The ERC project SES-LINK is slowly coming to an end (but our seslink group remains) and we used one of the last warm and sunny days this year to invite some distinguished guests to discuss current frontiers of complex adaptive systems (CAS) thinking and methods for analyzing social-ecological systems (SES). Social-ecological systems are complex adaptive systems – systems whose macro/system level characteristics and non-linear dynamics emerge from local interactions of heterogeneous actors and ecosystems within given biophysical, social and institutional environments. A better understanding of how and under which conditions these micro-level interactions give rise to macro-level phenomena such as regime shifts/ transformations or lock-ins is needed in order to govern them sustainably. An example would be the collapse of the Baltic Cod fisheries in the 80’s through the interaction of multiple fleets that increased their efforts (and interactions with the fish stocks) following the cod boom and changes in the institutional and economic settings.

The workshop has gathered researchers from Stockholm University (Sweden), Princeton University (USA), Linköping University (Sweden) and Stellenbosch University (South Africa). Among the guest presenters were:

• Simon Levin (Princeton University, theoretical ecology)
• Peter Hedström (Linköping University, analytical sociology)
• Rika Preiser (Stellenbosch University, philosophy)
• Andreas Duit (Stockholm University, political science)
• Örjan Bodin (Stockholm Resilience Centre, social-ecological networks)

The SES-LINK team presented examples of analyzing SES as CAS such as the collective management of a common pool resource (Nanda Wijermans), a mechanism explaining the influence of interest groups in the recent EU Common Fisheries Reform process (Kirill Orach), or the emergence of self-organization in small-scale fisheries (Emilie Lindkvist) and ideas on a co-evolutionary analysis of poverty alleviation strategies (Jamila Haider) .

A cosy place was found to host fruitful discussions.

With a very broad spectrum of academic backgrounds, we aimed to contribute to the development of a mechanism-based understanding of SES and the development of methods to study SES as CAS. The main objectives of the workshop were to discuss:

• challenges of conceptualizing and analyzing social, ecological or social-ecological systems as CAS, particularly with respect to understanding interactions between the micro and macro-level ,
• approaches to identify mechanisms that may explain system level phenomena, such as regime shifts or lock-ins , and
• how to combine empirical studies and modeling for the analysis of SES as CAS.

Prominent points of departure were for example the challenge to prove that a system really exhibits complex behavior and is different from just a collection of not-yet-understood, complicated patterns. The mechanism-based approach from Peter Hedström seems to be a promising way for unpacking macro-level phenomena into situational, action-formation, and transformational mechanisms. In those three steps is explained how the macro level is linked to the micro level, what micro-level processes act over time, and how the features of the micro-level state aggregate to or influence a macro level phenomenon. In our view, the agent-based modelling approach follows a similar logic. We agreed on the impression that the last one of those steps (how the macro-level phenomenon emerges from micro level actions) is currently the least understood.

With regards to modeling, discussions highlighted the dangers of taking a rather simple model for representing a much more complex system. The current work from Rika Preiser which specifies types of complex states and processes is helpful to distinguish the degrees to which complex features are included in system or model representations.

Finally, we brainstormed on issues and research questions in CAS thinking that we would like to address in the future, such as the need to account for more levels than just micro and macro, the fact that complexity is not binary but a gradient, the question of when and how to apply a complexity approach for the study of SES and how we can apply a mechanism-based approach to the study of SES phenomena.

We want to thank our guests for a great day of discussions around current SES and CAS research frontiers and want to forward interested readers to the recent call-for-sessions on the Resilience Conference 2017 in Stockholm, where we intend to organize a follow-up on this topic.

The Royal National City Park around the Stockholm University provided a perfect venue for enjoying a bit of seclusion.

Recommended readings:

• Hedström, P. & Ylikoski, P. Causal Mechanisms in the Social Sciences. Annu. Rev. Sociol. 36, 49–67 (2010).
• Levin, S. et al. Social-ecological systems as complex adaptive systems: modeling and policy implications. Environ. Dev. Econ. 18, 111–132 (2012).
• Rammel et al. (2007) Managing complex adaptive systems – A co-evolutionary perspective on natural resource management