Identifying prioritized planting areas for medicinal plant Thesium chinense Turcz. under climate change in China

As an important plant resource in China, medicinal plants dominate the Chinese herbal medicine market. The intensified human activities and the deteriorated ecological environment have caused the reduction or even extinction of medicinal plants nationwide. The artificial bionic cultivation of medicinal plants has become an important way for the healthy development of the Chinese medicine industry, given the increasing demand for Chinese medicinal materials. However, the blind introductions of medical plants ignoring the planting area's environmental suitability will waste many human and financial resources. Currently, species distribution models, widely used to predict the potential geographic distribution of species, enable the proper planning of prioritized planting areas with fully considered climatic factors. To scientifically and reasonably determine the best planting area of medicinal materials under current and future climate, we used the MaxEnt model to predict the suitable habitat for Thesium chinense Turcz., and determined the potential migration trends of its suitable areas. In addition, we also evaluated the main environmental variables that affect the distribution of T. chinense. In all the suitable habitat predictions, the training and testing area under the curve (AUC) values were greater than 0.9, indicating the robust performance of our model. Meanwhile, we found that annual mean temperature (Bio1), the maximum temperature of the warmest month (Bio5), annual temperature range (Bio7) and annual precipitation (Bio12) are the main environmental variables determining the T. chinense distribution, with the temperature being the most important factor under bionic cultivation conditions. The potential distribution areas of T. chinense are mainly the provinces along the middle and lower reaches of the Yangtze River. Under the future climate scenario, the highly suitable areas of T. chinense will generally increase, with the distribution ranges extending to higher latitudes. The Yellow River Basin may become another important planting area of T. chinense. Overall, the analysis provided the scientific basis for planning prioritized planting areas and improving bionic cultivation management techniques.