Analysis of carbon stock variation trends and driving factors in Dongting Lake area from 2003 to 2022

Abstract

[Objective] Dongting Lake, a crucial ecological barrier in China, not only plays a key role in regulating regional climate and maintaining biodiversity, but also has significant carbon sequestration capacity. Carbon stock and its variation trends in Dongting Lake area are analyzed in this study, and the effect of different hydrometeorological factors on the variation of carbon stock is investigated, aiming to provide a scientific basis for regional carbon management and ecological protection. [Methods] Based on the remote sensing data from 2003 to 2022 and the modified carbon density data, combined with the InVEST model, the dynamic variations of carbon stock in Dongting Lake area were quantitatively analyzed, and the spatiotemporal distribution characteristics of carbon stock and the influencing factors of carbon stock variations were discussed. [Results] (1) From 2003 to 2022, the average carbon stock in Dongting Lake was 7.605 6×10⁸ t, with the lowest value in 2007 at 7.368 4×10⁸ t and the highest in 2005 at 7.904 7×10⁸ t. Overall, the regional carbon stock showed a declining trend, with an average annual decrease of 0.12%.(2) Carbon stock was significantly affected by land use. The average values of carbon stock per unit area in hilly regions(forest land), plain regions(grassland and cultivated land), and water areas(water bodies and floodplains) were 27.05 kg/m², 14.27 kg/m², and 1.99 kg/m², respectively.(3) Variations in carbon stock were affected by hydrometeorological factors such as temperature and precipitation. Average annual temperature showed a negative correlation with carbon stock variations, while precipitation in winter(October to December) exhibited a positive correlation with carbon stock. [Conclusion] From 2003 to 2022, carbon stock in Dongting Lake area shows an overall declining trend, indicating a weakening of its carbon sink function. Significant differences are observed in carbon stock across different areas. The hilly regions contribute the most to carbon sink capacity due to their high forest coverage, while the water areas contribute the least. Land use changes, climate fluctuations, and hydrological conditions have significant effects on carbon stock. Rising temperatures inhibit carbon stock, while winter precipitation enhances carbon sequestration. Addressing climate change effectively and optimizing land use structure are key strategies for improving the carbon sink function of Dongting Lake area.

Keywords

carbon stock / InVEST model / Dongting Lake / land use change / influencing factors