Predicting the Distribution of Fagus orientalis L. Under the Future Climate Model

Abstract

Climate change is projected to shift species distributions, forcing ecological rearrangements at latitudinal and altitudinal margins. Modeling resilient future habitats under climate scenarios is essential for proactive biodiversity conservation. This study models the current and future potential distribution of Fagus orientalis Lipsky (Oriental beech) a key broadleaf foundation species forming critical trailing-edge populations in the West Asian–European transition zone. Predictive modeling was conducted using the Maximum Entropy (MaxEnt) algorithm integrated with SSP2-4.5 and SSP5-8.5 scenarios of the GISS-E2-1-G climate model. Predictors incorporated bioclimatic variables, Normalized Difference Vegetation Index (NDVI), and high-resolution topographic indices (elevation, slope, aspect). Model performance demonstrated high predictive accuracy, achieving a Training AUC of 0.954, Test AUC of 0.919, True Skill Statistic (TSS) of 0.572–0.599, and a Boyce Index of 0.645–0.913. Spatial change analysis traced geographic shifts and habitat fragmentation over the 2041–2060 and 2081–2100 horizons. Results indicate that current potential suitable habitat covers approximately 114,689.43 km². Although significant spatial contractions and low-altitude fragmentation were projected under both scenarios, the model validated a systematic range shift toward northern latitudes and higher elevations. Crucially, fine-scale topographic variables identified high-altitude massifs acting as vital micro-refugia capable of buffering regional extinction risks. By offering spatially explicit projections of habitat suitability and identifying key ecological refugia, these findings deliver a reproducible framework for assisted migration, target-driven ecological restoration, and genetic resource conservation, serving as a robust decision-support tool for developing climate-resilient forest management strategies.