Using Biomod2 and spatial quality modeling for comprehensive production zoning of Bupleurum chinense DC

Bupleurum chinense DC. (B. chinense), an important traditional medicinal herb in China, exhibits several pharmacological activities, including antidepressant, anti-inflammatory, and hepatoprotective effects. Its medicinal value is highly dependent on the types and contents of secondary metabolites, such as saikosaponins. With the growing global emphasis on natural medicines in recent years, the market demand for B. chinense has been expanding, increasing the need for stable yield and high medicinal quality.

This study constructed a comprehensive production zoning system by integrating ecological suitability modeling and spatial quality prediction. We utilized the Biomod2 platform to predict the distribution of ecological suitability and identify environmental factors affecting growth. Subsequently, a Principal Component Analysis - Multiple Linear Regression - Spatial Prediction framework was applied to evaluate spatial quality.

(1) The ensemble model constructed using the biomod2 platform (TSS = 0.851, AUC = 0.980) was employed to evaluate ecological suitability. The results indicated that the ecological suitability was higher in northern regions than in southern regions, with precipitation (Bio13, Bio17) and temperature (Bio6, Bio3, Bio2) were identified as the major driving factors. (2) Climatic factors (Bio15, Bio17) and soil factor (tp05) significantly affected saikosaponin content, while topographic factors exerted only a weak influence. Based on a regression model constructed via PCA-MLR-PC (R² = 0.28, VIF< 5, Cook's distance< 1 for 95% of observations), the relative content of the medicinal material was found to be higher in northern areas compared to southern areas. (3) The comprehensive production zoning of B. chinense showed that the high production zone was primarily observed in the Loess Plateau, the northern part of the North China Plain, and parts of the Northeast China Plain. The high production zone covered 1.1×10⁶km²; the medium production zone covered 0.7×10⁶km², and the low production zone had the covered 0.4×10⁶km².

The comprehensive framework that integrated both ecology and quality, representing the synergistic advantage between ecological suitability and medicinal quality. These findings distinguished different grades of production zones, providing a reference for prioritizing the development of high production zones and implementing differentiated cultivation strategies across various production zones.