نتایج جستجو برای: lack of vegetation
تعداد نتایج: 21169415 فیلتر نتایج به سال:
The degradation rate of Mediterranean steppes, especially in North Africa is 1% per year, and this considered a high rate of degradation. This study conducted in 2014 in the south slope of the Al-Jabal Al-Akhdar, northeast Libya to quantify the vegetation recovery rate and assess selected Vegetation Indices (VIs) for mapping rangelands degradation status using remote sensing technology. Throug...
Vegetation cover is an important component of terrestrial ecosystems that changes seasonally. Accurate parameterization of vegetation cover dynamics through developing indicators of periodic patterns can assist our understanding of vegetation-climate interactions. The current study was conducted to investigate and model vegetation changes in some phytogeographical regions of Iran including, Kha...
Based on the importance of runoff harvesting method in arid lands, effect of these systems on vegetation production and cover and soil moisture was evaluated. Soil and vegetation were sampled in three sampling areas (Control, Curved pits, Catchment ponds) using randomly-systematic method and in each site (50 hectares), 98 plots were sampled with intervals of 70 m within plots of 1*2 m and in to...
background: the purpose of this work is to discover and analyze errors and incidents in some radiotherapy centers, and to introduce methods that could reduce their occurrences, especially those which had happened due to the use of improper and inadequate equipment. this work is a first step toward clarifying the role of education in a risk-conscious culture, and changing the attitude of radioth...
Risks assessment of forest project implementation in spatial density changes of forest under canopy vegetation using artificial neural network modeling approach Nowadays, environmental risk assessment has been defined as one of the effective in environmental planning and policy making. Considering the position and structure of vegetation on the forest floor, the main role of forest under ca...
Normalized difference vegetation index and land surface temperature data, in a sample plot each from east, center and west of Nepal, from 2000 to 2015, were analyzed to identify and compare the trends of vegetation and temperature changes during the period. The data were obtained from moderate resolutions imaging spectro-radiometer. Normalized difference vegetation index charactiszes a resoluti...
Semi-steppe rangelands are a complex, highly dynamic and often multi-layered mosaic of grassland, shrubland, and intermediate communities. A few recent studies have explicitly or implicitly developed synthetic hypotheses about how interactive effects of human made disturbances initiate dynamic changes in plant community composition to cause a shifting mosaic of vegetation pattern across the lan...
Semi-steppe rangelands are a complex, highly dynamic and often multi-layered mosaic of grassland, shrubland, and intermediate communities. A few recent studies have explicitly or implicitly developed synthetic hypotheses about how interactive effects of human made disturbances initiate dynamic changes in plant community composition to cause a shifting mosaic of vegetation pattern across the lan...
Abstract. Rangeland vegetation dynamics encompass all processes of changes in vegetation composition and structure over time. Investigating the rangeland ecosystem dynamics makes it possible to determine the effects of climatic and management conditions on qualitative and quantitative changes of the vegetation in a specific period of time. Accordingly, data collection and measurements for evalu...
Abandonment of arable lands is the starting point of vegetation succession. The trajectory and speed of succession can be different according to the time of abandonment. The aim of this study is to assess the effect of abandonment periods on species richness, diversity and functional groups in shrublands and grasslands of Shirmard rangelands in Chaharmahal va Bakhtiri, Iran. A total of 96 abond...
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