Endemic medicinal plant distribution correlated with stable climate, precipitation, and cultural diversity.

Medicinal plants provide crucial ecosystem services, especially in developing countries such as China, which harbors diverse endemic medicinal plant species with substantial cultural and economic value. Accordingly, understanding the patterns and drivers of medicinal plant distribution is critical. However, few studies have investigated the patterns and drivers of endemic medicinal plants distribution in China. Here, we linked endemic medicinal plants distribution with possible explanatory variables, i.e., paleoclimate change, contemporary climate, altitudinal range and ethnic minority human population size at the prefecture city level in China. Our results show that endemic medicinal plants are concentrated in southern China, especially in southwestern China. Notably, both endemic medicinal plant species richness and the ratio of endemic medicinal plant species richness are negatively associated with glacial-interglacial anomaly in temperature, and positively associated with contemporary precipitation and altitudinal range. In addition, we found that endemic medicinal plant species richness is positively associated with ethnic minority population sizes as well as its ratio to the overall population size. These findings suggest that the distribution of endemic medicinal plants is determined by multiple drivers. Furthermore, our findings stress that dramatic future climate changes and massive anthropogenic activities in southern China pose great challenges to the conservation of China's endemic medicinal plants.