基于MaxEnt模型的中国沙棘潜在适宜分布区分析

中国沙棘主要分布于我国华北、西北、西南等地森林—草原过渡地带，是我国北方地区退耕还林、生态修复等工程的重要造林树种，对维持干旱、半干旱地区的生态环境稳定具有重要意义。探讨限制中国沙棘分布的主导气候因子，模拟其潜在适宜分布区，以期为中国沙棘在林业生态工程和生态经济林建设中的合理种植和推广提供理论依据。基于中国沙棘自然分布的328个地理样点，利用最大熵(MaxEnt)模型对中国沙棘的潜在分布区的主导气候因子进行分析，并预测中国沙棘的潜在分布范围。结果表明，基于气候变量的MaxEnt模型训练集和测试集受试者工作特征曲线下面积(AUC值)分别为0.962±0.001和0.949±0.001,均大于0.9,表明MaxEnt模型对中国沙棘潜在分布区的预测具有极高的准确度，可信度好。基于环境变量贡献率和刀切法的结果表明年降雨情况、生长季的水热状况、最干季降雨和最冷月最低温等是限制中国沙棘分布的主要气候因素，其中年降雨是限制中国沙棘分布的主导气候因子。通过模拟得到现代中国沙棘潜在地理分布的总适生区面积为165.1万km~2;其中高适生区和中适生区面积共93.3万km~2,主要集中分布于河北西部、北部，...

Identification of potential distribution area for Hippophae rhamnoides subsp. sinensis by the MaxEnt model

Hippophae rhamnoides subsp. sinensis is mainly distributed in the forest-grass transition zone and is an important afforestation tree species for the conversion of farmland to forests and ecological restoration projects in North, Northwest, and Southwest China, which plays an important role in maintaining the stability of the ecological environment. This paper tries to explore the dominant climatic factors that limit the distribution of H. rhamnoides subsp. sinensis in China, and to simulate its suitable distribution area. In order to provide a theoretical basis for the overall arrangement and promotion of H. rhamnoides subsp. sinensis in forestry ecological engineering and ecological economic forest construction. Based on 328 geographical distribution samples within the distribution range of H. rhamnoides subsp. sinensis, the maximum entropy (MaxEnt) model is used to predict the potential distribution range of H. rhamnoides subsp. sinensis in China. The receiver operating characteristic curve, Jackknife test and the precent contribution of the climatic factors are carried out to analyze to the climatic factors limiting the modern potential geographical distribution of H. rhamnoides subsp. sinensis, and the response curve is used to determine the suitable range of climatic factors. The results showed that the average values of the area under the receiver operating characteristic curve (AUC) of training and test data were 0.962±0.001 and 0.949±0.001 respectively, higher than 0.9, indicated the accuracy of the MaxEnt model was pretty high for modeling potential distribution regions of H. rhamnoides subsp. sinensis. The combined results from Jackknife test and the precent contribution of the climatic factors revealed that annual precipitation, temperature and precipitation of growth season, precipitation of driest quarter and min temperature of coldest month were the key climate factors that resctrited the distribution of H. rhamnoides subsp. sinensis in China. The total suitable area of the modern potentially geographical distribution of H. rhamnoides subsp. sinensis based on the climatic factors was 165.1×10⁴ km². And the total area of the potential most suitable region and suitable region of H. rhamnoides subsp. sinensis in China was 93.3×10⁴ km², mainly located in western and northern Hebei, Shanxi, northern Shaanxi and Qinling Mountains, southern Ningxia, eastern and southern Gansu, Qilian Mountains, eastern Qinghai, western Sichuan, eastern and central Tibet, moreover, there were few suitable region were located in northeastern Jilin, the central and southern Inner Mongolia, as well as northwestern Henan. These regions can be used as the dominant areas for the cultivation and prometon of H. rhamnoides subsp. sinensis.