Map simulation tool for the agro-ecological evaluation of land use change scenarios in tropical insular environment – DESCARTES (DEfinition, Simulation CARtog

In the dynamic landscape model, the landscape is considered as a system of entities (physical or abstract landscape elements , actors, etc. . ) interacting with each other through relationships of different types (spatial , functional , hierarchical , etc . ) . The description of these entities, their links, and the establishment of scenarios for the system are made with the Ocelet language. Ocelet comes with an interface for modeling and a simulation execution environment.
The collective learning methods used are structured around three main axes : two axes on the dynamics of collective learning (positions of the individual actors and their evolution under the influence of the collective; processes of information exchange, mediation and decision making within the group), and a more reflexive axis on the participants perceptions of the scenario planning.

The development, and presentation during workshops, of various demonstrators allowed the testing of the mapping tool to support a collective innovation process among stakeholders (planners, agricultural stakeholders and environmental managers), and opened new fields of research on collective learning, spatial simulation, and forecasting of ecosystem services.
Demonstrators developed so far are the consumption of the agricultural land by urban in St Pierre municipality, the risk of groundwater nitrate pollution 1. from agriculture activities at the island scale, and 2. from agriculture and urban activities at the catchment scale. Other models are being developed.

The scientific community has partnered with other research teams to respond to a tender TCO (territory of the West coast) to promote the integrated management of the watershed, and of the interface coastal territories.

Augusseau X., Bégué A., David D., [...], 2013. Simulation cartographique au service de l'innovation collective - Géoprospective territoriale à l'île de la Réunion. SAGEO Conference, Brest (FR), 23-26 septembre 2013, 17 p.
hal.cirad.fr/cirad-00850243

The DESCARTES project aims at developing a cartographic simulation tool for assessing land use change scenarios on a given territorial extent. It is designed to take into account the points of view of different stakeholders (e.g. public bodies, actors of the agricultural sector) as well as a set of constraints (e.g. demographic pressure, public policies, environmental regulations). This tool will be used to test the “consequences and coherences” in terms of services (production and environmental services) of land use allocation scenarios in a territorial project, in order to reach an agreement between different parties towards the production of efficient ecological services. In this project, the simulation tool comes in support of a collective innovation process with the stakeholders of the territory. It aims to (i) develop a participatory approach which includes partners and the scientific community into implementing the project within a learning process; (ii) develop appropriate landscape modelling allowing this approach and (iii) develop a method to spatialize the environmental services of agriculture and to integrate them in the simulations.

The simulation tool is applied on a study area located in Reunion Island. This island is representative of the issues and forthcoming stakes for agriculture: how to sustain development within a limited space, how to integrate new functions and to make up with new governance instances? The project considers two embedded spatial scales, that of the whole island which represent a “complete” territorial system, and that of a community of districts which gathers all the territorial issues of the island, and which has recently set up a landscape chart.

The construction of the cartographic simulation tool is based on recent research works carried out by our teams, pertaining to (i) the development of a language and a software environment for modelling dynamic landscapes (ANR Project STAMP) and (ii) the deployment of an online agricultural information system (Margouill@ Platform). The DESCARTES project therefore tackles a number of issues that are currently hindering the sustainable management of territories and resources.