Comparison of species distribution models (SDM) Non-parametric and parametric determination of dominant species of rangeland habitat (Case study: Khetteh riz Rangelands)

    Ecologists and environmental managers emphasize the use of predictive models to examine the species distribution patterns. The purpose of the present study was to investigate the efficiency of the generalized linear model (GLM) and generalized additive model (GAM) in determining the relationship between vegetation and environmental factors in Khetteh Riz Rangelands. Environmental factors studied included soil characteristics, topographic factors and climatic factors. A classified-random sampling was performed and three dominant species, Bromus tomentollus, Ferula ovina, and Agropyron repens, were identified. The results showed that in the GLM model for Ferula ovina species, the variables of phosphorus content and slope were effective. For species Bromus tomentollus and Agropyron repens, the variables of annual moisture, rainfall, silt, and slope were effective. In the GAM model, the available moisture, silt and organic matter were the factors affecting the distribution of Ferula ovina. The silt, potassium, pH, and annual moisture content were the factors affecting the distribution of Agropyron repens. In addition, slope and silt were the variables affecting the distribution of Bromus tomentollus in the GAM model. The values of AUC, calculated for the GLM (0.63) and GAM (0.70), indicate the accuracy of the model to be acceptable.