基于MaxEnt模型的油麦吊云杉西藏潜在适生区预测

为预测西藏自治区在实地调查中不可到达区域内油麦吊云杉的分布情况，通过MaxEnt生态位模型软件和ArcGIS软件预测其在西藏的潜在分布范围，用ROC曲线检测预测精度，用刀切法筛选主要环境变量，并通过主要环境变量的响应曲线分析适宜油麦吊云杉的生态环境条件。结果表明，建立的预测模型的A_UC为0.992,预测精度高；油麦吊云杉在西藏的分布范围主要位于藏东南区域，位于巴宜区、墨脱县的雅鲁藏布江沿线山地，波密县易贡藏布和帕隆藏布沿线山地，察隅县贡日嘎布曲、察隅河沿线山地，左贡县、芒康县南面的怒江、澜沧江沿线山地，与现地调查结果高度契合；年降水量、顶层土壤有机碳含量和年均温变化范围等条件对油麦吊云杉分布的影响最大。

Prediction of Tibet’s Potential Suitable Areas for Picea brachytyla Based on MaxEnt Model

In order to predict the distribution of Picea brachytyla in the unreachable area in the second national key protected wild plant resource survey in Tibet,the potential distribution area in Tibet was predicted by MaxEnt niche model software and ArcGIS software in this study.The prediction accuracy was tested by ROC curve,and the main environmental variables by jackknife test.The ecological environment conditions suitable for P.brachytyla were analyzed by the response curve of the main environmental variables.The results showed that the prediction accuracy was high,and the AUC value of the prediction model was 0.992.The distribution range of P.ascendens in Tibet was mainly located in the mountains along the rivers in the southeaster Tibet:the Yarlung Zangbo River in Bayi District and Medog County,the Yigong Zangbo and Palong Zangbo in Bomi County,the Gongrigabuqu and Chayu River in Chayu County,and the Nujiang River and Lancang River in the south of Zuogong County and Mangkang County,which were highly consistent with the results of the field investigation.The annual precipitation,organic carbon content in top soil and the range of annual temperature had the greatest impact on the distribution of P.brachytyla.