末次间冰期以来3种云杉属植物的历史分布变迁及避难所

Distribution changes and refugia of three spruce taxa since the last interglacial

基于物种现代分布信息和19个环境变量数据,利用最大熵模型(MaxEnt)模拟丽江云杉、紫果云杉和青杄在末次间冰期、末次盛冰期、全新世中期和现代的适生分布区,用云杉孢粉数据进行结果验证,探讨物种分布动态与气候变化的关系,推测其生物避难所.受试者工作特征曲线下方面积(AUC)以及孢粉数据验证结果显示,模拟结果较准确.结果表明:等温性、最暖季均温和最暖季均温分别是影响丽江云杉、紫果云杉和青杄分布的首要环境因子,相对于降水,温度对其分布的影响更重要;3种云杉的喜寒习性和分布地的深切峡谷地貌特征导致其在末次盛冰期扩张;青杄和紫果云杉在末次间冰期可能存在生物避难所,分别位于湖北神农架地区和四川二郎山及其邻近区.本研究较为准确地模拟了3种云杉属植物末次间冰期以来几个重要地质历史时期的适生分布,推测了青杄和紫果云杉的生物避难所,为深入分析云杉属植物现代分布格局的形成、预测其在气候变化背景下的变化趋势以及3种云杉林的可持续管理和保护提供了科学依据.

Based on the current distribution information and 19 environmental variables data,we used the maximum entropy model to simulate the suitable distribution of Picea likiangensis var.likiangensis,P. purpurea and P. wilsonii in the last interglacial,Last Glacial Maximum,MidHolocene and present. The results from such modelling were validated by pollen data. We analyzed the relationship between species distribution dynamics and climate change,and then speculated the cryptic refugia of those species. Both the areas under the receiver operating characteristic curves and the verification results from pollen data indicated high accuracy of the model results. Results showed that isothermality was the most important factor influencing the distribution of P. likiangensis var.likiangensis and mean temperature of the warmest quarter was the most important for the distribution of both P. purpurea and P. wilsonii. Temperature was more important than precipitation in driving species distributions. Three species expanded their distribution ranges in Last Glacial Maximum due to their cold-adapted ecological habitat and the deep canyon topography feature which benefited their migration. There might be refugia of both P. wilsonii and P. purpurea in last interglacial,and they respectively located in Shennongjia Mountain in Hubei and Erlang Mountain and its nearby mountains in Sichuan. Our results,to some extent,made accurate prediction of the suitable distribution of three spruce species in the key periods since last interglacial,and speculated refugia of P.purpurea and P. willsonii. Our findings provided reference for better understanding of the formation mechanism of the present distribution of Picea and prediction of distribution changes in the future and sustainable management and protection of three spruce species.