The Urbanized Area Evolution and Multi-factor Coupling Mechanisms in the Barcelona Metropolitan Region based on Landscape Ecological Indices

Abstract

Urban expansion is a multifaceted urbanization process that reflects not only changes in land use patterns but also the complex coupling between human activities and the natural environment. This study focuses on the Barcelona Metropolitan Region (BMR), applying landscape ecological indices to analyze the utilization patterns of continuous and discontinuous urban land between 2006 and 2018. A visual framework was developed to assess the expansion and contraction of urban and built-up areas. Using a multivariable interaction model, we identified NDVI and NDBI as the key factors most strongly associated with urban spatial dynamics. The results show that BMR has maintained a stable urban land scale, with high spatial cohesion and population density, where continuous urban textures dominate the landscape. A non-significant relationship was observed between NDVI and NDBI in promoting urban growth and mitigating decline. In conclusion, BMR has undergone compact development in recent years, supported by effective policy interventions, resulting in a more efficient and coherent urban structure. The strong coupling between NDVI, NDBI, and urban land change highlights their crucial role in guiding sustainable urban development. This study offers a comprehensive evaluation of urban texture evolution from both macro and micro perspectives and reveals the spatial heterogeneity and multi-factor interactions influencing urban distribution. The findings provide a scientific basis for urban planning and contribute to the global understanding of urbanization processes.