Integration of multi-scale stakes in governance by applying companion modelling to land use foresight

Decentralization of land use governance creates new challenges for participatory approaches, including the involvement of highly diverse participants and the search for coherence among multiple regulations. In France, the 2000 law of Urban Reform and Solidarity ("Solidarite et Renouvellement Urbain") provides a legal framework to land use decentralization. It requires the planning design process to be participative and to involve civil society through consultation phases. It also addresses the issue of coherence among legal planning documents along the scale hierarchy, the larger scale plan conditioning the others. In the Reunion Island, the multi-level institutional system includes a region, its four micro-regions and 26 districts; each having their own land use plan. The revision of the regional plan ("Schema d'Amenagement Regional", SAR) was the opportunity to revisit the various plans to make them more coherent across scales. This paper presents how research was included in this political process. The SAR revision was initially thought as a one-scale regular participatory foresight process in three stages, i.e. (1) a land use assessment (diagnostic); (2) the definition and discussion of contrasted scenarios; (3) the development of the final land use plan. The overall consultation process involved a large group of participants, including members of various institutions and of the civil society. They defined the logic of four contrasted land use scenarios, and sorted key challenges for the future of the Reunion Island. Stage 2 was however handled in an innovative way due to the collaboration with a research project called DOMINO- Reunion. The DOMINO-Reunion Project put together a team of researchers from various disciplinary backgrounds, and members of extension and support services for rural and agricultural development involved in the various debate on land use at each scale. Together, the team followed a companion modelling approach to develop a prototype of a dynamic model meant to assist the main players in building various land use scenarios and simulating their mid- to long-term consequences on urban, agricultural and natural stakes. A subset of participants of both processes, the SAR revision and DOMINO-Reunion, collaborated to adapt the model prototype to the SAR scenarios and feed the regional land use debate. This paper analyses how our companion modelling approach in two steps has helped integrating multi- scale stakes in the SAR revision process. It discusses specific challenges for participatory modelling, which are linked to power balance such as stakeholder's exclusion, over representation of specific interests and political co-optation, focussing on two specific processes: • the integration of multi-scale negotiation processes and indicators in the evolving model; • the implication of stakeholders, which are involved in various land use decision-making arena, in the participatory modelling of the system. We showed that companion modelling helped increase the representation and the weight of agricultural issues in the debate, although urban considerations still prevailed in the regional arena. The paper concludes on the benefits and drawback of integrating progressively different decision-marking scales in a participatory process.