基于MaxEnt的中国无患子属适生区区划及生态特征

Potential Distribution and Ecological Characteristics of Genus Sapindus in China Based on MaxEnt Model

【目的】基于我国无患子属空间分布数据,探索无患子属的适生区区划及主要生态特征,为无患子属种子调拨、种质资源多样性保护、引种栽培、合理选址提供科学依据。【方法】基于我国17省(区、市)无患子属226份种质资源空间分布数据,叠加分析后筛选133份代表性分布数据,结合24个生态因子,采用最大熵模型(MaxEnt)开展无患子属适生区区划并建立与生态因子的关系模型,运用受试者工作特征曲线(ROC曲线)检测模型精度,刀切法(Jackknife)筛选主导生态因子;结合ArcGIS系统实现我国无患子属适生区可视化。【结果】MaxEnt模型模拟结果可信度高,无患子属适生区区划结果ROC曲线训练集和测试集AUC值均达到0.990以上;无患子属适生区面积为248.71万km^(2),占国土面积的25.81%,其中无患子为240.66万km^(2)(占国土面积的24.99%)、川滇无患子为78.99万km^(2)(占国土面积的8.20%)、毛瓣无患子为100.40万km^(2)(占国土面积的10.42%);显著影响无患子适生区区划的生态因子为最暖季降水量(贡献率为57.1%)和等温性(贡献率为22.6%),川滇无患子为最暖季降水量(贡献率为37.9%)、最冷季平均气温(贡献率为15.9%)、海拔(贡献率为12.8%)和降水量变异系数(贡献率为11.2%),毛瓣无患子为年均温度变化范围(贡献率为19.6%)、最暖季降水量(贡献率为17.8%)、根系的氧气有效性(贡献率为11.9%)和等温性(贡献率为11.1%)。【结论】我国无患子属生态适生区广泛分布于华中和华南地区;无患子极适生区主要分布于我国福建省、广西壮族自治区、贵州省、重庆市、广东省北部、江西省南昌和赣州及四川盆地,川滇无患子极适生区集中于四川盆地、云南省昆明和曲靖,毛瓣无患子极适生区集中于云南省南部的玉溪、普洱、红河哈尼彝族自治州和文山壮族自治州;最暖季降水量是决定无患子属及各种适生区区划的最显著生态因子;无患子适宜在最暖季降水量400~800 mm、等温性为24%~35%的区域分布,川滇无患子适宜在海拔1200~3000 m、最冷季平均气温4~11℃的区域生存,毛瓣无患子更适合在年均温度变化范围较小(14~24℃),最暖季降水量较高(550~1550 mm)的热带地区分布。

【Objective】Based on the spatial distribution data of genus S apindus in China,the suitable range for distribution and main ecological characteristics of Sapindus were explored to provide the scientific basis for seed allocation,protection of genetic diversity of germplasm resources,introduction and cultivation,site selection of Sapindus.【Method】Based on the spatial distribution data of 133 representative accessions of germplasm resources of Sapindus which screened from^(2)26 accessions of germplasm resources by overlay analysis,combined with 24 ecological factors,the maximum entropy model(MaxEnt)was used to establish the relationship model with the ecological factors for the prediction of the potential distribution area of Sapindus.The model uses the receiver operating characteristic curve(ROC curve)to check the accuracy and uses the Jackknife method to screen the dominant ecological factors.The model is combined with the ArcGIS system to realize the visualization of Sapindus potential distribution area in China.【Result】Simulation of the MaxEnt model displayed a high credibility,and the AUC values of the training set and test set of the ROC curve of the Sapindus distribution were both above 0.990.The area of the potential distribution of Sapindus is 248.71×104 km^(2),accounting for 25.81%of the total land area of China.S.mukorossi is 240.66×104 km^(2)(24.99%),S.delavayi is 78.99×104 km^(2)(8.20%),and Sapindus rarak is 100.40×104 km^(2)(10.42%).The ecological factors that significantly affected the suitable distribution of S.mukorossi are the precipitation of the warmest quarter(57.1%)and Isothermality(22.6%).The significant ecological factors of S.delavayi are the precipitation of warmest quarter(37.9%),mean temperature of coldest quarter(15.9%),elevation(12.8%),and precipitation seasonality(11.2%).The significant ecological factors of S.rarak are temperature annual range(19.6%),precipitation of warmest quarter(17.8%),oxygen availability to roots(11.9%),and isothermality(11.1%).【Conclusion】The potential occurrence area of Sapindus are widely distributed in central and southern China;The highly favorable area of S.mukorossi is mainly distributed in Fujian Povince,Guangxi Zhuang Autonomous Region,Guizhou Province,Chongqing City,northern Guangdong Province,Nanchang,and Ganzhou Cty in Jiangxi Province and Sichuan Basin in Sichuan Province.The highly favorable area of S.delavayi is concentrated in Sichuan Basin in Sichuan Province,Kunming,and Qujing Cty in Yunnan Povince.The highly favorable area of S.rarak is concentrated in Yuxi,Pu’er,Honghe Hani Yi Autonomous Prefecture,Wenshan Zhuang Autonomous Prefecture,and other regions in southern Yunnan Province.The precipitation of the warmest quarter is the most significant ecological factor that determines the potential distribution area of the genus Sapindus and the three species of the genus.S.mukorossi is suitable for the region of precipitation of warmest quarter range from 400 mm to 800 mm,isothermality range from^(2)4%to 35%.Compared to S.mukorossi,S.delavayi is suitable for the region of high elevation(1200~3000 m)and moderate mean temperature of coldest quarter(4~11℃).And S.rarak is suitable for the tropical regions where the temperature annual range from 14℃to 24℃and the precipitation of warmest quarter range from 550 mm to 1550 mm.