نتایج جستجو برای: total vegetation cover decreased by 362
تعداد نتایج: 7530927 فیلتر نتایج به سال:
In recent decades, land use changes have been one of the most important environmental issues worldwide. This study was carried out to investigate and analyse land use changes in dust sources of south and south-east Ahwaz and surrounding lands using remote sensing technique. Firstly, based on the standard precipitation index (SPI), the years 1986, 2002 and 2016 were selected as years with near n...
Soil and water resources management of rivers has an important role because of direct relation withdifferent systems such as earth, life, social and people. Although the use of vegetation cover inbioengineering and biological stabilization and also soil and water resources management projects hasmany advantages, but improper methods of design and implementation cause hydraulic specificationsof ...
The present study was conducted to assess socio-economic impacts of deforestation of Hyrcanian forests in two basins of Do-Hezar and Se-Hezar, northern Iran. To this end, changes in the forest area were detected over the period between 1990 and 2006 based on land use land cover maps derived from Landsat and IRS satellite images. The land use changes were investigated by enhancement of the image...
For studying vegetation cover in Choghakhor wetland located in Chaharmahal-o-Bakhtiari province (W Iran), some zones of vegetation life forms were determined and also digitized in order to produce the primary map of plant cover by using LISS-IV sensor of IRS satellite with the spatial resolution of 5.8 m. As aquatic plants in Choghakhor wetland were fully grown, homogeneity or heterogeneity of ...
Terrestrial vegetation dynamics are closely influenced by both climate and by both climate and by land use and/or land cover change (LULCC) caused by human activities. Both can change over time in a monotonic way and it can be difficult to separate the effects of climate change from LULCC on vegetation. Here we attempt to attribute trends in the fractional green vegetation cover to climate vari...
the purpose of this research was to investigate the relationship between vegetation cover and soil characteristics in order to determine the most important soil factors which affect on quantitative variations and types of vegetation cover in the study area. the study area is located in west of tehran province and southeast of hashtgerd, next to najm-abad village. after field studies, the index ...
To determine suitable indices for vegetation cover and production assessment based on remote sensing data, simultaneous digital data with field data belonged to summer rangeland of southern part of Isfahan province were analyzed. During 2 years of monitoring, annuals, grasses, forbs and shrubs vegetation cover and total production data from sixty 1 square meter plots in each site were collected...
introduction: soil organic matter is influenced strongly by vegetation cover and management, therefore it is proposed as the main indicator of soil quality and health. the changes in soil organic matter status occur much more rapidly in the labile pools than in organic c. thus, labile pools can be used as early indicators of changes in total organic matter that will become more obvious in the l...
The present study discusses a method used to produce updated information about vegetation cover in arid and semi-arid zones, using RS data and GIS technique. In this method, Landsat ETM+ data in 2002 was collected in an area of about 60000 ha in Nodoushan basin, Yazd, Iran. To collect the necessary ground data, 50 sites of different vegetation types were selected and the percentage of vegetatio...
Many arid grassland communities are changing from grass dominance to shrub dominance, but the mechanisms involved in this conversion process are not completely understood. Aeolian processes likely contribute to this conversion from grassland to shrubland. The purpose of this research is to provide information regarding how vegetation changes occur in an arid grassland as a result of aeolian sed...
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