基于MaxEnt模型的兴安杜鹃在我国东北地区潜在适生区预测

Prediction of Potential Suitable Areas of Rhododendron dauricum in Northeast China Based on MaxEnt Model

兴安杜鹃为国家二级保护植物、东北早春珍稀观花树种,由于人为采挖导致种群数量减少、地理分布变窄.研究兴安杜鹃在东北地区的潜在适生区,为兴安杜鹃保育提供依据.基于兴安杜鹃54个地理分布信息和28个环境变量,将MaxEnt生态位模型和地理信息系统相结合,预测兴安杜鹃在我国黑龙江、吉林、辽宁3省的潜在适生区;通过ROC曲线检验模型精度,采用刀切法筛选主导环境变量及其适宜值.结果显示:模型预测的AUC为0.963,表明预测结果与兴安杜鹃实际分布地拟合度很高.高适生区主要位于辽宁省东部、吉林省中部及南部、黑龙江省东南部及大兴安岭、小兴安岭地区;中适生区和低适生区以高适生区为中心扩散.温度季节性变化标准差(bio4)、最暖季节降水量(bio18)、最干季节降水量(bio17)及土壤pH(t-ph)是影响兴安杜鹃潜在分布区的主要环境变量.

Rhododendron dauricum is a rare flowering tree species that blooms in early spring in Northeast China and is classified as a national ClassⅡprotected plant,due to human excavation,its population has decreased,and its geographical distribution has become narrower.Therefore,studying the potential habitat of Rhododendron dauricum in the Northeast region is crucial for its conservation.We used 54 geographical distribution data and 28 environmental variables of Rhododendron dauricum to predict its potential habitat in Heilongjiang,Jilin and Liaoning province by combining the MaxEnt niche model and geographic information systems(GIS).The accuracy of the model was tested by using the ROC curve,and the threshold method was used to select dominant environmental variables and their suitable values.The results showed that the predicted AUC value of the model was 0.963,indicating a high fit between the predicted results and the actual distribution of Rhododendron dauricum.The high suitable area was mainly located in the eastern part of Liaoning Province,the central and southern parts of Jilin Province,the southeastern part of Heilongjiang Province,and the Daxing’anling and Xiaoxing’anling regions.The medium suitable area and low suitable area spread out from the high suitable area.Temperature seasonality(bio4),precipitation of the warmest quarter(bio18),precipitation of the driest quarter(bio17),and soil pH(t-ph)were the main environmental variables affecting the potential distribution of Rhododendron dauricum.