Global Warming and Dispersal Limitations Drive the Suitable Habitat Distribution of Castanopsis indica, Castanopsis hystrix, Schima wallichii Forest in China

Global warming has increasingly threatened the suitable habitats of many species. However, ignoring dispersal limitations can substantially increase the uncertainty of species distribution predictions. This study employed optimised MaxEnt and MigClim models to explore the effects of global warming and dispersal limitations on the suitable habitat distribution of Castanopsis indica, Castanopsis hystrix, Schima wallichii (C. indica, C. hystrix, S. wallichii) forest in China. The results reveal that under current climatic conditions, this forest is mainly distributed in southwestern China. The key environmental factors influencing its distribution include isothermality, temperature seasonality, minimum temperature of the coldest month, and precipitation seasonality, among which temperature-related factors play a dominant role. Under future climate scenarios, the suitable habitat distribution of this forest is projected to expand overall and exhibit a northwestward migration trend. Notably, dispersal limitations significantly constrain the actual expansion of this forest, preventing it from keeping pace with climate change. The inclusion of dispersal limitations results in a contraction of the suitable habitat distribution of this forest under future climate scenarios, with the overall centroid migrating towards the southwest. In the future, C. indica, C. hystrix, S. wallichii forest will have some unoccupied suitable areas in China, which are primarily located north of its current suitable habitats. This study provides new insights for reducing uncertainties in species distribution predictions under climate change.