基于Maxent模型的冬虫夏草中国潜在适生区预测

Prediction of potential distribution of Ophiocordyceps sinensis in Chain based on Maxent model

冬虫夏草(Ophiocordyceps sinensis)是分布在青藏高原高寒地区稀缺的可再生生物资源,是我国传统名贵中药材,具有很高的药用价值和经济价值。目前对冬虫夏草的潜在适生区研究较少,对虫草资源的空间分布格局尚不清晰。明确冬虫夏草在我国的地理分布,对其保护及有效利用具有重要意义。研究共收集了175个分布点及24个环境因子数据,最终筛选出12个环境变量数据参与模型训练,利用Maxent模型预测冬虫夏草中国潜在适生区,通过ROC曲线分析模型预测效果,结合贡献率、置换重要值和刀切法检验分析环境变量对冬虫夏草分布的影响。结果显示:我国虫草主要分布于西藏、青海、甘肃、四川和云南五省,适生区总面积(高适宜分布区与中适宜分布区)为8.82927×10^(5)km^(2)。ROC评价结果显示,Maxent模型训练数据的AUC值高达0.959,表明预测结果准确度极高。对环境变量进行分析,影响冬虫夏草地理分布的主要环境因子是海拔,最暖季度平均温度,最暖季度降水量。本研究明确了冬虫夏草在我国的潜在适生分布区,为虫草的资源明确及生境保护提供了理论依据。

Ophiocordyceps sinensis is a rare and renewable biological resource in the Alpine region of Qinghai-Tibet Plateau.It is one of the most valuable traditional Chinese medicinal materials in China and has high medicinal and economic value.Previous studies on the Ophiocordyceps sinensis potential distribution are lacking,and spatial distribution of the resource is not clear.It is great significance for the protection and effective utilization to predict the potential geographical distribution patterns of Ophiocordyceps sinensis in our country.The data of 175 distribution points and 24 environmental factors were collected,and 12 environment variables were selected to participate in the model training in final by using ROC curveto to analyze the prediction effect and Maxent model and to predict the potential suitable area of Ophiocordyceps sinensis.The influence of environmental variables on the distribution of Ophiocordyceps sinensis was analyzed by the contribution rate,the permutation importance and the Jackknife test.The results showed that Ophiocordyceps sinensis was mainly distributed in Tibet,Qinghai,Gansu,Sichuan and Yunnan provinces,and the total area of suitable area(high and middle suitable area)was 882.927 million square kilometers.Results of ROC(receiver operating characteristic curve)evaluation showed that training data of predicted suitable distribution areas by Maxent model and AUC(the area under the ROC curve)of testing data were 0.959,indicating a high degree of accuracy in the prediction.Based on the analysis of environmental variables,the main environmental factors influencing the geographical distribution of Ophiocordyceps sinensis were altitude,mean temperature of warmest quarter(bio10)and precipitation of warmest quarter(bio18).This study identified the potential distribution areas of Ophiocordyceps sinensis in China and provided a theoretical basis for resource identification and habitat protection of it.