Habitat suitability and driving factors of the endangered medicinal plant Sinopodophyllum hexandrum under climate and land use change

Introduction Climate change and land-use change pose significant threats to the survival of endangered medicinal plants. This study focuses on the endangered medicinal plant Sinopodophyllum hexandrum . Methods Using 268 distribution records and an optimized MaxEnt model (RM = 4.0, FC=LQHPT), together with an OptimalParameters Geographical Detector (OPGD), the current and future habitat suitability,driving mechanisms, and the impact of land use change under variousclimate scenarios (SSP126, SSP370, SSP585) were systematically evaluated. Results The results indicate that: (1) The current suitable habitat area for S. hexandrum is 1.1608 × 10⁶ km², primarily distributed in Sichuan, Tibet, and Gansu along the eastern edge of the Qinghai-Tibet Plateau. High suitability areas are concentrated at altitudes between 2800–3500 m. (2) Future climate warming is projected to promote the northwestward expansion of suitable areas. Under the SSP585 scenario, the suitable habitat area is expected to increase to 1.8770 × 10⁶ km² by the 2090s, representing a 61.70% increase from the current area, with the habitat centroid shifting by 333.74 km. (3) Altitude (contribution rate of 34.5%, q = 0.245), minimum temperature of the coldest month (26.4%), and annual precipitation (20.7%) are the dominant factors influencing distribution. Interactions among environmental factors significantly enhance explanatory power, with the strongest synergistic effect observed for bio12 ∩ elevation (q = 0.685). (4) High-risk areas (as defined by the OPGD Risk Detector) cover 5.30 × 10⁴ km², with 75.3% located outside existing nature reserves. (5) Grassland (4.979 × 10⁵ km²) and forest land (4.731 × 10⁵ km²) are the primary carrier ecosystems, with moderately suitable grassland areas projected to increase under future climate scenarios. Discussion This study reveals the strict ecological requirements of S. hexandrum for high-altitude, low-temperature, and moderate‑precipitation environments, as well as the synergistic effects of hydrothermal coupling on its distribution. The findings provide a scientific basis for conservation planning, the designation of priority conservation areas, and climate‑adaptive management of endangered medicinal plants.