Abstract:

The exotic invasive weed Sonchus asper L. Hill. has strong adaptability, with fast seed germination and growth, large adult plant biomass, high seed production, rapid spread, and significant effects on crops and turfgrass. To clarify the habitat adaptability of Sonchus asper in China and identify the climatic and environmental variables influencing its distribution, an ensemble model was constructed using the Biomod2 package based on 146 geographic distribution records, eight climate factors, and six soil factors. This model predicted potentially suitable habitats for Sonchus asper in China under current conditions and future scenarios (2050s and the 2070s) across three climate scenarios (RCP2.6, RCP4.5, and RCP8.5). The results were as follows: 1) The ensemble model (EMcaByROC) achieved an AUC value of 0.943, indicating a high accuracy. 2) Under the current climate scenario, the plant is mainly distributed in the central and eastern regions of China, with a potential suitable area of 2.67×10⁶ km², accounting for 27.8% of the total area of China, while under the future scenarios, the area of its suitable area shows an increasing trend, especially under the RCP8.5 scenario, with the areas of suitable areas in the 2050s and 2070s being 3.41×10⁶ km², and 3.88×10⁶ km², representing increases of 22% and 31% compared to the current period. 3) The analysis of ecological niche change showed that the lowest ecological niche overlap value of 0.829 was recorded for the RCP8.5 scenario for the sequestration chrysanthemum, which showed greater migration and further expansion of suitable habitat. 4) The key variables influencing its distribution were the annual temperature range (bio7), mean temperature of the wettest quarter (bio8), soil pH (water), and total nitrogen content (total N). This study elucidates changes in the suitable habitat distribution of Sonchus asper in China, identifies critical environmental drivers, and provides theoretical support for understanding its invasion dynamics, early monitoring, and implementation of control measures to prevent its spread.

Key words: climate change, Biomod2, Sonchus asper, geographic distribution, ecological niche overlap

摘要：

外来入侵杂草续断菊（Sonchus asper L. Hill.）适应性强，种子萌发生长快，成株生物量大，结籽量多，蔓延扩散快，对作物、草坪等产生较大的影响。为明确续断在中国的生境适应性及影响其分布的气候环境变量，根据146条地理分布数据，结合8个气候因子和6个土壤因子，利用Biomod2包构建集成模型预测了续断菊在当前及未来2050s、2070s在3种气候情景下（RCP2.6、RCP4.5和RCP8.5）中国的潜在适生区。结果表明：1）集成模型（EMcaByROC）的AUC值为0.943，具有较高准确度；2）当前气候情境下续断菊主要分布在中国中部和东部地区，潜在适生区面积为2.67×10⁶ km²，占中国总面积的27.8%，而在未来情景下，其适生区面积呈上升趋势，尤其在RCP8.5情景下，2050s和2070s适生区面积分别为3.41×10⁶ km²和3.88×10⁶ km²，较当前时期分别增加了22%和31%；3）生态位变化分析显示，续断菊在RCP8.5情景下，生态位重叠值最低为0.829，表现出较大的迁移，适宜栖息地进一步扩大；4）影响续断菊分布的主要气候和土壤变量分别是气温年较差（bio7）、最湿季均温度（bio8）和酸碱度（pH，water）、总氮含量（total N）。该研究阐述了续断菊在中国的适宜生境分布变化，分析了影响其分布的主要环境变量，有助于了解该物种入侵动态及危害，以及开展早期监测预警，为及时采取防控措施阻止其传播扩散提供了一定的理论支持。

关键词: 气候变化, Biomod2, 续断菊, 地理分布, 生态位重叠