Climate Change-Driven Shifts in Ecologically Suitable Areas of Six Polygonum Medicinal Species and Their Implications for Ecological Cultivation and Conservation in China

Abstract

Polygonum L., a large genus within Polygonaceae, comprises numerous species of medicinal value. However, their utilization is still primarily dependent on wild resources, which are facing growing threats from overharvesting and climate-induced habitat deterioration. This study assessed climate change impacts on six Polygonum medicinal species (P. capitatum, P. perfoliatum, P. hydropiper, P. tinctorium, P. orientale, and P. chinense) using optimized MaxEnt models. Specifically, we predicted current and future (2050s and 2070s) suitable areas under three climate scenarios (SSP126, SSP245, SSP585), analyzed key ecological factors, and mapped suitability shifts to identify priority areas for conservation and sustainable cultivation. Temperature (bio_01) and precipitation (bio_18, bio_13, or bio_14) were major key factors for all species except P. tinctorium, which was mainly influenced by SNDPPT and bio_02. Currently, all six species shared high to moderate suitability in Guizhou, Guangxi, and Chongqing, but differed in pattern. P. capitatum, P. chinense, and P. tinctorium were mainly confined to Yunnan, Sichuan, Guangdong, and Fujian, whereas P. hydropiper also extended to Hunan, Hubei, Zhejiang, and Shanghai, P. perfoliatum to Jiangxi and northeastern Sichuan, and P. orientale uniquely reached Shandong, Hebei, Beijing, and Tianjin. Based on these, current germplasm conservation should prioritize areas with relatively concentrated and continuous highly to moderately suitable areas, whereas ecological cultivation should focus on the most continuous highly suitable areas. Additionally, all six species showed future contraction in southern and/or southeastern China, while expansion northward, northwestward and/or northeastward. P. tinctorium showed the smallest spatial change and greatest stability. P. capitatum and P. chinense shared stable Yunnan–Guizhou–Sichuan cores, whereas P. perfoliatum, P. hydropiper, and P. orientale also expanded to Qinghai, Ningxia, and Northeast China. Accordingly, an area-specific approach is recommended for managing the six Polygonum species in future: stable areas should be prioritized for long-term cultivation and in situ conservation, contraction areas for germplasm protection, and expansion areas for introduction trials and adaptive evaluation.