2000—2020年陕西省陆地生态系统NPP时空变化与潜力

Spatial and Temporal Variation and Potential of NPP in Terrestrial Ecosystems in Shaanxi Province from 2000 to 2020

[目的]在“双碳”战略实施背景下,准确评估陆地生态系统固碳现状、速率与潜力对实现“碳中和”目标意义重大。陕西省横跨3个气候带,南北气候差异大,植被类型丰富。近年来,由于多项生态工程(退耕还林还草、三北防护林等)的实施,陕西省植被覆盖度进一步提升至60.7%,固碳能力巨大。陆地生态系统NPP(植被净初级生产力)是反映植被固碳能力的重要指标,然而,关于陕西省NPP的时空动态变化,以及NPP未来潜力的空间分布鲜有研究。[方法]以陕西省陆地生态系统为研究对象,利用CASA模型和邻域相似空间分布法评估陕西省植被NPP及其潜力的时空分布特征。[结果](1)陕西省植被总固碳量在2000年和2020年分别为687,1020 Tg,增加333 Tg,增幅为48.5%。(2)陕西省NPP呈南高北低,中间存在最高值或最低值的空间分布态势,平均值在2000年和2020年分别为333.2,494.8 gC/m^(2),共增加161.6 gC/m^(2),增加幅度呈北高南低的分布态势。(3)陕西省生态系统NPP的实际最大潜力为2304 Tg,相比于2020年增加41.3%,空间分布态势表现为由南到北逐渐降低,且空间分布特征均表现高度空间自相关特性,但局部差异较大。[结论]陕西省植被总固碳量在2000—2020年显著增加,同时,未来植被固碳潜力巨大。评估和预测陕西省区域尺度生态系统NPP时空动态变化及潜力空间分布特征,可为科学评价提升区域碳汇能力提供一定的评价体系和理论参考。

[Objective]In the context of the“dual-carbon”goal,accurately assessing the status,rate and potential of carbon sequestration in terrestrial ecosystems is crucial for achieving“carbon neutrality”.Shaanxi Province,which spans three climatic zones and have a large difference in climate between north and south,with abundant vegetation types.In recent years,the vegetation coverage in Shaanxi has been further improved due to the implementation of various ecological projects(Grain for Green,Three-North Shelterbelt,etc.).Its vegetation coverage reaches up to 60.7%,what resulted in huge carbon sequestration capacity.Net primary productivity(NPP),as one of the most important indicators to reflect the carbon sequestration capacity of vegetation,there are few studies on spatial and temporal dynamic changes of NPP and the spatial distribution of NPP potential in the future in Shaanxi province.[Methods]Based on these,we evaluated the temporal and spatial distribution characteristics of vegetation NPP and its potential in Shaanxi province through the CASA model and the neighborhood similarity spatial distribution method.[Results](1)Total carbon sequestration by vegetation increased by 333 Tg,with an increase of 48.5%from^(2)000 to 2020 in Shaanxi province.(2)NPP was higher in the south and lower in the north,with the highest or lowest value in the middle.The average value in 2000 and 2020 were 333.2 g C/m^(2)and 494.8 g C/m^(2),respectively,with a total increasement of 161.6 g C/m^(2),and the increase amplitude showed a distribution trend of high in the north and low in the south in Shaanxi.(3)The carbon sequestration potential was 2304 Tg which increased by 41.30%compared with the 2020.The spatial distribution trend was gradually decreasing from south to north,and the spatial distribution characteristics showed high spatial autocorrelation characteristics,but the local differences were large.[Conclusion]The total vegetation carbon sequestration in Shaanxi province increased significantly from^(2)000 to 2020,and there is huge potential for vegetation carbon sequestration in the future.This study calculated the spatial and temporal dynamic changes and predicted potential spatial distribution characteristics of NPP in the regional scale ecosystem in Shaanxi province,which can provide an evaluation systematic and theoretical reference for scientific evaluation and improvement of regional carbon sink capacity.