[Correlation Between Green Space Carbon Storage and Landscape Pattern at Different Grid Scales in Harbin]

Green space can sequester carbon and release oxygen, which is key to affecting the carbon cycle of terrestrial ecosystems. The future development scenarios and their correlation of green space pattern and carbon storage are clarified, which is crucial for scientific decision-making in green space system planning. Based on the green space land cover data for Harbin in 2010 and 2020, the FLUS model was used to predict the land cover change trend of the study area under the natural development (ND) and ecological protection (EP) scenarios in 2030. The InVEST model and Fragstats 4.2 software were used to measure the carbon storage and landscape indicators of green space in Harbin, respectively, and analyze the spatiotemporal variation law. The Spearman correlation coefficient was used to determine the correlation between carbon storage and landscape indicators at different grid scales, and the linear regression equation was used to further explore their linear relationship. The results showed that: ① The green space carbon reserves of Harbin in 2010 and 2020 were 2 578.11×10⁶ t and 2 573.15×10⁶ t, respectively. In 2030, the carbon storage of the ND scenario was reduced by 1.18×10⁶ t, while that of the EP scenario was increased by 0.44×10⁶ t, and the carbon density of wetland was the highest. ② In 2030, the Shannon's diversity index (SHDI), Shannon's evenness index (SHEI), and landscape division index (DIVISION) all showed a downward trend under the two scenarios, with a large decline in the ND scenario, a continuous decline in the contagion index (CONTAG) under the ND scenario, and a slight increase in the EP scenario. ③ SHDI, SHEI, and DIVISION were significantly negatively correlated with green space carbon storage, while CONTAG was significantly positively correlated with green space carbon storage. The optimal analysis grid scale was 4.50 km×4.50 km. ④ The degree of linear fitting between SHDI and DIVISION and carbon storage-related models was low, while carbon storage could explain 33.82% of SHEI changes and 29.92% of CONTAG changes, respectively, and the model fit was good. In the future planning of green space in Harbin, ecological protection should be strengthened, wetland areas should be protected, afforestation should be continued, and landscape patch fragmentation should be avoided with 4.50 km as the management unit to ensure good connectivity and sprawl of cultivated land to increase carbon storage.