未来气候变化情景下三峡库区马尾松林生物量固碳动态与空间分异

Dynamics and spatial differentiation of biomass carbon sequestration of Pinus massoniana forests in the Three Gorges Reservoir Area under future climate change scenarios

为了解气候变化对三峡库区主导森林类型的固碳动态与空间格局的影响,本文基于森林资源规划设计调查数据、生态过程模型(3-PG)和探索性空间分析,预估了2009-2050年3种气候情景(BS、RCP4.5和RCP8.5)下三峡库区马尾松林生物量固碳速率变化及其空间分异。3种气候情景下马尾松林生物量固碳速率变化趋势一致,均由2009年的4.59Mg C·hm^-2·a^-1迅速降低并在2026年由正值变为负值后趋于平稳。2050年BS、RCP4.5和RCP8.5这3种情景的固碳速率分别为-0.14、-0.15和-0.15 Mg C·hm^-2·a^-1。模拟期间气候变化将使三峡库区马尾松林固碳速率增加8.31%~9.71%。三峡库区马尾松林固碳速率具有随海拔升高而增加的趋势,在全局尺度上不存在显著的空间集聚特征,但在局部尺度上却显示出库区中部(开州区、万州区)和东部(秭归县)存在"高-高"集聚模式、库区南部(丰都县、巴南区)存在"低-低"集聚模式;渝北区、万州区、巫山县和秭归县为热点,而巴南区及奉节县为冷点。未来需要根据固碳速率的时空动态加强对三峡库区马尾松林的管理,以促进林业的可持续发展,保障区域生态安全。

To understand how climate change would affect carbon sequestration rate in main types of forests in the Three Gorges Reservoir Area(TGRA)at different spatial and temporal scales,an ecological process model(3-PG)and exploratory spatial analysis were used to simulate biomass carbon sequestration rate and spatial autocorrelation of Pinus massoniana forests under three climate scenarios(BS,RCP4.5 and RCP8.5)from 2009 to 2050 based on forest resources planning and design survey datasets.Biomass carbon sequestration rate of P.massoniana forests showed a similar tendency under the three climate scenarios,which decreases dramatically from4.59 Mg C·hm^-2·a^-1 in 2009 and then levels off in 2026 after changing from positive to negative.In 2050,carbon sequestration rates under BS,RCP4.5 and RCP8.5 scenarios would be-0.14,-0.15 and-0.15 Mg C·hm^-2·a^-1,respectively.Under a changing climate,carbon sequestration rate would increase by between 8.31%and 9.71%in the P.massoniana forests in the TGRA,and the carbon sequestration rate would increase with altitude.Although there wereinsignificant spatial autocorrelations of carbon sequestration rate at the global scale,we found a significant spatial autocorrelation at local scale.There was a"High-High"aggregation pattern in the central part(Kaizhou and Wanzhou districts)and the eastern part(Zigui County)of the TGRA,and a"Low-Low"pattern in the southern part(Fengdu County and Banan District)of the TGRA.Yubei,Wanzhou,Wushan,and Zigui were the hotspots,while Banan District and Fengjie County were cold spots.Management of P.massoniana forests in the TGRA should be improved in the future based on spatial and temporal changes in carbon sequestration rate,with the aim to promote the sustainable development of forestry and guarantee regional ecological security.