不同气候条件下沙冬青属植物在我国的潜在分布——基于生态位模型预测

沙冬青属（Ammopiptanthus）植物是古地中海第三纪孑遗濒危物种，包括沙冬青（Ammopiptanthus mgolicus）和矮沙冬青（Ammopiptanthus nanus），主要分布在我国西北干旱、半干旱地区，其不仅具有较高的研究价值，同时对我国西北干旱地区生态环境具有十分重要的作用。近年来由于全球气候变化及人为干扰等因素，沙冬青属植物天然分布面积骤缩，濒临灭绝。本研究利用MaxEnt模型、Bioclim模型和Domain模型对沙冬青属植物在我国末次间冰期（Last Interglacial）、末次冰盛期（Last Glacial Maximum）、当代和2050年（RCP4.5和RCP8.5）4个时期气候情景下的潜在适生区进行预测。结果表明：MaxEnt模型对沙冬青属植物潜在分布区的预测具有极高的准确度，所有模型的平均受试者工作特征曲线下面积（AUC测试值）均高于0.80。当代沙冬青最佳及高适生区占全国总面积的2.78%，主要集中在内蒙古中部、宁夏北部和甘肃北部等地；未来沙冬青最佳及高适生区在现有分布范围呈现向外扩张的趋势，主要分布在内蒙古鄂托克旗、鄂尔多斯、阿拉善左旗、宁夏吴忠和甘肃民勒县等地。当代矮沙冬青最佳及高适生区占全国总面积的2.23%，主要集中在新疆南部；未来矮沙冬青最佳及高适生区向新疆乌恰县南部、乌鲁木齐北部移动和扩大，主要分布在新疆乌恰县、乌苏市、吐鲁番市和乌鲁木齐市。未来2050年（RCP4.5和RCP8.5）两种气候情景下沙冬青和矮沙冬青的潜在分布总面积均有所增加，与当代相比变化不明显，但不同适生等级的潜在分布面积变化较大，在更高的CO₂排放量（RCP8.5）情景下沙冬青和矮冬青的最佳及高适生区范围的预测结果都将减少。从气候因素角度考虑，研究表明未来气候情景下沙冬青属植物的适生区变化过程中，年均温（Bio1）、最湿月降水量（Bio13）和温度季节性变化（Bio4）是影响沙冬青属植物分布的关键因子，并为我国西北干旱半干旱地区具有重要的经济价值并将持续其生态服务功能。

Predicting the potential distribution of Ammopiptanthus species in China under different climates using ecological niche models

Ammopiptanthus plants, including Ammopiptanthus mgolicus and Ammopiptanthus nanus, are tertiary endangered species of paleo-Mediterranean origin that are primarily distributed in arid and semi-arid regions in northwestern China. A. mgolicus and A. nanus not only play an important role in the ecological environment of northwestern China but are also important species for scientific research. Global climate change and anthropogenic activities have caused the distribution of Ammopiptanthus plants to shrink, and currently they are on the verge of extinction. In this study, ecological niche models (MaxEnt model, Bioclim model, and Domain model) were used to predict the past (Last Interglacial and Last Glacial Maximum), current, and future (RCP4.5 and RCP8.5 scenarios in 2050) potential distributions of Ammopiptanthus plants in China. The accuracy of the MaxEnt model for modeling the potential distribution of Ammopiptanthus plants was high, and average values of the area under the receiver operator characteristic curve (AUC test value) were higher than 0.80 for all models. The best suitable and high suitable areas for the current potential distribution of A. mgolicus accounted for 2.78% of the total area of China and primarily occupied central Inner Mongolia, Ningxia, and Gansu. The best suitable and high suitable areas of the future potential distribution of A. mgolicus revealed expansion into central Inner Mongolia, northern Gansu, and northern Ningxia by 2050, with much of the distribution concentrated in Etuoke Banner, Ordos, and Alxa Zuoqi of Inner Mongolia; Wuzhong City of Ningxia; and Minle City of Gansu. The best suitable and high suitable areas of the current potential distribution of A nanus accounted for 2.23% of the total area of China and primarily occupied southern Xinjiang. The best suitable and high suitable areas of the future potential distribution of A. nanus revealed expansion into southern Wuqia County and north of Urumqi in Xinjiang by 2050, with much of the distribution concentrated in Wuqia County, Wusu City, Turpan City, and Urumqi City in Xinjiang. The potential distributions of A. mgolicus and A. nanus by 2050 in two climate scenarios (RCP4.5 and RCP8.5) were predicted to change little relative to the current potential distribution, but the level of suitability of many areas within the potential distribution was predicted to change substantially. However, suitable areas of habitat for A. mgolicus and A. nanus were predicted to decrease under the higher CO₂ emissions scenario (RCP8.5). Annual average temperature (Bio1), precipitation of wettest month (Bio13), and variation in temperature seasonality (Bio4) were the most important factors contributing to changes in the potential distributions of Ammopiptanthus plants. In the future, Ammopiptanthus plants will make important economic contributions and perform vital ecological service functions in arid and semi-arid regions of northwest China.