Quantitative assessment of spatiotemporal dynamics in vegetation NPP, NEP and carbon sink capacity in the Weihe River Basin from 2001 to 2020

Abstract

Vegetation carbon storage is crucial role in terrestrial ecosystems, impacting material and energy conversion processes. The combined influence of climate change and anthropogenic activities underscores their significance in achieving carbon neutrality. Understanding regional climate change necessitates the examination of spatiotemporal variations in net primary productivity (NPP) and net ecosystem productivity (NEP) of vegetation, as well as quantifying the relative contributions of climate change and anthropogenic activities to vegetation dynamics. This study conducts a comprehensive analysis of NPP and NEP changes and influencing factors in the Weihe River Basin (WHRB) employing various analytical techniques, including the Mann-Kendall (M-K) test, partial correlation analysis, and a land use and cover change (LUCC) matrix. The relative contributions of anthropogenic activities and climate change to NPP are investigated through a two-step linear regression approach. Results indicate a significant increase in NPP and NEP within the WHRB from 2001 to 2020, with both climate change and anthropogenic activities exerting positive impacts on vegetation growth. Conversion from grassland to forest results in the greatest net increase in NEP, while conversion to cropland leads to the largest net decrease. Climate change and anthropogenic activities contribute 4.6 gC·m−2·a−1 (64.16%) and 2.57 gC·m−2·a−1 (35.84%) to NPP, respectively. The capacity for vegetation carbon sink demonstrates an overall increase from 2001 to 2020, with higher values observed in the southern region and lower values in the northern region. The western region and areas along the river have transitioned from carbon sinks to carbon sources, while the potential for source-to-sink transformation has gradually intensified from the central to eastern, northern, and southeast regions. This study enhances the understanding of drivers and patterns of vegetation dynamics in response to climate change and anthropogenic activities in the WHRB. The findings provide valuable scientific insights for improving NPP and carbon sink capacities and advancing sustainable development objectives.