Research Institute of Forestes and Rangelands Iranian Journal of Range and Desert Research 1735-0875 33 2 2026 06 22 Determining soil factors affecting soil organic carbon storage in rangeland and desert habitats of South Khorasan Determining soil factors affecting soil organic carbon storage in rangeland and desert habitats of South Khorasan 101 121 135835 10.22092/ijrdr.2026.135835 FA Rostam Moslempour Assistant Professor, Department of Rangeland and Watershed Management and Research Group of Drought and Climate Change, Faculty of Natural Resources and Environment, University of Birjand, Birjand, Iran Samira Hossein Jafari Assistant Professor, Department of Nature Engineering and Medicinal Plants, Faculty of Agriculture, University of Torbat Heydarieh, Torbat Heydarieh, Iran Reza Yari Assistant Professor, Khorasan-e-razavi Agricultural and Natural Resources Research and Education Center, Agricultural Research, Education and Extension Organization (AREEO), Mashhad, Iran Journal Article 2026 07 19 Extended Abstract Background and objectives: Iran has a high potential in carbon storage due to the large extent of rangelands. Rangeland ecosystems are atmospheric carbon sinks. Soil is an important source of carbon storage and it has been proved that carbon storage in soil is more than three times the storage in the atmosphere and vegetation. Knowing the amount of soil carbon sequestration and storage can be used as a useful and practical tool to better understand soil carbon cycle. Therefore, the purpose of this research is to investigate and determine the most important soil factors affecting the amount of soil carbon storage in Zirkouh and Ferdows habitats in South Khorasan with different plant types. Methodology: The present research was carried out in South Khorasan province in rangeland habitats of Zirkouh, including Artemisia sieberi, Zygophyllum eurypterum, and Tamarix stricta plant types, and in the desert areas of Ferdows, including Calligonum polygonoides, Seidlitzia rosmarinus, Stipagrostis pennata, and Zygophyllum eurypterum types. 60 squares of 4×4 meters were established in the representative area of each habitat by random-systematic method, and, canopy cover percentage and plant density was estimated in each plot. Then, 10 plants were randomly selected. Soil samples were taken to a depth of 70 cm in the plots, under the canopy cover of the plant. Soil physical and chemical properties were determined in the laboratory. The correlation diagram (Pearson correlation coefficient) between environmental characteristics and carbon storage was drawn. First, ordinary multiple linear regression (OLS) analysis was used to examine the relationships, and the multiple collinearity between environmental characteristics and organic carbon storage was examined by the variance inflation factor (VIF) criterion. Since normality and multiple collinearity are assumptions of ordinary regression, two regression models: Partial Least Squares (PLS) and Principal Component Regression (PCR), were used in the present study. Results: The results of descriptive statistics showed that in Zirkouh habitat, the highest and lowest changes in soil carbon storage are in Tamarix habitat (Mean=20.77, SD=11.66) and Artemisia habitat (Mean=13.83, SD=1.81), respectively. In Ferdows region, the highest and lowest changes in the amount of soil carbon storage were observed in Calligonum (Mean=6.96, SD=1.57) and Zygophyllum (Mean=5.36, SD=0.80) habitats, respectively. In Zirkouh habitat, carbon storage had a significant negative correlation with sand (p≤0.05) and a significant positive correlation with canopy cover percentage, N, P, silt, EC (p≤0.01), lime and K (p≤0.05). Interestingly, sand percentage had a significant negative correlation with all measured soil properties in this diagram. In Ferdows region, carbon storage had a significant negative correlation with gypsum and potassium (p≤0.05) and a significant positive correlation with N. In the present study, two models of partial least square regression (PLS) and principal component regression (PCR) were used. In PLS regression method as the best model, in Zirkouh habitat, the parameters such as sand, silt, phosphorus and canopy cover percentages remained as significant variables in the model and among them, silt percentage had the most impact in predicting carbon storage. In Ferdows habitat, the parameters including organic carbon, silt, nitrogen, potassium and gypsum remained as significant variables in the model. Conclusion: Investigating the effective factors on carbon storage can help managers and decision makers in choosing management methods and modifying existing methods in order to reduce atmospheric carbon density. The results of this research showed that among the two models of partial least square regression (PLS) and principal component regression (PCR), PLS model is the best model to determine the factors affecting carbon storage. There was a positive relationship between vegetation cover and soil nutrients (N, P, K) and carbon storage in the Zirkouh habitat, which emphasizes the role factors related to fertility in carbon storage. By implementing appropriate range management strategies—such as protection, improvement, and restoration of vegetation cover—we can increase soil organic carbon storage. This approach can help prevent air pollution, reduce vegetation degradation, and ultimately mitigate the harmful effects of climate change. Extended Abstract Background and objectives: Iran has a high potential in carbon storage due to the large extent of rangelands. Rangeland ecosystems are atmospheric carbon sinks. Soil is an important source of carbon storage and it has been proved that carbon storage in soil is more than three times the storage in the atmosphere and vegetation. Knowing the amount of soil carbon sequestration and storage can be used as a useful and practical tool to better understand soil carbon cycle. Therefore, the purpose of this research is to investigate and determine the most important soil factors affecting the amount of soil carbon storage in Zirkouh and Ferdows habitats in South Khorasan with different plant types. Methodology: The present research was carried out in South Khorasan province in rangeland habitats of Zirkouh, including Artemisia sieberi, Zygophyllum eurypterum, and Tamarix stricta plant types, and in the desert areas of Ferdows, including Calligonum polygonoides, Seidlitzia rosmarinus, Stipagrostis pennata, and Zygophyllum eurypterum types. 60 squares of 4×4 meters were established in the representative area of each habitat by random-systematic method, and, canopy cover percentage and plant density was estimated in each plot. Then, 10 plants were randomly selected. Soil samples were taken to a depth of 70 cm in the plots, under the canopy cover of the plant. Soil physical and chemical properties were determined in the laboratory. The correlation diagram (Pearson correlation coefficient) between environmental characteristics and carbon storage was drawn. First, ordinary multiple linear regression (OLS) analysis was used to examine the relationships, and the multiple collinearity between environmental characteristics and organic carbon storage was examined by the variance inflation factor (VIF) criterion. Since normality and multiple collinearity are assumptions of ordinary regression, two regression models: Partial Least Squares (PLS) and Principal Component Regression (PCR), were used in the present study. Results: The results of descriptive statistics showed that in Zirkouh habitat, the highest and lowest changes in soil carbon storage are in Tamarix habitat (Mean=20.77, SD=11.66) and Artemisia habitat (Mean=13.83, SD=1.81), respectively. In Ferdows region, the highest and lowest changes in the amount of soil carbon storage were observed in Calligonum (Mean=6.96, SD=1.57) and Zygophyllum (Mean=5.36, SD=0.80) habitats, respectively. In Zirkouh habitat, carbon storage had a significant negative correlation with sand (p≤0.05) and a significant positive correlation with canopy cover percentage, N, P, silt, EC (p≤0.01), lime and K (p≤0.05). Interestingly, sand percentage had a significant negative correlation with all measured soil properties in this diagram. In Ferdows region, carbon storage had a significant negative correlation with gypsum and potassium (p≤0.05) and a significant positive correlation with N. In the present study, two models of partial least square regression (PLS) and principal component regression (PCR) were used. In PLS regression method as the best model, in Zirkouh habitat, the parameters such as sand, silt, phosphorus and canopy cover percentages remained as significant variables in the model and among them, silt percentage had the most impact in predicting carbon storage. In Ferdows habitat, the parameters including organic carbon, silt, nitrogen, potassium and gypsum remained as significant variables in the model. Conclusion: Investigating the effective factors on carbon storage can help managers and decision makers in choosing management methods and modifying existing methods in order to reduce atmospheric carbon density. The results of this research showed that among the two models of partial least square regression (PLS) and principal component regression (PCR), PLS model is the best model to determine the factors affecting carbon storage. There was a positive relationship between vegetation cover and soil nutrients (N, P, K) and carbon storage in the Zirkouh habitat, which emphasizes the role factors related to fertility in carbon storage. By implementing appropriate range management strategies—such as protection, improvement, and restoration of vegetation cover—we can increase soil organic carbon storage. This approach can help prevent air pollution, reduce vegetation degradation, and ultimately mitigate the harmful effects of climate change.

https://ijrdr.areeo.ac.ir/article_135835_c505bb4a05af28afcba80c83196bf1ea.pdf

Research Institute of Forestes and Rangelands Iranian Journal of Range and Desert Research 1735-0875 33 2 2026 06 22 Effects of Different Livestock Grazing Intensities on the Structural and Functional Characteristics of Ecological Patches in the Rangelands of the Mouteh Wildlife Refuge Effects of Different Livestock Grazing Intensities on the Structural and Functional Characteristics of Ecological Patches in the Rangelands of the Mouteh Wildlife Refuge 122 141 136287 10.22092/ijrdr.2026.136287 FA Zahra Heidari Ghahfarrokhi Ph.D. in Range Management, Department of Nature Engineering, Faculty of Natural Resources and Earth Sciences, Shahrekord University, Shahrekord, Iran Pejman Tahmasebi Associate Professor, Department of Nature Engineering, Faculty of Natural Resources and Earth Sciences, Shahrekord University, Shahrekord, Iran Ali Asghar Naghipour Associate Professor, Department of Nature Engineering, Faculty of Natural Resources and Earth Sciences, Shahrekord University, Shahrekord, Iran. Journal Article 2026 10 03 Abstract Background and Objectives The functional condition of rangeland ecosystems is strongly influenced by the structural and compositional characteristics of vegetation patches and the intervening interpatch spaces. Landscape Function Analysis (LFA) is a widely used approach for assessing patch organization and evaluating key functional attributes of rangeland ecosystems. The present study aimed to investigate the effects of different livestock grazing intensities on the structural characteristics and functional performance of ecological patches in the rangelands of the Mouteh Wildlife Refuge, central Iran. Materials and Methods Three rangeland sites representing different levels of livestock grazing pressure were selected along a grazing-intensity gradient. At each site, two representative areas were selected, and within each area, three transects, each at least 30 m long and separated by more than 60 m, were established. Along the transects, at least three replicates of each major patch type, including shrub patches and plant hummocks (grasses and forbs), as well as interpatch spaces, were identified and evaluated. Three major LFA functional indices, including stability, infiltration, and nutrient cycling, were assessed using LFA software based on 11 soil-surface indicators recorded in the field. In total, 162 patches and interpatch spaces were evaluated. Structural and functional characteristics of patches were compared among grazing intensities using one-way analysis of variance (ANOVA; aov function), followed by Duncan’s multiple range test (duncan.test) in R software. Results The highest values of the structural attributes of ecological patches, including the landscape organization index, number of patches per 10 m, patch area index, total patch area, and mean patch length and width, were recorded under light grazing intensity. In contrast, the highest structural values for interpatch spaces, including mean, minimum, and maximum interpatch lengths, were observed under heavy grazing intensity. In contrast to interpatch spaces and plant hummock patches, most soil-surface indicators in shrub patches differed significantly among grazing intensities (p ≤ 0.001 and p ≤ 0.01). With increasing grazing intensity, soil cover, perennial vegetation cover, crust stability, soil erosion type and severity, and slaking-test scores decreased, with the highest values recorded under light grazing (4.000, 7.429, 2.357, 3.500, and 5.429, respectively). Light grazing also resulted in the highest overall stability and infiltration indices (49.619% and 24.351%, respectively), as well as the highest values in interpatch spaces (47.994% and 23.079%), plant hummock patches (42.917% and 22.651%), and shrub patches (56.528% and 29.700%). The highest nutrient-cycling index values were also recorded under light grazing, both overall and in plant hummock patches (15.707% and 15.490%, respectively). Conclusion Appropriate rangeland management, particularly in arid and semi-arid environments, plays a critical role in maintaining and improving the structural organization and functional condition of ecological patches. Maintaining adequate vegetation cover and a diverse combination of shrubs, grasses, and forbs can enhance patch connectivity, soil-surface protection, and overall ecosystem functionality. The findings indicate that light grazing pressure is more compatible with the maintenance of organized patch structures, greater patch extent, and higher functional integrity. Consequently, grazing management based on appropriate stocking rates and controlled grazing intensity can contribute to maintaining rangeland resilience, reducing soil degradation, and sustaining key ecosystem functions in the Mouteh Wildlife Refuge. Abstract Background and Objectives The functional condition of rangeland ecosystems is strongly influenced by the structural and compositional characteristics of vegetation patches and the intervening interpatch spaces. Landscape Function Analysis (LFA) is a widely used approach for assessing patch organization and evaluating key functional attributes of rangeland ecosystems. The present study aimed to investigate the effects of different livestock grazing intensities on the structural characteristics and functional performance of ecological patches in the rangelands of the Mouteh Wildlife Refuge, central Iran. Materials and Methods Three rangeland sites representing different levels of livestock grazing pressure were selected along a grazing-intensity gradient. At each site, two representative areas were selected, and within each area, three transects, each at least 30 m long and separated by more than 60 m, were established. Along the transects, at least three replicates of each major patch type, including shrub patches and plant hummocks (grasses and forbs), as well as interpatch spaces, were identified and evaluated. Three major LFA functional indices, including stability, infiltration, and nutrient cycling, were assessed using LFA software based on 11 soil-surface indicators recorded in the field. In total, 162 patches and interpatch spaces were evaluated. Structural and functional characteristics of patches were compared among grazing intensities using one-way analysis of variance (ANOVA; aov function), followed by Duncan’s multiple range test (duncan.test) in R software. Results The highest values of the structural attributes of ecological patches, including the landscape organization index, number of patches per 10 m, patch area index, total patch area, and mean patch length and width, were recorded under light grazing intensity. In contrast, the highest structural values for interpatch spaces, including mean, minimum, and maximum interpatch lengths, were observed under heavy grazing intensity. In contrast to interpatch spaces and plant hummock patches, most soil-surface indicators in shrub patches differed significantly among grazing intensities (p ≤ 0.001 and p ≤ 0.01). With increasing grazing intensity, soil cover, perennial vegetation cover, crust stability, soil erosion type and severity, and slaking-test scores decreased, with the highest values recorded under light grazing (4.000, 7.429, 2.357, 3.500, and 5.429, respectively). Light grazing also resulted in the highest overall stability and infiltration indices (49.619% and 24.351%, respectively), as well as the highest values in interpatch spaces (47.994% and 23.079%), plant hummock patches (42.917% and 22.651%), and shrub patches (56.528% and 29.700%). The highest nutrient-cycling index values were also recorded under light grazing, both overall and in plant hummock patches (15.707% and 15.490%, respectively). Conclusion Appropriate rangeland management, particularly in arid and semi-arid environments, plays a critical role in maintaining and improving the structural organization and functional condition of ecological patches. Maintaining adequate vegetation cover and a diverse combination of shrubs, grasses, and forbs can enhance patch connectivity, soil-surface protection, and overall ecosystem functionality. The findings indicate that light grazing pressure is more compatible with the maintenance of organized patch structures, greater patch extent, and higher functional integrity. Consequently, grazing management based on appropriate stocking rates and controlled grazing intensity can contribute to maintaining rangeland resilience, reducing soil degradation, and sustaining key ecosystem functions in the Mouteh Wildlife Refuge.

https://ijrdr.areeo.ac.ir/article_136287_a4300cb045282421b42f93d6e95d7ad1.pdf

Research Institute of Forestes and Rangelands Iranian Journal of Range and Desert Research 1735-0875 33 2 2026 06 22 Technical and Economic Evaluation of Alhagi camelorum Forage Production by Flood Irrigation Method in arid and desert area Technical and Economic Evaluation of Alhagi camelorum Forage Production by Flood Irrigation Method in arid and desert area 142 157 135836 10.22092/ijrdr.2026.135836 FA Jalal Barkhordari p.o.box 89165-517 Yazd,Iran mollasadra, shahidan ashraf ave. safaeia, Yazd,Iran Journal Article 2026 07 19 Abstract Background and Objectives In arid and desert regions, due to the irregular spatial and temporal distribution of precipitation, a valuable volume of seasonal floods has become unavailable in the form of evaporation, and on the other hand, the lack of suitable land and irrigation water has created great limitations for the production of livestock fodder. Therefore, the use of creative methods adapted to the natural conditions of the region in utilizing the potential of dry muddy floods of dry rivers in arid regions is essential to solve this problem. Methodology In this study, in the Miankouh Flood spreading Station, with the aim of evaluating the effect of flood irrigation and sediments accompanying floods on the production of Alhagi camelorum forage, after providing the technical conditions for the establishment of this plant in terms of uniform flood distribution and no waterlogging, Alhagi camelorum seeds were established and grown along with muddy floods behind the embankments. After establishment The stability of the thorn bushes, the percentage of canopy cover, density and forage production of the thorn bushes were measured using 1x1 square meter plots in 30 plots in three transects parallel to the embankment and 10 plots in the thorn fields on the edge of the project without flood irrigation conditions as a control in three years (1401, 1402 and 1403) were measured and statistically analyzed. Also, samples of the produced forage under flood irrigation and control conditions were prepared according to the standard and analyzed in the laboratory to evaluate the qualitative components. The economic feasibility of the produced forage was also evaluated and analyzed in comparison with common forages using the engineering economics method. Results Comparison of the survey results showed that the production rate and percentage of canopy cover were significant at the 1% level and the density rate at the 5% level. The forage production rate in the first year of establishment was 1.83 tons per hectare and in the third year after the complete establishment of the bushes and appropriate flooding of the area was 39.7 tons per hectare of dry forage was recorded. Also, comparing the results of the analysis of the quality of the forage produced by the flood irrigation method and the control, a significant increase in crude protein of 14.33% was obtained, which is comparable to common forages such as alfalfa. The benefit-cost ratio in this project has been calculated to be 1/4, which means that for every 1 Rial invested in Alhagi camelorum floodplain agriculture, 1.4 Rials of benefit is generated. Conclusion As a result, by utilizing the potential of seasonal muddy floods, most of which are usually wasted due to evaporation, and utilizing desert sandy land, it is possible to produce economic fodder with appropriate quantitative and qualitative yield from the drought-resistant species of Alhagi camelorum under flood irrigation conditions in arid and desert areas, similar to the project area. Abstract Background and Objectives In arid and desert regions, due to the irregular spatial and temporal distribution of precipitation, a valuable volume of seasonal floods has become unavailable in the form of evaporation, and on the other hand, the lack of suitable land and irrigation water has created great limitations for the production of livestock fodder. Therefore, the use of creative methods adapted to the natural conditions of the region in utilizing the potential of dry muddy floods of dry rivers in arid regions is essential to solve this problem. Methodology In this study, in the Miankouh Flood spreading Station, with the aim of evaluating the effect of flood irrigation and sediments accompanying floods on the production of Alhagi camelorum forage, after providing the technical conditions for the establishment of this plant in terms of uniform flood distribution and no waterlogging, Alhagi camelorum seeds were established and grown along with muddy floods behind the embankments. After establishment The stability of the thorn bushes, the percentage of canopy cover, density and forage production of the thorn bushes were measured using 1x1 square meter plots in 30 plots in three transects parallel to the embankment and 10 plots in the thorn fields on the edge of the project without flood irrigation conditions as a control in three years (1401, 1402 and 1403) were measured and statistically analyzed. Also, samples of the produced forage under flood irrigation and control conditions were prepared according to the standard and analyzed in the laboratory to evaluate the qualitative components. The economic feasibility of the produced forage was also evaluated and analyzed in comparison with common forages using the engineering economics method. Results Comparison of the survey results showed that the production rate and percentage of canopy cover were significant at the 1% level and the density rate at the 5% level. The forage production rate in the first year of establishment was 1.83 tons per hectare and in the third year after the complete establishment of the bushes and appropriate flooding of the area was 39.7 tons per hectare of dry forage was recorded. Also, comparing the results of the analysis of the quality of the forage produced by the flood irrigation method and the control, a significant increase in crude protein of 14.33% was obtained, which is comparable to common forages such as alfalfa. The benefit-cost ratio in this project has been calculated to be 1/4, which means that for every 1 Rial invested in Alhagi camelorum floodplain agriculture, 1.4 Rials of benefit is generated. Conclusion As a result, by utilizing the potential of seasonal muddy floods, most of which are usually wasted due to evaporation, and utilizing desert sandy land, it is possible to produce economic fodder with appropriate quantitative and qualitative yield from the drought-resistant species of Alhagi camelorum under flood irrigation conditions in arid and desert areas, similar to the project area.

https://ijrdr.areeo.ac.ir/article_135836_ebf8abeae960005a4ea6248cf5e396e1.pdf

Research Institute of Forestes and Rangelands Iranian Journal of Range and Desert Research 1735-0875 33 2 2026 06 22 Habitat Prediction of Thymus kotschyanus Based on Environmental Factors Using Logistic Regression and Interpolation (Case Study: Dolanieh Habitat in Piranshahr County) Habitat Prediction of Thymus kotschyanus Based on Environmental Factors Using Logistic Regression and Interpolation (Case Study: Dolanieh Habitat in Piranshahr County) 157 176 135838 10.22092/ijrdr.2026.135838 FA Somayyeh Souri Ph.D Student, Department of Plant production and Genetics. Faculty of Agriculture, University of Maragheh, East Azarbaijan, Iran Shahryar Dashti Assistant Professor, Department of Plant Production Engineering and Genetics, Faculty of Agriculture, University of Maragheh Yousef Ajani 3- Assistant Prof., Botany Division, Research Institute of Forests and Rangelands, Agricultural Research Education and Extension Organization (AREEO), Tehran, Iran Esmaeil Karimi Assistant Professor, Department of Plant Production and Genetics, Faculty of Agriculture, University of Maragheh, East Azarbaijan Elham Noori Researcher, Forests, Research Division, Research Institute of Forests and Rangelands, Agricultural Research Education and Extension Organization (AREEO), Tehran, Iran Journal Article 2026 07 19 Abstract Background and Objectives Environmental factors can significantly influence the distribution of plant species. Predicting suitable habitats for species requires a thorough understanding of these influences. Thymus is one of the most important genera in the Lamiaceae family, comprising over 215 species widely distributed across the world, particularly in the Mediterranean region. The present study aims to predict the habitat suitability of Thymus kotschyanus using logistic regression modeling and spatial interpolation methods in the Dolaniyeh region of Piranshahr County. Materials and Methods Topographic variables including elevation, slope, and aspect were derived from the region’s Digital Elevation Model (DEM), while climatic parameters such as average temperature and precipitation were obtained from the Dolanaya synoptic station. A total of 94 presence and absence points of Thymus kotschyanus were systematically and randomly sampled. Binary logistic regression was used in SPSS software to evaluate the relationship between species presence and environmental factors. Spatial variation in habitat suitability was assessed using deterministic and geostatistical interpolation techniques. Results The results indicated that the probability of T. kotschyanus presence had a negative relationship with variables such as latitude, slope aspect, leaf width, soil organic carbon, calcium carbonate, copper, and mean monthly and annual precipitation, as well as sand and clay content. In contrast, variables such as slope, leaf length, plant height, electrical conductivity, pH, zinc, iron, and average temperature showed a positive relationship with the probability of species presence. The likelihood of Thymus presence increases in arid and semi-arid areas with suitable slopes. Spatial distribution mapping revealed that the eastern part of the study area had the highest probability of presence, which gradually decreased toward the southwest. In most parts of the region, the probability of presence was below 0.25, while in a few localized areas, it approached 1.00. Conclusion Based on the results of the regression models, which showed significant effects of environmental variables such as elevation, slope, aspect, and precipitation on the distribution of T. kotschyanus in the study area, these models can serve as effective tools for identifying potential habitats and mapping the species’ geographic range. Considering the increased presence in the eastern region and a notable decline in the southwest, the findings of this study provide a scientific foundation for grazing management strategies and cultivation planning of T. kotschyanus tailored to the ecological capacity of different zones, contributing to the sustainable utilization and conservation of this valuable medicinal species. Abstract Background and Objectives Environmental factors can significantly influence the distribution of plant species. Predicting suitable habitats for species requires a thorough understanding of these influences. Thymus is one of the most important genera in the Lamiaceae family, comprising over 215 species widely distributed across the world, particularly in the Mediterranean region. The present study aims to predict the habitat suitability of Thymus kotschyanus using logistic regression modeling and spatial interpolation methods in the Dolaniyeh region of Piranshahr County. Materials and Methods Topographic variables including elevation, slope, and aspect were derived from the region’s Digital Elevation Model (DEM), while climatic parameters such as average temperature and precipitation were obtained from the Dolanaya synoptic station. A total of 94 presence and absence points of Thymus kotschyanus were systematically and randomly sampled. Binary logistic regression was used in SPSS software to evaluate the relationship between species presence and environmental factors. Spatial variation in habitat suitability was assessed using deterministic and geostatistical interpolation techniques. Results The results indicated that the probability of T. kotschyanus presence had a negative relationship with variables such as latitude, slope aspect, leaf width, soil organic carbon, calcium carbonate, copper, and mean monthly and annual precipitation, as well as sand and clay content. In contrast, variables such as slope, leaf length, plant height, electrical conductivity, pH, zinc, iron, and average temperature showed a positive relationship with the probability of species presence. The likelihood of Thymus presence increases in arid and semi-arid areas with suitable slopes. Spatial distribution mapping revealed that the eastern part of the study area had the highest probability of presence, which gradually decreased toward the southwest. In most parts of the region, the probability of presence was below 0.25, while in a few localized areas, it approached 1.00. Conclusion Based on the results of the regression models, which showed significant effects of environmental variables such as elevation, slope, aspect, and precipitation on the distribution of T. kotschyanus in the study area, these models can serve as effective tools for identifying potential habitats and mapping the species’ geographic range. Considering the increased presence in the eastern region and a notable decline in the southwest, the findings of this study provide a scientific foundation for grazing management strategies and cultivation planning of T. kotschyanus tailored to the ecological capacity of different zones, contributing to the sustainable utilization and conservation of this valuable medicinal species. Abstract Background and Objectives Environmental factors can significantly influence the distribution of plant species. Predicting suitable habitats for species requires a thorough understanding of these influences. Thymus is one of the most important genera in the Lamiaceae family, comprising over 215 species widely distributed across the world, particularly in the Mediterranean region. The present study aims to predict the habitat suitability of Thymus kotschyanus using logistic regression modeling and spatial interpolation methods in the Dolaniyeh region of Piranshahr County. Materials and Methods Topographic variables including elevation, slope, and aspect were derived from the region’s Digital Elevation Model (DEM), while climatic parameters such as average temperature and precipitation were obtained from the Dolanaya synoptic station. A total of 94 presence and absence points of Thymus kotschyanus were systematically and randomly sampled. Binary logistic regression was used in SPSS software to evaluate the relationship between species presence and environmental factors. Spatial variation in habitat suitability was assessed using deterministic and geostatistical interpolation techniques. Results The results indicated that the probability of T. kotschyanus presence had a negative relationship with variables such as latitude, slope aspect, leaf width, soil organic carbon, calcium carbonate, copper, and mean monthly and annual precipitation, as well as sand and clay content. In contrast, variables such as slope, leaf length, plant height, electrical conductivity, pH, zinc, iron, and average temperature showed a positive relationship with the probability of species presence. The likelihood of Thymus presence increases in arid and semi-arid areas with suitable slopes. Spatial distribution mapping revealed that the eastern part of the study area had the highest probability of presence, which gradually decreased toward the southwest. In most parts of the region, the probability of presence was below 0.25, while in a few localized areas, it approached 1.00. Conclusion Based on the results of the regression models, which showed significant effects of environmental variables such as elevation, slope, aspect, and precipitation on the distribution of T. kotschyanus in the study area, these models can serve as effective tools for identifying potential habitats and mapping the species’ geographic range. Considering the increased presence in the eastern region and a notable decline in the southwest, the findings of this study provide a scientific foundation for grazing management strategies and cultivation planning of T. kotschyanus tailored to the ecological capacity of different zones, contributing to the sustainable utilization and conservation of this valuable medicinal species. Abstract Background and Objectives Environmental factors can significantly influence the distribution of plant species. Predicting suitable habitats for species requires a thorough understanding of these influences. Thymus is one of the most important genera in the Lamiaceae family, comprising over 215 species widely distributed across the world, particularly in the Mediterranean region. The present study aims to predict the habitat suitability of Thymus kotschyanus using logistic regression modeling and spatial interpolation methods in the Dolaniyeh region of Piranshahr County. Materials and Methods Topographic variables including elevation, slope, and aspect were derived from the region’s Digital Elevation Model (DEM), while climatic parameters such as average temperature and precipitation were obtained from the Dolanaya synoptic station. A total of 94 presence and absence points of Thymus kotschyanus were systematically and randomly sampled. Binary logistic regression was used in SPSS software to evaluate the relationship between species presence and environmental factors. Spatial variation in habitat suitability was assessed using deterministic and geostatistical interpolation techniques. Results The results indicated that the probability of T. kotschyanus presence had a negative relationship with variables such as latitude, slope aspect, leaf width, soil organic carbon, calcium carbonate, copper, and mean monthly and annual precipitation, as well as sand and clay content. In contrast, variables such as slope, leaf length, plant height, electrical conductivity, pH, zinc, iron, and average temperature showed a positive relationship with the probability of species presence. The likelihood of Thymus presence increases in arid and semi-arid areas with suitable slopes. Spatial distribution mapping revealed that the eastern part of the study area had the highest probability of presence, which gradually decreased toward the southwest. In most parts of the region, the probability of presence was below 0.25, while in a few localized areas, it approached 1.00. Conclusion Based on the results of the regression models, which showed significant effects of environmental variables such as elevation, slope, aspect, and precipitation on the distribution of T. kotschyanus in the study area, these models can serve as effective tools for identifying potential habitats and mapping the species’ geographic range. Considering the increased presence in the eastern region and a notable decline in the southwest, the findings of this study provide a scientific foundation for grazing management strategies and cultivation planning of T. kotschyanus tailored to the ecological capacity of different zones, contributing to the sustainable utilization and conservation of this valuable medicinal species.

https://ijrdr.areeo.ac.ir/article_135838_19d6e504198c3158f9f3017bc5707c27.pdf

Research Institute of Forestes and Rangelands Iranian Journal of Range and Desert Research 1735-0875 33 2 2026 06 22 Long Term Monitoring of Inundation Dynamics in Namak Lake Using Satellite Imagery in Google Earth Engine Long Term Monitoring of Inundation Dynamics in Namak Lake Using Satellite Imagery in Google Earth Engine 195 214 135837 10.22092/ijrdr.2026.135837 FA Samaneh Razavizadeh Assistant Professor, Desert Research Division, Research Institute of Forests and Rangelands, Agricultural Research, Education and Extension Organization (AREEO), Terhran, Iran Journal Article 2026 07 19 Abstract Background and Objectives Lakes and wetlands in arid and semi-arid regions play a crucial role in sustaining ecosystems, regulating local climate, controlling dust storms, and preserving biodiversity. Lake Namak, as one of the major evaporitic–saline basins of the Central Iranian Plateau, has experienced a noticeable decline in surface area and increasing instability in its water coverage over recent decades. Reduced hydrological persistence in this lake can intensify dust emissions and weaken regional ecological functions. Despite its importance, long-term analyses based on continuous satellite time series remain limited. Therefore, the objective of this study is to monitor and analyze the spatiotemporal changes in the inundated area of Lake Namak during 1995–2024 using Landsat imagery and the Google Earth Engine platform. Materials and Methods In this study, Landsat satellite imagery from Landsat 5, Landsat 7, and Landsat 8 acquired between 1995 and 2024 was used. To harmonize data from different sensors and minimize inconsistencies, surface reflectance products were employed, and cloud and cloud-shadow pixels were masked using standard algorithms. All processing and analyses were conducted within Google Earth Engine, enabling access to a long-term satellite archive and efficient data processing. To extract water bodies, the Normalized Difference Water Index (NDWI) was calculated for each image using the green and near-infrared bands. A threshold value was then determined empirically based on comparisons with false-color composites and visual interpretation, and binary water/non-water maps were generated. Water-covered areas were subsequently calculated at monthly, seasonal, annual, and decadal scales. Trend analysis was performed using time-series assessment and linear regression to determine the direction and magnitude of changes over time. Additionally, the non-parametric Sen’s Slope estimator was applied to obtain a more robust estimate of change rates and to reduce the influence of outliers. To evaluate the stability of the lake’s inundation regime, the Transition and Seasonality layers from the JRC Global Surface Water dataset were analyzed within Google Earth Engine. Results Time-series analysis of Landsat imagery revealed a decreasing and unstable trend in the extent of Lake Namak’s inundated area over the past three decades. The mean inundated area in the first decade (1995–2004) was about 154.4 km², decreasing to 48.1 km² in the second decade (2005–2014) and to approximately 41.1 km² in the third decade (2015–2024). Annually, the maximum water extent occurred in 2001 (about 383.6 km²), while the minimum was recorded in 2014 (about 1 km²), indicating strong interannual variability. Trend analysis using linear regression confirmed a significant negative trend, and the negative slope highlighted continuous decline in inundation. Similarly, Sen’s Slope analysis yielded negative annual change rates, indicating a persistent long-term reduction with higher robustness. Seasonal patterns showed that spring exhibited the highest inundation, with about 10% of the lake’s surface containing water, followed by winter with about 5.4%, while summer and autumn displayed minimal inundation. Monthly analysis showed maximum inundation in March, April, and May. The Transition layer indicated that approximately 70.4% of the lake area remained unchanged, while about 15.9% fell into the “new seasonal” class and around 13% into the “seasonal” class, reflecting the expansion of temporary water bodies. Seasonality results showed that more than 71.1% of the lake surface lacked persistent inundation, with most water-covered areas present only one to three months per year. Conclusion The findings indicate that Lake Namak has undergone a substantial reduction in surface area and hydrological persistence over the past three decades, with both linear regression and Sen’s Slope confirming the declining trend. The dominance of short-term and seasonal inundation reflects increasing hydrological instability. Continuation of this trend may lead to major environmental consequences, including increased salinity, intensified evaporation, and expansion of dust-source areas. The use of satellite imagery and Google Earth Engine provides an effective framework for long-term monitoring of such dynamic environments. Abstract Background and Objectives Lakes and wetlands in arid and semi-arid regions play a crucial role in sustaining ecosystems, regulating local climate, controlling dust storms, and preserving biodiversity. Lake Namak, as one of the major evaporitic–saline basins of the Central Iranian Plateau, has experienced a noticeable decline in surface area and increasing instability in its water coverage over recent decades. Reduced hydrological persistence in this lake can intensify dust emissions and weaken regional ecological functions. Despite its importance, long-term analyses based on continuous satellite time series remain limited. Therefore, the objective of this study is to monitor and analyze the spatiotemporal changes in the inundated area of Lake Namak during 1995–2024 using Landsat imagery and the Google Earth Engine platform. Materials and Methods In this study, Landsat satellite imagery from Landsat 5, Landsat 7, and Landsat 8 acquired between 1995 and 2024 was used. To harmonize data from different sensors and minimize inconsistencies, surface reflectance products were employed, and cloud and cloud-shadow pixels were masked using standard algorithms. All processing and analyses were conducted within Google Earth Engine, enabling access to a long-term satellite archive and efficient data processing. To extract water bodies, the Normalized Difference Water Index (NDWI) was calculated for each image using the green and near-infrared bands. A threshold value was then determined empirically based on comparisons with false-color composites and visual interpretation, and binary water/non-water maps were generated. Water-covered areas were subsequently calculated at monthly, seasonal, annual, and decadal scales. Trend analysis was performed using time-series assessment and linear regression to determine the direction and magnitude of changes over time. Additionally, the non-parametric Sen’s Slope estimator was applied to obtain a more robust estimate of change rates and to reduce the influence of outliers. To evaluate the stability of the lake’s inundation regime, the Transition and Seasonality layers from the JRC Global Surface Water dataset were analyzed within Google Earth Engine. Results Time-series analysis of Landsat imagery revealed a decreasing and unstable trend in the extent of Lake Namak’s inundated area over the past three decades. The mean inundated area in the first decade (1995–2004) was about 154.4 km², decreasing to 48.1 km² in the second decade (2005–2014) and to approximately 41.1 km² in the third decade (2015–2024). Annually, the maximum water extent occurred in 2001 (about 383.6 km²), while the minimum was recorded in 2014 (about 1 km²), indicating strong interannual variability. Trend analysis using linear regression confirmed a significant negative trend, and the negative slope highlighted continuous decline in inundation. Similarly, Sen’s Slope analysis yielded negative annual change rates, indicating a persistent long-term reduction with higher robustness. Seasonal patterns showed that spring exhibited the highest inundation, with about 10% of the lake’s surface containing water, followed by winter with about 5.4%, while summer and autumn displayed minimal inundation. Monthly analysis showed maximum inundation in March, April, and May. The Transition layer indicated that approximately 70.4% of the lake area remained unchanged, while about 15.9% fell into the “new seasonal” class and around 13% into the “seasonal” class, reflecting the expansion of temporary water bodies. Seasonality results showed that more than 71.1% of the lake surface lacked persistent inundation, with most water-covered areas present only one to three months per year. Conclusion The findings indicate that Lake Namak has undergone a substantial reduction in surface area and hydrological persistence over the past three decades, with both linear regression and Sen’s Slope confirming the declining trend. The dominance of short-term and seasonal inundation reflects increasing hydrological instability. Continuation of this trend may lead to major environmental consequences, including increased salinity, intensified evaporation, and expansion of dust-source areas. The use of satellite imagery and Google Earth Engine provides an effective framework for long-term monitoring of such dynamic environments.

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