Modeling the cascading effects of urban expansion on population-food-ecology patterns under China's cropland requisition-compensation balance policy

Abstract

The human-land system reflects complex links among population growth, urban expansion, and resource-environment dynamics, where rising food demand and urbanization directly occupy cropland and ecological land while indirectly affecting distant ecosystems through cropland compensation. The cascading effect triggered by urban expansion not only directly encroaches on surrounding cropland and ecological land but also indirectly impacts ecological areas in remote regions through the cropland compensation mechanism. Based on this understanding, this study proposes a multivariate coupled simulation framework comprising three modules: population, ecology, and food, which are independent yet interact with one another, and exhibit both flexibility and scalability to simulate dynamic feedback and hysteresis effects among these factors. Taking Hubei Province of China as an example, this framework explores how urban expansion triggers cascading impacts on regional ecological patterns, under the guiding principle of the cropland balance policy that seeks to align land occupation with equivalent compensation. Results show that the indirect ecological land take triggered by urban expansion is up to 87 times greater than direct land take, indicating far more extensive cascading effects. Although cropland protection policies have increased the total cropland area, both cropland and ecological land exhibit outward spatial displacement, implying that spatial mismatches and hidden ecological costs remain unresolved. This study enhances the understanding of complex human–land interactions and provides a scientific basis for optimizing regional resource allocation and promoting sustainable land use. • A coupled population-food-fand simulation framework is developed to simulate urban expansion-induced cascading effects on ecological systems. • Findings reveal the potential impacts of urban expansion in Hubei Province can be up to 87 times greater than direct land occupation. • Cropland compensation alleviates quantity loss but induces spatial mismatch and ecological costs.