Variation and influencing factors of terrestrial ecosystem carbon fluxes in China

Terrestrial ecosystem plays a significant role in global carbon budget. Understanding the variations and controlling mechanisms of ecosystem carbon fluxes is crucial for comprehending carbon cycles and assessing carbon budget. Using observed flux data, this study examined the spatial variation and influencing factors of carbon fluxes across China's terrestrial ecosystems. The results show that typical terrestrial ecosystems in China generally act as carbon sinks. There are clear geographical patterns in carbon fluxes, which tend to decrease linearly with increasing latitude and altitude, while increase linearly with increasing longitude. Carbon fluxes are positively correlated with mean annual temperature, mean annual precipitation, fractional vegetation cover, and leaf area index, while they show negative correlations with mean annual radiation. From 2002 to 2020, China’s terrestrial ecosystem productivity exhibited a slight increasing trend. The structural and functional properties contribute to this trend, with varying regional contributions. In the Northern regions of China, increasing structural properties, such as leaf area index, play a dominant role, while in the Southern and West regions, photosynthetic capacity is more significant. This study enhanced the understanding of the geographical patterns of carbon fluxes in China and provided a theoretical foundation for assessing the regional carbon budgets.