Modeling the potential distribution of Nothotsuga longibracteata in China under current and future climate scenarios...

Nothotsuga longibracteata is an endangered tree species endemic to China whose conservation is constrained by limited information on habitat suitability. Using the biomod2 platform, we developed an ensemble model integrating climatic, topographic, edaphic, and human-related variables to predict its current and future potential distribution under climate change. The ensemble model consistently outperformed individual algorithms across evaluation metrics. The most important predictors were precipitation of the coldest quarter (Bio19), mean diurnal temperature range (Bio2), human footprint, elevation, precipitation of the warmest quarter (Bio18), and mean temperature of the driest quarter (Bio9). Under current conditions, the suitable habitat for N. longibracteata covers approximately 872.5 × 10³km², concentrated in Hunan, Jiangxi, and Guangxi, with high-suitability areas primarily in southern Hunan, northeastern Guangxi, and northwestern Guangdong. Future projections revealed a decoupling between habitat extent and habitat quality, with low-suitability areas expanding while moderate- and high-suitability habitats declined, accompanied by shifts in the distribution centroid toward higher latitudes and elevations. This pattern suggests that changes in total suitable area alone may underestimate decline risk. Given the limited overlap between suitable habitat and existing protected areas, we recommend prioritizing in situ conservation in core regions, especially Hunan and Guangxi, while considering Hubei, Anhui, and Chongqing as potential areas for assisted migration and climate-adaptive cultivation.Clinical Trial Registration: Not applicable.