Assessment of changes in landscape ecological risk and carbon sequestration services in Mile City, Yunnan Province

Changes in land use often impact landscape ecological risk and carbon storage. Taking Mile City as a representative of typical mountainous cities, this study selected the land cover data in 2000, 2010 and 2020 to quantitatively assess the spatial heterogeneity and evolution trends of landscape ecological risk and carbon storage. This assessment was conducted through the application of landscape ecological risk assessment and the InVEST model. Additionally, economic and social data were incorporated into the analysis, and models such as PLUS, SPSS, and GeoDa were utilized to simulate and explore the correlations and spatial agglomeration features of landscape ecological risk (change) and carbon storage (change) over different periods of time. The results showed that: 1) The landscape ecological risk in the study area increased from 2000 to 2020, with northern regions being low risk and medium risk zones, while southern regions were either high risk or extremely high risk zones, this pattern continued to increase in size and clusters in the northeast and southeast regions; 2) The carbon sequestration services in Mile City from 2000 to 2020 showed high-values in the north-east regions and low values in the northwest-central regions. Over 20 years, the overall carbon storage and economic value of carbon sinks decreased; 3) Except for cropland protection scenario, carbon storage and the economic value of carbon sinks increased. This was especially true in the ecological protection scenario where the size of the regions showed deteriorated landscape ecological risk and reached the largest level under the cropland protection scenario; 4) There was a significant negative correlation between landscape ecological risk and carbon storage, both in terms of quantity and space from 2000 to 2010. The correlation changed from negative to positive from 2010 to 2020, with spatial clusters of high risk - low carbon storage and low risk - high carbon storage, which were distributed in the northern and central regions. This study demonstrates that landscape ecological risk has a negative effect on carbon sequestration services. In the future, attention should be given to the eastern forest land with high risk - high carbon storage, so as to formulate targeted ecological protection and management strategies. These efforts could ensure that the ecosystems will enjoy sustainable carbon sequestration services and risk mitigation in the course of economic growth.