Potential distribution, range dynamics, and livestock exposure risk of Veratrum nigrum L. in China under climate...

Climate change may alter the spatial distribution of toxic plants and increase their spatial overlap with grazing livestock, thereby posing risks to grassland ecosystems and animal health. Veratrum nigrum L., a medicinal plant with strong toxicity, is widely distributed in Eurasian temperate regions and frequently causes livestock poisoning. In this study, we predicted the current and future potential distribution of V. nigrum in China and quantified the associated grazing risk. We developed a MaxEnt model optimised with the multi-objective evolutionary algorithm NSGA-III to balance predictive accuracy, model complexity, and generalisation. The model performed well (AUC = 0.898, TSS = 0.687), and elevation, precipitation of the wettest month, and mean temperature of the driest quarter emerged as the dominant environmental drivers. The current suitable habitat of V. nigrum covered 236.17 × 10⁴ km². Under future climate scenarios, the total suitable area is projected to increase by 18-41%, with highly suitable habitat expanding by up to 185% and the distribution centroid shifting south-westward. Spatial risk assessment based on pixel-wise overlap between habitat suitability and livestock density revealed that cattle face the highest exposure risk (83.54 × 10⁴ km²), followed by sheep (80.98 × 10⁴ km²) and goats (68.04 × 10⁴ km²). Risk hotspots were mainly concentrated in central China and the Sichuan Basin. These findings provide a spatially explicit basis for evaluating toxic-plant risk and informing adaptive grazing management under climate change.