Trade-offs or synergies? Identifying dynamic land use functions and their interrelations at the grid scale in urban agglomeration

The land systems in global urban agglomerations have undergone profound changes in today's rapidly urbanizing world and have produced huge impacts on the ecological environment. To address the issues triggered by ir-rational land use, assessing dynamic land use functions (LUFs) and identifying their interrelations at the grid scale can help to formulate targeted land use policy and implement effective spatial zoning schemes for achieving sustainable land development. In this context, the Beijing-Tianjin-Hebei (BTH) urban agglomeration was selected as an empirical research area, and multiple LUFs and their changes-through the lens of production-living -ecological (PLE) functions-were identified at the grid scale. Next, trade-offs/synergies among PLE functions were traced. In the BTH region, LUFs were spatially heterogeneous and clustered. Ecological function (EF) and production function (PF) were mostly in the northeastern forested mountains and the southeastern plains, respectively, while the living function (LF) was concentrated in the urban core. Notably, the PF and LF improved while the EF declined during 2000-2020. Simultaneously, the LUFs exhibited trade-offs in general with spatial heterogeneity, which are typical outcomes of land systems as people assign different values to land. Finally, we proposed multiple land use management measures for the seven different function advantage zones. This study suggests that dynamic LUF trade-offs should be integrated into land-use decisions in addressing sustainability challenges and promoting development of the land system healthily and orderly.