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Controllability montpellier
Controllability montpellier
Controllability montpellier
Controllability montpellier
Controllability montpellier
Controllability montpellier
Controllability montpellier
Controllability montpellier
Controllability montpellier
Controllability montpellier
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Controllability montpellier

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  • 1. When to adapt or when to transform? Using network controllability to assess how manageable are regime shifts ! ! Juan-Carlos Rocha
  • 2. Regime Shifts Transformations Figures from Arctic Resilience Assessment Interim Report 2012
  • 3. • Systems can be represented as a network of interacting elements • Identifying controlling nodes is possible using only structural information of the network: • # of driving nodes correlates with degree distribution • driver nodes tend to avoid high- degree nodes • Heterogeneous networks (most real) are difficult to control. Homogeneous dense networks are more controllable = fewer driving nodes Liu et al, 2012
  • 4. Are regime shifts controllable? To what extent can we manage them? • Critics to Liu et al.: • Topology is not enough • Internal dynamics • “We argue that more important than issues of structural controllability are the questions of whether a system is almost uncrontrollable, whether it is almost unobservable…” Cowan et al, 2012
  • 5. • Focus on edge dynamics: heterogeneous and sparse networks have more controllable edge dynamics than homogeneous dense networks. • Contradictory results? Are regime shifts controllable? To what extent can we manage them?
  • 6. Driver … is any natural or human- induced factor that directly or indirectly causes a change in an [eco]system. A direct driver unequivocally influences ecosystem processes. An indirect driver operates more diffusely by altering one or more direct drivers.
  • 7. Bivalves collapse Bivalves abundance Dissolved oxigen Biodiversity Habitat structural complexity Local water movements + + + + + Fishing Plankton and filamentous algae - Water turbidity - - B B R R Nutrients input Agriculture Urbanization SewageFertilizer Use Deforestation + + + + + Demand for food & fibre + mid-predator fish - - + + B Filtration + - Erosion + + Nutrients in water -+ + + + Logging + + Flooding + Disease - + sedimentation + - Shellfish harvest - + + B B Urban Storm Water Runoff + + Precipitation Variability + + Aquaculture + + Hurricane - +
  • 8. My own critiques • Unmatched nodes change if the periphery of the causal networks change - The limits of the system blur • Unmatched nodes change when joining causal networks to understand cascading effects. • I believe there is opportunities to combine network science and resilience science to answer the question: When do we build resilience and where do we need transformational change? Causal Loop Diagrams for 19 regime shifts around the world
  • 9. Subscribe to our newsletter www.stockholmresilience.su.se/subscribe Thank you! Does it make sense?? Ideas, tomatoes or opportunities for collaboration: e-mail: juan.rocha@su.se twitter: @juanrocha slides: http://criticaltransitions.wordpress.com/ | data: www.regimeshifts.rog

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