چكيده انگليسي :
Forests and rangelands are renewable resources with economic, social, and environmental benefits. However, both human and natural factors significantly contribute to the degradation of the Zagros forests. The tree species of the Zagros region, as perennial woody plants, play a nurse role for understory rangeland plants and help preserve them under climatic stress conditions. Therefore, this study investigated the natural habitat of key perennial woody species in the Zagros forests of Lorestan to determine their ecological niche and provide guidance for forest restoration projects.In this research, bioclimatic environmental data, including 19 bioclimatic parameters, physiographic data such as slope and elevation, and forest cover inventory data of Lorestan province (2004–2008) were used as biological data. The dominant tree and shrub species were identified based on the highest frequency and mean crown diameter, including Quercus brantii, Daphne mucronata, Acer monspessulanum, Amygdalus orientalis, Amygdalus scoparia, Crataegus spp., Cerasus microcarpa, Amygdalus lycioides, Pistacia atlantica, and Pistacia khinjuk. The geographical coordinates of each species' stands were recorded. The MaxEnt species distribution model was applied to determine species response curves and ecological niches. Additionally, using the eHOF package in R software, different species response models to key environmental variables were analyzed, with the best model selected based on the Akaike Information Criterion (AIC) to determine species tolerance and optimal ecological ranges.According to the MaxEnt model, the key environmental factors influencing species distribution in Lorestan province were annual temperature range (Bio7) and seasonal precipitation (Bio15), followed by minimum temperature of the coldest month, precipitation in the coldest season, and slope. The results indicated that Quercus brantii, Pistacia atlantica, Amygdalus scoparia, and Cerasus microcarpa thrived in temperature ranges of 41–45°C and seasonal precipitation around 87 mm, while Amygdalus lycioides, Pistacia khinjuk, and Amygdalus orientalis showed optimal conditions at 37–41°C with 88–90 mm of seasonal precipitation. The minimum temperature in the coldest month was optimal at approximately -5°C for Quercus brantii, Pistacia atlantica, Crataegus spp., and Cerasus microcarpa, whereas Amygdalus lycioides and Amygdalus orientalis exhibited better adaptation to lower temperatures. Daphne mucronata had the best presence conditions at 250 mm precipitation in the wettest month and 22°C in the driest season.Among physiographic factors, elevations between 500 and 2500 m were most suitable for Amygdalus scoparia and Daphne mucronata, while slopes of 0–5 degrees provided optimal conditions for Pistacia atlantica, Amygdalus lycioides, Pistacia khinjuk, and Amygdalus orientalis. The distribution analysis revealed that Quercus brantii, Cerasus microcarpa, Amygdalus scoparia, Acer monspessulanum, and Crataegus spp. were found throughout the province, except in the northern and northeastern regions. Meanwhile, Pistacia atlantica, Pistacia khinjuk, Amygdalus lycioides, and Amygdalus orientalis were predominantly distributed in the southern and southwestern parts, whereas Daphne mucronata was more concentrated in the central, southern, and southeastern regions.The eHOF model analysis, based on selected variables from MaxEnt and correlation analysis, indicated that the annual temperature range best matched a Type III response model, while seasonal precipitation, slope, and elevation showed the highest fit to an asymmetric unimodal Type V model.
