Data from：The Correlation Between Blue Carbon Storage and Landscape Fragmentation: A Micro-Scale Perspective on Two Decades of Coastal Wetland Change in China

Coastal wetlands represent key carriers of blue carbon ecosystems, yet their carbon sequestration function is increasingly compromised by landscape fragmentation. A systematic, national-scale analysis of how fragmentation affects carbon storage remains lacking, limiting the effectiveness of conservation efforts. This study examined China's coastal wetlands using a 3 km grid resolution to map the spatiotemporal patterns of wetland fragmentation from 2000 to 2020. The InVEST model was applied to calculate carbon stocks. Geographically Weighted Regression and Random Forest were then employed to investigate the effects of fragmentation on carbon storage. The results show that over the past two decades, China’s coastal wetlands experienced a net loss of 660.88 km², with degradation rates accelerating initially before slowing down. While tidal flats and aquaculture ponds shrank significantly, mangroves and salt marshes increased variably. Landscape fragmentation intensified in most regions, especially around Liaodong Bay, the Yangtze River Delta, and eastern Hainan, though a notable reversal occurred after 2015, leading to overall stabilization. Total carbon storage declined from 62.68 Tg to 50.41 Tg, with natural wetlands showing an initial decrease followed by a partial recovery. Spatially, carbon storage was higher in the north and lower in the south, with increasing polarization over time. Landscape fragmentation significantly reduced carbon stocks, with the index of total area (TA) exhibiting the strongest positive linear effect. Different landscape metrics influenced carbon storage nonlinearly and varied by period and region. Based on these spatial and temporal patterns, targeted management strategies were proposed to enhance wetland conservation and carbon sequestration capacity. This study offers a transferable framework for supporting coastal wetland conservation with climate goals.