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

Abstract

[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 2000 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/m2 and 494.8 g C/m2, respectively, with a total increasement of 161.6 g C/m2, 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 2 304 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 2000 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.

Keywords

• carbon sequestration amount
• carbon sequestration rate
• carbon sequestration potential
• model simulation