Journal of Rangeland

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Land degradation is known as an important global problem due to its influence on the sustainability of agricultural productions. This problem became more serious in developing countries due to their increasing population pressures on land and the patterns of resource use. This study aimed to evaluate the effects of agricultural activities on soil properties and land degradation in Khatam City, Yazd province. Soil, elevation and land use maps were produced using ArcGIS9.3 and ENVI software. Four dominant land use classes in the study area were mono-culture irrigated land, multi-culture irrigated land, orchard lands and rangelands (control treatment). Soil samples were collected and their SAR, salinity and acidity in surface and sub-soil layers were measured. Evaluating the factors in a split plot design showed that there is significant differences between soil properties in various land uses.  Results indicated that mono-culture and multi-culture agriculture lands were less disturbed compared to the other land uses due to their appropriate management condition. The soil properties of rangeland were in poor condition and may cause desertification in future.

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This research conducted with overall objective of collecting the Strategic data for Sustainable use of the rangelands. The statistical population are experts from the Department of Natural Resources and Watershed Management in Kerman province. Based on the results of the research, the most important strengths and weaknesses of sustainable exploitation of rangelands were lack of organization for that restorion of exploitation cooperatives is of the ways that promotes the sustainability of the use. Results also suggest that deed the rangelands to them under certain monitoring system could be useful. Of the weakness of the system is the low cultureal understanding of sustainability among the local communities. Overgrazing is one the reason of the weakness. Opportunities and threats in this field were ‘Coherent, long-term, goal-oriented, and verifiable stage-and-end planning to ensuring the successful implementation of the natural resource sub-projects. The treats are known as reduction of economic power and poverty among local communities due to the droughts and pressure on rangelands. Appropriate strategies using quantitative matrix management (QSPM) were determined. The most important strategies were ‘keeping the agricultural land values low in suck away that rangelands do not change to cultivated lands, land use change. Identification of land users and determination of stocking rates as it has been recoded in their grazing licences.

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Drought is a recurrent and temporary natural occurrence causing a great damage to human life and natural ecosystems. In this research, the standardized precipitation index (SPI) was used to assess drought. For this purpose, monthly statistics of 15 meteorological station were used and SPI were calculated using MATLAB software in the Jazmourian wetland. Then, their maps were provided in different periods using ArcGIS software. The NDVI map was prepared using MODIS satellite imagery (MOD13A2) for the period of 2000-2015. Then correlation between them was studied by Pearson correlation coefficient. Based on the SPI results the highest droughts have occurred in 2007, 2008, 2009 and 2014. The results of Man-Kendal trend test at meteorological stations showed that there was a significant increase in Hoseinabad Salehabad station, while in other stations the trend was not significant. The NDVI trend has changed in different years. The classes of 0-0.1 and >0.4 have decreased during this time interval, but the classes of 0.1-0.2, 0.2-0.3, and 0.3-0.4 showed an increasing trend. According to the results of Pearson correlation coefficient, the highest correlation was found between SPI and NDVI at Miandeh, Dashtkoch and Cherigan stations and the lowest correlation was found in the stations of FathAbad Esfandaghe, Kahnak Shibani, Kerad Dalfard and Tang Sargaz.

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Rangelands are one of the most important natural resources of Iran in terms of its vastness and ecosystem values. Therefore, in this research, the conservation value of Rig Ishaqabad, Sirjan county, Kerman province, rangeland has been estimated using the One- and- One- Half- Bounded Dichotomous Conditional Valuation method. Influential factors on willingness of individuals payment for protect the rangeland also have been investigated using the logit model and the maximum likelihood estimation. The sample size was 133 persons based on Mitchell and Carson method. Required data were collected through questionnaire and direct interview with 140 people in the study area. The results showed that the number of family size, locality, the importance of environmental protection, the membership in environmental organizations and the monthly cost of recreation were positive variables. On the other side age and bid price were two negative variables on the willingness to pay. According to the calculations, the monthly willingness to pay per Sirjani household was 85731.5 Rials. Results also showed that the total monthly and annual conservation value of Rig Ishaqabad rangeland of Sirjan are 7.0 and 84.6 milliard Rials, respectively. On this basis the total annual conservation value of each hectare was estimated as 6.6 million Rials that indicates the high importance of this rangeland from the people’s perspective is in the region.

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Regarding the heavy damage of droughts to plant communities and soil moisture, the present study aimed to derive the SPEI drought index using the climatic data, temperature and rainfall, and to calculate the EVI vegetation cover and CWSI soil moisture indices through satellite data processing. Then variations of the indices and their correlation with drought was addressed. Looking at the trend of drought variations in Isfahan province shows a frequent drought over a 19-year period. The most severe droughts happened in 2001, 2008, and 2010 at which the minimum indices vegetation cover and soil moisture were observed. The trend of the variations of SPEI, EVI, and CWSI revealed their ascending trend by 88.54%, 13.14%, and 90.72% and their descending trend by 2.93%, 78.33%, and 9.28%, respectively. Out of the increases of the indices, 6.93%, 6.32%, and 63.56% were significant at the P < 0.05 level, respectively. Out of all decreases, 0.33%, 7.45%, and 8.75% were significant at the same level, respectively. The test of the correlation of SPEI index with soil moisture and vegetation cover indices indicated that the effect of SPEI on these two indices was positive across 87.23% of the province and negative across 56.56%. As a result quantity and quality of the vegetation cover and soil moisture have declined. The information produced by these climatic data and satellite imagery can considerably help policymakers and planners to cope with the drought and its impacts on vegetation cover and soil moisture.

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Background and objectives: Terrestrial ecosystems depend on vegetation to connect water, soil, air, and other components. Using remote sensing technology, this study explores vegetation dynamics in Khorasan, including their response to land use changes and climate changes between 2001 and 2020. This study aimed to investigate and analyze the effects of climatic factors on vegetation dynamics.
Methodology: In this study, satellite and climate data are used. The National Meteorological Organization provided climate data, and the USGS provided satellite data on vegetation indicators. This research used monthly NDVI and EVI indices to investigate the vegetation cover from 2001 to 2020. These monthly images with a spatial resolution of 1 km were prepared from the MODIS terra sensor satellite. Using the IDW interpolation method, the climate data of 39 investigated stations were prepared, and their maps were prepared in ArcGIS. Linear regression simulated trends in vegetation index and climate parameters over 2001-2020 in QGIS. NDVI and EVI indices were correlated with climatic parameters to investigate changes in vegetation cover.
Results: Based on the trend of land use changes in Khorasan, the main land uses are barren lands, agricultural lands, forests, rangelands, open shrubland, savanna, and built-up areas. During this period, barren lands, agricultural lands, forests, and rangelands decreased by 2.57, 0.41, 0.0009, and 1.02 %, respectively, while open shrubland, savannas, and built-up areas increase by 3.98, 0.0031, and 0.0072 %. Examining the change slope of the vegetation cover index and climatic parameters in these 20 years showed that the change slope of the vegetation cover index EVI and NDVI in these 20 years are positive and increasing, respectively 72.81% and 85.46% of Khorasan, which can be said in general According to these two indicators, vegetation cover is increasing in more than 85% of Khorasan's natural lands. Examining the slope of rainfall and temperature changes in this period of time showed that these indicators had positive and increasing changes in 76.59 and 58.71% of the area of Khorasan, respectively. The correlation results between EVI and NDVI vegetation indices with rainfall show that there was a positive correlation between these two indices in 87.27 and 90.71 % of Khorasan. Correlation between vegetation indices EVI and NDVI and temperature showed that there was a negative correlation of about 74.27 and 77.26% respectively in the studied area. Most land use areas barren lands, agricultural lands, rangelands, and open shrublands have a positive correlation between the EVI vegetation cover index and rainfall in semi-arid, dry, and semi-arid climates. These correlation results show open shrublands, rangelands, and barren lands had 49.18, 80.96, and 100% positive correlations, respectively. The results of this correlation in the semi-humid climate in rangelands and forest land uses were positive at 95.30% and 1.15%, respectively. The results of the correlation between EVI and temperature in the semi-arid climate in semi-arid, dry and semi-arid climates show that this relationship in most barren lands, rangelands and open shrublands is negative. Also, the results of this correlation in the Mediterranean climate show that this correlation is positive in the use of barren lands, rangelands and open shrublands 40.99, 91.02 and 23.08 %. The results of this correlation in the semi-humid climate show that this relationship is 100 and 98.06 % positive in barren lands, and rangelands, respectively, and 1.94 % negative in open shrublands. In the majority of areas, such as barren lands, agricultural lands, rangelands, and open shrublands, there is a positive correlation between NDVI and rainfall in extra-arid, dry, semi-arid, and Mediterranean climates. In the Mediterranean climate, barren lands, rangelands, and open shrubland use are all 100% positive, 62.15 and 77.0.1 respectively. In semi-humid climates, barren lands and pastures are used 52.56 % and 38.63 %, respectively. A negative correlation was found between NDVI and temperature in extra-arid, dry, semi-arid and Mediterranean climates in most of the land use areas barren lands, agricultural lands, rangelands, and open shrublands. Based on the results of the correlation, barren lands, rangelands, and open shrublands are 99.60, 93.66, and 100% positive, respectively. According to the correlation results between NDVI and temperature in semi-humid climates, barren lands and rangelands have a 100% positive correlation.
Conclusion: The destruction and restoration of vegetation have become a major challenge in Iran. Land degradation and desertification conditions will increase due to the interaction of human activities and climate change. North Khorasan, Razavi and South Khorasan were studied separately and in detail at the climate and land use levels. Consequently, the findings of this study can be very useful and necessary for the implementation of policies and projects to promote vegetation restoration by men and politicians in the field of natural resources and the environment.

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Background and objectives: Vegetation is a critical component of ecosystems and is significantly impacted by climatic events, including drought. Indices such as the Enhanced Vegetation Index (EVI) and Potential Evapotranspiration (PET) are effective tools for evaluating drought effects, obtained through the MODIS sensor. Numerous studies have identified climatic factors, including drought, as primary determinants of plant community growth and dynamics. Thus, monitoring drought and vegetation changes is essential for effective regional management. This study aims to assess the effects of drought on vegetation and potential evapotranspiration using MODIS sensor data.
Methodology: The Palmer Drought Severity Index (PDSI) was utilized to assess drought, while EVI and PET indices were derived from MODIS satellite images. Temperature and precipitation data from 13 synoptic stations in Tehran Province, spanning 2001 to 2021, were obtained monthly from the national meteorological organization. Using Inverse Distance Weighting (IDW), the corresponding maps were plotted in ArcGIS. Terra satellite series images from the USGS database were used to obtain EVI and PET data. The MOD13A3 sensor with a 1 km spatial resolution in monthly intervals provided EVI data, while the MOD16A2 sensor with a 500 m spatial resolution in 8-day intervals supplied PET data. Trends in PDSI, EVI, and PET were calculated using linear regression and the non-parametric Kendall test. Pearson correlation coefficient was applied to investigate the correlations between indices. Additionally, correlation analysis evaluated the impact of drought on EVI and PET in different climates.
Results: The 20-year average analysis indicated an increase in the PDSI (average 95.1) in the region. The average vegetation index was approximately 0.076, and the average PET was around 26.57 mm/m². Slope analysis using the Kendall test showed a 13.73% increase in vegetation and a 100% increase in drought indices, while PET decreased by 83.86%. The study revealed negative correlations between drought and vegetation (97.59%) and PET (18.68%), and positive correlations for vegetation (3.40%) and PET (82.31%). Examining the relationship between drought and EVI and PET indices in different climates revealed a positive relationship in 58.66% of the dry climate and a negative relationship in 35.82%, a negative relationship in 63.54% and 51.78% of the semi-arid climate, a positive relationship in 98.61% and a negative relationship in 68.73% of the humid climate, and a negative relationship in 4.74% and 82.49% of the semi-humid climate.
Conclusion: Conclusion: The research demonstrates that extracting EVI and PET indices from MODIS sensor data provides insights into drought damage. The PDSI results indicate the growth trend of drought across different climates. The correlation between vegetation cover and drought (WUE-PDSI) suggests improved ecosystem resistance to drought. The findings highlight the significant relationship between drought and changes in vegetation and evapotranspiration potential. Natural resource managers and decision-makers can utilize these results to manage vegetation and develop strategies to combat this destructive phenomenon in arid and semi-arid areas.