Evaluating Habitat Suitability for the Endangered Sinojackia xylocarpa (Styracaceae) in China Under Climate Change Based on Ensemble Modeling and Gap Analysis

Sinojackia endemic to China, comprises five species, and each has restricted distribution but with high value in landscaping. However, how such species respond to climate change remains unclear. We selected S. xylocarpa as a representative, built an ensemble model in Biomod2 to forecast its potential distribution, identify its key influencing factors, and analyze its conservation gaps in China’s nature reserves. The four leading factors were precipitation of driest quarter, mean temperature of warmest quarter, precipitation of warmest quarter, and elevation. This species was mainly distributed in southeast China. Its suitable area was 69.72 × 104 km2, accounting for 6.26% of China’s total territory. Nevertheless, only 3.91% was located within national or provincial nature reserves. Under future climates, its suitable areas would averagely decrease by 10.97% compared to the current, with intensifying habitat fragmentation. Collectively, its centroid is expected to shift northeastward in the future. Therefore, our findings first demonstrate that future climate change may have an adverse effect on its distribution. We recommend conducting a supplementary investigation within the projected suitable range, and establishing new conservation sites for S. xylocarpa in China. Moreover, this study can provide valuable reference for conserving other endangered Sinojackia species under global warming.