Abstract: Fagus species are renowned for their superior timber and ecological value in paleoecological research. However, climate change has been a contributing factor to the decline of Fagus species. Moreover, because Fagus species are primarily confined to temperate mountainous regions– where sampling and long-term monitoring are challenging–conservation research on these trees remains very limited. To address this gap, the MaxEnt model was used to simulate potential habitat distributions and centroid migration trends of Fagus species under different climate scenarios (SSP126, SSP245 and SSP585) for the 2050s, 2070s and 2090s. Additionally, the study assessed niche differentiation and utilised the GeoDetector to evaluate environmental drivers of distribution changes. The results showed that the most suitable Fagus for Fagus species were concentrated in the high-elevation regions of southern China. The areas of highly and moderately suitable Fagus were 4.00 × 10⁵ km² and 6.18 × 10⁵ km², respectively. Minimum temperature of the coldest month (BIO6) and precipitation of the driest month (BIO14) were identified as the main environmental factors influencing species distribution and habitat differentiation. Future projections indicated an expansion of suitable Fagus. Under the SSP588 scenario, a pronounced expansion trend was observed, with increases of 3.87 × 10⁵ km² (2050s), 5.59 × 10⁵ km² (2070s) and 5.82 × 10⁵ km² (2090s). Notably, habitat centroids exhibited a northwestward migration trajectory. Additionally, the results showed that by the 2090s, significant niche differentiation was projected to occur exclusively under the SSP126 and SSP585 scenarios. These findings clarify climatic determinants of Fagus species, offering actionable insights for sustainable use.

Key words: Fagus species, suitable habitat, MaxEnt, Geographical detector, niche