# Complex socio-ecological systems/Background

Folke, C. 2006. Resilience: The emergence of a perspective for social-ecological systems analyses. Global Environmental Change 16: 253-267.
In this article, Carl Folke reviews the origin and evolution of the resilience approach as applied to socio-ecological systems. Research on discovery of multiple "stable states" or basins of attraction in ecosystems during the 1960-1970s led scientists to review and challenge the view of a dominant stable equilibrium in ecosystems. Crawford Stanley Holling, a prominent ecologist, was one of the forerunners of the concept with his seminal work on ecology of predation (1973). He proposed that resilience determines the persistence of relationships within a system and is a measure of the ability of these systems to absorb change of state variables, driving variables, and parameters, and still persist. Since then, the resilience perspective has grown to influence other disciplines in social, economic and political fields. The author presents different possible interpretations developed for the concept, from more narrow ones related to engineering resilience to the social-ecological resilience approach, which focuses on adaptive capacity, transformability, learning and innovation. Folke conducts an extensive literature review on research done in resilience by diverse scholars, and concludes pointing out some implications of applying the resilience approach in policy making and sustainable development.
Scheffer, M,, S. Carpenter, J. Foley, C. Folke and B. Walker. 2001. Catastrophic shifts in ecosystems. Nature 413: 591-596.
This paper's main contribution to the resilience of socio-ecological systems is presenting empirical evidence of alternative stable states related to the dynamics or shift in ecosystems. The authors summarize results from research carried out in lakes, coral reefs, woodlands, deserts and oceans, in which for certain environmental conditions, a given ecosystem will switch between two alternative stable states, separated by an unstable equilibrium that marks the "border of attraction" of the states. According to the authors, this phenomenon has implications for ecosystem's response to environmental change. The authors state that catastrophic shifts from one state to the other occur typically unannounced, and early signals of these changes are sometimes difficult to note. Resilience in this case would refer to the size of the valley or basin of attraction around a state, corresponding to the maximum perturbation that can be taken without causing a shift to an alternative stable state. Due to the dynamic character of these states, they might also be named "dynamic regimes". They recognize that disturbance is a natural component of ecosystems that promotes diversity and renewal processes. They conclude that efforts directed to ecosystem management should address the gradual changes that affect resilience rather than merely controling disturbance.
SUMMARY OF CLASS DISCUSSION AND MAIN FOLLOW-UP QUESTIONS
A key point from the Folke article (Table 1) is that the resilience concept has evolved, from engineering resilience (i.e. return time to a relatively constant and stable equilibrium), to ecological resilience (i.e. buffer capacity and persistence -- how much shock the system can absorb without losing function), to social-ecological resilience. This latter, most recent concept (since 2004) incorporates the ability to re-organize and undergo change while still retaining essentially the same function, structure, identity and feedbacks. In this sense, resilience is about adaptive capacity, learning and self-organization.
This evolution of the concept highlights that research on resilience is still in the exploratory phase. Frontier areas include social learning, visioning and scenario building, social networks, leadership, organizational change, adaptive capacity and transformability.