Centennial-scale spatiotemporal heterogeneity of ecosystem service interactions: Implications for spatial management.

Over the past century, China has experienced unprecedented land use and land cover changes (LULCC). Centennial-scale evaluation of ecosystem services (ESs) is essential for effective environmental management but remains scarce. A "Landscape Pattern-ESs-Management" framework was developed to quantify the century-scale LULCC impact on ESs and help to make future management policies. Taking Dongting Lake Region as an example, this study focused on water yield, water retention, flood regulation, water purification, soil conservation, and carbon storage. To explore the trade-offs and synergies among these ESs, we employed spearman's correlation, geographically weighted regression, and self-organizing maps clustering algorithm. The results showed that cropland expansion, at the expense of lakes and forests, was the most significant LULCC over the last century, with rapid urbanization becoming prominent after the 1980s. The area of Dongting Lake in the 2020s was less than half of that in the 1900s. While the spatial patterns and distribution of ESs remained relatively stable, their temporal evolution exhibited notable differences. Synergies were primarily observed between water yield, water retention, soil conservation and carbon storage. The boundaries of trade-offs and synergies closely aligned with the 50 m elevation contour. Notably, ESs bundles have significant scale effects. At the grid scale, the FR-WP synergy bundle decreased significantly, mainly in the lake area. At the county scale, the FR-dominated bundle declined, while the WP-dominated bundle increased. Although hilly areas constitute only 35 % of the region, they contribute over 45 % of multiple ESs and experience the most drastic LULCC and ESs bundles transitions. The shrinking of lake and hilly areas underscores the need to prioritize the two regions in future ecosystem management. This study highlights the long-term landscape dynamics under intensive human-nature interactions and provides a transferable method for historical land change detection. It also offers a scientific framework for century-scale environmental evaluation and making sustainable policies.