基于Maxent模型的未来气候变化情景下胡杨在中国的潜在地理分布

胡杨(Populus euphratica)是全世界干旱和半干旱区急需优先保护的林木基因资源，预测未来气候变化情景下胡杨在中国的潜在地理分布将为胡杨种群资源的保护和管理提供科学依据，并为绿洲恢复过程中胡杨的合理种植和配置提供有价值的理论指导。本研究基于胡杨在中国地区的92条有效分布记录和10个环境因子变量，利用Maxent模型和ArcGIS软件预测了未来气候变化情景下胡杨在中国的潜在地理分布，综合环境因子变量贡献率及置换重要值、刀切法检验评估制约现代胡杨潜在地理分布的重要因子，采用响应曲线确定环境因子变量的适宜区间，定量确定胡杨未来受威胁的潜在地理分布区域和面积。结果表明：（1）Maxent模型的预测准确度极高，受试者工作曲线面积（AUC值）达0.932，现代胡杨潜在地理分布的总适生区面积为289.94×104km2，主要位于内蒙古中西部地区（额济纳旗和阿拉善地区）、新疆大部分地区、甘肃北部和西北部地区、青海中西部地区和宁夏北部地区；（2）影响胡杨的潜在地理分布的主要环境因子变量为气温因子变量（年均温和最冷月最低温）和降水因子变量（最湿月降水量和最干季降水量），最湿月降水量是影响胡杨潜在地理分布的关键因素；（3）在未来4种气候变化情景下，胡杨不同等级潜在地理分布区的面积较现代潜在地理分布区面积均有不同程度的缩小，且整体上看胡杨的潜在地理分布区有向高海拔区域迁移的趋势。

Potential geographical distribution of populus euphratica in China under future climate change scenarios based on Maxent model

Populus euphratica is a forest genetic resource that is urgently needed to be protected in arid and semi-arid regions of the world. Predicting the potential geographical distribution of Populus euphratica in China under the future climate change scenario will provide a scientific basis for the protection and management of Populus euphratica population resources,It also provides valuable theoretical guidance for the rational planting and allocation of Populus euphratica in the process of oasis restoration.Based on 93 effective distribution records and 10 environmental factor variables of Populus euphratica in China, the potential geographical distribution of Populus euphratica in China was predicted by Maxent model and ArcGIS software. Combined with the contribution rate of environmental factor variables and the important value of replacement, the knife cutting method was used to test and evaluate the important factors restricting the modern potential geographical distribution of Populus euphratica, and the response curve was used to determine the suitable range of environmental factor variables. Quantitative determination of potential geographical distribution and area of Populus euphratica threatened in the future. The results show that: (1) The prediction accuracy of the Maxent model is extremely high, and the work curve area (AUC value) of the subject is 0.932. The total suitable area of the modern potential geographical distribution of Populus euphratica is 289.94×104km2, mainly located in the central and western regions of Inner Mongolia. (Ejina Banner and Alashan Region), most of Xinjiang, northern and northwestern Gansu, central and western Qinghai, and northern Ningxia;(2) the main environmental factor variables affecting the potential geographical distribution of Populus euphratica are temperature factor variable (annual average temperature and coldest monthly lowest temperature) and precipitation. The factor variables (the wettestmonthly precipitation and the driest season precipitation) and the wettest monthly precipitation is the key factor affecting the potential geographical distribution of Populus euphratica; (3) Under the next four climate change scenarios, the area of potential geographical distribution of different grades of Populus euphratica will be smaller than that of modern potential geographical distribution, and on the whole, the potential geographical distribution of Populus euphratica tends to migrate to the high altitude area.