Résumé
Due to their isolation, limited resources, and high population density, small islands are particularly vulnerable to multi-sectoral crises. The study of sustainability on small islands raises, among other challenges, the need to balance the use of local resources -such as water, food and energy-while effectively managing urban sprawl. This paper introduces a systemic approach that explores the interdependencies among multiple resources and production systems, framed within the Water-Energy-Food (WEF) nexus, with a specific focus on assessing land use competition driven by the dynamics of land use change. In this paper, we propose a novel approach of the WEF nexus through the optimization of scenarios that make use of Geographical Information Systems (GIS) integrated with a robust optimization model. The contributions include constructing integrated scenarios that encompass agricultural production, electricity production, and urban sprawl dynamics, highlighting their impacts on land use change and their combined effects on energy and food production from several local resources by 2035. The model is applied to Reunion Island, using real-world data to build insightful scenarios that facilitate informed decision-making. Our proposed model functions as a spatial analysis tool, enabling the identification of optimal agricultural parcels for urban development and potential areas for electricity and food production within a systemic approach. Besides, it provides medium-term projections regarding the impact of integrated scenarios on local food and energy production. As such, it serves as a relevant decision-support tool for local policymakers at the island scale.