The Basics of Complex Adaptive Systems Theory

New Reality Climate variability - change in average, variation, and/or extreme values

New Reality Novel ecosystems will be increasingly common Creation of novel ecosystems via biotic or abiotic change (modified from Suding et al. 2004). A natural ecosystem is collapsed into the range of values found in zone A. (a) An ecosystem is altered by directional environmental drivers (AB) or the addition or loss of an important species (AC). (b) Once in the new state (either B or C), internal restructuring due to new biotic and abiotic interactions further alters community composition through changes in abundances or species losses, and through changes in biogeochemical interactions. Seastedt et al. 2008, Frontiers in Ecology, 547-553 Novel ecosystems will be increasingly common

Complexity management objective “Complexity” management approach Management objective C Complexity management objective A Ecosystem characteristics Increase ecosystem resilience and adaptability, and promote desirable outcomes B Management objective Time Silvicultural interventions Modified from Puettmann et al.

Ecosystems are Complex Adaptive Systems, making them resilient Interactions Bottom-up Self-organization Emergence Feedbacks Adaptive Initial conditions Memory Open to outside Fuzzy boundaries Non-equilibrium Non-linear Tipping points Stable System Connection begets complexity and resilience

Neither rigid or chaotic, complex systems are integrated and resilient

https://www.youtube.com/watch?v=g5evD6AQeCQ

Ecosystems are “Complex Adaptive Systems” A system with many parts The parts interact (inter-dependent, feedbacks) Emergence or synergy The whole is greater than the sum of the parts (interactions give rise to emergent properties). Bottom-up self-organization Adaptive, Evolving System memory Fuzzy, open boundaries Feedback loops, cross scales Non-linear, sometimes chaotic Indeterminate, unpredictable Self-organization Emergent properties System memory Non-equilibrium, open to outside Fuzzy boundaries Adaptive

Feedbacks are the key to self-organization of terrestrial ecosystems Ehrenfeld et al. (2005)

https://www.youtube.com/watch?v=BfnY9gn6ktk

Characteristics of Complex Adaptive Systems Unpredictable: because interactions non-linear Contagion: easy spread due to interconnection Modularity: some parts more intra-connected than inter-connected (e.g., above- and belowground foodwebs) Redundancy Resilient

Complex Adaptive Systems Traditional Science Focus on parts Top-down Deterministic Reductionist Disciplinary Linear Prediction Complex Systems Science Interactions Bottom-up Self-organization Holistic Interdisciplinary Non-linear Surprises

Forest ecosystems: cross-scale interactions and emergence of self-organization Forest structure is emergent property

Neural networks underpin the brain as a complex adaptive system “mindful practice” “use it or lose it” Neural networks underpin the brain as a complex adaptive system “neurons that wire together, fire together”

Forest Dynamics Equilibrium view Complexity view Time succession disturbance Essentially one pathway to stability Disturbance seen as an aberration

Because of complexity, ecosystems are wired for healing, to a point

Insight 18: Resilience is the birthplace of powerful hope and creativity

  http://www.ted.com/talks/gavin_schmidt_the_emergent_patterns_of_climate_change