Predicting the potential habitat of Wych elm (Ulmus glabra Huds.) using the Maxent model in Kheyrod forest

Investigating the relationship between distribution of plant species and environmental factors is one of the main issues in plant ecology. Habitat suitability or species distribution models, are defined as statistical analysis algorithms which relates species data to the environmental predictor variables. This study aims at predicting the habitat suitability of Wych elm species in Kheyroud forest using Maxent model. Wych elm is one of the most invaluable native species in Hyrcanian forest. However, due to the outbreak of Dutch elm disease in recent decades and illegal cutting of this species, its dominance has been significantly decreased. Therefore, the primary and secondary topographic attributes derived from digital elevation model with 12.5 m resolution along with soil characteristics, soil fertility, and geology maps, were extracted at each Wych elm location. Using selective sampling and inventory data, 873 Wych elm individuals were recorded. The results showed that Maxent model has a high potential to predict the suitable habitats for Wych elm based on AUC criterion. Altitude and valley depth were the most important variables in determining the habitat suitability for Wych elm species. Moreover, 32.57% of the study area has an acceptable potential for the presence of this species. Due to the optimal moisture, thermal, and topographic conditions in mid-lands, this area is the best habitat for this species in Kheyrod forest. The generated model can be used as a tool for the forest experts and managers to help conservation and rehabilitation of Wych elm in this forest.