气候变化背景下光核桃的潜在分布区和生态位变化

Potential distribution area and niche change of Prunus mira under context of climate change

【目的】探究气候变化对光核桃分布和生态位的影响,为光核桃资源的保护和开发提供理论支撑。【方法】本研究根据光核桃的216条地理分布数据,结合11个气候、土壤和地形因子,调用ENMeval程序包优化后的最大熵值模型(MaxEnt)模拟我国光核桃潜在分布区在未来3种气候条件下的空间分布格局,并使用ecospat软件包分析光核桃气候生态位变化,以确定影响光核桃分布的主要环境变量。【结果】(1)优化后的MaxEnt模型可准确预测光核桃的潜在地理分布区,分布区主要位于青藏高原和云贵高原等较高海拔地区,总面积约为360711.8 km2,其中拉萨河谷、雅鲁藏布江中游河谷、怒江、澜沧江、金沙江等干热河谷等地为光核桃高度适生区;(2)在未来气候条件下,光核桃适生区整体呈向西南收缩趋势,生境适宜度总体呈下降趋势;(3)影响光核桃分布的主要环境变量为气温年较差、等温性和海拔,光核桃未来时期与当前时期生态位的重叠率随气候变化加剧逐渐降低。【结论】随着未来气候变化,我国光核桃适生区将向纬度与海拔相对较高的地区进行迁移,光核桃气候生态位也将与当前生态位逐渐分化,温度和海拔是影响光核桃分布的主要环境因子。基于上述结果,我们应在当前和未来环境适宜度均无显著变化的区域设立保护地,以减少全球气候变暖影响,同时也可避免人类活动对光核桃资源的进一步破坏。

[Objective]This paper investigates the effects of environmental changes on the distribution and niche of Prunus mira to provide theoretical support for the conservation and development of P.mira resources.[Method]In this study,based on 216 geographical distribution data of P.mira,we combined 11 climatic,soil and topographic factors,invoked the maximum entropy value model(MaxEnt)optimized by ENMeval program package to simulate the spatial distribution pattern of potential distribution areas of P.mira under three future climatic conditions.The ecospat package was also used to analyze the changes in the climatic niche of P.mira to determine the main environmental variables affecting the distribution of P.mira.[Result](1)The optimized MaxEnt model can accurately predict the potential geographical distribution areas of P.mira.The distribution areas were mainly located in higher altitude areas such as the Qinghai-Tibet Plateau of northwestern China and the Yunnan-Guizhou Plateau of southwestern China,with a total area of about 360711.8 km2,among which the Lhasa River Valley,the middle Yarlung Tsangpo River Valley,the Nujiang River,the Lancang River,the Jinsha River and other dry and hot river valleys were highly suitable areas for P.mira.(2)Under future climatic conditions,the overall trend of P.mira suitable area was shrinking to the southwest,and the overall trend of suitable area was decreasing.(3)The main environmental variables affecting distribution of P.mira were annual difference in temperature,isothermality and elevation;the overlap between niche of P.mira and the current niche in the future period gradually decreased with increasing climate change.[Conclusion]With future climate change,P.mira will migrate to areas with relatively higher latitude and altitude,and the climatic niche of P.mira will gradually diverge from the current niche,with temperature and altitude being the main environmental factors affecting the distribution of P.mira.Based on the above results,we should establish conservation sites in areas where there is no significant change in both current and future environmental suitability to reduce the effects of global warming,and also to avoid further damage to P.mira resources from disruptive human activities.