Large Variability in Response to Future Climate and Land-Use Changes of François' Langur in China

Understanding how climate and land-use change influence habitat suitability is essential for the conservation of the François' langur (Trachypithecus francoisi). In this study, climatic, land-use, and topographic variables were integrated to model the current distribution and future dynamics of suitable T. francoisi habitats in southwestern China. The model performed well, climatic factors were the primary determinants of distribution, particularly precipitation of the driest month (BIO14), mean diurnal temperature range (BIO2), and precipitation seasonality (BIO15); additionally, forest cover, slope, and elevation further improved model performance. Suitable habitat currently covers 53,109 km² (10.75% of the study area) and is mainly concentrated in Chongqing and Guizhou, with smaller areas in Guangxi. Future projections indicate substantial habitat redistribution and an overall decline in suitable area under both scenarios. By the 2050s and 2070s, suitable habitats will show strong spatial turnover, with coexistence of retained, newly suitable, and lost areas. Suitable habitat is projected to shift toward northern areas. These results suggest that conservation priorities should shift focus northward under climate warming, with emphasis on protecting mountainous refuges and improving habitat connectivity.