ACE/ABM Research Area:
Coupled Natural and Human Systems

Last Updated: 16 January 2023

Site Maintained By: Leigh Tesfatsion Research Professor & Professor Emerita of Economics Courtesy Research Professor of Electrical & Computer Engineering Heady Hall 260 Iowa State University Ames, Iowa 50011-1054 http://www2.econ.iastate.edu/tesfatsi/ tesfatsi AT iastate.edu ACE Website ACE Course (Self-Study eBook)

Table of Contents: Basic Issues Overviews General Readings Elinor Ostrom CNH Systems Research (2009 Nobel Prize Winner) Software, Toolkits, and Demos Resource Sites, Groups, & Early Individual Researchers

Basic Issues

• Long-term sustainability of coupled natural and human (CNH) systems
• Tragedy of the commons (over-use by humans of common natural resources)
• Impacts of alternative rules and regulations on CNH systems
• Evolution of institutions for collective action in CNH systems
• Possible extinction of specific cultures (e.g., the Anasazi) due to drought and other natural causes
• Extending traditional approaches to the study of natural systems to include humans in the loop (economic geography, socio-hydrology, ...)

Overviews

• Li An, "Modeling Human Decisions in Coupled Human and Natural Systems: Review of Agent-Based Models" (pdf,713KB), Ecological Modelling, Vol. 229 (March), 2012, 35-30.

• Christian J. E. Castle and Andrew T. Crooks, "Principles and Concepts of Agent-Based Modelling for Developing Geospatial Simulations" (pdf,1M), UCL Working Paper Series, Paper 110, UCL Centre For Advanced Spatial Analysis, University College London, 2006.

• J. Doyne Farmer, Cameron Hepburn, Penny Mealy, Alexander Teytelboym, "A Third Wave in the Economics of Climate Change" (pdf,853KB), Environmental Resource Economics, Vol. 62, 2015, 329-357.

  Abstract: The authors argue that four key isses remain inadequately addressed by economic models of climate change, namely: (1) uncertainty; (2) aggregation, heterogeneity, and distributional implications; (3) technological change; and (4) realistic damage functions for the economic impact of the physical consequences of climate change. Following a survey of two-generations of climate-change models, the authors consider the potential of two more recent candidate approaches -- dynamic stochastic generation equilibrium (DSGE) modeling, and agent-based modeling (ABM).

• Tatiana Filatova, Peter H. Verburg, Dawn Cassandra Parker, and Carol Ann Stannard, "Spatial Agent-Based Models for Socio-Ecological Systems: Challenges and Prospects" (pdf,117KB), Environmental Modelling and Software, Vol. 45, July 2013, 1-7.

• Volker Grimm and Steven F. Railsback, Individual-Based Modeling and Ecology (Book Site), Princeton University Press, Princeton, NJ, Spring 2005.

  Abstract: "This book is the first major reference on individual-based modeling and its use to develop the theoretical understanding of how ecological systems work, an approach the authors call `individual-based ecology.' The book first provides a general primer on modeling: how to design models that are as simple as possible while still allowing us to address the problems we need to study, and how to move us to address the problems we need to study, and how to move efficiently through a cycle of model design, implementation, and analysis. Next, the general problems of theory and conceptual framework for individual-based ecology are addressed... A review of over 30 studies illustrates the wide variety of ecological problems that have already been addressed with individual-based models."

• Auke Hoekstra, Maarten Steinbuch, and Geert Verbong, Creating Agent-Based Energy Transition Management Models that Can Uncover Profitable Pathways to Climate Change Mitigation (pdf,3.5MB), Complexity, Hindawi, Volume 2017, Article ID 1967645, 23pp. https://doi.org/10.1155/2017/1967645

  Abstract: "The energy domain is still dominated by equilibrium models that underestimate both the dangers and opportunities related to climate change. In reality, climate and energy systems contain tipping points, feedback loops, and exponential developments. This paper describes how to create realistic energy transition management models: quantitative models that can discover profitable pathways from fossil fuels to renewable energy. ... The agent-based approach is found to be uniquely suited for the complex adaptive sociotechnical systems that must be modelled. But the choice for agent-based models does not mean a rejection of other approaches because they can be accommodated within the agent-based framework. We conclude with practical guidelines."

• William Kaye-Blake, Frank Y. Li, A. McLeish Martin, Alan McDermott, Scott Rains, Steve Sinclair, Annette Kira, "Multi-Agent Simulation Models in Agriculture: A Review of Their Construction and Uses" (pdf,457KB), Agribusiness and Economics Research Unit (AERU), Research Report No. 318, Lincoln University, Christchurch, New Zealand, March 2010.

• Jianguo Liu et al., "Complexity of Coupled Human and Natural Systems" (article site), Science 317, 2007, 1513-1516. DOI: 10.1126/science.1144004

  Abstract: Integrated studies of coupled human and natural systems reveal new and complex patterns and processes not evident when studied by social or natural scientists separately. Synthesis of six case studies from around the world shows that couplings between human and natural systems vary across space, time, and organizational units. They also exhibit nonlinear dynamics with thresholds, reciprocal feedback loops, time lags, resilience, heterogeneity, and surprises. Furthermore, past couplings have legacy effects on present conditions and future possibilities.

• James Nolan, Dawn Parker, G. Cornelis van Kooten, and Thomas Berger, "An Overview of Computational Modeling in Agricultural and Resource Economics" (pdf,200KB), Canadian Journal of Agricultural Economics 57(4), December 2009, 417-429.

  Abstract: The authors provide numerous examples of collaborative, multimethod research related to collective action and the commons. They examine the pros and cons of case studies, meta-analyses, large-N field research, experiments and modeling, and empirically grounded agent-based models, and they consider how these methods contribute to research on collective action for the management of natural resources. Using their findings, the authors outline a revised theory of collective action that includes three elements: individual decision making, microsituational conditions, and features of the broader social-ecological context.

• Billie L. Turner II et al., "Land System Science and the Social-Environmental System: The Case of Southern Yucatán Peninsular Region (SYPR) Project," Current Opinion in Environmental Sustainability, Vol. 19, 2016, 18-29. Available online at ScienceDirect.

  Abstract: "Land system science axiomatically addresses social-environmental systems by integrating the dynamics of land uses (social) and land covers (environment), invariably including the use of remote sensing data and often, spatially explicit models of land change. This kind of research is illustrated through the Southern Yucatán Peninsular Region project (1997–2008) aimed at understanding, predicting, and projecting spatially explicit land change in a region with juxtaposed land uses-agriculture and a biosphere reserve."

• John Wainwright and Mark Mulligan (Eds.), Environmental Modelling: Finding Simplicity in Complexity, Second Edition, John Wiley & Sons, Ltd, 2013. Print ISBN: 9780470749111; Online ISBN: 9781118351475; DOI: 10.1002/9781118351475

  Publisher Abstract: "Simulation models are an established method used to investigate processes and solve practical problems in a wide variety of disciplines. Central to the concept of this second edition is the idea that environmental systems are complex, open systems. The authors present the diversity of approaches to dealing with environmental complexity and then encourage readers to make comparisons between these approaches and between different disciplines."

• Robert Wallace, Amy Geller, and V. Ayano Ogawa (Eds.), Assessing the Use of Agent-Based Models for Tobacco Regulation, 2015 Report, Institute of Medicine of the National Academies, Washington, D.C. Available by title search from the National Academies Press.

  Note: For a thoughtful constructive discussion of presentation and evaluation issues for agent-based models developed for policy use, see: (i) Chapter 3: "Building Effective Models to Guide Policy Decision Making" (pdf,275KB); (ii) Chapter 4: "An Evaluation Framework for Policy-Relevant Agent-Based Models" (pdf,309KB); and (iii) Chapter 6: "Data and Implementation Needs for Computational Modeling for Tobacco Control" (pdf,270KB).

General Readings

• Special issue of the Journal of Artificial Societies and Social Simulation (JASSS) on Agent-Based Modelling, Game Theory, and Natural Resource Management Issues (html), Volume 4, No. 2, March 2001. (Abstracts and full texts of papers for this electronic journal are freely available online.)

• Shady Atallah, Miguel Gómez, Jon Conrad and Jan Nyrop, "An Agent-Based Computational Bioeconomic Model of Plant Disease Diffusion and Control: Grapevine Leafroll Disease" (pdf,1.2MB), Working Paper WP 2013-11, Cornell University (Dyson), February 2013.

  Abstract: Grapevine leafroll disease threatens grape harvests in the United States and around the world. This viral disease reduces yield, delays fruit ripening, and affects wine quality. Its spatial-dynamic diffusion process remains poorly understood and little is known about profit-maximizing control strategies. In this article, we model the disease spatial-dynamic diffusion in a vineyard, evaluate nonspatial and spatial control strategies, and rank them based on expected net present values.

• Paul Charteris, Bruce L. Golden, and Dorian J. Garrick, "Livestock Breeding Industries as Complex Adaptive Systems", Proceedings of the 14th Conference of the Association for the Advancement of Animal Breeding and Genetics," Vol. 14, 2001, 461-464.

• Stephen J. DeCanio, Economic Models of Climate Change: A Critique, Palgrave (Macmillan), 224pp., August 2003, ISBN: 1-4039-6336-3 (paperback).

  Publisher Abstract: "The climate policy debate has been dominated by economic estimates of the costs of policies to reduce greenhouse gas emissions. Yet the models used to derive those estimates are based on assumptions that have largely gone untested. The conventional approach embodies structural features that rule out alternative market outcomes and possibilities for profitable energy-efficiency improvements in industry. The models' characterizations of decision-making by individuals and firms is seriously incomplete and in many cases inconsistent with the empirical evidence. In addition, the pattern of distribution of `climate rights' is crucial to determining the economic consequences of different ethical approaches to the problem of intergenerational equity. Bringing these considerations to the forefront shows how domestic and international policy solutions might be found. DeCanio concludes that a much more active approach to climate protection is justified."

  Stephen J. DeCanio is Professor of Economics at the University of California, Santa Barbara.

• Volker Grimm and others, "Pattern-Oriented Modeling of Agent-Based Complex Systems: Lessons from Ecology", Science, 11 November 2005, Vol. 310, No. 5750, pp. 987-991. Published article accessible here with Science subscription.

  Abstract: Agent-based complex systems are dynamic networks of many interacting agents; examples include ecosystems, financial markets, and cities. The search for general principles underlying the internal organization of such systems often uses bottom-up simulation models such as cellular automata and agent-based models. No general framework for designing, testing, and analyzing bottom-up models has yet been established, but recent advances in ecological modeling have come together in a general strategy we call pattern-oriented modeling. This strategy provides a unifying framework for decoding the internal organization of agent-based complex systems and may lead toward unifying algorithmic theories of the relation between adaptive behavior and system complexity.

• Atakelty Hailu and Steven Schilizzi, "Learning in a `Basket of Crabs' An Agent-Based Computational Model of Repeated Conservation Auctions" (pdf,229KB), Discussion Paper, School of Agriculture and Resource Economics, The University of Western Australia, 2003. Accessed on 5/19/03.

  Abstract: "Auctions are increasingly being considered as a mechanism for allocating conservation contracts to private landowners. This interest is based on the widely held belief that competitive bidding helps minimize information rents. This study constructs an agent-based model to evaluate the long term performance of conservation auctions under settings where bidders are allowed to learn from previous outcomes. The results clearly indicate that the efficiency benefits of one-shot auctions are quickly eroded under dynamic settings. Furthermore, the auction mechanism is not found to be superior to fixed payment schemes except when the latter involve the use of high prices."

  Additional Note: This study begins with careful description of the empirical auction problem at hand, and the difficulties encountered in trying to use the existing theoretical auction literature (constrained by analytical tractability concerns) to investigate this problem. It also provides an exceptionally thoughtful discussion of the potential role of human-subject and computational-agent experiments in helping to advance the understanding of real-world auctions.

• Scott Heckbert, Tim Baynes, and Andrew Reeson, "Agent-Based Modeling in Ecological Economics" (pdf,234KB), Annals of the New York Academy of Sciences 1185(1), 2010, 39-53.

  Abstract: "Interconnected social and environmental systems are the domain of ecological economics, and models can be used to explore feedbacks and adaptations inherent in these systems. Agent-based modeling (ABMB) represents autonomous entities, each with dynamic behavior and heterogeneous characteristics. Agents interact with each other and their environment, resulting in emergent outcomes at the macroscale that can be used to quantitatively analyze complex systems. ABM is contributing to research questions in ecological economics in the areas of natural resource management and land-use change, urban systems modeling, market dynamics, changes in consumer attitudes, innovation, and diffusion of technology and management practices, commons dilemmas and self-governance, and psychological aspects to human decision making and behavior change. Frontiers for ABM research in ecological economics involve advancing the empirical calibration and validation of models through mixed methods, including surveys, interviews, participatory modeling, and, notably, experimental economics to test specific decision-making hypotheses. Linking ABM with other modeling techniques at the level of emergent properties will further advance efforts to understand dynamics of social-environmental systems."

• W. Jager, M. A. Janssen, H. J. M. De Vries, J. De Greef, and C. A. J. Vlek, "Behaviour in Commons Dilemmas: Homo Economicus and Homo Psychologicus in an Ecological-Economic Model", Ecological Economics Vol. 35, 2000, 357-379.

• Marco A. Janssen (ed.), Complexity and Ecosystem Management: The Theory and Practice of Multi-Agent Systems, Edward Elgar Publishers, Cheltenham, UK, 2002.

• Marco A. Janssen and Wander Jager, Preface to the Special Issue on the Human Actor in Ecological-Economic Models, Ecological Economics Vol. 35, 2000, 307-310.

• David S. Kirby, Gwenhael Allain, Patrick Lehodey, Adam Langley, "Individual/Agent-Based Modelling of Fishes, Fishers, and Turtles" (pdf,266KB), Report, Oceanic Fisheries Programme, Secretariat of the Pacific Community, Numea, New Caledonia, July 2004.

  Abstract: This paper provides a brief review of individual/agent-based modelling and its actual and potential applications to fisheries in the Western and Central Pacific Ocean.

• Roland H. Lamberson (ed.), "Natural Resource Modeling: Special Issue on Individual-Based Models", The Rocky Mountain Mathematics Consortium, Volume 15, Number 1, March 2002.

  Abstract: This special issue is based on the symposium "Advancing the Individual-Based Modeling Approach: New Tools and Concepts," at the annual meeting of the Ecological Society of America, Snowbird, Utah, August 10, 2000. The goal of the volume is to reconsider the status of individual-based models, present some promising new approaches, and give some examples of successful new models. For more information about this volume, visit here.

• Stephen Lansing and James N. Kremer, "Emergent Properties of Balinese Water Temple Networks: Coadaptation on a Rugged Fitness Landscape", American Anthropologist, Vol. 95, 1993, pp. 97-114. Published article available at JSTOR.

  Abstract: Over hundreds of years, Balinese farmers have developed an intricate hierarchical network of "water temples" dedicated to agricultural deities in parallel with physical transformations of their island deliberately undertaken to make it more suitable for growing irrigated rice. The water temple network plays an instrumental role in the coordination of activities related to rice production. Representatives of different water temple congregations meet regularly to decide cropping patterns, planting times, and water usage, thus helping to synchronize harvests and control pest populations. Lansing and Kremer develop an ecological simulation model to illuminate the system-level effects of the water temple network, both social and ecological. Their anthropological study illustrates many important ABM concepts, including emergent properties, fitness landscapes, co-adaptation, and the effects of different institutional designs.

  Note: For an analysis and critique of this paper, see Marco Janssen, "Coordination in Irrigation Systems: An Analysis of the Lansing-Kremer Model of Bali" (pdf,787KB), Working Paper, Indiana University, downloaded 6/7/05.

• David A. Robalino, Social Capital, Technology Diffusion, and Sustainable Growth in the Developing World, Ph.D. Dissertation (Linked List of Chapters, html), RAND Report RGSD-151, 2000.

  Abstract: The author develops an agent-based macro-econometric model for the developing world that endogenizes the process of technology diffusion by formalizing the role of social interactions. Among other things, the model is used to address the question of how to allocate aggregate income to the creation of human and produced capital, and how to distribute over time the consumption of natural resources and environmental resources, in order to generate a sustainable growth path that maximizes intertemporal social welfare.

• J. Rouchier, F. Bousquet, M. Requier-Desjardins, and M. Antona, "A Multi-Agent Model for Describing Transhumance in North Cameroon: Comparison of Different Rationality to Develop a Routine", Journal of Economic Dynamics and Control 25, March 2001, pages 527-559.

• James A. Wilson et al., "Costly Information and the Evolution of Self-Organization in a Small, Complex Economy", Journal of Economic Behavior and Organization, vol. 90, 2013, pp. 576-593. doi:10.1016/j.jebo.2012.12.019

• James A. Wilson, James M. Acheson, and Teresa R. Johnson, "The Cost of Useful Knowledge and Collective Action in Three Fisheries", Ecological Economics, Vol. 96, Dec. 2013, pp. 165-172. doi: 10.1016/j.ecolecon.2013.09.012

Elinor Ostrom CNH Systems Research (2009 Nobel Prize Winner)

• Theodore C. Bergstrom, "The Uncommon Insight of Elinor Ostrom" (pdf,110KB), March 26, 2010.

  Abstract: "Elinor Ostrom received the 2009 Sveriges Riksbank Prize in Economic Sciences in Memory of Alfred Nobel, better known as the Nobel Prize in Economics. In this short paper, Bergstrom provides a thoughtful non-technical summary of her major contributions. Here is a brief excerpt from his introduction: "Elinor Ostrom pursues a third approach to study of (common pool resources). The heart of Ostrom's method is to examine case studies of existing communities that have developed institutions suited to the particular technical problems that arise in their specific environments. Ostrom emphasizes that every real-world commons has its own peculiarities. She argues that actual commons problems are usually far more complex than the models that economists like to write down."

• Marco A. Janssen and Elinor Ostrom, "Governing Social-Ecological Systems", Chapter 30 (pp. 1465-1509) in Leigh Tesfatsion and Kenneth L. Judd (editors), Handbook of Computational Economics, Vol. 2: Agent-Based Computational Economics, Handbooks in Economics Series, North-Holland, Amsterdam, Spring 2006.

  Abstract: "Social-ecological systems are complex adaptive systems where social and biophysical agents are interacting at multiple temporal and spatial scales. The main challenge for the study of governance of social-ecological systems is improving our understanding of the conditions under which cooperative solutions are sustained, how social actors can make robust decisions in the face of uncertainty and how the topology of interactions between social and biophysical actors affect governance. We review the contributions of agent-based modeling to these challenges for theoretical studies, studies which combines models with laboratory experiments and applications of practical case studies."

• Elinor Ostrom and Xavier Basurto, "Crafting Analytical Tools to Study Institutional Change" (pdf,225KB), Journal of Institutional Economics, Vol. 7, No. 3, 2011, 317-343.

  Abstract: "Most powerful analytical tools used in the social sciences are well suited for studying static situations. Static and mechanistic analysis, however, is not adequate to understand the changing world in which we live. In order to adequately address the most pressing social and environmental challenges looming ahead, we need to develop analytical tools for analyzing dynamic situations -- particularly institutional change. In this paper, we develop an analytical tool to study institutional change, more specifically, the evolution of rules and norms. We believe that, in order for such an analytical tool to be useful to develop a general theory of institutional change, it needs to enable the analyst to concisely record the processes of change in multiple specific settings so that lessons from such settings can eventually be integrated into a more general predictive theory of change."

• Elinor Ostrom, "Beyond Markets and States: Polycentric Governance of Complex Economic Systems" (pdf,2.6MB), Nobel Prize Lecture, Stockholm, Sweden, December 8, 2009.

• Elinor Ostrom, "Collective Action and the Evolution of Social Norms" (pdf, 2.5MB), Journal of Economic Perspectives Vol. 14, 2000, 137-158.

  Abstract: "(This paper describes) avenues of research on the underpinnings of collective action, first focusing on the experimental evidence and potential theoretical explanations, and then on the real-world empirical evidence. ... A central finding is that the world contains multiple types of individuals, some more willing than others to initiate reciprocity to achieve the benefits of collective action. Thus, a core question is how potential cooperators signal one another and design institutions that reinforce rather than destroy conditional cooperation."

• Elinor Ostrom, Roy Gardner, and James Walker, Rules, Games, and Common-Pool Resources, University of Michigan Press, Ann Arbor, 1994.

• Elinor Ostrom, "Anlyzing Long-Enduring, Self-Organized, and Self-Governed Common Pool Resources" (pdf,3.1MB), Chapter 3 (pp. 58-102) in Elinor Ostrom, Governing the Commons: The Evolution of Institutions for Collective Action, Cambridge University Press, MA, 1990.

• Amy R. Poteete, Marco A. Janssen, and Elinor Ostrom, Working Together: Collective Action, the Commons, and Multiple Methods in Practice (book site), Princeton University Press, May 2010, 376pp.

• Edella C. Schlager and Elinor Ostrom, "Property-Rights Regimes and Natural Resources: A Conceptual Analysis" (pdf,2.2MB), Land Economics, Vol. 68, 1992, 249-262.

  Abstract: The term "common-property resource" is an example of a term repeatedly used to refer to property owned by a government or by no one. It is also used for property owned by a community of resource users. Such usage leads to confusion in scientific study and policy analysis. In this paper we develop a conceptual schema for arraying property-rights regimes that distinguishes among diverse bundles of rights ranging from authorized user, to claimant, to proprietor, and to owner. We apply this conceptual schema to analyze findings from a variety of empirical settings including the Maine lobster industry.

Software, Toolkits, and Demos

• Annotated list of pointers to ACE/CAS General Software and Toolkits

• Annotated list of pointers to ACE/CAS Computational Laboratories and Demonstration Software

• Yao Hu, Ximing Cai, and Benjamin DuPont, "Design of a web-based application of the coupled multi-agent system model and environmental model for watershed management analysis using Hadoop", Environmental Modelling & Software Vol. 70, 2015, 149-162.

  Abstract: This study develops a cyberinfrastructure design for complex watershed management problems that couples together a multi-agent system model with an environmental model. Two design goals are stressed: (i) Enable parallel programming to improve computational efficiency; and (ii) provide a web-based application in a cloud computing environment to ensure user accessibility and scalability.

• Dave Murray-Rust, Derek T. Robinson, Eleonore Guillem, Eleni Karali, and Mark Rounsevell, "An open framework for agent-based modelling of agricultural land use change", Environmental Modelling & Software 61, 2015, 19-38.

  Abstract: This paper presents a new open source agent-based modelling framework (Aporia) that has the goal of reducing the complexity and difficulty of constructing high-fidelity land use models. Aporia is designed to be modular, flexible and open, using a declarative compositional approach to create complex models from subcomponents. The framework is illustrated for two land-use case studies exploring different socio-economic scenarios and behavioural characteristics for Swiss and Scottish farmers.

• Leigh Tesfatsion, Chris R. Rehmann, Diego S. Cardoso, Yu Jie, and William J. Gutowski, "An Agent-Based Platform for the Study of Watersheds as Coupled Natural and Human Systems" [ (Preprint,pdf,1.2M), (code/data repository site)], Environmental Modelling & Software, Vol. 89, March, 2017, 40-60. http://dx.doi.org/10.1016/j.envsoft.2016.11.021

  Abstract: This study describes the architecture and capabilities of an open source agent-based Java platform that permits the systematic study of interactions among hydrology, climate, and strategic human decision-making in a watershed over time. To demonstrate the platform's use and capabilities, an application is presented in accordance with ODD protocol requirements that captures, in simplified form, the structural attributes of the Squaw Creek watershed in central Iowa. Illustrative findings are reported for the sensitivity of farmer and city social welfare outcomes to changes in three key treatment factors: farmer land-allocation decision method, farmer targeted savings, and levee quality effectiveness for the mitigation of city flood damage.

• Marco A. Janssen has developed a replication of Artificial Anasazi Model, an agent-based model that simulates the population dynamics between 800 and 1350 in the Long Houe Valley in Arizona.

• Cormas (Le Cirad, France): Multi-agent dynamic simulation software used by Rouchier et al. to model renewable resource management problems.

• Echo is a simulation tool for ecological modelling. Echo was originally developed by John Holland and Terry Jones at the Santa Fe Institute to investigate mechanisms which regulate diversity and information-processing in complex adaptive systems, i.e., systems comprised of many interacting adaptive agents. Echo agents interact via combat, mating, and trade to develop strategies for ensuring survival in resource-limited environments. The result is complicated networks of interactions and resource flows that resemble species communities in ecological systems. A NetLogo Echo Demo is available.

• Garvin H. Boyle has developed a program in C++, called Model Economies (ModEco), for the modeling and study of sustainable economic systems. Targeted for a Windows desktop, ModEco is designed as a laboratory in which users can design a simple economy by selecting options and changing parametric values and then run a demonstration of that economy. Genetic algorithms control pricing strategies which evolve as time passes. Some features, such as municipal grants, can be toggled on or off, enabling or disabling channels of flow of value between economic stores of value. Some parametric values can be altered to regulate the flow of value between stores. Realtime output enables the user to see changes in the economy as it evolves. Optional comma-separated value files (text-based CSV files) can be produced, collecting a wide variety of micro- and macro-economic data. These files can then be imported into MS Excel for analysis. The larger goal of the ModEco project is to demonstrate the most simple complete economy possible (from farmer’s field, to food, to fertilizer) which is consistent with the conservation laws of physics. The specific goal is to abstract an irreducible list of fundamental characteristics of a sustainable economy. The associated website provides access to downloadable software and a variety of working notes and papers describing data analysis activities undertaken so far. The software is in alpha-release state (little user documentation, manual installation, time-limited version control) and is offered as-is, but further development is intended. The author would welcome all correspondence about the software.

• Simulistics develops and distributes Simile, which is modeling and simulation software for complex dynamic systems in the earth, environmental and life sciences. Simile uses a unique logic-based declarative modeling technology to represent the interactions in these systems in a clearly structured and visually intuitive way.

• Thomas Maxwell, Ferdinando Villa, and Robert Costanza, all with the International Institute for Ecological Economics (Center for Environmental Science, University of Maryland SysteMB), have developed an integrated environment for high-performance spatial modeling called the Spatial Modeling Environment (SME). From the SME home page: "This environment, which transparently links icon-based modeling environments with advanced computing resources, allows modellers to develop simulations in a user-friendly, graphical environment, requiring no knowledge of computer programming. Automatic code generators construct (spatial) simulations and enable distributed processing over a network of parallel and serial computers, allowing transparent access to state-of-the-art computing facilities. The environment imposes the constraints of modularity and hierarchy in model design, and supports archiving of reusable model components defined in our Modular Modeling Language (MML)."

• The UrbanSim Project, is dedicated to the development of agent-level simulation of urban development, transportation, and environmental impacts of alternative policy strategies. The UrbanSim software, including full source code, is available for download via this website. It has been applied in various metropolitan regions throughout the U.S. and abroad.

• WACCShed (Java), an agent-based platform for the study of water and climate change (WACC) issues for watersheds modeled as coupled natural and human systems

Resource Sites, Groups, & Early Individual Researchers

• ACE/CAS Research Sites and Groups, an annotated list of pointers maintained by Leigh Tesfatsion (Economics, Iowa State University, Ames).

• Andrew Crooks (George Mason University) maintains a blog focusing on Geographical Information Science (GIS) and Agent-Based Modeling (ABM).

• Nicholas Magliocca (PhD Geography and Environmental Systems, U of Maryland) maintains a blog about modeling the human dimensions of change, titled Agent-Based Virtual Labs. The blog covers issues relating broadly to the social, economic, and cultural interactions that are changing the planet’s surface and climate. These issues are explored with posts relating to agent-based modeling (ABM), and how ABMs can be used as virtual laboratories to explore possible motivations for (and effects of) observed human behaviors in interaction with natural systems.

• The Consumat Page, maintained by Marco Janssen (Arizona State University), introduces the "consumat approach" for the study of environmentally-related behaviour, such as common-pool resource usage problems.

• Dawn Parker (University of Waterloo) maintains a resource website for researchers interested in multi-agent systems models of land-use and cover-change(MAS/LUCC). Visitors to this MAS/LUCC Resource Page will find links to literature, conferences and workshops, descriptions of ongoing research projects, and software tools.

• François Bousquet (Cirad, France): Multi-agent simulations of natural and renewable resource management (CORMAS); Ecological economics; Economic exchanges and spatial organization; Use of such models in the field to aid coordination.

• Joe Henrich (Departments of Psychology and Economics, University of British Columbia, Vancouver, CA): Biological evolution of cultural transmission and learning capacities; Evolution of cooperation; Common pool resource and public goods problems; Cross-cultural experimental games; Economic behavior and ethnography among the Mapuche of southern Chile.

• Elena Irwin (Department of Agricultural, Environmental, and Development Economics, Ohio State University, Columbus): Interacting agents, spatial externalities, and the evolution of land-use patterns.

• Wander Jager (Faculty of Management and Organization, University of Groningen, The Netherlands): The consumat approach (multi-agent modeling of consumer behavior); Behavioral dynamics; Market behavior; Environmentally sustainable development.

• Marco A. Janssen (School of Human Evolution and Social Change, Arizona State University, Tempe, AZ): The consumat approach (multi-agent modeling of consumer behavior); Complex adaptive systems; Modeling human dimensions of global environmental change; Self-organization of institutions; Interactive models for science-policy dialogue; Multi-agent modeling and evolutionary computation; The collapse of ancient societies.

• Dawn Parker (School of Planning, University of Waterloo, CA): Development of integrated socio-economic and biophysical models of land-use change using agent-based modeling; geographic information systems; Behavioral economics applications in environmental and resource economics.

Copyright © Leigh Tesfatsion. All Rights Reserved.