Linking species distribution and chemistry to support the management of Saposhnikovia divaricata under global change.

Saposhnikovia divaricata is a Level III nationally protected wild medicinal plant in China. Due to its high medicinal and economic value, its wild populations have been severely depleted in recent years. This study used the MaxEnt and Biomod2 models to identify the limiting factors, main environmental factors, and the impact of future climate change on the distribution of S. divaricata. Additionally, by incorporating future land use data, the study analyzed the effects of land use changes on the habitats of S. divaricata. To more effectively plan the wild tending areas, this study employed full subset regression to identify the environmental factors influencing the chromones of S. divaricata, and quantified their spatial distribution both currently and in the future. Finally, with the coupling of the above results by the Zonation, the priority protection areas for S. divaricata, as well as the orientation and comprehensive wild tending areas of the four chromones were planned. The results indicate that, in the future, upper climate change is projected to have an overall positive effect on the potential suitable habitat of S. divaricata, with the total suitable area increasing by approximately 3.85% under the 2090s-SSP370 scenario compared to the current. In contrast, under most scenarios, lower land use changes are expected to cause a decline in suitable habitat area within the current suitable area, with a reduction of about 4.66% under the 2090s-SSP126 scenario. The existing nature reserves cover only 13.13% of the HPPA areas for S. divaricata, indicating a serious lack of protection for the species. Based on this, the study has proposed a potential protection area for S. divaricata and recommends targeted wild tending in hotspot counties. The results of this study will contribute to the protection of wild resources and the restoration of S. divaricata populations, as well as provide new insights for the protection and utilization of other rare and endangered medicinal plants.