Potential Geographic Distribution of the Rare and Endangered Plant Sauvagesia rhodoleuca in China Under Climate Change Scenarios

Abstract

Sauvagesia rhodoleuca, a monospecific endemic to China, belongs to the Ochnaceae. It holds significant academic value in studying the evolution and phylogeny of this family's flora, and its rhizomes have medicinal properties. Due to human activities and habitat destruction, the wild population of this species has sharply declined, and it has been listed as a national second-class protected plant. It is now only sporadically distributed in mid-low mountain forests of Guangxi and Guangdong at an altitude of 400-1000 m. To reveal its potential distribution and response to climate change, this study optimized parameters of the MaxEnt model using 29 distribution points and 38 environmental variables. The ENMeval package was used to simulate suitable area distributions under current and future (2050s, 2070s) SSP126, SSP245, and SSP585 scenarios. The results showed that the optimized MaxEnt model had AUC values > 0.988, indicating high prediction accuracy. Bio14, T_BS, T_CLAY, and Bio8 were identified as the main environmental drivers, with hydrothermal conditions dominating the distribution pattern. Under current climate conditions, the total suitable habitat area was estimated at 146.81 × 10⁴ km², concentrated in southern China. Projections under future scenarios (2050s and 2070s) across SSP126, SSP245, and SSP585 scenarios indicated significant range expansion, with the most pronounced increase (63.81% expansion) observed under the high-emission SSP585 scenario in the 2070s. The distribution centroid showed a consistent northward shift, with new suitable habitats emerging primarily in Fujian, Hunan, Jiangxi, and Zhejiang. This study provides a scientific basis for wild resource conservation and cultivation introduction of S. rhodoleuca, recommending prioritized conservation of high-suitability areas like Dayao Mountain National Nature Reserve of Guangxi and cultivation introduction planning in new areas like Hunan and Jiangxi, while considering environmental requirements for medicinal component accumulation.

Keywords: MaxEnt model; Sauvagesia rhodoleuca; climate change; environmental factor; potential geographic distribution.