Can Ecological Niche Modeling of Prickly Juniper (Juniperus oxycedrus L.) Predict Future Forest Distribution Limits...

Climate change is expected to alter the distribution limits of woody species in Mediterranean and semi-arid regions, especially near forest-steppe transition zones. In this study, ecological niche modeling (ENM) was applied to examine the current and future habitat suitability of prickly juniper (Juniperus oxycedrus L.) in Türkiye under three Shared Socioeconomic Pathways (SSP1-2.6, SSP3-7.0, and SSP5-8.5) for the periods 2011-2040, 2041-2070, and 2071-2100. Species-environment relationships were quantified using the Maximum Entropy (MaxEnt) algorithm. From 48 candidate MaxEnt models, the optimal model was selected based on statistical performance and showed a high mean training AUC (AUC = 0.869, SD = 0.017). Null model testing confirmed that predictive performance exceeded random expectations (AUC_null = 0.593, SD = 0.011; Z = 28.294, p < 0.00001). Among all predictors, precipitation of the driest month (bio14) and slope showed the highest contributions, accounting for 24.9% and 24.3%, respectively. Present-day suitability reveals that J. oxycedrus has a wide distribution in the interior Anatolian and Mediterranean uplands. Future projections indicate limited habitat loss during the early projection period, followed by substantial reductions toward the end of the century, particularly under high-emission scenarios. Late-century projections suggest that suitable habitats become increasingly restricted to mountainous areas, including the Taurus range and selected highland regions of Central and northern Türkiye. Overall, the findings underline that climate adaptation is closely linked to how biome boundaries are managed in relation to ecological thresholds. Expanding forest cover beyond natural environmental limits may not represent an effective adaptation strategy.