Presenter/Author Information

Michel Etienne
Christophe Le Page

Keywords

natural resource management, agent-based simulation, multi-agent system, spatial entities

Start Date

1-7-2002 12:00 AM

Description

In Southern France, the Causse Méjan is a natural ecosystem of high biological diversity. Sheep farmers, foresters, and a National Park are interacting in this land subject to pine encroachment by Pinus sylvestris and P. nigra at different temporal and spatial scales. The stakeholders are concerned by this global biological process although it affects their management goals (sheep production, timber production, nature conservation) in very different ways. An agent-based model has been built with the Cormas platform. Vegetation changes in terms of structure, composition and productivity were simulated by a cellular automata that was initialised as a spatial grid of 5726 cells representing each 4 ha and incorporating GIS data from 1990 on vegetation structure and composition and topography. The global landscape dynamics results from a combination of the natural vegetation dynamics processes related to pine dispersion and the operations performed by three kind of agents. 37 sheep farmer agents are initialised from a database. Their grazing management strategy is based on their production system, grazing pressure, distance to the shed, and their environmental awareness. The strategies of the two forester agents are related to the forest land tenure and the legal constraints to afforestation management. A National Park agent is devoted to pine trees control according to the land's value -in terms of flora and fauna- and the maintenance of open landscapes. This paper particularly emphasises the usefulness of defining spatial entities at different levels, to describe the natural dynamics processes and to integrate the specific way each agent represents its environment to determine what to do and where. The model may be used as a stimulating tool to let the stakeholders exchange their feelings about the process of pine encroachment. If this approach is successful, it may lead to the development of common land management strategies.

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Jul 1st, 12:00 AM

Modelling contrasted management behaviours of stakeholders facing a pine encroachment process: an agent-based simulation approach

In Southern France, the Causse Méjan is a natural ecosystem of high biological diversity. Sheep farmers, foresters, and a National Park are interacting in this land subject to pine encroachment by Pinus sylvestris and P. nigra at different temporal and spatial scales. The stakeholders are concerned by this global biological process although it affects their management goals (sheep production, timber production, nature conservation) in very different ways. An agent-based model has been built with the Cormas platform. Vegetation changes in terms of structure, composition and productivity were simulated by a cellular automata that was initialised as a spatial grid of 5726 cells representing each 4 ha and incorporating GIS data from 1990 on vegetation structure and composition and topography. The global landscape dynamics results from a combination of the natural vegetation dynamics processes related to pine dispersion and the operations performed by three kind of agents. 37 sheep farmer agents are initialised from a database. Their grazing management strategy is based on their production system, grazing pressure, distance to the shed, and their environmental awareness. The strategies of the two forester agents are related to the forest land tenure and the legal constraints to afforestation management. A National Park agent is devoted to pine trees control according to the land's value -in terms of flora and fauna- and the maintenance of open landscapes. This paper particularly emphasises the usefulness of defining spatial entities at different levels, to describe the natural dynamics processes and to integrate the specific way each agent represents its environment to determine what to do and where. The model may be used as a stimulating tool to let the stakeholders exchange their feelings about the process of pine encroachment. If this approach is successful, it may lead to the development of common land management strategies.