应用生态位模型预测檫木在浙江省的潜在适生区与主导环境因子

Prediction of Potential Suitable Habitat and Dominate Environmental Factors of Sassafras tzumu in Zhejiang with MaxEnt Model

以浙江省生态监测样地数据库中的181个檫木样本实测分布点数据为研究对象,应用最大熵模型理论,采用最大熵模型(MaxEnt)和地理信息系统(ArcGIS)对其在浙江省的潜在适生区进行预测,用ROC曲线检测模型精度、刀切法筛选主导环境因子及其最适范围。结果表明:MaxEnt模拟的训练集AUC(ROC曲线与横坐标围成的区域面积)值为0.898,测试集AUC值为0.902,说明预测结果具有较高参考价值。檫木在浙江省的高适生区主要位于浙中的大盘山脉、天姥山一带,浙北的径山、莫干山脉、天目山脉一带及周边区域,面积达到1.16万km^2;中适生区则主要在高适生区的外围,以及西天目山和新安江流域北部,面积达1.54万km^2;低适生区则主要在中适生区的外围,以及新安江流域中上游、遂昌、泰顺等地,面积达到2.40万km^2;不适宜区域主要在低适生区的外围,其面积为5.18 km^2。模型模拟得出数字高程(DEM)、最干季降水量、最冷季平均气温等条件是影响檫木分布的主要环境变量,其中海拔为50~750 m,最干季降水量300~650 mm,最冷季平均气温0~5.5℃为最适环境条件。

With the comprehensive survey data of 181 Sassafras tzumu(Hemsl.)Hemsl.samples taken from Zhejiang ecological monitoring plots database,we used ArcGIS and MaxEnt model to predict its potential distribution area in Zhejiang.Then ROC curve is used to detect the model precision,and jackknife test method is adopted to screen the dominant environmental factors and their optimal range.Training AUC is 0.898,and the testing AUC is 0.902 with a better forecast,so it has a high reference value.The highly suitable growth area of S.tzumu in Zhejiang is mainly in the Dapan Mountains and Tianmu Mountain in the middle of Zhejiang,Jingshan,Moganshan vein,Tianmu Mountain area and the surrounding area in the north of Zhejiang,the area is 1.16×10~4km^2.The medium suitable growth area is mainly in the periphery of the high suitable area,the west Tianmu mountain area and the north of the Xin’an river basin,the area is 1.54×10~4km^2.The low suitable growth area is mainly in the periphery of the medium suitable growth area,as well as the middle and upper reaches of the Xin’an river basin,Suichang,Taishun and other places,the area is 2.40×10~4km^2.The unsuitable area is mainly in the periphery of the low suitable growth area,the area is 5.18×10~4km^2.Digital elevation model(DEM)screened with Jackknife test method,precipitation of the driest quarter(PDQ)and mean air temperature of the coldest quarter(MTCQ)are the main environmental factors that affect the distribution of S.tzumu.The most suitable range of them are 50-750 min DEM,30-650 mm in PDQ,and 0-5.5℃in MTCQ.