ِAli Tavili; S. Motahareh Hosseini; Mohammad Jafari; Ali Golkarian
Abstract
MAXENT model was used to evaluate the probability of Dorema ammoniacum development in rangelands of Southern Khorassan. Presence data of D. ammoniacum was recorded based on field survey and GPS application. Nine environmental information layers were used to model potential habitat of the understudy species. ...
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MAXENT model was used to evaluate the probability of Dorema ammoniacum development in rangelands of Southern Khorassan. Presence data of D. ammoniacum was recorded based on field survey and GPS application. Nine environmental information layers were used to model potential habitat of the understudy species. Relationship between species presence and environmental parameters was determined using maximum entropy. Map of species distribution was achieved. Results showed that the probability of D. ammoniacum is higher in regions with the following environmental characteristics; elevation of 1017-1933 m, average temperature of 13.96 to 15.17 ºC, average precipitation of 112- 131 mm, slope of 0-14% and LST range between -4 to 10 ºC. An AUC of 92 demonstrated that MAXENT is a suitable model for prediction of D. ammoniacum distribution and potential habitat.
Mahboobeh Abasi; Mohammad Ali Zare Chahouki; Hossein Bagheri
Abstract
The main objectives of this study were to prepare a prediction map of the potential habitat of Agropyron intermedium and Find important factors influencing the establishment and distribution of this species and the preferred tendency of the species was relative to environmental factors Using the Maxent ...
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The main objectives of this study were to prepare a prediction map of the potential habitat of Agropyron intermedium and Find important factors influencing the establishment and distribution of this species and the preferred tendency of the species was relative to environmental factors Using the Maxent model. For modeling, region condition information was prepared including topography, climate, geology and soil, satellite images, digital elevation model (DEM), geology map, and climatology data. Then soil and plants sampling was performed and Soil samples were transferred to the lab. Soil properties were measured including gravel, pH, EC, lime, organic matter, N, K, P, sand, clay, and silt in the laboratory. Geostatistical methods were used for data analysis and mapping of environmental variables and the Maxent model was used for prediction maps. Kappa coefficient indicates that the Maxent model predicted A. intermedium habitat at a very good level (kappa = 0.85). Also, the accuracy of the classification of habitat maps predicted in the Maxent model is acceptable according to the analysis of the area under the curve (AUC = 0.771). The results showed that topographic variables and clay soil factor in the occurrence and distribution of A. intermedium has the greatest effect and increasing lime and ec have a negative influence on the presence of this species. A. intermedium is a desirable species that in addition to being used in creating hand-planted pastures, it is very important in improving and developing rangelands, especially in cold regions. Therefore, maintaining genetic and scientific,
Mahsa Ghazimoradi; Mostafa Tarkesh; Hossein Bashari; Mohammad Reza Vahabi
Abstract
In this study, the ability of Generalized Additive Model (GAM) for mapping potential distribution of Ferula ovina Boiss, and the description of species response curves to environmental variables were examined in Fereidonshar region with area of 1000 square kilometers located in West of Isfahan province. ...
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In this study, the ability of Generalized Additive Model (GAM) for mapping potential distribution of Ferula ovina Boiss, and the description of species response curves to environmental variables were examined in Fereidonshar region with area of 1000 square kilometers located in West of Isfahan province. The presence and absence data of the species were collected from 278 sites (including 138 presence sites and 140 absence sites) by random systematic method, and 9 soil variables, 22 climate variables and 3 physiographic variables were mapped with pixel size of 72*72 square meters by using interpolation techniques (krigging, Inverse Distance Weighting) for the entire studied area. Then, the relationships between presence and absence of the species with the environmental variables were examined by GAM method. According to the results, the presence of Ferula ovina was inversely correlated with some environmental variables including soil silt and clay contents and also its distribution was directly correlated with slope, distance from sea level, organic matter content, soil saturation percentage and average annual temperature. The model evaluation conducted by the separate data gave Kappa coefficient equal to 0.64 and ROC area under curve equal to 0.86. According to the produced potential habitat map and the response curves of the species, the presence of Ferula ovina is more likely in the habitats with mean annual temperature: 9-11 degree centigrade, slop: 25-50%, elevation: 1950-3000 meter (Above sea level), CaCO3 content of soil: 10-30%, organic matter: 4-6%, silt: 10-30% and soil saturation percentage: 45-60%. The GAM enables managers to identify appropriate areas for rangelands rehabilitation and protection programs. The produced model has a suitable performance in identifying regions with high growth potential and rangelands rehabilitation and protection programs.
