Multi-level agent-based modelling of social-ecological systems: Bridging the gap between the micro and macro levels

Social-ecological systems (SESs) are complex adaptive systems that encompass multiple spatial, temporal, and organisational scales and levels. The dynamics of SESs are driven by interactions among processes occurring both within and across different levels. These multi-level interactions generate patterns of system behaviour that emerge at different spatial, temporal, and organisational levels. This has profound implications for managing SESs. Agent-based models (ABMs) are known for their ability to simulate emergent phenomena and are powerful tools for modelling SESs. However, most multi-level ABMs focus merely on individual/micro-level interactions and aggregated/macro-level interactions and rarely capture the true multi-level dynamics of SESs, which often include effects that cascade across multiple levels. We describe a conceptual framework for multi-level ABMs that couple processes occurring at intermediate levels with those occurring at micro and macro levels, and, more importantly, propose a mathematical construct that embodies the generic features of a truly multi-level ABM. We then discuss our proposed model within the context of past and potential future multi-level agent-based modelling efforts.