Robustness of norm-driven cooperation in the commons

Abstract

Sustainable use of common-pool resources such as fish, water or forests depends on the cooperation of resource users that restrain their individual extraction to socially optimal levels. Empirical evidence has shown that under certain social and biophysical conditions, self-organized cooperation in the commons can evolve. Global change, however, may drastically alter these conditions. We assess the robustness of cooperation to environmental variability in a stylized model of a community that harvests a shared resource. Community members follow a norm of socially optimal resource extraction, which is enforced through social sanctioning. Our results indicate that both resource abundance and a small increase in resource variability can lead to collapse of cooperation observed in the no-variability case, while either scarcity or large variability have the potential to stabilize it. The combined effects of changes in amount and variability can reinforce or counteract each other depending on their size and the initial level of cooperation in the community. If two socially separate groups are ecologically connected through resource leakage, cooperation in one can destabilize the other. These findings provide insights into possible effects of global change and spatial connectivity, indicating that there is no simple answer as to their effects on cooperation and sustainable resource use.

Cross-scale cooperation enables sustainable use of a common-pool resource

“…This constitutes a CSI, since the weak perturbation from system-level dynamics generates a phase transition in subsystem 1, from multistable to monostable behaviour, and this cannot be predicted by analysing either subsystem in isolation. This is consistent with [26], in which this shift was described using agent-based methods 1 . Notably, cooperation never collapses in the collaborative norm scenario; operating under a norm set with the benefit of communication between subsystems preserves cooperation where it otherwise fails.…”

“…We model subsystem resource dynamics as the sum of local processes and subsystem interactions. Following TSL [25], [26], the resource stock of, for example, subsystem 1 (R (1) (t)) is replenished by its environment at constant rate (c (1) ) and lost at a rate that depends on the square of the resource occupation (ratio of the stock to its maximum value, R (1) m , determined by limits such as the capacity of a reservoir). Resource is also harvested by the subsystem community of n (1) agents, collectively exerting effort E (1) (t).…”

Foresight is required to enforce sustainability under time-delayed biodiversity loss

“…Following previous studies [11,12], we assume that social pressure decreases the utility of defectors, U d = U u − w(q) · δ U , so that it may become more profitable for defectors to shift their consumption and comply to the sustainable norm. The severity of the ostracism function, w(q) = w max e t·e r·q , increases with the proportion of conformers in the population, q, and depends on the maximum sanctioning w max , the sanctioning effectiveness threshold t, and the growth rate of the function, r. In addition to depending on the number of conformers in the community, graduated sanctioning and equity considerations leads conformers to act more strongly against defectors which consumption is the most unsustainable [3].…”

“…The proportion of conformers then follows a replicator dynamics [11,12], i.e. varies both with the proportion of conformers q, and the difference between the sustainable consumption utility, U s , and the average consumption utility,…”

“…The enforcement of cooperation strongly hinges on the ecological characteristics of SESs. Previous experimental and theoretical studies have emphasized the role of resource productivity and mobility [10] as well as temporal variability [11,12] on the robustness of cooperation. Evidence from the literature on natural resource management shows that the interaction between fast and slow ecosystem processes affects the optimal management strategy [13], while inappropriate management may reinforce undesirable feedbacks and push the SES into a social-ecological trap [14].…”