基于集合模型预测外来植物反枝苋的入侵趋势

Prediction of Invasive Trend of Alien Plant Amaranthus retroflexus Based on Ensemble Model

反枝苋(Amaranthus retroflexus L.)是一种入侵较早、分布范围广、危害程度严重的全国性分布恶性杂草。为了及时防控反枝苋,阻止或减缓进一步扩散蔓延,亟需明确其在中国的适宜生境及入侵趋势。基于296个分布点和32个环境变量,利用集合物种分布模型分析反枝苋在当前(1970-2000年)的潜在适生区,并预测未来(2021-2040年和2041-2060年)3种气候情景下(SSPs1-2.6、SSPs2-4.5和SSPs5-8.5)的分布格局,综合分析影响反枝苋地理分布的主要环境变量及入侵趋势。结果表明,1)通过3种模型精度评价指标(AUC、KAPPA和TSS),集合模型(EM)模拟和预测的结果最为准确,当前气候条件下反枝苋主要的潜在适生区分布在华北地区、华中地区、华东地区、华南地区、西南地区的东部、西北地区的南部和北部些许地区,分布面积为4.39×10^(6) km^(2)。反枝苋的潜在分布重心位于陕西省延安市宜川县,地理坐标为110.32°E,36.13°N。2)影响反枝苋潜在分布的主要环境变量为年平均温度(Bio1)、土地利用覆盖(LUCC)、海拔(Altitude)和年降水量(Bio12)。3)在2030年和2050年的3种不同气候情景下,随着年份和排放情景的增加,反枝苋的总适生区面积均会增加,并且扩张区的面积远大于收缩区的面积,扩张面积的比率在11.2%-21.4%。反枝苋在未来均有向高纬度地区扩散的趋势,华北地区的东部和东北地区的南部扩散面积最为显著,西北地区的南部和西南地区的东部也在逐渐扩散。该研究结果将有助于对该物种入侵动态的早期预警,为及时采取防控措施阻止其传播扩散提供理论支持。

Amaranthus retroflexus L.is a nationally distributed malignant weed with early invasion and wide distribution that causes serious harm.To promptly prevent and control A.retroflexus and effectively slow down or avoid its further spread,there is an urgent need to identify suitable habitats and invasion trends in China.Based on 296 distribution points and 32 environmental variables,using the meta-species distribution model,this study analyzed the potential suitable areas for A.retroflexus in the current period(1970–2000)and predicted the potential distribution pattern for A.retroflexus under three climate scenarios(SSPs1-2.6,SSPs2-4.5,and SSPs5-8.5)in the future(2021–2040 and 2041–2060).Furthermore,the main environmental variables and invasion trends affecting the geographical distribution of A.retroflexus were explored comprehensively.The results demonstrated that 1)through the three model accuracy evaluation indexes(AUC,KAPPA and TSS),the results of ensemble model(EM)simulation and prediction were proved to be the most accurate.Under the current climatic conditions,the main potential suitable areas of A.retroflexus were distributed in North China,Central China,East China,South China,the eastern part of Southwest China,and the southern and northern parts of Northwest China,with a distribution area of 4.39×10^(6) km^(2).The potential distribution center of A.retroflexus is located in Yichuan County,Yan’an City,Shaanxi Province,with geographical coordinates of 110.32°E and 36.13°N.2)The main environmental variables affecting the potential distribution of A.retroflexus included the annual average temperature(Bio1),land use and cover(LUCC),altitude,and annual precipitation(Bio12).3)Under the three different climate scenarios in 2030 and 2050,with an increase in the year and emission scenario,the total suitable area of A.retroflexus will increase,and the expansion area will become much larger than the contraction area,accounting for 11.2%–21.4%.In addition,A.retroflexus will tend to spread to higher latitudes in the future.The diffusion areas in the eastern part of North China and southern part of Northeast China were the most significant.A.retroflexus also gradually spread in the southern part of Northwest China and the eastern part of Southwest China.Overall,the results of this study will contribute to the early warning of the invasion dynamics of this species and provide theoretical support for timely prevention and control measures to prevent further spread.