Evolving Ostrom’s first principle: The dynamic evolution of common property rights and their role in resource management

Abstract When and how can collective property rights evolve to effectively manage otherwise open access resources? We introduce a generic but formal modelling framework that explores under what conditions collective property rights over natural resources emerge, the causal mechanisms through which such rights aid in sustainability and the challenges that groups face in maintaining them. Our focus is on both the origins of collective property rights, and the co-evolutionary interactions driving their emergence and stabilization. Results suggest that, in the presence of inter-group conflict over resources, groups must establish and enforce rules regarding access and exclusion before implementing effective internal management. This is because when groups lack boundaries, inter-group conflict erodes surplus gains and impairs groups' ability to identify sustainable management targets. We compare these theoretical insights with empirical data from Pemba, Tanzania on the relationship between inter-group conflicts, and investments in boundaries and internal management. We find that inter-group conflict is positively correlated with support for boundaries but negatively correlated with investment in tree planting activities, supporting our theoretical insights on the evolutionary drivers of collective property rights when borders are porous. We discuss these results in the context of strategies to overcome collective action dilemmas and connections to cultural multi-level selection.