Maryam Asadi; Arash Malekian; Ali Salajegheh
Abstract
GCM models are widely used to assess climate change on a global scale, but outputs of these models are not sufficient and accurate to assess climate change at local and regional levels. Therefore, in this study, SDSM model was used for micro-scaling of CanESM2 model data and climate conditions of Semirom ...
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GCM models are widely used to assess climate change on a global scale, but outputs of these models are not sufficient and accurate to assess climate change at local and regional levels. Therefore, in this study, SDSM model was used for micro-scaling of CanESM2 model data and climate conditions of Semirom region based on three scenarios of RCP2.6, RCP4.5 and RCP8.5 in the period 2020 to 2100. The results of model evaluation based on NCEP database showed that the model was more accurate in estimating and predicting temperature data especially mean temperature. Comparison of observation and simulated data of temperature and precipitation of GCMs in the baseline period (1980 to 2005) based on NCEP predictor variables showed the mean correlation of precipitation data of 0.52, mean temperature of 0.88, maximum temperature of 0.80 and minimum temperature of 0.70 for validation and verification periods. The results of the estimation of precipitation variations in different scenarios also predicted a decrease of at least 7.24% and a maximum of 18.55% for the time period of 2020 to 2100 compared to the baseline period (1980-2005). The results of precipitation prediction also show the changes of precipitation pattern. The comparison of the scenarios also shows that the RCP2.6 scenario as the most optimistic scenario has the least rainfall while the RCP8.5 scenario predicts the highest rainfall reduction. Examination of the predicted changes in temperature also shows an increase for the mean, minimum and maximum temperatures,
Fazel Amiri; Hossein Arzani
Abstract
Range inventory is the recognition and evaluation of potential and actual production in order of optimal utilization of this valuable natural resource. Determination of range suitability for medical and industrial plants, considering sustainable utilization and creating models for medical and industrial ...
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Range inventory is the recognition and evaluation of potential and actual production in order of optimal utilization of this valuable natural resource. Determination of range suitability for medical and industrial plants, considering sustainable utilization and creating models for medical and industrial plants use in Ghareh Aghach of Semirom watershed by FAO (1991) and GIS, was the main objective of this research. Determination of range suitability for medical and industrial plants use, in Ghareh Aghach of Semirom watershed based on a method suggested by FAO and GIS was the main objective of this research. Two criteria’s of vegetation cover and accessibility to water resources were integrated to determine suitability model of medical and industrial plants on rangeland. In vegetation cover criteria, the samples were randomly collected along 3 two hundred meter transects in each vegetation type. Vegetation cover percentage, composition, abundance, and the presence or absence, diversity, production, application and consumption of medicinal plants and industrial were measured using 1m2 quadrates. Accessibility to road and slope determine and by integrating these two criteria, suitability maps based on FAO method were prepared. The results showed that from 7158.69 hectares of study rangelands, 3.69% ha (0.05%), 1761.1 ha (24.6%), 3217.7 ha (44.95%) and 2176.17 ha (30.4%) of the area were classified to S1, S2, S3 and N suitability classes for medical and industrial plant utilization.
Seyyed Morteza Abtahi
Abstract
The purpose of this study was to investigate vegetation dynamics and range conditions considering the climatic conditions and soil properties in Doolat Gharin in the South of Isfahan province of an area equal to 25 square kilometer. For this purpose, after determining vegetation types and associated ...
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The purpose of this study was to investigate vegetation dynamics and range conditions considering the climatic conditions and soil properties in Doolat Gharin in the South of Isfahan province of an area equal to 25 square kilometer. For this purpose, after determining vegetation types and associated species, the type of rangeland utilization, grazing season, the type of livestock and other relevant information, and vegetation data including canopy cover of annuals, perennial forbs, shrubs, total canopy cover, soil moisture and carbon were determined during four years. Data was collected along three transects in each vegetation types. For each transect 10 plots were established. The size of plots was 1 x 2 m, considering the life form of dominant species. Embrothermic diagram was drawn according to the monthly temperature and precipitation data of Semirom station. Data was analyzed of variance and means comparison were made using Duncan method. According to the results, significant differences were observed between years for canopy cover of annuals, shrubs, forbs, grass, soil cover and soil moisture and Bromus tomentellus (P<0.01) and total canopy cover, Poa bulbosa and soil organic carbon (P<0.05). In this site, the amount of vegetation and its variation are affected by precipitation changes.
Fatemeh Hadian; Reza Jafari; Hossein Bashari; Saeed Soltani
Abstract
Because soil moisture condition affects vegetation changes hence, monitoring of drought and vegetation changes are among valuable management tools in these ecosystems. Nowadays, satellite images are used as a low-cost and fast method for vegetation study in different scales. Vegetation change is assessed ...
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Because soil moisture condition affects vegetation changes hence, monitoring of drought and vegetation changes are among valuable management tools in these ecosystems. Nowadays, satellite images are used as a low-cost and fast method for vegetation study in different scales. Vegetation change is assessed using vegetation spectral characteristics. This study aimed to analyze and monitor the vegetation cover changes in 4 rangelands and one forest type site in south of Isfahan and southeastern of Chaharmahal and Bakhtiary province during 1997-2009 ّField sampling were used for measuring the percentage of canopy cover in all vegetation types using step-point method in radial direction (6000 points per vegetation type). Regression analysis technique was used to ensure if vegetation cover can be measured properly using a Landsat images from 2009. Then NDVI indices were derived from 12 Landsat images between 1997 to 2009 (all images were taken from 22th of May to 5th of Jun each year) to monitor vegetation changes. According to results, there was significant correlation between NDVI indices and canopy cover in all vegetation types. Evaluating the canopy cover changes indicated that the precipitation had various effects on different vegetation types based on their plant form and ecological condition. T
