This paper reflects on collaborative landscape research conducted in Reunion Island, an outermost region of the European Union. On this 2,500 km2 tropical island also considered a major international biodiversity hotspot, land-use planners must address important challenges, especially growing population densities and urban sprawl that cause important pressure on agricultural land and natural ecosystems. While progress has been made towards land-use zoning and planning at the island scale, entrenched interests and a lack of communication between the agricultural, urban and environmental sectors continue to hinder the design and implementation of integrated land-use plans at the local level. This paper presents an approach to territorial foresight where urban development scenarios and spatial models were co-constructed with a collective of institutional actors in order to facilitate dialogue on future urbanization patterns and impacts on landscapes. It describes how spatially explicit models and simulations of urban development, first used as demonstrators, have raised individual interests and expectations and facilitated the structuring of a collaborative research network. Models and scenarios were then questioned, redesigned collectively and used as boundary objects to facilitate a shift away from statistical and sectorial readings towards more territorialized and integrated perspectives. Analysing inputs, reactions and feedback from the actors involved in the research, this paper discusses the role and potential value of landscape modelling and simulation in mediating debates among planning stakeholders and creating social learning situations.