Davod Nazari Chaleshtori; Pejman Tahmasbi; Ali asghar Naghipour; Hojatollah Khedrigharibvand
Abstract
The achievement of sustainable rangeland management depends on addressing the socio-economic issues of rangeland users, particularly securing their livelihoods. This study aimed to determine the minimum rangeland area required for a sustainable livelihood under different rangeland and climatic conditions ...
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The achievement of sustainable rangeland management depends on addressing the socio-economic issues of rangeland users, particularly securing their livelihoods. This study aimed to determine the minimum rangeland area required for a sustainable livelihood under different rangeland and climatic conditions by examining four regions with two rangeland conditions—good and poor—located in steppe and semi-steppe vegetation zones. Annual forage production was estimated using a double sampling method. The socio-economic information of the statistical population was collected through interviews and the Statistical Center of Iran and Statistical Yearbooks. Rangeland related expenses and incomes of rangeland users were calculated. By examining the costs and incomes, minimum rangeland area was determined in such a way that it can provide the household expenses according to the level of livelihood. Based on the results minimum rangeland area for a sustainable livelihood each household, respectively, in poor rangeland situations; in steppe and semi-steppe rangelands with the area of 932 and 830 hectares, it had the highest amount and in semi-steppe rangelands with a good condition, the area of 81 hectares had the lowest amount in a 100-day grazing season. In general, the rangeland condition and climate affect the economic area of the rangeland for each household. These findings could help rangeland policy makers in recognizing and solving the socio-economic issues of rangeland users. It is suggested that, within a comprehensive study framework, the minimum economic level of the country’s rangelands- under different rangeland conditions and across various climates- be determined. This economic level should then be incorporated into macro-level planning to ensure sustainable rangeland management.
Mehran Fatemi; Atefeh Jebali; Asghar Zare Chahouki
Abstract
پلایای نمکی در مناطق خشک، بهعنوان اکوسیستمی منحصربهفرد و حساس نقش حیاتی در تعادل محیطی و پایداری اکولوژیکی دارند. پژوهش حاضر با هدف ارزیابی روند تغییرات ژئومورفولوژیکی ...
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پلایای نمکی در مناطق خشک، بهعنوان اکوسیستمی منحصربهفرد و حساس نقش حیاتی در تعادل محیطی و پایداری اکولوژیکی دارند. پژوهش حاضر با هدف ارزیابی روند تغییرات ژئومورفولوژیکی پلایای نمکی ابرکوه تلاش نموده تا با بهرهگیری از تکنیکهای جدید سنجش از دوری در محیط گوگل ارث انجین (GEE) به پایش رخسارههای ژئومرفولوژیک و تغییرات محیطی در منطقه پلایای نمکی ابرکوه در بازۀ زمانی 2002 تا 2024 بپردازد. بدینمنظور، از تصاویر ماهوارهای لندست 5 و 8 برای تهیه نقشههای طبقهبندی رخسارههای ژئومورفولوژیکی و تحلیل شاخصهای طیفی پوششگیاهی (NDVI، SAVI، EVI و TSAVI)، آب (MNDWI)، رطوبت خاک (NDMI) و شوری خاک (SI) استفاده گردید. نتایج نشان داد که رخسارههای ژئومورفولوژیکی این پلایا در طی سالهای اخیر دستخوش تغییرات قابل توجهی شده است. کاهش سطح پهنههای آبی، پوششگیاهی به ترتیب در حدود 65%و 51% نسبت به ابتدای سال بررسی و افزایش سطح اراضی شور، رسی و ماسهای به ترتیب در حدود 23%، 66% و 103% از جمله مهمترین تغییرات مشاهده شده بود. تحلیل شاخصهای طیفی نیز نشاندهنده روند کاهشی معنادار در سطح آب و روند افزایشی معنادار در شوری خاک به ترتیب در سطح 1% و 5% بود. همچنین، با وجود روند افزایشی و معنیدار شاخصهای پوشش گیاهی، نقشههای طبقهبندی شده کاهش سطح پوششگیاهی را نشان داد، که این تفاوت ناشی از تأثیر بازتاب طیفی نمک و گچ در این منطقه بیابانی است. نتایج پژوهش حاکی از وجود تغییرات در مرز رخسارههای ژئومرفولوژیکی پلایای نمکی ابرکوه میباشد که بخش عمدهای از این تغییرات میتواند بهدلیل وقوع خشکسالی و فعالیتهای انسانی باشد.
Elham Rafiei Sardooi; Mina Eghtedarnejad; Shapour Kohestani
Abstract
Since that the traditional methods are based on meteorological station data and more investigate meteorological drought, hence, the application of remote sensing techniques and satellite images have been considered as a useful tool for monitoring of agricultural drought. In this study, the relationship ...
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Since that the traditional methods are based on meteorological station data and more investigate meteorological drought, hence, the application of remote sensing techniques and satellite images have been considered as a useful tool for monitoring of agricultural drought. In this study, the relationship between the meteorological drought index (SPI) and remote-sensing-based indices (VCI, TCI and VHI) has been studied in Bam plain. In this regard, using Terra satellite images (Modis sensor) and precipitation data of synoptic and rain gauge stations in the study area, the occurred changes were detected over the 15-year period. In this study, with respect to high temporal accuracy and spectral coverage and accessibility, MOD13A3 and MOD11A1 products extracted from MODIS sensor were used during 2009 to 2023. Then, indices of VCI, TCI and VHI were compared with Standard Precipitation Index (SPI). The results of drought mapping with the SPI index during 2010 to 2024 showed that the drought severity has increased from north to south in the study area. So that, extremely drought is detected in the southern regions of the plain and extremely wet is detected in the northern regions. The annual correlation coefficient between SPI, VCI and SPI indices is 0.70 and 0.53, respectively. It shows high significant positive correlation at level of 0.05. The correlation coefficient between SPI and TCI is 0.11 which shows a weak correlation but significant positive at level of 0.05. Therefore, VCI and VHI Indices have more correlation with annual precipitation and have acceptable results compared with TCI Index.
vahideh moradzadeh; Ardavan Ghorbani; Leila Nemati Sham-Asbi; Mehdi Moameri; Zeinab Hazbavi; Ali Teymourzadeh; Behzad Behtari
Abstract
Rangelands, as natural ecosystems, play a significant role in maintaining carbon balance of the environment. This study aimed to Identification of Carbon Sequestration Patterns under the Influence of Climatic, Soil, and Topographic Factors in the Rangelands of Northern Sabalan, located in Meshginshahr ...
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Rangelands, as natural ecosystems, play a significant role in maintaining carbon balance of the environment. This study aimed to Identification of Carbon Sequestration Patterns under the Influence of Climatic, Soil, and Topographic Factors in the Rangelands of Northern Sabalan, located in Meshginshahr County. Soil sampling was conducted in two types of vegetation cover- grassland and shrubland- across four main geographical directions and at two soil depths (0–15 and 15–30 cm). Data were collected for 24 different soil properties. To perform statistical analyses, the normality of the data was first assessed, followed by a one-way analysis of variance (ANOVA) and Duncan’s multiple range test to compare the mean values of different properties between grasslands and shrublands. Principal Component Analysis (PCA) was also used to evaluate data structure. The results revealed that clay content, silt, organic carbon, particulate organic carbon, total nitrogen, and soil carbon sequestration were significantly higher in grasslands than in shrublands (p<0.01). In contrast, sand content, pH, and electrical conductivity were significantly higher in shrublands than in grasslands (p<0.01). The northern slope exhibited higher levels of clay, silt, organic carbon, and carbon sequestration compared to the southern slope. Additionally, increasing soil depth led to decreases in organic carbon, total nitrogen, and carbon sequestration. PCA showed that the first two components explained 36.30% of the total variance. Sand content, precipitation, and organic carbon having the highest correlation with the first component, while slope percentage and litter showing the strongest correlation with the second component. These findings indicate that soil physical and chemical properties- particularly those affected by climatic gradients and topography- significantly influence carbon sequestration.
Sahereh Safarlaki; Azadeh Safadoust; Mahmood Rostaminia; Seyedeh Bahareh Azimi
Abstract
Accurate spatial data on soil property distribution is crucial for monitoring of land resources, informed management practices, and robust environmental modeling, especially in arid and semi-arid regions. This study aimed to develop a spatial prediction model for soil salinity in the Meymeh Plain, Dehloran ...
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Accurate spatial data on soil property distribution is crucial for monitoring of land resources, informed management practices, and robust environmental modeling, especially in arid and semi-arid regions. This study aimed to develop a spatial prediction model for soil salinity in the Meymeh Plain, Dehloran Province. The Random Forest (RF) algorithm was employed to investigate spatial variations in soil salinity within the surface (0–30 cm) and subsurface (30–60 cm) soil layers. Soil samples were collected from 100 sites, analyzed for electrical conductivity (EC), and the spatial variability of soil salinity was modeled using random forest (RF) analysis. Seven environmental variables of Greenery, Diffuse Radiation, Valley Bottom Flatness Index, Normalized Difference Vegetation Index, Salinity Index, Wind Direction Index, and Brightness were selected based on the Variance Inflation Factor, including parameters from a digital elevation model and Sentinel-2 satellite reflectance data. The model used 80% of the data for calibration and 20% for validation, with performance assessed through root mean square error (RMSE), coefficient of determination (R²), and concordance correlation coefficient (CCC). The RF model showed high prediction accuracy for surface EC and relatively acceptable results for subsurface layers. The R² for the surface layer was 0.92, and for the subsurface layer was 0.37; the RMSE for the surface and subsurface layers was 0.22; and the CCC for the surface layer was 0.82 and for the subsurface layer was 0.97. Overall, topographic derivatives demonstrated a greater influence on predicting soil salinity in both surface and subsurface layers compared to remote sensing data. The multi-resolution valley bottom flatness index with high spatial resolution was identified as the most important predictor of soil salinity, highlighting the impact of topographic factors in the study area.
Mahin Fooladi; Iman Islami
Abstract
Rangelands, as one of the most important natural ecosystems, play a crucial role in maintaining biodiversity and supporting the livelihoods of local communities. This study aimed to identify and analyze the barriers to sustainable rangeland management in the Qashqai nomadic communities of Abadeh County. ...
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Rangelands, as one of the most important natural ecosystems, play a crucial role in maintaining biodiversity and supporting the livelihoods of local communities. This study aimed to identify and analyze the barriers to sustainable rangeland management in the Qashqai nomadic communities of Abadeh County. Using a qualitative approach and grounded theory methodology (Strauss and Corbin), data were collected through semi-structured interviews with local stakeholders. Nineteen participants were selected through snowball sampling based on theoretical saturation. Data were analyzed using open, axial, and selective coding, resulting in a conceptual model outlining the key obstacles to sustainable rangeland management in Qashqai nomadic communities of Abadeh County. The findings revealed that the main barriers to sustainable rangeland management include causal conditions (increasing pressure on rangelands, structural and systemic problems, and environmental degradation), contextual conditions (ecological and geographical limitations, socioeconomic challenges, and weak infrastructure and management), and intervening factors (external influences, technological and social transformations, crises and dysfunctions, and regional cooperation). Improvement strategies comprised rangeland ecosystem restoration, empowerment and participation of local communities, economic and legal support, sustainable development, and international cooperation. The consequences included ecological improvement, socioeconomic prosperity, reduced pressure on rangelands, increased investment, and pollution mitigation. The results emphasize the necessity of integrating indigenous knowledge with modern technologies and strengthening the participation of nomadic communities in decision-making to achieve sustainable rangeland management. This study offers practical strategies to improve rangeland management and ensure their long-term sustainability in the region.
Hossein Moradi; Mohammad Jafari; ِAli Tavili; Hossein Azarnivand; Mohammad Tahmoures; Esmaeil Alizadeh
Abstract
Integrated rangeland ecosystem management is recognized as an effective strategy for improving vegetation cover, forage production, and enhancing sustainability in arid and semi-arid regions. In this study, the effects of various conservation and ecosystem restoration measures (including seeding, Transplanting, ...
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Integrated rangeland ecosystem management is recognized as an effective strategy for improving vegetation cover, forage production, and enhancing sustainability in arid and semi-arid regions. In this study, the effects of various conservation and ecosystem restoration measures (including seeding, Transplanting, terracing combined with transplanting, contour banding with transplanting, pitting with seeding, and contour furrowing with transplanting) were investigated on vegetation characteristics and forage production in the rangelands of Vardij village, Tehran Province. Sampling was conducted systematically and randomly during the growing season using 4 m² plots along 100-meter transects. Vegetation characteristics were precisely recorded and the related data were analyzed. The results indicated that the aforementioned conservation measures had significant effects on vegetation variables, leading to a remarkable increase in vegetation canopy cover and a reduction in bare soil. The highest mean canopy cover (59.97%) and the lowest percentage of bare soil (7.93%) were observed in the transplanting treatment, whereas the control rangelands had the lowest canopy cover (23.2%) and the highest bare soil percentage (29.2%). Other methods, such as seeding and terrace transplanting, also showed positive effects on vegetation cover improvement. Regarding forage production, the transplanting treatment yielded the highest mean production (423 kg/ha), followed by seeding (367 kg/ha) and terrace transplanting (388 kg/ha). The control rangelands exhibited the lowest forage yield. These findings highlight the crucial role of conservation and restoration measures in enhancing vegetation cover and rangeland sustainability. Accordingly, it is recommended that future management plans utilize a combination of methods, including transplanting and seeding, to improve the quality and sustainability of rangeland ecosystems.
Sirous Shamshiri; Bijan Azad; Majid Karimpourrihan
Abstract
Drought is among the most severe climatic hazards in arid and semi-arid regions, and its increasing intensity and frequency in recent decades have substantially impaired the structure and functioning of terrestrial ecosystems. Nevertheless, field-based evidence on drought impacts on woody vegetation ...
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Drought is among the most severe climatic hazards in arid and semi-arid regions, and its increasing intensity and frequency in recent decades have substantially impaired the structure and functioning of terrestrial ecosystems. Nevertheless, field-based evidence on drought impacts on woody vegetation in dryland ecosystems, particularly with respect to vegetation density dynamics, remains limited. This study aimed to assess the effects of drought, using the standardized drought indices SPI and PNPI, on density variations of two woody species, Acacia ehrenbergiana Hayne and Ziziphus spina-christi, in the Espakeh Plain, Sistan and Baluchestan Province, Iran. Furthermore, transformed drought index time series were employed to investigate temporal lags in species density responses to wet and dry periods. The results demonstrated that density differences of both species between wet and dry periods were statistically significant, and that vegetation density variations exhibited a strong correspondence with the transformed SPI index. Time-series analysis revealed a lag of one to two years in density responses following wet and drought events, with the lowest densities of both species occurring one to two years after the most severe drought. Based on the SPI index, Spearman correlation coefficients between vegetation density and wet and dry periods were 0.62 and 0.96 for A.ehrenbergiana, and 0.88 and 0.74 for Z.spina-christi, respectively. In contrast, the PNPI index showed limited explanatory power for A.ehrenbergiana, likely due to differences in the computational frameworks of the drought indices applied in this region. Overall, drought resulted in a significant decline in the density of both species in the study area, with A.ehrenbergiana and Z.spina-christi densities decreasing from 17.33±7.22 and 8.44±4.51 to 8.66±4.78 and 5.11±3.32 individuals per hectare, respectively. Given the greater vulnerability of Z.spina-christi to drought stress, the development and implementation of climate-adaptive management strategies are essential to ensure its conservation and long-term persistence.
