不同碳排放模式下云南榧树适生区分布研究

研究气候变化背景下云南榧树适生区分布，有助于理解该物种分布区的变迁历史和未来保护策略的制定。基于45个有效地理分布点以及19个环境气候变量，利用Maxent模型与ArcGIS对不同时期云南榧树的适生区进行模拟，其ROC特征曲线下的面积接近于1,MaxEnt模型的预测准确度高，可用于预测云南榧树适生区。结果表明，刀切法Jackknife和气候累计贡献率显示，影响云南榧树分布的主导环境变量为最暖季度降水量(bio18)和最冷月份最低温(bio6)。自末次盛冰期至全新世中期再到当前，云南榧树种群质心迁移路线为高黎贡山—丽江—维西，面积变化呈先增加再减少的趋势，当前我国云南榧树主要分布于云南、四川和西藏等地区，预测2070年在4种不同碳排放模式下，云南榧树适生区均发生不同程度的北移，且碳排放越高北移程度越明显。随着历史时间的推移，云南榧树适生区呈向北迁移的趋势，在未来全球气候变暖的情景下，云南榧树的分布面积不会减少，四川极可能成为云南榧树新的分布区。

Distribution of Suitable Areas of Torreya yunnanensis Under Different Carbon Emission Modes

Torreya yunnanensis is a national key protected plant.Studying the distribution of suitable habitat of T.yunnanensis under the background of climate change will help us to understand the historical changes of the species distribution area and the formulation of future conservation strategies.Based on 45 occurrence records and 19 climatic variables,the potential suitable areas of T.yunnanensis in different periods were simulated by MaxEnt model and ArcGIS.The area under the receiver operating characteristic curve was close to 1,indicating that the MaxEnt model had high prediction accuracy and could be used to predict the suitable distribution area of T.yunnanensis.The results of Jackknife method and the contribution rate of climate showed that the dominant environmental variables affecting the distribution were the precipitation of the warmest quarter (bio18) and the min temperature of the coldest month (bio6).From the last glacial maximum to the middle Holocene,and then to the present,the centroid migration route was Gaoligong Mountain-Lijiang-Weixi,with an area change trend of first increasing and then decreasing.At present,T.yunnanensis is mainly distributed in Yunnan,Sichuan and Tibet,it is predicted that the suitable growth area would migrate northward in varying degrees under four different carbon emission modes in 2070,and the higher the carbon emission,the more obvious the northward shift.With the passage of historical time,the suitable area showed a trend of migrating northward.The distribution area would not decrease under future global warming,and Sichuan Province would be likely to become a new distribution area.