基于MaxEnt模型新疆枣潜在适生区预测

【目的】研究全球气候变化对新疆枣潜在分布的影响,划分新疆枣不同等级的适生区,为新疆枣产业的持续稳定发展提供参考。【方法】基于新疆枣地理分布的调查数据和2种气候情景(RCP4.5和RCP8.5),利用GIS技术和MaxEnt生态位模型相结合的方法,在全球气候变化背景下,对新疆枣的当前及未来(2050和2070年)潜在适生区分布进行预测。【结果】在当前气候条件下,新疆枣适生区主要分布在南疆和东疆地区。其中适生区总面积达到11.3×10~4 km^2,占新疆土地总面积的6.8%。采用受试者工作特征曲线(ROC曲线)对MaxEnt模型预测结果进行评价,结果显示训练数据集和测试数据集的曲线下的面积值(AUC值)分别为0.988和0.978,说明模型预测结果较为理想。刀切法分析结果显示,影响新疆枣当前分布的气候因子主要为最热月最高温度、最冷月最低温度、最暖季度均温、最冷季度均温、6月最高气温、7月最高气温、8月最高气温、12月最低气温、1月最低气温和2月最低气温。在未来气候条件下,新疆枣适生区面积有着一定的增加,但适生区的区域变化较小。【结论】Maxent模型预测结果与新疆枣的实际分布重合度较高。低温是影响新疆枣潜在适生区分布的重要因素。在全球气候变暖的趋势下,新疆枣整个潜在适生区面积呈现增加的特点且有向高纬度区域迁移的趋势,北疆地区开始出现较少部分的低适生区。

Potential suitable area forecast of jujube in Xinjiang based on MaxEnt model

【Objective】Impacts of global climate changes on potential distribution of jujube in Xinjiang were studied,and different grades of suitable areas of jujube in Xinjiang were divided,in order to provide some references for sustainable and stable development of jujube industry in Xinjiang.【Method】Based on survey data of geographical distribution of jujube in Xinjiang and two climate conditions(RCP4.5 and RCP8.5),by using combination methods of GIS technology and MaxEnt ecological niche model,in the context of global climate change,distributions of current and future(2050 and 2070)potential suitable areas of jujube in Xinjiang were predicted.【Result】Suitable areas of jujube in Xinjiang are mainly distributed in southern Xinjiang and eastern Xinjiang.Total area of suitable areas is 11.3×104 km2,accounting for 6.8%of total land area in Xinjiang.Through adopting receiver operating characteristic curves(ROC curve)to evaluation results of forecast results of MaxEnt model,the results show areas under curve(AUC value)of training data set and test data set are 0.988 and 0.978,respectively.It indicates that forecast results are ideal.The results of analysis using Jackknife method show that,under current climate conditions,major climatic factors affecting current distribution of jujube in Xinjiang are maximum temperature of the hottest month,minimum temperature of the coldest month,average temperature of the warmest quarter,average temperature of the coldest quarter,maximum temperature in June,maximum temperature in July,maximum temperature in August,minimum temperature in December,minimum temperature in January,and minimum temperature in February.Under future climate conditions,suitable areas of jujube in Xinjiang will be increased,but change of suitable areas will be less.【Conclusion】The forecast results of Maxent model have higher coincidence with actual distribution of jujube in Xinjiang.Low temperature is an important factor affecting distribution of potential suitable areas of jujube in Xinjiang.Under trend of global climate warming,potential suitable areas of jujube in Xinjiang are being increased and have a trend of migration to high latitudes.A small number of low-yielding areas begin to appear in northern Xinjiang region.