Modeling habitat distribution of Festuca ovina-Astragalus gossypinus by using maximum entropy method in the Chaharbagh rangelands of Iran

Abstract

The study was aimed to estimate the geographic distribution of Festuca ovina-Astragalus gossypinus in the Chaharbagh rangeland in Golestan province by using Maximum Entropy (MaxEnt) modeling technique. Sampling of vegetation was carried out f ollowing systematic random sampling approach. Soil properties (texture, organic carbon, pH, EC and N) were determined by standard methods. Geostatistical methods were used for mapping soil properties. Environmental variable maps were prepared. The agreement of predictive map with the actual map was checked by calculating Kappa coefficient value. Accuracy of predictive models was evaluated using the area under curve (AUC). Study revealed that Jackknife method and response curve were most important methods for environmental predictor variables. Correspondence of actual map with the predictive one was at satisf actory level (Kappa coefficient=0.65). The habitat requirements of Festuca ovina-Astragalus gossypinus indicated that the highest probability of presence occurred in the soils with N (0.14- 0.18%), sand (35-38%), clay (20-24%) contents and low lime (11-13%) content.