Setareh Bagheri; Reza Tamartash; Mohammad Jafari; Mohammad Reza Tatian; Arash Malekian
Abstract
Plain ecosystem is highly vulnerable to environmental changes, and drought is the most famous ecosystem change driver that is difficult to identify after its occurrence. In this research, to study the slope of vegetation changes against drought, the NDVI index of MODIS images and the SPI index from 2001 ...
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Plain ecosystem is highly vulnerable to environmental changes, and drought is the most famous ecosystem change driver that is difficult to identify after its occurrence. In this research, to study the slope of vegetation changes against drought, the NDVI index of MODIS images and the SPI index from 2001 to 2016 were used and the map of vegetation changes against drought with five drought stress classes included very low classes, Low, moderate, high and very high, so that a suitable assessment of the drought can be made at specified time scales. The results of slope pattern of spatial change of vegetation against drought showed that across the plain vegetation changes have declined, and from east to west of Qazvin plain, the slope of vegetation changes and land susceptibility to drought have been reduced. So that the most percentage of area in a one-month drought related to the drought class is very low, but in droughts of 3, 6, 9, 12, 24 and 48 months, the highest percent of the area belonged to moderate and high drought classes. The results of this study, the determination of the level of vegetation changes in against drought in the past years and prediction of these changes in the future years, can be used in the planning and optimal use of resources, control changes in the future.
Zeinab Jafariyan; Leila Tayefeh Seyyed Alikhani; Reza Tamartash
Abstract
Carbon sequestration potential of three species including Agropyron elengatum, Stipa barbata and Artemisia aucheri was evaluated in parts of a semi-arid rangeland in this study. After determination and selecting key areas as study sites, sampling from vegetation and soil, based on randomized systematic ...
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Carbon sequestration potential of three species including Agropyron elengatum, Stipa barbata and Artemisia aucheri was evaluated in parts of a semi-arid rangeland in this study. After determination and selecting key areas as study sites, sampling from vegetation and soil, based on randomized systematic method, was done and 90 plant and 45 soil samples were taken, respectively. Shooting and rooting organs of the species were separated from each other after transfer to the laboratory and carbon sequestration coefficient of plant organs was determined with combustion method.Then carbon sequestration coefficient of different species, organs and soil under these species were analyzed. The results showed that carbon sequestration rate between studied three species, had significantly statistical difference (p