Assessing the impacts of climate change on the potential distribution of the medicinal plant Bidens biternata in China using Biomod2

Introduction Climate change is expected to reshape the potential distribution of medicinal plants, with direct implications for conservation, cultivation zoning, and sustainable utilization. This study aimed to assess the current and future habitat suitability of Bidens biternata in China under climate change. Methods Using the biomod2 R package (v4.2-6), we developed an ensemble species distribution model based on 493 raw occurrence records compiled from field surveys, GBIF, and CVH, which were spatially thinned to 197 independent records at a 5-km grid. After collinearity screening, 15 environmental predictors were retained. Twelve algorithms were calibrated using 1,000 pseudo-absence points, and future suitability was projected under SSP126, SSP245, SSP370, and SSP585. Results The committee-averaging ensemble model showed high predictive performance, with TSS = 0.842 and AUC = 0.96. Temperature-related predictors, especially bio2, bio3, and bio8, dominated model performance. Under the current climate baseline, highly suitable habitat was mainly concentrated in monsoonal eastern and southern China and parts of Southwest China, covering 2.68 × 10 5 km 2 (17.20%). Future projections indicated an expansion of highly suitable habitat during 2021–2080, followed by late-century divergence under higher-forcing pathways, with broader marginally suitable belts and reduced highly suitable fractions. Centroid trajectories indicated an overall northward to northwestward shift, whereas MESS/MoD diagnostics distinguished persistent suitability cores from climatically novel expansion fronts. Discussion These findings identify more reliable conservation and cultivation priority areas in the middle-lower Yangtze region, South China, the Sichuan Basin, and parts of Southwest China. Northern frontier zones should be treated as validation and trial-introduction areas rather than immediate large-scale production bases.