基于岩性分区的广西植被净生态系统生产力时空演变特征研究OA

Net Ecosystem Productivity(NEP)serves as a key indicator for assessing carbon source/sink dynamics in terrestrial ecosystems,and understanding the evolution of its spatiotemporal heterogeneity and driving mechanisms is highly significant for regional carbon neutrality.Although lithology,as a fundamental unit of surface material composition,profoundly influences NEP,current research predominantly focuses on climate-vegetation interactions,while the spatiotemporal evolutionary characteristics of lithologically-driven effects have received insufficient attention.Leveraging China's gridded NEP data(1981-2020)and lithological zoning maps,this study systematically elucidates the spatiotemporal evolution of NEP in Guangxi and its association with lithology using Theil-Sen trend analysis and Mann-Kendall tests.The results showed that:1)Temporally,annual mean NEP exhibited a"decline-then-rise"trend.Fluctuating decreases were observed from 1981 to 1991,followed by a significant accelerated increase post-2000(1991-2020).Over the 40 years,NEP values ranged between 211.35 and 279.56 g·m-2·a-1.2)Spatially,carbon source areas were concentrated in central and southern Guangxi,while carbon sinks dominated northern and western regions(with stronger sequestration intensity in the southeast).From 2000 to 2020,NEP significantly increased in 60.08%of the regions(the northwest was the core growth area),while NEP decreased in some areas in the eastern,northeastern and southwestern regions,and the carbon sink function deteriorated.3)Lithologic disparities significantly influenced NEP differentiation.Karst areas exhibited lower mean NEP values(154.04-226.23 g·m-2·a-1)compared to non-karst regions(253.40-313.33 g·m-2·a-1),yet demonstrated a faster recovery rate.Due to rocky desertification control and tree species optimization,limestone areas surpassed dolomite zones in NEP after 2011.This study elucidates the critical regulatory role of lithology in shaping the spatiotemporal patterns of NEP,and demonstrates the effectiveness of ecological restoration measures in enhancing carbon sequestration across different lithological settings.These findings provide scientific support for developing tailored ecological strategies to strengthen regional carbon sink capacity in karst regions.