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Complexity and Ecosystem Management: The Theory and Practice of Multi-agent Systems

Janssen, M.A. (ed.) 2002
Edward Elgar Publishers, Cheltenham UK/ Northampton, MA, USA

Journal Articles

Valuation of the Leuser Ecosystem in Sumatra

Beukering, P.J.H. van, H.S.J. Cesar and M.A. Janssen

2002 Asean Biodiversity 2(2): 17-20.

Organic food consumption: a multi-theoretical framework of consumer decision making

Vindigni, G., M.A. Janssen and W. Jager

2002 British Food Journal 104: 624-642.


An approach is introduced to combine survey data with multi-agent simulation models of consumer behaviour to study the diffusion process of organic food consumption. This methodology is based on rough set theory, which is able to translate survey data into behavioural rules. The topic of rule induction has been extensively investigated in other fields and in particular in learning machine, where several efficient algorithms have been proposed. However, the peculiarity of the rough set approach is that the inconsistencies in a data set about consumer behaviour are not aggregated or corrected since lower and upper approximation are computed. Thus, we expect that rough sets theory is suitable to extract knowledge in the form of rules within a consistent theoretical framework of consumer behaviour.


How uncertainty stimulates over-harvesting in a resource dilemma: three process explanations

Jager, W., M.A. Janssen and C.A.J. Vlek

2002 Journal of Environmental Psychology 22(3): 247-263.


We report on a series of computer simulation experiments regarding the management of a common resource. We were particularly interested in the effects of uncertainty and satisfaction on the harvesting behaviour of simulated agents. The experimental study of long-term dynamics of threatened resources can hardly be carried out using human subjects. We therefore experimented with simulated consumers, the so-called consumats, whose properties are derived from a comprehensive, multitheoretical model of consumer behaviour. A consumat is equipped with needs and abilities, and may engage in different cognitive processes, such as deliberation, social comparison, imitation, and repetition of previous behaviour. In a first simulation experiment we show as to how uncertainty may stimulate an imitation effect that promotes over-harvesting. In two subsequent series of experiments, we show that increased uncertainty results in an increased ‘optimism’ of consumats regarding future outcomes, an increased likelihood of imitative behaviour, and a lesser adaptation of harvesting behaviour during resource depletion. These ‘process-effects’ promote higher levels of harvesting from a collective resource. The main experimental conclusions and the issue of validating simulation results are discussed.


The roles of computer models in the environmental policy life cycle

van Daalen, C.E., L. Dresen and M.A. Janssen

2002 Environmental Science and Policy 5(3): 221-231.


In this article, we identify four typical roles played by computer models in environmental policy-making, and explore the relationship of these roles to different stages of policy development over time. The four different roles are: models as eye-openers, models as arguments in dissent, models as vehicles in creating consensus and models for management. A general environmental policy life cycle is used to assess the different roles models play in the policy process. The relationship between the roles of models and the different stages of the policy life cycle is explored with a selection of published accounts of computer models and their use in environmental policy-making.

Keywords: Computer models; Environmental policy; Policy life cycle; Policy process


Stimulating diffusion of green products, co-evolution between firms and consumers

Janssen, M.A. and W. Jager

2002 Journal of Evolutionary Economics  12(3): 283-306.


This paper presents a model-based analysis of the introduction of green products, which are products with low environmental impacts. Both consumers and firms are simulated as populations of agents who differ in their behavioural characteristics. Model experiments illustrate the influence of behavioural characteristics on the success of switching to green consumption. The model reproduces empirical observed stylised facts and shows the importance of social processing and status seeking in diffusion processes. The flexibility of firms to adapt to new technology is found to have an important influence on the type of consumers who change their consumption to green products in the early phase of the diffusion process.

Keywords: Diffusion processes – Consumer behaviour – Social networks – Service economy


Resilience management in social-ecological systems: a working hypothesis for a participatory approach

Walker, B., S. Carpenter, J.M. Anderies, N. Abel, G. Cumming, M.A. Janssen, L. Lebel, J. Norberg, G. Peterson and R. Pritchard

2002 Conservation Ecology 6(1): 14.


Approaches to natural resource management are often based on a presumed ability to predict probabilistic responses to management and external drivers such as climate. They also tend to assume that the manager is outside the system being managed. However, where the objectives include long-term sustainability, linked social-ecological systems (SESs) behave as complex adaptive systems, with the managers as integral components of the system. Moreover, uncertainties are large and it may be difficult to reduce them as fast as the system changes. Sustainability involves maintaining the functionality of a system when it is perturbed, or maintaining the elements needed to renew or reorganize if a large perturbation radically alters structure and function. The ability to do this is termed “resilience.” This paper presents an evolving approach to analyzing resilience in SESs, as a basis for managing resilience. We propose a framework with four steps, involving close involvement of SES stakeholders. It begins with a stakeholder-led development of a conceptual model of the system, including its historical profile (how it got to be what it is) and preliminary assessments of the drivers of the supply of key ecosystem goods and services. Step 2 deals with identifying the range of unpredictable and uncontrollable drivers, stakeholder visions for the future, and contrasting possible future policies, weaving these three factors into a limited set of future scenarios. Step 3 uses the outputs from steps 1 and 2 to explore the SES for resilience in an iterative way. It generally includes the development of simple models of the system’s dynamics for exploring attributes that affect resilience. Step 4 is a stakeholder evaluation of the process and outcomes in terms of policy and management implications. This approach to resilience analysis is illustrated using two stylized examples.


Rangelands, pastoralists and governments: inter-linked systems of people and nature

Walker, B.H. and M.A. Janssen

2002 Philosophical Transactions of the Royal Society London: Biological Sciences 357(1421): 719-725.


We analyse commercially operated rangelands as coupled systems of people and nature. The biophysical components include: (i) the reduction and recovery of potential primary production, re ected as changes in grass production per unit of rainfall; (ii) changes in woody plants dependent on the grazing and re regimes; and (iii) livestock and wool dynamics in uenced by season, condition of the rangeland and numbers of wild and feral animals. The social components include the managers, who vary with regard to a range of cognitive abilities and lifestyle choices, and the regulators who vary in regard to policy goals.

We compare agent-based and optimization models of a rangeland system. The agent-based model leads to recognition that policies select for certain management practices by creating a template that governs the trajectories of the behaviour of individuals, learning, and overall system dynamics. Conservative regu- lations reduce short-term loss in production but also restrict learning. A free-market environment leads to severe degradation but the surviving pastoralists perform well under subsequent variable conditions. The challenge for policy makers is to balance the needs for learning and for preventing excessive degra- dation. A genetic algorithm model optimizing for net discounted income and based on a population of management solutions (stocking rate, how much to suppress re, etc.) indicates that robust solutions lead to a loss of about 40% compared with solutions where the sequence of rainfall was known in advance: this is a similar gure to that obtained from the agent-based model.

We conclude that, on the basis of Levin’s three criteria, rangelands with their livestock and human managers do constitute complex adaptive systems. If this is so, then command-and-control approaches to rangeland policy and management are bound to fail.

Keywords: rangelands; complex adaptive system; resilience; institutions; agent-based models


Progress in integrated assessment and modelling

Parker, P., R. Letcher, A. Jakeman, M. B. Beck, G. Harris, R. M. Argent, M. Hare, C. Pahl-Wostl, A. Voinov, M. Janssen et al.

2002 Environmental Modelling and Software 17(3): 209-217.


Environmental processes have been modelled for decades. However, the need for integrated assessment and modeling (IAM) has grown as the extent and severity of environmental problems in the 21st Century worsens. The scale of IAM is not restricted to the global level as in climate change models, but includes local and regional models of environmental problems. This paper discusses various definitions of IAM and identifies five different types of integration that are needed for the effective solution of environmental problems. The future is then depicted in the form of two brief scenarios: one optimistic and one pessimistic. The current state of IAM is then briefly reviewed. The issues of complexity and validation in IAM are recognised as more complex than in traditional disciplinary approaches. Communication is identified as a central issue both internally among team members and externally with decision-makers, stakeholders and other scientists. Finally it is concluded that the process of integrated assessment and modelling is considered as important as the product for any particular project. By learning to work together and recognise the contribution of all team members and participants, it is believed that we will have a strong scientific and social basis to address the environmental problems of the 21st Century.

Keywords: Integrated assessment and modelling; Integration; Communication; Multi-disciplinary teams


Grazing management, resilience and the dynamics of a fire driven rangeland system

Anderies, J.M., M.A. Janssen and B.H. Walker

2002 Ecosystems 5(1): 23-44.


We developed a stylized mathematical model to explore the effects of physical, ecological, and economic factors on the resilience of a managed fire-driven rangeland system. Depending on grazing pressure, the model exhibits one of three distinct configurations: a fire-dominated, grazing-dominated, or shrub-dominated rangeland system. Transaction costs and costs due to shrub invasion, via their effect on grazing decisions, strongly influence which stable configuration is occupied. This, in turn, determines the resilience of the rangeland system. These results are used to establish conditions under which management for profit is consistent with the maintenance of resilience.

Keywords: resilience; rangelands; multiple states; complex systems.


Faciliteren van zelfregulerend waterbeheer: inbedding van conflicterende functies van water in een schaarse ruimte

Goosen, H. and M.A. Janssen

2002 Landschap 19: 77-86.

Belastend Materiaal

Van den Bergh, J.C.J.M, H. Verbruggen and M.A. Janssen

2002 Economische Statistische Berichten 87: 783-785.

Book Chapters

A future of surprises

Janssen, M.A.

2002 In Panarchy: Understanding Transformations in Human and Natural Systems, edited by L. Gunderson and C.S. Holling, pp. 241-260, Island Press.

Modeling human dimensions of global environmental change

Janssen, M.A.

2002 In Encyclopedia of Global Environmental Change, edited by T. Munn, Vol. 5: Social and economic dimensions of global environmental change, by P. Timmerman (ed.), pp. 394-408, John Wiley and Sons Ltd, London, UK.

An application of immunocomputing to the evolution of rules for ecosystem management

Janssen, M.A. and D. Stow

2002 In Proceedings of the 2002 Congress on Evolutionary Computation, pp. 687-692, Institute of Electrical and Electronics Engineers (IEEE), Piscataway, NJ, USA.


This paper discusses the evolution of rules between people for the management of ecosystems. Four aspects of the rules are discussed: coding, creation, selection, and memory. The immune system provides us a useful metaphor to relate these four aspects into a coherent framework. We sketch a framework for a computational model to study the evolution of rules for the management of ecosystems.


Complexity and Ecosystem Management: The Theory and Practice of Multi-agent Systems

Janssen, M.A. (Introduction)

2002 In Complexity and Ecosystem Management: The Theory and Practice of Multi-agent Systems, edited by Janssen, M.A., pp. 1-10, Edward Elgar Publishers, Cheltenham UK/ Northampton, MA, USA.

Changing the rules of the game: lessons from immunology and linguistics for self-organization of institutions

Janssen, M.A.

2002 In Complexity and Ecosystem Management: The Theory and Practice of Multi-agent Systems, edited by M.A. Janssen, pp. 35-47, Edward Elgar Publishers, Cheltenham UK/ Northampton, MA, USA.

Using artificial agents to understand laboratory experiments of common-pool resources with real agents

Jager, A. and M.A. Janssen

2002 In Complexity and Ecosystem Management: The Theory and Practice of Multi-agent Systems, edited by Janssen, M.A., pp. 75-102, Edward Elgar Publishers, Cheltenham UK/ Northampton, MA, USA.

Implications of spatial heterogeneity of grazing pressure on the resilience of rangelands

Janssen, M.A., J.M. Anderies, M. Stafford Smith and B.H. Walker

2002 In Complexity and Ecosystem Management: The Theory and Practice of Multi-agent Systems, edited by Janssen, M.A., pp. 103-124, Edward Elgar Publishers, Cheltenham UK/ Northampton, MA, USA.


Methodological Considerations for Agent-Based Modeling of Land-Use and Land-Cover Change

Berger, T., M. Goodchild, M.A. Janssen, S.M. Manson, R. Naijlis, and D.C. Parker
2002 p. 7-25, in Agent-Based Models of Land-Use and Land-Cover Change, D.C. Parker, T. Berger and S.M. Manson (eds.), LUCC Report Series No. 6, Louvain-la-Neuve, Belgium. [this description does not match the pdf file attached: Meeting the challenges of complexity]

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