Tipping point dynamics are fundamental drivers for sustainable transition pathways of social-ecol... more Tipping point dynamics are fundamental drivers for sustainable transition pathways of social-ecological systems (SES). Current research predominantly analyzes how crossing tipping points causes regime shifts, however, the analysis of potential transition pathways from these social and ecological tipping points is often overlooked. In this paper, we analyze transition pathways and the potential outcomes that these may lead to via a stylized model of a system composed of interacting agents exploiting resources and, by extension, the overall ecosystem. Interactions between the social and the ecological system are based on a perception-exploitation framework. We show that the presence of tipping points in SES may yield counter-intuitive social-ecological transition pathways. For example, the high perception of an alarming ecological state among agents can provide short-term ecological benefits, but can be less effective in the long term, compared to a low-perception condition. This work...
Social norms are the dominant behavioural patterns in a group that affect how people follow rules... more Social norms are the dominant behavioural patterns in a group that affect how people follow rules and regulations. A new modelling study shows, for different localities around the world, how the combination of biophysical context and social norms affects cooperation in water conservation.
Using an empirically grounded model of hunter-gatherer foraging strategies we examine how differe... more Using an empirically grounded model of hunter-gatherer foraging strategies we examine how different resource distributions affect optimal group size, movement frequency and average daily return rate per hunter. The total amount of resources in the environment remained the same, but was modified to contain more dispersed or more clumped resource distributions, and vegetation types are located in a less or more patchy environment. The results show that the optimal group size is not affected by resource distributions. However, more clumped resources in a more patchy environment leads to much higher return rates compared to more dispersed and less patchy environments. The more clumped and patchy environment also favors more complex mobility strategies in which camps are moved in an adaptive fashion to specific locations in the landscape. Human foragers, by knowing the landscape and the spatial location of better habitats, and moving to facilitate hunting in those areas, can gain a substantial advantage from that knowledge.
Using a real-time, spatial, renewable resource environment, we observe participants in a set of e... more Using a real-time, spatial, renewable resource environment, we observe participants in a set of experiments formulating informal rules during communication sessions over three decision rounds. In all three rounds, the resource is open access. Without communication, the resource is persistently and rapidly depleted. With face-to-face communication, we observe informal arrangements to divide up space and slow down the harvesting rate in various ways. We observe that experienced participants, who have participated in an earlier experiment where private property was used as one way of controlling harvesting in this renewable resource environment, are more effective in creating rules, although they mimic the private-property regime of their prior experience. Inexperienced participants need an extra round to reach the same level of resource use, but they craft diverse arrays of novel rule sets. KEY WORDS • common-pool resources • laboratory experiments • communication • institutional inno...
Savanna rangelands are characterized by dynamic interactions between grass, shrubs, fire and live... more Savanna rangelands are characterized by dynamic interactions between grass, shrubs, fire and livestock driven by highly variable rainfall. When the livestock are grazers (only or preferentially eating grass) the desirable state of the system is dominated by grass, with scattered trees and shrubs. However, the system can have multiple stable attractors and a perturbation such as a drought can cause it to move from such a desired configuration into one that is dominated by shrubs with very little grass. In this paper, using the rangelands of New SouthWales in Australia as an example, we provide a methodology to find robust management strategies in the context of this complex ecological system driven by stochastic rainfall events. The control variables are sheep density and the degree of fire suppression. By comparing the optimal solution where it is assumed the manager has perfect knowledge and foresight of rainfall conditions with one where the rainfall variability is ignored, we fou...
Abstract. A major challenge in the development of computational models of collective behavior is ... more Abstract. A major challenge in the development of computational models of collective behavior is the empirical validation. Experimental data from a spatially explicit dynamic commons dilemma experiment is used to empirically ground an agent-based model. Four distinct patterns are identified in the data. Two naïve models, random walk and greedy agents, do not produce data that match the patterns. A more comprehensive model is presented that explains how participants make movement and harvest decisions. Using pattern-oriented modeling the parameter space is explored to identify the parameter combinations that meet the four identified patterns. Less than 0.1 % of the parameter combinations meet all the patterns. These parameter settings were used to successfully predict the patterns of a new set of experiments.
Tipping point dynamics are fundamental drivers for sustainable transition pathways of social-ecol... more Tipping point dynamics are fundamental drivers for sustainable transition pathways of social-ecological systems (SES). Current research predominantly analyzes how crossing tipping points causes regime shifts, however, the analysis of potential transition pathways from these social and ecological tipping points is often overlooked. In this paper, we analyze transition pathways and the potential outcomes that these may lead to via a stylized model of a system composed of interacting agents exploiting resources and, by extension, the overall ecosystem. Interactions between the social and the ecological system are based on a perception-exploitation framework. We show that the presence of tipping points in SES may yield counter-intuitive social-ecological transition pathways. For example, the high perception of an alarming ecological state among agents can provide short-term ecological benefits, but can be less effective in the long term, compared to a low-perception condition. This work...
Social norms are the dominant behavioural patterns in a group that affect how people follow rules... more Social norms are the dominant behavioural patterns in a group that affect how people follow rules and regulations. A new modelling study shows, for different localities around the world, how the combination of biophysical context and social norms affects cooperation in water conservation.
Using an empirically grounded model of hunter-gatherer foraging strategies we examine how differe... more Using an empirically grounded model of hunter-gatherer foraging strategies we examine how different resource distributions affect optimal group size, movement frequency and average daily return rate per hunter. The total amount of resources in the environment remained the same, but was modified to contain more dispersed or more clumped resource distributions, and vegetation types are located in a less or more patchy environment. The results show that the optimal group size is not affected by resource distributions. However, more clumped resources in a more patchy environment leads to much higher return rates compared to more dispersed and less patchy environments. The more clumped and patchy environment also favors more complex mobility strategies in which camps are moved in an adaptive fashion to specific locations in the landscape. Human foragers, by knowing the landscape and the spatial location of better habitats, and moving to facilitate hunting in those areas, can gain a substantial advantage from that knowledge.
Using a real-time, spatial, renewable resource environment, we observe participants in a set of e... more Using a real-time, spatial, renewable resource environment, we observe participants in a set of experiments formulating informal rules during communication sessions over three decision rounds. In all three rounds, the resource is open access. Without communication, the resource is persistently and rapidly depleted. With face-to-face communication, we observe informal arrangements to divide up space and slow down the harvesting rate in various ways. We observe that experienced participants, who have participated in an earlier experiment where private property was used as one way of controlling harvesting in this renewable resource environment, are more effective in creating rules, although they mimic the private-property regime of their prior experience. Inexperienced participants need an extra round to reach the same level of resource use, but they craft diverse arrays of novel rule sets. KEY WORDS • common-pool resources • laboratory experiments • communication • institutional inno...
Savanna rangelands are characterized by dynamic interactions between grass, shrubs, fire and live... more Savanna rangelands are characterized by dynamic interactions between grass, shrubs, fire and livestock driven by highly variable rainfall. When the livestock are grazers (only or preferentially eating grass) the desirable state of the system is dominated by grass, with scattered trees and shrubs. However, the system can have multiple stable attractors and a perturbation such as a drought can cause it to move from such a desired configuration into one that is dominated by shrubs with very little grass. In this paper, using the rangelands of New SouthWales in Australia as an example, we provide a methodology to find robust management strategies in the context of this complex ecological system driven by stochastic rainfall events. The control variables are sheep density and the degree of fire suppression. By comparing the optimal solution where it is assumed the manager has perfect knowledge and foresight of rainfall conditions with one where the rainfall variability is ignored, we fou...
Abstract. A major challenge in the development of computational models of collective behavior is ... more Abstract. A major challenge in the development of computational models of collective behavior is the empirical validation. Experimental data from a spatially explicit dynamic commons dilemma experiment is used to empirically ground an agent-based model. Four distinct patterns are identified in the data. Two naïve models, random walk and greedy agents, do not produce data that match the patterns. A more comprehensive model is presented that explains how participants make movement and harvest decisions. Using pattern-oriented modeling the parameter space is explored to identify the parameter combinations that meet the four identified patterns. Less than 0.1 % of the parameter combinations meet all the patterns. These parameter settings were used to successfully predict the patterns of a new set of experiments.
Environmental Science & Policy 5 (2002) p. 221-231
In this article, we identify four typical roles played by computer models in environmental policy... more 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.
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