MaxEnt model reveals northward and elevational expansion of climate suitability for Camellia oleifera growth in China

Camellia oleifera possesses significant energy, medical and environmental benefits. The influence of climate change on C. oleifera distribution is a critical concern. This study aims to evaluate the climate suitability change of C. oleifera. Based on the bioclimatic scenario data, the MaxEnt model is used to simulate and predict the climate suitability of C. oleifera from 1980s to 2100, and analyzing the spatiotemporal characteristics and changes of climate suitability. (1) The AUC value of the model is 0.929, indicating very good evaluation results. Precipitation of driest quarter, annual precipitation, mean temperature of coldest quarter, temperature annual range, isothermality, mean temperature of wettest quarter, precipitation of warmest quarter, and elevation are the eight main environmental factors that determine the climate of C. oleifera. (2) Optimum regions of C. oleifera are mainly southern China, roughly south of the Yangtze River and east of Yunnan-Guizhou Plateau. Suitable and above area ratio increased from 19.3% to 24.59%. As the elevation increases, the climate suitability first increases and then decreases. (3) The distribution of different suitability levels primarily transitions from low to high levels. Changes in the northern boundary, standard deviation ellipse, and central elements of the optimal regions indicate a trend of northward expansion in climate suitability for C. oleifera. Additionally, the elevation gradient suggests a trend of suitability extending towards higher altitudes. The climate suitability changes of C. oleifera indicate that there are more regions in China suitable for planting C. oleifera due to future climate warming.