Spatial-temporal pattern of vegetation carbon sequestration and its response to rocky desertification control measures in a karst area, in Guangxi Province, China

The terrestrial ecosystem in southwestern China has been a long-term carbon sink, but its spatial-temporal pattern during the previous two decades and its response to karst rocky desertification control measures (KRDC) still merit further quantification, particularly where higher levels of carbon capture by vegetation are proposed in the context of a 'carbon neutrality' goal. Satellite datasets, field data from previous studies, and the geostatistical soil respiration model enabled a focus on the karst landscape in Guangxi Province in Southwest China, to probe the spatial-temporal pattern of the ability to capture carbon during 2001-2020 and assess its response to KRDC. The results showed that the interannual variation in the average net ecosystem productivity (NEP) exhibited a remarkable tendency to increase at a rate of 4.15 g C m(-2) yr(-1) (p < 0.01). A major period of increase was identified from 2006 to 2011, which represented the second stage of the KRDC. The terrestrial ecosystems of karst area have always acted as carbon sinks. Human activity was the dominant factor in the development of NEP and covered an area of 79.30%. The karst area offers climate change characteristics of 'wetness' and 'light stress,' which can promote the ability of vegetation carbon to serve as a carbon sink (0.18 g C m(-2) yr(-1)). Furthermore, the closing mountains for afforestation is the most effective way to artificially increase the carbon sink. Quantifying vegetation ecosystem carbon sinks and sources in this study is highly significant for understanding regional carbon dynamics and guiding carbon capture policies to design and mitigate land degradation.