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How one builds, checks, validates and interprets a model depends on its ‘purpose’. This is true even if the same model code is used for different purposes. This means that a model built for one purpose but then used for another needs to be re-justified for the new purpose and this will probably mean it also has to be re-checked, re-validated and maybe even re-built in a different way. Here we review some of the different purposes for a simulation model of complex social phenomena, focusing on seven in particular: prediction, explanation, description, theoretical exploration, illustration, analogy, and social interaction. The paper looks at some of the implications in terms of the ways in which the intended purpose might fail. This analysis motivates some of the ways in which these ‘dangers’ might be avoided or mitigated. It also looks at the ways that a confusion of modelling purposes can fatally weaken modelling projects, whilst giving a false sense of their quality. These distinctions clarify some previous debates as to the best modelling strategy (e.g. KISS and KIDS). The paper ends with a plea for modellers to be clear concerning which purpose they are justifying their model against.

Agent-based modelling (ABM) simulates Social-Ecological-Systems (SESs) based on the decision-making and actions of individual actors or actor groups, their interactions with each other, and with ecosystems. Many ABM studies have focused at the scale of villages, rural landscapes, towns or cities. When considering a geographical, spatially-explicit domain, current ABM architecture is generally not easily translatable to a regional or global context, nor does it acknowledge SESs interactions across scales sufficiently; the model extent is usually determined by pragmatic considerations, which may well cut across dynamical boundaries. With a few exceptions, the internal structure of governments is not included when representing them as agents. This is partly due to the lack of theory about how to represent such as actors, and because they are not static over the time-scales typical for social changes to have significant effects. Moreover, the relevant scale of analysis is often not known a priori, being dynamically determined, and may itself vary with time and circumstances. There is a need for ABM to cross the gap between micro-scale actors and larger-scale environmental, infrastructural and political systems in a way that allows realistic spatial and temporal phenomena to emerge; this is vital for models to be useful for policy analysis in an era when global crises can be triggered by small numbers of micro-level actors. We aim with this thought-piece to suggest conceptual avenues for implementing ABM to simulate SESs across scales, and for using big data from social surveys, remote sensing or other sources for this purpose.

Agent-based models are popular in common-pool resource management to represent complex systems and stimulate collective action and management, where they are used to evaluate scenarios of stakeholders’ choice in participatory simulations. We developed the “CoComForest” (COllaborative COMmunity FOREST management) model to support community forest management (CFM) and non-timber forest product (NTFP) harvesting in Nan Province, northern Thailand. The model was used as a computer-based role-playing game to support sharing of perceptions and knowledge among stakeholders, and in participatory simulations to explore future CFM scenarios. The Unified Modelling Language was used to build the conceptual model, subsequently implemented under the CORMAS (COmmon-pool Resource and Multi-Agent System) simulation platform. Several tests were conducted in the laboratory for verification and calibration before using this tool with 21 diverse stakeholders during a field workshop. Three different participatory gaming and simulation sessions were organized. The first one focused on the co-validation of the model with participants. They accepted most of the model functionalities and the scheduling of the rounds of play. The model was used in the subsequent two sessions to simulate the scenarios of firebreak establishment and introduction of outsiders intensively harvesting NTFPs, respectively. The results showed that the intensive harvesting practices of outsiders accelerated the depletion of resources, whereas the prevention of wildfire by establishing firebreaks could increase the resource availability in the landscape. The debriefing session at the end of the workshop focused on the analysis of simulation results and the relationships between the players’ decision-making and their actual circumstances. Individual in-depth interviews conducted after the workshop helped to evaluate the use of this model with local stakeholders. Most participants considered the model as a useful common representation of the system they manage collectively. Its use in participatory simulations facilitated communication among the stakeholders searching for an adapted and acceptable collective action plan to improve CFM at the sub-district level in order to prevent the overharvesting of NTFPs by outsiders.

© 2018 Elsevier Ltd Various tools and methods are used in participatory modelling, at different stages of the process and for different purposes. The diversity of tools and methods can create challenges for stakeholders and modelers when selecting the ones most appropriate for their projects. We offer a systematic overview, assessment, and categorization of methods to assist modelers and stakeholders with their choices and decisions. Most available literature provides little justification or information on the reasons for the use of particular methods or tools in a given study. In most of the cases, it seems that the prior experience and skills of the modelers had a dominant effect on the selection of the methods used. While we have not found any real evidence of this approach being wrong, we do think that putting more thought into the method selection process and choosing the most appropriate method for the project can produce better results. Based on expert opinion and a survey of modelers engaged in participatory processes, we offer practical guidelines to improve decisions about method selection at different stages of the participatory modeling process.

This paper is a reflexive analysis of a three-year participatory water research project conducted in the Upper East Region (UER) of Ghana, whose explicit objective was to initiate a multi-level dialogue to support the national Integrated Water Resources Management (IWRM) policy framework. The transdisciplinary team adopted the Companion Modeling approach (ComMod), using role-playing games and a computerized agent-based model to support the identification of a problemshed centered on issues of river bank cultivation, erosion, and flooding, and initiate a multi-level dialogue on ways that this problemshed could be tackled. On the basis of this experience, we identify three key criteria for transdisciplinary research to support innovative water governance: (1) the iterative adaptation of tools and facilitation techniques based on feedback from participants, (2) a common understanding of the objectives pursued and the approach used among researchers, who need to explicit their posture, and crucially, (3) the co-identification of a problemshed that diverse stakeholders are interested in tackling. Finally, we argue that the context in which research is funded and conducted in the development sector constitutes a challenge for researchers to be &ldquo, participants like any other&rdquo, in the projects they coordinate, which constitutes a barrier to true transdisciplinarity.

International audience; The objective of this paper is to question the increasingly common choice to build and use spatially explicit models, especially in the case of participatory agent-based modelling processes. The paper draws on a combination of lessons from literature and the case of a companion modelling process conducted in the context of a conflict about land and forest management in Northern Thailand. Using insights from negotiation theories, we analyze specifically the influence of spatial representations on the way people interacted, discussed and learnt from each other in the participatory modelling process. We argue that models that are spatially too explicit and realistic can actually impede the exploration of innovative and integrative scenarios in which ecological, social and economic objectives are mutually enriching. Indeed, spatial representations might lead to think in terms of boundaries and segregated space, and therefore prevent from thinking in terms of multifunctional space and from finding innovative and integrative solutions.

This paper aims at presenting the new functionalities of Cormas, a generic Agent-Based Modeling (ABM) platform dedicated to common-pool resources management. As free software, Cormas is used by an international community of researchers willing to understand the relationships between societies and their environment. It is intended to facilitate the design of ABM as well as the monitoring and analysis of simulation scenarios. To meet the increasing demand of our community of practice, the Cormas development has taken an innovative direction oriented towards the collective design of models and interactive simulation. In accordance with the principles of participatory methods and serious games, many experiments developed with Cormas combine two layers of complexity: the natural dynamic of the system, simulated by the computer, and the stakeholders' interactions and decisions played by the actors. Between these two extremes, a range of intermediate situations exists where some decisions are human and others are computer-specified. The term hybrid agent simulation covers these intermediary situations. The main idea is to enable the stakeholders to interact with the execution of a simulation by modifying the behavior of the agents and the way they use the resources. Thus, it is possible to collectively explore scenarios to better understand how a desired situation may be reached. This may feed back into the collective design of the model. As our intention is to involve more deeply the stakeholders into the modeling process, it is necessary to have an easily changeable tool to act on the simulation and to modify the conceptual model on the fly. After having explained the purpose and the philosophy of the Companion Modeling, this paper presents how the Cormas functionalities (asymmetry of information, agent manipulation, modification of behavior, stepping back and distributed simulation) are put into practice through three experiments with stakeholders facing actual environmental challenges. (Résumé d'auteur)

Landscape dynamics are driven by complex interactions among ecological, social, economic, and policy factors. In conservation areas, these factors are usually related to an increasing number of diverse land resource managers and users. Land use conflicts occur frequently because they have different interest, objectives and perceptions of landscape resources and their use. Sharing these different, but all legitimate, perceptions of the landscape and its use among concerned stakeholders is a pre-requisite for better collective land management, particularly in conservation areas. This research is using the integrative companion modeling approach to co-construct an agent-based model representing the dynamic interactions between vegetation dynamics, reforestation efforts, and livestock grazing in the upper watershed of Nan province, northern Thailand. The paper focuses on the participatory modeling process implemented with local stakeholders at this site. Three main investigation tools were used to exchange and gather knowledge on ecological and human decision making processes: field surveys (land use history and analysis of vegetation dynamics at the landscape level), farmers' interviews (analysis of individual decision making and determining factors across different farm types), and institutional analysis in relation with changes in land use policy and related state interventions. This knowledge was first assembled in simple gaming exercises presented to local herders and foresters to further enrich and validate the researchers' understanding of key interactions regulating vegetation and land use dynamics. The outputs of these collaborative modeling activities were used to design a hybrid agentbased hybrid simulator blending a role-playing game and a computer program developed under the CORMAS platform. This simulation tool, representing the complex human and ecological interactions at the landscape level, allowed stakeholders to criticize and improve this comprehensive formalization of the landscape dynamics. It was also used to introduce simulation exercises with local stakeholders and to stimulate them to identify possible future land management scenarios mitigating the current conflict.

International audience; For many conservation scientists, interdisciplinarity and participation can be efficient in the management of biodiversity. For both methods, new tools and new participative processes such as the so-called “co-modeling process” are required. The key questions addressed in this article are how group dynamics shape the model and why certain perspectives dominate in a process designed to be democratic. It is necessary, therefore, in order to appreciate the design and the legitimacy of the model that has been co-constructed, to address the questions of both the stakeholders' interests and their status in the process. Our case study is a co-modeling program based in a French biosphere reserve. It enabled us to highlight the key role of the mediator who had to govern social relationships and translate disciplinary jargon into a common technical language through a list of co-modeling rules.

Don Hoi Lord, a coastal wetland in the upper gulf of Thailand, is famous for the razor clam (Solen regularis), which is a source of food and income for local fishermen. However, the razor clam population is significantly decreasing so the aim of this study was to analyze the razor clam fishery and develop a management plan engaging the different stakeholders in collective discussions. A participatory modelling approach was used, including (a) agent-based modelling (ABM) and (b) role-playing games (RPG). First, an individual-state distribution model of the razor clam population was designed and calibrated to synthesise knowledge. Two RPG sessions supported by this biological model were organised to initiate collective learning and promote discussion among stakeholders. After playing with the baseline scenario showing the actual harvesting situation, discussions led to the definition of alternative scenarios for clam management such as establishment and rotation of zones closed for harvesting, and quota systems. These scenarios developed during the RPG sessions were more deeply investigated with an agent-based model that included fishermen agents and the individual-state distribution model of the razor clam population. Simulations of different scenarios (reserve, quota and combination of reserve and quota) were produced to enable better informed discussion between different stakeholders. Stakeholders have acknowledged that management through rotating reserves is not efficient if the duration of reserves is too short. They have realised that the efficiency of reserves is hard to assess without better data on clam recruitment. They have also explored another management option which is the quota system. In the final stage, the local participatory process was endorsed by the incumbent regional policy-making actor. Unfortunately, because of rapid administrative rotation the project abruptly lost support. This unexpected event emphasises the need for continuous monitoring of all actors entering and/or leaving the system, which can radically change the interactions among them and, therefore, the whole management context.

Erosive runoff is a recurring problem and is a source of sometimes deadly muddy floods in the Pays de Caux (France). The risk results from a conjunction of natural factors and human activity. Efficient actions against runoff in agricultural watersheds are well known. However they are still difficult to implement as they require co-operation between stakeholders. Local actors thus need tools to help them understand the collective consequences of their individual decisions and help to initiate a process of negotiation between them. We decided to use a participatory approach called companion modelling (ComMod), and, in close collaboration with one of the first group of local stakeholders, to create a role-playing game (RPG) to facilitate negotiations on the future management of erosive runoff. This paper describes and discusses the development of the RPG and its use with other groups of local stakeholders within the framework of two game sessions organized by two different watershed management committees. During the joint construction step, stakeholders shared their viewpoints about the environment, agents, rules, and how to model runoff in preparation for the creation of the RPG. During the RPG sessions, two groups of eight players, including farmers, mayors and watershed advisors, were confronted with disastrous runoff in a fictive agricultural watershed. Results showed that they managed to reduce runoff by 20–50% by engaging a dialogue about grass strips, storage ponds and management of the intercrop period. However, further progress is still needed to better control runoff through the implementation of better agricultural practices because, during the RPG sessions, the watershed advisors did not encourage farmers to do so. Because of the complexity of management problems, results of jointly constructing the game and the RPG sessions showed that modelling and simulation can be a very useful way of accompanying the collective learning process. This new way of working was welcomed by the participants who expressed their interest in organizing further RPG sessions

Publication Inra prise en compte dans l'analyse bibliométrique des publications scientifiques mondiales sur les Fruits, les Légumes et la Pomme de terre. Période 2000-2012. http://prodinra.inra.fr/record/256699; International audience; A stochastic individual-based model called COSMOS was developed to simulate the epidemiology of banana weevil Cosmopolites sordidus, a major pest of banana fields. The model is based on simple rules of local movement of adults, egg laying of females, development and mortality, and infestation of larvae inside the banana plants. The biological parameters were estimated from the literature, and the model was validated at the small-plot scale. Simulated and observed distributions of attacks were similar except for five plots out of 18, using a Kolmogorov-Smirnov test. These exceptions may be explained by variation in predation of eggs and measurement error. An exhaustive sensitivity analysis using the Morris method showed that predation rate of eggs, demographic parameters of adults and mortality rate of larvae were the most influential parameters. COSMOS was therefore used to test different spatial arrangements of banana plants on the epidemiology of C. sordidus. Planting bananas in groups increased the time required to colonise plots but also the percentage of banana plants with severe attacks. Spatial heterogeneity of banana stages had no effect on time required to colonise plots but increased the mean level of attacks. Our model helps explain key factors of population dynamics and the epidemiology of this tropical pest. (C) 2009 Elsevier B.V. All rights reserved.

Low coral islands are heavily dependent on groundwater for freshwater supplies. The declaration by the government of Kiribati of water reserves over privately owned land has led to conflicts, illegal settlements, and vandalism. Also, the water consumption tends to increase toward Western-like standards, and human pollution has already contaminated most freshwater lenses. This project aims to provide relevant information to local stakeholders to facilitate dialogue and devise sustainable water management practices. A computer-assisted role-playing game is implemented to fulfill this aim. The following three-stage methodology is applied: collecting local and expert knowledge, blending the di ferent viewpoints into a game-based model, and playing the game with the di ferent stakeholders to explore di ferent scenarios. Although game sessions delivered successful outcomes, the final stage of the project is characterized by the upheaval of contradictory government stands that undermine the whole process. It is argued that heterogeneous viewpoints may be handled in a satisfactory manner during the gaming sessions but that long-term hidden agendas may override the outcomes. Beyond the inherent question of legitimacy attached to such approaches, some players clearly must deal with constraints that are often genuinely considered external to the ongoing negotiation process.

[Notes_IRSTEA]Guest editorial of symposium on simulation and gaming in natural resource management Special issue, Part I [Departement_IRSTEA]RE [TR1_IRSTEA]GES / USAGES; Guest editorial of symposium on simulation and gaming in natural resource management.

[Notes_IRSTEA]Introduction. Symposium on simulation and gaming in natural resource management Special issue, Part I [Departement_IRSTEA]RE [TR1_IRSTEA]GES / USAGES; Nowadays, computer-mediated simulations and games are widely used in the field of natural resource management (NRM). They have proved to be useful for various purposes such as supporting decisionmaking processes and training. First, the specificities of the NRM research field are highlighted. Then, based on the analysis of the articles presented in this special issue of Simulation & Gaming, some key features related to the implementation of gaming in such a context are introduced. Finally, after reviewing the benefits of using simulation games in NRM, the authors stress the ethical issue of changing social relationships among stakeholders by playing a game with some of them

International audience; A role-playing game (RPG) supported by computer simulations, called BUTORSTAR, has been developed in the context of a LIFE-Nature European Programme (2001-2005) aiming to improve reedbed management for the conservation of a vulnerable heron, the Eurasian Bittern. The agent-based model simulates the impacts of reedbed management resulting from decisions made by farmers, reed harvesters, hunters, and naturalists. The model is based on an archetypal wetland made of a virtual landscape. Different water regimes are proposed, each one adapted to a particular wetland use. Land-use and water-management decisions are made by the players at both estate and management-unit levels. These decisions are entered into the model each year as the results of the negotiation process between the players. This RPG is designed to promote student awareness of (a) biological and hydrological interdependencies and their dynamics on different spatial and temporal scales, (b) the technical and socioeconomic factors involved in the different types of reedbed use, and (c) the usefulness of the negotiation process for establishing collective management rules. It is shown that BUTORSTAR creates a continuum of learning that crosses the traditional boundaries between disciplines and allows players to conduct multipurpose experiments that contribute to their comprehensive understanding of socioecosystems

GIS, graphic modeling and MAS: evolution of a rural system of a french tropical island and its relation to polluting pressure. Changes in agricultural activities have effects on the polluting pressure. In this paper we introduce a methodology to contribute to the knowledge and the modeling of the rural system organizing these activities, as well as to test its evolution. GIS, "chorèmes" and MAS, used jointly, characterize this methodolgy, allowing a local and regional, constructivist and dynamic understanding of the rural system. By doing so, we come to emphasize the role of land ownership and spatial management of exploitations on qualitative and spatial variability of polluting pressure., La mutation des activités agricoles a des répercussions sur la pression polluante exercée sur les sols et les eaux. Nous proposons une démarche pour contribuer à la connaissance du système rural organisateur de ces activités, à sa modélisation et à l'appréhension de sa capacité d'évolution. Cette démarche repose sur l'utilisation d'un SIG, des chorèmes et d'un système multi-agent. Les allers-retours entre ces outils permettent une approche à la fois locale et régionale, aboutissant à une connaissance approfondie du système. Il en ressort le rôle majeur joué par le foncier et le fonctionnement spatial des exploitations dans la variabilité quantitative, qualitative et spatiale de la pression polluante.

Understanding and predicting how bird populations and land cover respond to natural and anthropogenic changes is a major challenge for environmental planning. Multi-agent modelling enables horizontal relationships (spatial configurations) and vertical relationships (socio-economic organisation) to be integrated. GEMACE is a multi-agent model for simulating farming-hunting-duck interactions in the Camargue (Southern France). For an archetypal region, we simulated land-use conversion and ecological change in space and time resulting from the interaction between environment and human drivers. A wintering duck population is simulated and distributed heterogeneously in its habitats. The duck population is affected by various environmental factors such as land-use changes, wetland management, hunting harvest, and disturbance. Land-use decisions are made at farmland level by farmers and hunting managers. Important biophysical drivers are water and salt through land relief, land-use history, infrastructure, spatial neighbourhood, and current land use. Important human drivers are the economic conditions of the world agricultural market and land-use strategy. Through three scenario runs, we discuss the implications that can be drawn from this modelling application with regard to the viability of a spatial conservation management alternative and multi-field research on sustainable development.

La demarche d'accompagnement a un processus de decision sur un territoire, acceptant l'incompletude des analyses ainsi que la subjectivite des choix d'avenir, suggere un repositionnement de l'expertise, et particulierement des systemes d'information pour l'aide a la decision, dans une position plus humble "d'accompagnement" a un processus de decision interne et iteratif. L'enjeu pour l'appui technique n'est alors plus de d'effectuer le "bon" diagnostic, de deceler la "bonne" solution, mais de faire emerger un processus de decision qui soit le plus autonome dans ses progres. Pour cela, la methode d'autoconception des systemes d'information a ete testee. Son hypothese est que le systeme d'information le plus maitrisable et le plus adapte a un acteur sera celui qu'il a concu lui-meme. Ce nouveau type "d'acces" a l'information signifie en consequence que l'utilisateur est rendu capable d'abord d'analyser le systeme d'information, y compris dans ces faiblesses, mais aussi de l'amender et de meme de le concevoir lui-meme selon ses propres perceptions. C'est cette demarche qui a ete applique dans un programme d'experimentations au Senegal, pour la conception endogene d'un support d'accompagnement a la gestion concertee territoriale qui associait SIG, SMA et jeux de roles. (Resume d'auteur)

The increasing importance of individual-based modelling (IBM) in population dynamics has led to the greater availability of tools designed to facilitate their creation and use. Yet, these tools are either too general, requiring the extensive knowledge of a computer language, or conversely restricted to very specific applications. Hence, they are of little help to non-computer expert ecologists. In order to build IBM's without hard coding them nor restricting their scope too much, we suggest a component programming, assuming that each elementary task that forms the behaviour of an individual often follows the same path: an individual must locate and select information in order for it to be processed, then he must update his state, the state of other individuals, or the state of the rest of the ‘world’. This sequence is well suited to translation into elementary computerised components, that we call primitives. Conversely, task building will involve stringing out well-chosen primitives and setting their parameter values or mathematical formulae. In order to restrict the number of primitives and to simplify their use, ‘information’ must be carried through well defined structures. We suggest the use of the multi-agents system paradigm (MAS) which originates from the distributed artificial intelligence and defines agents as autonomous objects that perceive and react to their environment. If one assumes that a model can be described entirely with the help of agents, then primitives only handle agents, agent state or history. This greatly simplifies their conception and enhances their flexibility. Indeed, only 25 primitives, split into six groups (locate, select, translate, compute, end, and workflow control) proved to be sufficient to build complex IBM's or cellular automata drawn from literature. Furthermore, such a primitive-based multi-agents architecture is very flexible and facilitates all the steps of the modelling process, in particular the simulation engine (agents call and synchronisation), the results analysis, and the simulation experiments. Component programming may also facilitate the design of a domain specific language in which these models could be written and exported to other simulation platforms.

The increasing diversity of stakeholders, who often hold differing and conflicting land-use perceptions and strategies, underlines tile growing need for innovative methods and tools to support a negotiation process aimed at an enhanced and more decentralised land-use management policy. Land-use management is a complex issue and thus presents an irreducible uncertainty that entails a variety of legitimate perspectives. Due to this complexity. the decision-making process should be incremental, iterative and continuous. This means that the acts of decision making will always be imperfect but will move progressively closer towards a shared satisfactory resolution. However, which tools will best fit such a theoretical starting point ? Our team is seeking to develop an innovative florin of participatory modelling fitting these hypotheses. As regards regional planning, a novel way to put these assumptions Into practice has been under way since 1997 in the Senegal River Valley. This experiment, called 'Self Cormas', is being conducted to test a directed self-designing of modelling tools Geographic Information Systems (GIS) and Multi-Agent Systems (MAS) by stakeholders and principals. From the initial stages as little prior design work as possible is executed by the modellers. The process has been organised in the form of participatory workshops, including role-playing games, to support a local decentralisation policy at ail operational level (2,500 km2). This sort of accompaniment leads to discussions. appraisals and decisions concerning the planning of land-use management. Just a few months after the first workshops, this process has already culminated in autonomous applications, from local to regional levels.

The issue that is addressed in this paper concerns the way interacting agents should understand their environment so that a common good used by the whole group would last. We synthesise the results of four models with agents interacting in artificial societies in which they have to share a resource. The four societies were built using multi-agent based simulation models that address issues related to the use of common renewable goods. The resources that are used by the artificial communitues of agents are of two types: for some, agents must co-ordinate to exploit the resources; for others, the distribution of goods among agents is directly dependent on the distribution of the agents in space. But that classification cannot necessarily hold: the good use of the resources relies on an even distribution of agents in space, but this can be obtained with individual processes in some cases whereas in others it implies co-ordination too., Cet article s'intéresse aux modes de compréhension de l'environnement par des agents en interaction afin qu'un bien commun en usage dans un groupe soir durable. Nous résumons les résultats de quatre modèles comprenant des agents en interaction dans des sociétés artificielles au sein des quelles ils doivent partager une ressource. Ces quatre sociétés ont été conçues à partir de modèles de simulation basés sur des systèmes multi-agents, dédiés à une question d'usage de biens en propriété commune. Les ressources utilisées par ces communautés d'agents artificielles sont de deux types : pour les unes les agents doivent se coordonner pour exploiter les ressources ; pour les autres, la distribution de biens parmi les agents dépend uniquement de leur distribution spatiale. Mais cette classification ne peut pas toujours tenir : le bon usage des ressources dépend d'une distribution régulière des agents dans l'espace, ce qui peut être obtenu par des processus individuels dans certains cas alors que dans d'autres cas cela implique aussi une coordination.

We present a simulator designed to help scientists who are not experts in computing, such as biologists, to build up, run, and update their models in the field of fish population dynamics. This simulator, written in Smalltalk, is built upon multi-agents concepts and is well suited to model systems where individual or spatial aspects are involved. It provides tools to set the state and the behavior of the agents and to set their environment. The pre-defined components should preferably be used, but help for customizing components or programming new ones i s supplied, in order to build more complex agents. The simulator manages qualitative and quantitative variables with simple or composed units, dependencies on parameters, synchronous and asynchronous modes within and between agents, and the importation of ASCII files for the scenario scripts or for the initial stocking of the agents. Four examples of applications are presented.

International audience; This paper describes how the Cormas platform has been used for 12 years as an artefact to foster learning about agent-based simulation for renewable resource management. Among the existing generic agent-based simulation platforms, Cormas occupies a tiny, yet lively, place. Thanks to regular training sessions and an electronic forum, a community of users has been gradually established that has enabled a sharing of ideas, practices and knowledge, and the emergence of a genuine community of practice whose members are particularly interested in participatory agent-based simulation.