Precise quantification of terrestrial gross primary production (GPP) has been recognized as one of the most important components in understanding the carbon balance between the biosphere and the atmosphere. In recent years, although many large-scale GPP estimates from satellite data and ecosystem models have been generated, few attempts have been made to compare the different GPP products at national scales, particularly for various climate zones. In this study, two of the most widely-used GPP datasets were systematically compared over the eight climate zones across China’s terrestrial ecosystems from 2001 to 2015, which included the moderate resolution imaging spectroradiometer (MODIS) GPP and the breathing Earth system simulator (BESS) GPP products. Additionally, the coarse (0.05^o) GPP estimates from the vegetation photosynthesis model (VPM) at the same time scale were used for auxiliary analysis with the two products. Both MODIS and BESS products exhibited a decreasing trend from the southeast region to the northwest inland. The largest GPP was found in the tropical humid region with 5.49 g C m⁻² d⁻¹ and 5.07 g C m⁻² d⁻¹ for MODIS and BESS, respectively, while the lowest GPP was distributed in the warm temperate arid region, midtemperate semiarid region and plateau zone. Meanwhile, the work confirmed that all these GPP products showed apparent seasonality with the peaks in the summertime. However, large differences were found in the interannual variations across the three GPP products over different climate regions. Generally, the BESS GPP agreed better than the MODIS GPP when compared to the seasonal and interannual variations of VPM GPP. Furthermore, the spatial correlation analysis between terrestrial GPP and the climatic factors, including temperature and precipitation, indicated that natural rainfall dominated the variability in GPP of Northern China, such as the midtemperate semiarid region, while temperature was a key controlling factor in the Southern China and the Tibet Plateau area.

Southwest China has one of the largest karst landscapes on the Earth and an ecologically fragile environment. A better understanding of how ecosystem services function in karst areas helps ecological preservation and policy implementation. However, little effort has been made to evaluate the long-term dynamics of ecosystem services across Southwest China. This study systematically analyzed the spatio-temporal patterns and the values of three typical ecosystem service functions, including water conservation, carbon sequestration, and soil conservation, as well as the effects of precipitation and land use changes between 2000 and 2020. The results showed that water conservation exhibited an overall decrease from southeast to northwest, while soil conservation showed the opposite trend. The regions with an increasing trend in carbon sequestration were mainly distributed in Guizhou, Guangxi, and Sichuan. Compared to the year 2000, the percentage of water conservation and soil conservation decreased by 4.50% and 0.76%, respectively. However, carbon sequestration increased by 94.35%. The total value of ecosystem services in Southwest China showed a 90.00% increase in 2020 relative to 2000. Water conservation and carbon sequestration had a much closer correlation with precipitation. The impact of soil conservation was more significantly influenced by land use changes.