Distribution and Habitat Suitability of Artemisia annua in China Under Climate Change Scenarios.

Artemisia annua is a medicinal plant of high therapeutic and economic value, yet its wild resources have declined markedly in recent decades. Climate change is expected to further alter its geographical distribution, posing challenges to both conservation and sustainable utilization. Here, we applied a Maximum Entropy (MaxEnt) model that integrates climatic, topographic, and soil variables to assess the current and future suitable habitats of A. annua in China under three CMIP6 shared socioeconomic pathways (SSP126, SSP245, and SSP585) for the mid-21st century (2050s) and late-21st century (2090s). We hypothesized that winter temperature conditions and precipitation seasonality would be the principal climatic constraints on habitat suitability, and that future climate change would drive an overall contraction and northeastward shift of suitable areas, with stronger changes under higher-emission scenarios. The model was optimized using the ENMeval framework by tuning the regularization multiplier and feature classes, thereby reducing overfitting and improving ecological realism. Model predictions indicate that the current suitable habitat of A. annua covers approximately 2.02 × 106 km2, mainly distributed across central and southwestern China. Habitat suitability is primarily constrained by winter temperature conditions, precipitation seasonality, and elevation, highlighting the dominant role of climatic tolerance and topographic mediation in shaping its ecological niche. Under future climate scenarios, the total suitable area is projected to contract, with the most pronounced reductions occurring under the high-emission SSP585 pathway. Spatially, suitable habitats are expected to shift northeastward, with the centroid migrating from northern Sichuan toward southern Shaanxi, reflecting a climate-driven redistribution toward cooler regions. By distinguishing stable, contracting, and expanding zones of suitable habitat, this study provides a spatially explicit assessment of A. annua's vulnerability and adaptive potential under climate change. Our findings offer ecological insights into the species' climate sensitivity and provide a scientific basis for dynamic conservation planning and sustainable industrial distribution under future environmental change.