Modelling the Interactions between Ecological and Social Dynamics
description
Transcript of Modelling the Interactions between Ecological and Social Dynamics
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Modelling the Interactions between
Ecological and Social Dynamics
in Integrated Natural Resources Management
The usefulness of
Multi-Agent Systems (MAS)
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MAS and Natural Resources Management
A spatial grid
some entities holding natural resources with their own dynamics
Some entities representing management units
Several agents using or managing the resources hold by the environment
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MAS and Natural Resources Management
Behaviours and interactions at different levels of organisation
Investigating collective organisation modes and collective decision making processes (testing contrasted scenarios)
A modelling approach to build common representations of a system shared by the stakeholders (scientists, local people, policy makers, politicians)
Adaptive models (run-time modifications) for adaptive management
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A “Companion” Modelling Approach
model
field
simulations
hypothesisquestions
Experiments’ plan
discussion of hypothesisnew questions
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Interacting withDecision Making Processes
model
field
simulations
Decision Making Processes
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Which future for the Causse Méjan grasslands ?
Michel ETIENNE, Christophe LE PAGEINRA, CIRADAVIGNON, MONTPELLIER (France)
A multi-agent approach to solve environment and land management problems
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1950
2000
The current land dynamics
cereals, hay
grasslands
Natural increase ofWoodland pines
afforestation
population
?
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Historical context
Plantations or spontaneous encroachment of pine are not manage
The encroachment and the reafforestations of adults are or enter in phase of dispersion
Original grasslands (anthropological origin) are threatened
Breeders, foresters and defenders of the nature express multiple and often conflicting social demands
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pineencroachment sheep
farmpine
afforestation
native grasslands
croplands
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The questions
How to imagine landscape changes in a man-made natural environment according to contrasting strategies of land management ?
How to account simultaneously for productive and heritage stakes ?
How to support the concertation between agents concerned by the same ecological dynamics ?
11 … or afforestations
Encroachment as a pioneer front from
…native woodlands ...
The ecological process 1
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… > 15 year-old Scots pines
Encroachment from isolated … > 30 year-old black pines ...
The ecological process 2
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Seed catchment 2
Dispersal model
ridge 1
ridge 2
Any grassland cell under the wind is invaded
Any cell far from the seed-bearersbut located inside their seed catchmenthas a probability to be invaded related
to grazing presssure
Any cell where mature trees are growing upand located at the eastern edge of a catchment
is capable to send seeds to the following catchment
Scots pine over15 years-oldor black pine over 30 years-old
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The agent-based approach
To represent the bare zone of the Causse Méjan on the basis of the current scientific knowledge on the ecological dynamics and the pratices of the local agents (MAS 1)
To make this formalisation accessible to the local agents and share a certain representation of the system with them (Simplified MAS)
To stimulate reactions of stakeholders facing a virtual situation that is close to their reality (pine encroachment) (Role game)
To collectively imagine possible management scenarios and to assess their consequences (MAS 1)
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the MAS conception
A territory defined by combining vegetation structures that shelter different resources according to the agents
tree + shrub + grassland
shrub + grassland
tree + shrub
grassland
tree + grassland
crop
tree
shrub
4 ha/cell
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the MAS conception
Three categories of agents with diverse objectives but which practices modify clearly the pine tree dynamics
Farmers who wish to continue living from sheep husbandry on the Causse
Foresters who wish to make profit from investments realised 30 years ago
Conservationists who are missioned to conserve a very rich but very instable environment
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Sheep farmer (ewes/cell/year)
Productive impacts
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0,5
1,5
2,5
0
2,5
0
5
Forester (m3/ha)
0
20 à 50
50 à 100
0
20 à 50
10 à 20
100 à 300
0
BlackPine
0
10 à 30
30 à 50
0
10 à 30
1 à 5
50 à 100
0
Scots pine
big + small trees, low density
small trees, low density
big + small trees, high density
grassland
a few big trees
a few small trees
big trees, high density
big trees, low density
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Ecological impact on protected flora
disappearance of Gagea pratensis, Adonis vernalis
disappearance of Gentiana clusii
disappearance of Orchis coriophora
disappearance of all protected species
disappearance of Gagea villosa
disappearance of Saponaria bellidifolia
no disappearance
no disappearance
small trees, low density
big + small trees, high density
grassland
a few big trees
a few small trees
big trees, high density
big trees, low density
big + small trees, low density
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Ecological impact on fauna
+ than 25 % on 6 cells
+ than 50 % on 6000 cells
+ than 10 % of pine canopy cover on 1 cell
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Modelling farmers
A farm defined by an equilibrium between crops, rangelands and forests
A certain amount of work for controlling pine trees
Sheep rearing practices using more or less rangelands according to their production system
Forestry pratices linked with the availability of incentives
Land tenure fixed until retirement A plausible future for the farm after retirement
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Farmers actions
Balance
Zoning
Evaluating range condition
Grazing
Consuming forage
AdjustingAdapting grazing pressure
Intervening or not
on pine trees
Uprooting or mowingThinning or felling
Negociating or not with the partners
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Grassland
Paddock
Shrubland
Grassland with young pines
Crop
Grassland with pines
Wood
Schematic representation of a Farm
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Paddocks
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Modelling conservationists
A landscape to conserve defined by a strong dominance of « open land»
Law regulations An ability to get financial support for the
control of pine encroachment A clear vision of the fauna, flora and landscape
stakes A small owned land An ability to influence public policy
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Conservationists actions
Zoning
Locating zones with high heritage valueor farmers with good practices
Choosing
Moving to the most intesresting zone
Visiting other problematic cells
Scanning
Clearing
Uprooting the pine trees
Balance / survey
Deciding or not to continue to
clear pine trees
Negociating or not with the partners
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Modelling foresters
Management units determined according to the origin of the pine stands (afforestation, natural encroachment)
Regimented woodlands Woodlands divided into woodlots in order to plan
the forest management more easily An ability to liberate capital and work force to plant
and exploit pine trees A productive vision of pine trees A patchy and extending land tenure
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Foresters actions
Balance
Inventory
Evaluating pine stands condition
Thinning and/or Harvesting
Making profit from timber production
PlanningScheduling an operation calendar
Deciding or not to go on
producing pine
Planting or not
Negotiating or not withthe partners
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7 land management strategies
let nature work let farmers and foresters worklet save the heritage hotspotslet block the ecological processLet associate naturalists and farmersLet develop silvopastoralismLet recreate the steppe
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Comparing three scenariosaccording to the “vegetation” point of view
Let Nature work
Silvopastoralismconcerted with naturalists
Let recreate the steppe
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Different points of view for a same simulation
Timber production(forester)
Cutting small pines(farmers - PNC)
Heritage interest(PNC)
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The role playing game conception
The land is described by a cellular-automata able to simulate the vegetation dynamics according to the applied management
the players, on the spatial entities they are used to manage and according to the results of the negotiations they decide to conduct as their territory is changing
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Simplification of the model
The constraints of a ludic application to reduce the time of playing and the role of the
computers to simulate at least 25 years of vegetation dynamics to warranty the participation of 4 sheep farmers (1 per
type) 2 naturalists and 1 forester (maximum 10, 5 et 2)
The need to simplify the representations a smaller land same size and characteristics of the farms simple indicators adapted to the players uses
The adaptation of the rules same rules on vegetation dynamics completely open negotiations
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The game land
2000 cells (5 ha/cell) defining... a serie of pine seed dispersion catchments
submitted to a nort-western wind,and agreggated into 10 sheep farms
composed of 50 ha of croplands, 8 paddocks of 50 ha of rangelands, shrublands and woodlands
3 private forests and 1 hunting groundgrasslands and croplands shelter many
endangered species
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forest
shrublands
steppe
crops
+ +
+
+
+
Natural resources
each color corresponds to the overlapping of vegetation layers
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The farmer land
grasslands
a paddock
shrublands
grasslands spottedwith pine trees
croplands
grasslands invadedby pine trees
woodlands
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The conservationist markers
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indffpratio
j coupes
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After a brief introductionto the game rules
meanwhile the PNC analysesthe land on the computer
The game setting 1
each farmer receivesa farm ...
…and moves to his tablewith an observer...
...in order to elaboratethe grazing calendar
10 minutes laterthe grazing calendar
is put into the computer
and the land dynamicsis simulated
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The game setting 2
Each farmer receivesa new map of
his farm
and thinks aboutthe strategy to develop
with the pine trees
meanwhile the PNCset up a negotiation strategy
Then for 10 minutesnaturalists, foresters
and farmers negotiate
Lastly the operationsplanned during the negotiation
are put into the computer
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To make easier the modelling of the interaction between players
To share collectively a representation of the pine encroachment process
To leave totally open the players creativity to develop original strategies of operation and negotiation
A role playing game (RPG)...
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The MAS permits to test several options of the pine dynamics management and to visualise it according to different view-points
The coupling with a role playing game permits to imagine plausible adaptation strategies of the agents practices to an unusual ecological process
and to elaborate new markers into the MAS in order to better account for the way the agents perceive the pine trees
The feed-back between MAS and RPG
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Perspectives
to compare the impact of contrasting land planning policies on the state of Nature and on the dynamics of farm and forestry activities
to stimulate a collective awareness of environmental problems and to identify the main conflictual points between the agents
to support long term planning during collective negotiations on the management of so-called natural resources
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Reality
the National Park created a fund to support the preventive control of pine encroachment
The Chambre d’Agriculture and the Communauté de Communes set up a collective reflexion on the problem of pine trees
A Local Concerted Management Plan was elaborated and financed to pay collectively planned operations
The Forest Service and the National Park are looking for new procedures to permit anticipated interventions on stratgic ridges
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An Approach Combining an Agent-Based Modeland a Role-Playing Game
Applied Agent-Based
model
1.Expert knowledge
Role game
2.Social validationCollective and adaptive learning
3.Collectivelydiscussed scenarios
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Combining ABM and RpG
to produce and collect information and knowledge about behaviours,
to present and explain the model to the stakeholders, and to validate it,
to test scenarios and compare them, by the mean of simulation
Building a common representation
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Experiments Irrigated schemes in Senegal
Land allocation between grazing and rice cropping activities in Senegal
Negotiations between a shepherd and a forester in a Mediterranean ecosystem
Discussions between foresters, shepherds and a national park in an ecosystem facing pine encroachment (South of France),
Agricultural land-use in North-Vietnam,
Environmental mediation about phytogenetics resources management in Madagascar