2003—2022年洞庭湖区碳储量变化趋势及驱动因素分析

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

摘要

【目的】作为我国重要的生态屏障，洞庭湖不仅在调节区域气候和维持生物多样性方面发挥着关键作用，也具有显著的固碳能力。旨在分析洞庭湖区的碳储量及其变化趋势，探索不同水文气象要素对碳储量变化的影响，为区域碳管理与生态保护提供科学依据。【方法】基于2003—2022年的遥感数据与修正后的碳密度数据，结合InVEST模型，量化分析洞庭湖区域碳储量的动态变化，探讨碳储量的时空分布特征以及碳储量变化的影响因素。【结果】(1)2003—2022年洞庭湖区碳储量均值为7.605 6×10⁸ t, 2007年的碳储量最小，为7.368 4×10⁸ t, 2005年的碳储量最大，为7.904 7×10⁸ t,区域碳储量整体呈下降趋势，年均下降0.12%;(2)碳储量受土地利用的影响显著，丘陵区(林地)、平原区(草地和耕地)和水域(水体和滩地)单位面积的碳储量均值分别为27.05 kg/m²、14.27 kg/m²和1.99 kg/m²;(3)碳储量的变化受到气温、降雨量等水文气象要素影响，年平均温度与碳储量变化呈负相关，冬季(10月至12月)降水量与碳储量呈正相关。【结论】2003—2022年洞庭湖区碳储量总体呈下降趋势，表明区域碳汇功能减弱。碳储量在不同区域间存在显著差异，其中丘陵区因森林覆盖率高对碳汇能力贡献最大，水域最低。土地利用变化、气候波动和水文条件显著影响碳储量，气温升高抑制碳储存，冬季降水则增加促进碳汇。合理应对气候变化以及优化土地利用结构是提升洞庭湖区碳汇功能的重要策略。

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.

关键词

碳储量 / InVEST模型 / 洞庭湖 / 土地利用变化 / 影响因素

Key words

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

基金资助

国家自然科学基金项目(52179004)

湖南省水利科技计划项目(XSKJ2022068-04)