Abstract:【Aim】Ambrosia trifida, an invasive alien plant, exhibits strong ecological adaptability, causing severe damage to agriculture, forestry, animal husbandry and related industries in China, while posing significant threats to ecosystems and biodiversity. Studying the potential geographic distribution of A. trifida in Guizhou province is crucial for monitoring, early warning, and control of this plant.【Method】The information of 108 domestic occurrence records and 38 environmental and soil variables, as well as the MaxEnt model, ArcGIS software, and Pearson correlation analysis, were employed to predict the potential suitable areas of A. trifida in Guizhou under historical (1970—2000) and future climate scenarios (SSP1-26, SSP2-45, SSP3-70, and SSP5-85).【Result】The AUC value of the MaxEnt model constructed with 19 variables reached 0.945, indicating higher predictive reliability. The presence probability of A. trifida increased with increases in mean diurnal range (b2, 2.79-11.56℃), isothermality (b3, 15.38-24.16), precipitation of driest month (b14, 0-4.83 mm or greater than 16.54 mm), precipitation of coldest quarter (b19, 0-16.26 mm), precipitation seasonality (b15, coefficient of variation: 11.53-51.06 or 90.28-144.72), and precipitation of warmest quarter (b18, 0-83.71 mm or 219.99-418.74 mm). Under historical conditions, the total suitable area of A. trifida in China was 199 910 km2(20.82% of the national territory), with high, medium, and low suitable areas accounting for 0.61%, 5.84%, and 14.37%, respectively. In Guizhou, the medium suitable areas (15.49%, 25 800 km2) concentrated in central-eastern Guiyang City, central-southwestern Qiandongnan Prefecture, and parts bordering Bijie City and Zunyi City. The low suitable area was 71 900 km2, accounting for 43.21%. No high suitableareas were identified. Over the four future scenarios and periods, the sum of low and medium suitable areas fluctuated between 48 400 km2 and 86 800 km2. Compared to the current situation, this represented a decline of 11.15% to 50.49%. Unsuitable areas will still dominate, and there will still be no high suitable areas.【Conclusion】Elevation (el), mean diurnal range (b2), isothermality (b3), precipitation of driest month (b14), precipitation of coldest quarter (b19), precipitation seasonality (b15), precipitation of warmest quarter (b18), and soil sulfate content (t_CaSO4) were identified as critical factors influencing the distribution of A. trifida. In Guizhou, 58.71% of the area was suitable. Under four future scenarios, medium and low suitable areas showed initial expansion followed by contraction toward central and southwestern Guizhou. The contraction/expansion of medium suitable areas was concentrated in Zunyi Ccity, Tongren City, and border between Qiandongnan Prefecture and Qiannan Prefecture, while that of low suitable areas occurred in central-western regions (Anshun City, Liupanshui City, and Qianxinan Prefecture). This study provides critical insights for early monitoring, intervention, and control of A. trifida to mitigate its ecological and economic impacts in Guizhou.
