Geospatial modelling of widely distributed oriental-beech forests syntaxa in the Northwestern Caucasus

Abstract

For the first time in the Northwestern Caucasus, we applied the maximum entropy method (MaxEnt) to estimate the potential distribution of widespread oriental-beech forest syntaxa belonging to the alliance Myosotido dissitiflorae–Fagion orientalis Shevchenko et al. 2026. The models demonstrated good performance (AUC = 0.85–0.95) with variables characterizing precipitation, temperature, and altitude. Maps were constructed, and potential distribution areas of oriental-beech forests in the region were identified. The most significant bioclimatic predictors in the models of all studied syntaxa were found to be precipitation seasonality and annual precipitation. The potential distribution area of oriental-beech forest syntaxa was found to encompass the foothill, mid-mountain, and high-mountain zones of the central and eastern parts of the Northwestern Caucasus, with the exception of the western part of the region and the Black Sea coast, where these syntaxa are found only locally in well-watered mesorelief conditions. Geospatial modelling revealed significant similarities between oriental-beech and hornbeam forests in terms of their growing conditions in the Northwestern Caucasus. Therefore, the oriental-beech and hornbeam forests of the Northwestern Caucasus can be considered as mosaic elements within the oligo- or polydominant stands of broadleaf forests in the region. The resulting models of the potential distribution of oriental-beech forests can be used in geobotanical mapping, forest vegetation inventories, and clarification of syntaxa distribution boundaries in the Northwestern Caucasus and Northwestern Transcaucasia. The obtained results are essential for informed conservation planning and sustainable use of the region’s unique oriental-beech forests, rich in endemic animal and plant species, under conditions of modern anthropogenic impact.