Prediction of Potential Distribution and Response of Changium smyrnioides to Climate Change Based on Optimized MaxEnt Model.

Changium smyrnioides, an endangered herb known for its medicinal roots, contains essential amino acids that are vital for human health but cannot be synthesized by the body. However, wild populations of this species have been steadily declining due to the combined impacts of climate change and anthropogenic activities. In this study, we employed an optimized MaxEnt model to predict the potential distribution of C. smyrnioides under different climate scenarios and to evaluate its responses to climate change. Our findings demonstrated that the MaxEnt model achieved optimal performance with a regularization multiplier of 0.5 and a feature combination of linear and quadratic terms. Among the environmental variables, three emerged as the most critical factors shaping the species' potential distribution: elevation, precipitation of the driest month (bio14), and isothermality (bio2/bio7 × 100, bio3). Currently, the primary suitable habitats for C. smyrnioides are concentrated in Jiangsu Province, with an estimated 21,135 km² classified as highly suitable. The analysis further indicated that, in response to rising temperatures, C. smyrnioides is likely to shift its distribution northeastward across China. Notably, the results suggested that the total area of suitable habitats would increase over time under projected climate scenarios. Based on the predicted centroid migration of suitable habitats, Anhui Province was identified as a critical future conservation zone for C. smyrnioides. This region could serve as a vital refuge, ensuring the long-term survival of the species under changing climatic conditions. Overall, this study provides key insights into the ecological responses of C. smyrnioides to climate change, offering evidence-based guidance for the development of effective conservation strategies aimed at safeguarding this endangered herb.