Scenario-Based Assessment of Carbon Storage and Habitat Quality under Land Use Change: Insights from Shandong Province, China

Land-use change crucially affects ecosystem services, and an accurate assessment of its evolution is key to regional sustainability. Taking Shandong Province as a case study, this research employs the PLUS model to simulate land use changes from 2000 to 2020 and to project spatial transitions under multiple scenarios for 2030 and 2040. Meanwhile, the InVEST model was employed to assess changes in carbon storage (CS) and habitat quality (HQ). Key findings include: (1) Cultivated land decreased by 12.3% while construction land expanded by 51.04%, mainly at the expense of farmland and forests, forming an“urban east–agricultural west” spatial pattern. (2) CS declined by about 63 million tons, primarily due to urban expansion. (3) HQ decreased by 3.6%, with significant ecological fragmentation in central mountains and the Yellow River Delta due to urbanization and intensified agriculture. (4) Under the ecological conservation scenario, CS could increase by 12.5% and HQ improve to 0.572 by 2040; in contrast, the business-as-usual scenario projects continued declines. These results highlight the trade-offs between land development and ES, underscoring the need to enhance ecological zoning, compensation mechanisms, and corridor construction. Findings provide a scientific basis for sustainable land use and ecosystem management.