基于MaxEnt模型预测气候变化下苜蓿切叶蜂的潜在地理分布

Potential geographical distribution of Megachile rotundata under climate change based on MaxEnt model

【目的】苜蓿切叶蜂Megachile rotundata是苜蓿的高效传粉昆虫之一,为明确苜蓿切叶蜂的潜在地理分布区域,为指导苜蓿切叶蜂的扩繁地选择及引种风险评估提供依据。【方法】本研究基于当前苜蓿切叶蜂在全球的分布点,使用MaxEnt模型评估其在不同气候情景下全球以及中国的潜在地理分布,筛选主导其分布的环境因子。【结果】MaxEnt模型的曲线下面积(Area under curve,AUC)值为0.951,模型预测结果可靠性较高;最热季节的平均气温bio10是影响苜蓿切叶蜂分布最主要的气候因子,累积贡献率为31.4%。历史气候情景下,苜蓿切叶蜂在全球的分布集中在欧洲和北美洲,在中国集中于中西部地区的西藏、青海、甘肃、新疆和宁夏等地;未来气候情景下,其在全球的总适生区收缩,在中国的总适生区扩张。苜蓿切叶蜂在全球的高适生区分布随气候变暖逐渐北移,高适生区面积在低强迫时增加,高强迫时减小;在中国的高适生区随气候变暖不断增加,主要集中于西藏和青海等地。【结论】苜蓿切叶蜂在中国的适生区较为广泛,未来实现进一步扩繁的可能性较高,最热季节的平均气温bio10可作为选择适宜扩繁地的首要考虑因素,且在引种和本土扩繁时需加强风险评估、有害生物检疫及蜂群管理。

[Aim]The alfalfa leafcutter bee(Megachile rotundata)is one of the most efficient pollinators of alfalfa.The aim of this study was to determine its potential geographic distribution and provide scientific guidance for selecting suitable areas for its brood production and to assess the risks of its introduction.[Methods]Based on the current global distribution of M.rotundata,we assessed the potential geographical distribution globally and in China under different climatic conditions and classified the dominant bioclimatic variable using the MaxEnt model.[Results]The results showed that the average area under curve(AUC)of the MaxEnt model was 0.951,indicating reliable prediction results.The mean temperature of the warmest quarter,bio10,had the greatest impact on the distribution of M.rotundata,accounting for 31.4%of the total.Under historical climatic conditions,the global distribution of M.rotundata was concentrated in Europe and North America.The distribution in China occurred in the central and western regions,including Tibet,Qinghai,Gansu,Xinjiang,and Ningxia.Under projected future climatic conditions,habitable zones for M.rotundata are predicted to contract,whereas suitable areas in China are predicted to expand.As the climate warms,the most habitable areas for M.rotundata show a northward shift.These areas are projected to expand under the low forcing climate scenario but shrink under a high forcing climate scenario.Climate warming has resulted in an increase in the number of highly suitable areas for M.rotundata,particularly in regions such as Xizang and Qinghai.[Conclusion]M.rotundata has a relatively wide area of suitable habitat in China,indicating a high potential for future population expansion.The mean temperature of the warmest quarter,bio10,should be considered as the primary factor when selecting suitable areas for its reproduction.Additionally,risk assessment,pest quarantine,and bee management should be strengthened in China during its introduction and local brood production.