effects of climate change on streamflow of the Xiying and Zamu ...
Arid and semi-arid zones account for one third of the earth's surface land area and cover most parts of the developing nations in the world including Latin America, Africa, and parts of India and South East Asia. Nevertheless, these ecosystems are not exclusive of developing countries because they also exist in developed nations such as United States of America, Spain, Australia, and Israel, am...
Concentrations of copper (Cu), lead (Pb), chromium (Cr), mercury (Hg), and arsenic (As) were measured in arid agricultural and irrigated agricultural soils collected in Daba Village, Shajiawuan Village, Gangou Village and Sifangwu Village, located in central Gansu Province, China. Concentrations except Hg and Pb were lower than the background values in grey calcareous soil in the selected arid ...
Interactive Digital Television (iDTV) has facilitated and expanded the communication and interaction in activities of knowledge acquisitions, entertainment, and recreation in the distance learning field. This new way of teaching and learning has been called t-Learning. In this context, the Learning Objects (LOs) have an important role in assisting in the electronic courses’ development. Due the...
Landscape metrics are useful tools in investigating spatial structure and in describing the heterogeneity of landscapes, but are sensitive to grain size. Thus, it is necessary to determine the appropriate grain size before researching landscape patterns. However, there have been few large-scale investigations in high-precision research about the effect of grain size on landscape patterns, espec...
The objective of this paper is to provide an overview of the primary results of the Semi-Arid Land–Surface–Atmosphere (SALSA) Program in the context of improvements to our overall understanding of hydrologic, ecologic, and atmospheric processes and their interactions in a semi-arid basin. The major findings and future research needs associated with the different core components of the program a...
Hypotheses about the origin of vegetation pattern formation in semi-arid areas around the world almost all include a common feature of semi-arid areas: the presence of a positive feedback between plant density and water infiltration. We investigate whether this positive feedback and the spatial redistribution of runoff water are sufficient to explain vegetation pattern formation. For this purpo...
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