气候变化下矩镰荚苜蓿的地理分布格局及潜在适生区预测

该研究基于标本和文献信息，选取19个环境因子和1个海拔因子，利用ArcGIS软件和MaxEnt模型对矩镰荚苜蓿(Medicago archiducis nicolai)在5个气候情景(末次间冰期、末次盛冰期、全新世纪中期、当前和未来气候)下的地理分布进行空间重建，模拟预测了气候变化背景下的分布格局和潜在适生区变迁。预测结果显示：(1)当前气候下，矩镰荚苜蓿集中分布在青藏高原东缘与黄土高原的交汇地带，具体包括青海东部 南部、甘肃中部 西南部、四川西北部、宁夏南部、西藏东部和陕西西部边缘。(2)高海拔、寒冷和干燥是矩镰荚苜蓿适生区的主要环境特征。(3)不同气候下潜在适生区的总面积变化相对稳定，但高度适生区对气候变化较敏感，从末次间冰期到末次盛冰期，高度适生区从青海东部的河湟谷地向甘肃中部的洮河谷地东移，全新世纪中期又西移至河湟谷地，但始终没有迁离出陇中盆地。(4)未来气候(2070s)背景下，矩镰荚苜蓿的高度和中度适生区面积较当前气候有小幅增加，但潜在适生区面积和分布格局仍保持稳定。研究表明，在青藏高原东缘地带，由昆仑山、祁连山和秦岭三大山脉造就的高原盆谷，为矩镰荚苜蓿提供了安全的就地避难所，形成了其独特而稳定的狭域分布格局，未来气候变化(2070s)对该植物不会造成很大威胁。

Geographical Distribution Pattern and Prediction of Potential Suitable Areas of Medicago archiducis nicolai under Climate Change

Based on specimens and literature information, this study selected 19 environmental factors and 1 altitude factor, to simulate and predict the distribution pattern and potential suitable area changes of Medicago archiducis nicolai under the background of climate change. This research has reconstructed the geographical distribution of M. archiducis nicolai in five climate scenarios (the last interglacial, the last glacial maximum, the mid holocene century, current and future) by ArcGIS software and MaxEnt model. The prediction results showed that: (1) under the current climate, M. archiducis nicolai was mainly distributed in the intersection zone between the eastern edge of the Qinghai Tibet Plateau and the Loess Plateau, including the eastern and southern parts of Qinghai, the central and southwestern parts of Gansu, the northwestern part of Sichuan, the southern part of Ningxia, the eastern part of Tibet and the western edge of Shaanxi. (2) High altitude, cold and dryness were the main environmental features of the M. archiducis nicolai appropriate areas. (3) It was relatively stable that the change in total area of the suitable areas in different climates, but the highly suitable areas were more sensitive to climate change. From the last interglacial period to the last glacial maximum, the highly suitable area moved eastward from the Hehuang valley in eastern Qinghai to the Taohe valley in central Gansu, and then moved westward to the Hehuang valley in the middle of the new century, but it did not move out of the Longzhong Basin. (4) Compared with the current climate, the suitable areas of the highly and moderately of M. archiducis nicolai were slightly increased in the 2070s, but the distribution pattern and potential suitable areas remained stable. The analysis showed that in the eastern margin of the Qinghai Tibet Plateau, the basins and valleys created by the Kunlun Mountains, the Qilian Mountains and the Qinling Mountains provided a safe refuge in situ for M. archiducis nicolai, formed a unique and stable narrow distribution pattern, and the future climate change (2070s) would not pose a great threat to the plant.