Prediction of distributional patterns of four major Camellia oilseed species in China under climate and land use changes

Predicting changes in suitable areas under climate and land use changes, and identifying persistent suitable areas for economically valuable plant species, are critical for future conservation and cultivation. Camellia chekiangoleosa, Camellia drupifera, Camellia oleifera and Camellia reticulata serve as important woody oilseed species in China, providing both economic and ecological benefits. Here, we predict the distributions of the four species under climate and land use changes (SSP126, SSP245 and SSP585 in 2070) combining two dispersal constraint scenarios (full dispersal and 20 km/decade) by using ensemble species distribution models. The results showed that the current potential suitable areas of the four species coincided with their current known distribution regions; most of these areas are of high suitability. Among the environmental variables, climatic factors have stronger effects on the distribution of the four species than land use factors. In response to climate and land use changes, the range sizes of C. chekiangoleosa and C. drupifera were projected to increase, while for C. oleifera and C. reticulata the range would contract. In addition, the centroid of the suitable range would shift in different directions and distances for different species. As a result of distinctive range shifts, the studied species have their own specific areas of persistent suitability in southern China. Notably, except for the widespread C. oleifera, there is almost no overlap in the persistent suitable areas among the other three species. This study gives us a better understanding of the impact of climate and land use changes on the major Camellia oilseed species in China, thus guiding the selection of sites for oil tea plantations and the conservation of germplasm resources.