Socio-ecological systems: Challenges for modelling and management Christopher Britton-Foster

Levin S., Xepapadeas T., Crépin A-S., Norberg J., De Zeeuw A,. Folke C., Huges T., Arrow K., Barret S., Daily G., et al Social-ecological systems as complex adaptive systems: modeling and policy implications. Environment and Development Economics 18:

Outline Overview CAS are non-linear CAS processes have differing time scales CAS have spatiotemporal heterogeneity CAS involve strategic interactions The current state and management strategies

Overview Last time: Catastrophic regime shifts brought on by human actions This time: How to incorporate key elements of CAS into models that predict catastrophic regime shifts – Management implications

CAS are non-linear Hysteresis Kinzig et al, 2006

CAS are non-linear May have Skiba points: branching points where different trajectories could lead to different basins of attraction Resulting steady-state depends on history Management: - Know the different possible trajectories - Consider the system’s history

CAS processes have different time scales Different processes occur at different rates – Can give the illusion of a constant state for the slow processes – The lag effect Management: – Singular perturbation analysis separates slow and fast dynamics within the model

CAS have spatiotemporal heterogeneity Patchiness of populations – Spatially – Temporally Short-range and long-range effects Management: – Different quotas or taxes that vary over spatial zones and over time

CAS can have strategic interactions Strategic interactions – Cooperative: agreement on an optimal trajectory – Non-cooperative: Open-loop: outcome depends on initial state only Closed-loop: strategies are updated continually (feedback strategy) Management – Widely studied in economics – Important to understand people’s motivations for decision-making

Current state of management Uncertainties: – Inadequate inventories of ecosystem components – Functional dynamics in CAS – Limited modelling capacity Options for improved management: – Try to predict regime shifts and use precautionary principle – Implement adaptive controls

Questions Is it feasible to incorporate these complexities into models and management decisions? Do you think it is harder to predict the human element, or the ecosystem element of socio- ecological systems?