Abdalhossein Boali; Hamidreza Asgri; Ali Mohammadian Behbahani; Abdolrassoul Salmanmahiny; Babak Naimi
Abstract
Introduction: Desertification involves processes that are both the product of natural factors and the mismanagement of human beings. Adafic parameters and processes affecting soil condition, climate, groundwater, vegetation and management are the most important factors affecting the phenomenon of desertification ...
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Introduction: Desertification involves processes that are both the product of natural factors and the mismanagement of human beings. Adafic parameters and processes affecting soil condition, climate, groundwater, vegetation and management are the most important factors affecting the phenomenon of desertification in many arid and semi-arid regions. These parameters are investigated using different models in different regions.Therefore, this study was conducted to evaluate the desertification intensity based on groundwater and soil criteria in the west of Golestan province.Material and methods: To determine the work unit map, topographic, geological, aerial photo interpretation, panchromatic band and multispectral Landsat satellite images and field visits were used. In this study, the Madalus method was used to prepare a map and evaluate the desertification situation. The geostatistical methods used in this research include kriging method, local estimator method (GPI), radial function method (RBF) and distance distance method (IDW). in Madalus model, 6 criteria and 20 indicators were used to evaluate the intensity of desertification. The scoring of each of the indicators was determined at the unit level in the region. The map of each criterion is also obtained through the geometric mean relationship between the indicators. To evaluate the accuracy of the model results, the desertification class in each of the work units according to the field evidence, observational and visual evaluation was performed and then the statistical comparison of the model desertification class with an expert opinion was performed. SPSS software and Mann-Whitney non-parametric test were used to validate the model results.Results and discussion: In this study, according to the histogram of the data, the normality of the parameters was investigated. The mean square squared error (RMSE) was used to determine the most appropriate interpolation method. The weighted average score of desertification intensity of area 135 was obtained, which indicates the middle class. In terms of zoning of desertification intensity, the region was classified into three classes: low and insignificant with a frequency of 27 and medium with a frequency of 60 and severe with a frequency of 13. Among the criteria of desertification, the criterion of management and policy with an average weight of 148 points is the dominant and effective criterion of desertification, followed by the criterion of vegetation (145), the criterion of soil (141), the criterion of erosion (138), the criterion of climate. (122) and groundwater criteria (121) were in the next rank of effective desertification criteria in the region. Also, the most important indicators of desertification are the indicators of drought resistance, conservation operations and soil salinity, respectively. These indicators have increased the trend of desertification in the work units of abandoned lands, saline and wetland lands and saline lands located in the northeastern parts of the region.Based on the spatial distribution of classes with low and insignificant desertification intensity in the southern and eastern part of the region, the middle class in the western, central and northern parts and finally the severe desertification class are located in the northeastern parts of the region.Conclusion: According to the obtained results, which indicate high evapotranspiration of the region, expansion of land salinity, unprincipled road construction and incomplete drainage.it seems that the management of desertification in the west of Golestan province, as one of the agricultural hubs, should be in the managerial priority of the officials and experts of the executive departments.Accordingly, it is proposed in order to control the process of desertification and achieve sustainable development in the region .treatment of industrial and domestic effluents for reuse for various purposes, Use of modern irrigation systems for agricultural lands, Placing low-yield crops in terms of water consumption in the region's crop rotation and As well as the necessary training to justify farmers to use pesticides and chemical fertilizers in the area.
Faraham Ahmadzadeh; Elham Ebrahimi; Babak Naimi
Volume 15, Issue 4 , January 2018, , Pages 215-232
Abstract
Introduction: Carnivores have always been exposed to threatening processes because of their placement at the top of the food pyramid. Nowadays, approximately 65% of carnivores are listed as Critically Endangered or Vulnerable in the IUCN Red List of threatened species. On a global scale, in order Carnivora, ...
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Introduction: Carnivores have always been exposed to threatening processes because of their placement at the top of the food pyramid. Nowadays, approximately 65% of carnivores are listed as Critically Endangered or Vulnerable in the IUCN Red List of threatened species. On a global scale, in order Carnivora, the Hyaenidae family is the smallest with only four species. Hyaena hyaena is the only member of the Hyaenidae faimly in Iran, which is listed as “Near Threatened” (NT) in the IUCN Red List. The current study aimed to model the species distribution of the striped hyaena (Hyaena hyaena), which has a wide distribution in Iran. Materials and methods: Using nineteen layers of climatic variables, the correlations between those variables were analyzed and then highly correlated variables were excluded from the modeling process. Finally, eight species distribution models from the sdm package (GLM, GAM, BRT, SVM, RF, MARS, CART, and FDA) in R software were used. Given that the output of species distribution models are often uncertain, which is an undeniable fact, one possible solution to estimate the difference between projections and reduce the uncertainty, is the use of ensemble prediction system instead of using a single modeling method. Therefore, after determining the potential habitats of the Hyaena hyaena with those eight mentioned models and by using the ensemble prediction system, the best regions for the distribution of this species in Iran were estimated. Results and discussion: The results of this study showed that annual mean temperature, seasonal precipitation and precipitation of the warmest season have the most influence on the distribution of Hyaena hyaena. In general, FDA, GAM, BRT, CART and GLM models are fairly reliable, the MARS model is very reliable, and SVM and RF models are completely reliable. The results showed that the GLM, GAM, BRT, MARS, CART, RF models demonstrate that the suitable areas for Hyaena hyaena are generally the central regions of Iran, while the SVM and FDA models predicted the southern margin of the Caspian sea to make the best regions for the distribution of this species. Conclusion: The difference in the predictions that each model makes confirms the uncertainty between models. Therefore, the necessity of using Ensemble method is revealed. The results of the Ensemble model showed that the most suitable regions for the Hyaena hyaena species distribution are semi-arid and central steppe regions of Iran.
