【摘要】 目的：对近危树种乐昌含笑在中国境内的适生区域进行划分，明晰其地理分布与环境因子间的关系，为科学引种栽培及资源保护利用提供参考。方法：通过查询数据库及野外实地调查获得乐昌含笑的现有分布样本数据和26个环境因子数据，利用刀切法（Jackknife）评估关键环境因子的重要性，并采用最大熵模型（MaxEnt）和地理信息系统软件（ArcGIS）分析了当前气候条件下乐昌含笑在中国的适生区分布情况。结果：MaxEnt模型预测得到的受试者工作特征曲线（ROC）下的测试数据面积值（AUC）为0.984，表明模型预测准确。模型预测的乐昌含笑高适生区（P> 0.7）和适生区（0.5 <P≤0.7）主要分布在103.04°～122.20°E、21.70°～32.07°N范围内，多集中在我国长江流域中下游南部区域，分布面积分别约为43.73 km2和87.69 km2。影响乐昌含笑适生区分布的主导环境因子包括最暖季度平均降水量、最冷月份最低温、昼夜温差月均值及最干月份降水量，对模型的贡献率分别为68.5%、14.2%、9.0%及5.2%。当最暖季度平均降水量为450～1 100 mm、最冷月份最低温为-0.5～5.5℃、昼夜温差月均值为7.0～8.5℃及最干月份降水量为30～55 mm时，乐昌含笑表现出良好适生性，存在概率值P≥0.5。结论：乐昌含笑树种分布主要受限于水分和热量两个环境因素，MaxEnt模型预测的乐昌含笑适生区能够准确地反映乐昌含笑在中国的地理分布特征，为乐昌含笑引种栽培、资源保护及开发利用提供了理论依据。更多还原

【Abstract】 Objective: To divide the suitable distribution of the endangered tree species Michelia chapensis in China, clarify the relationship between its geographical distribution and environmental factors, and provide reference for its introduction, cultivation, and resource protection and utilization.Methods: The existing distribution sample data of M. chapensis and 26 environmental factor data were obtained by querying databases and conducting field investigations. The importance of key environmental factor was evaluated using the Jackknife method, and the maximum entropy(MaxEnt) model and geographic information system software(ArcGIS) were used to predict the suitable distribution of M. chapensis in China under current climate conditions. Results: The AUC value of the test data predicted by the model was 0.984, indicating that the accuracy of the model was high. The height suitable zone(P > 0.7) and suitable zone(0.5 < P ≤ 0.7) predicted by the model for M.chapensis were mainly distributed in the range of 103.04° to 122.20° E and 21.70° to 32.07° N, mostly concentrated in the southern region of the middle and lower reaches of the Yangtze River Basin in China, with distribution areas of 43.73 km2 and 87.69 km2, respectively. Four most important environmental variables affecting its distribution were average precipitation in the warmest quarter, lowest temperature in the coldest month, monthly average temperature difference between day and night, and precipitation in the driest month, with contribution rates of 68.5%, 14.2%, 9.0% and 5.2%, respectively. When the average precipitation in the warmest quarter was in the range of 450 to 1 100 mm, the lowest temperature in the coldest month was in the range of-0.5 to 5.5 ℃, the monthly average temperature difference between day and night was in the range of 7.0 to 8.5 ℃, and the precipitation in the driest month was in the range of 30 to 55 mm, M. chapensis showed good adaptability, with a probability value of P ≥ 0.5. Conclusion: The distribution of M. chapensis was mainly limited by two environmental factors: water and heat. The MaxEnt model could accurately reflect the geographical distribution characteristics of M. chapensis in China. The research provided a theoretical basis for the scientific introduction, cultivation, resource protection and development of M.chapensis.更多还原