Linking Resilience and Robustness in Coupled Natural-Human Systems and Uncovering their Trade-offs

Resilience and robustness are concepts in systems thinking that have grown in importance and popularity. For many complex natural-human systems, however, resilience and robustness are difficult to quantify and the connections and trade-offs between them difficult to study. Most studies have either focused on qualitative approaches to discuss their connections or considered only either resilience or robustness under particular classes of disturbances. In this study, we present a modelling framework to address the linkage between resilience and robustness more systematically. Our analysis is based on a stylized dynamical model that operationalizes a widely used conceptual framework, which explicitly links social agents, natural resources, and infrastructure in social-ecological systems. The model captures essential feedbacks between human decisions (policies, governance structure, strategic behavior) and natural resource dynamics. Importantly, the model enables us to rigorously delineate the boundaries of conditions under which the coupled natural-human system under consideration can be sustained in a long run, define robustness and resilience related to these boundaries, and consequently investigate their connections. The results reveal fundamental trade-offs between robustness and resilience. The results also show how the nature of such trade-offs varies with the choices of certain policies (e.g., taxation and investment in public infrastructure), internal stresses, and uncertainty in social-ecological settings.