Adaptive cycle and Panarchy

Gunderson & Holling 2002

Adaptive cycle of recovery (succession) after disturbance

r=growth (pioneer; stand initiation)K=carrying capacity (competition, niche specialization) (mature to old-growth)Ω=release, new opportunities (disturbance)α=re-organization and recovery (new forest seeds in)

Complex system undergoes change through ‘adaptive cycle’

Metaphor Ecology Biological Psychological Economic

1 Exploitation Birth Development Growth

2 Conservation Maturity Sanity Consolidate

3 Release Death Madness Collapse

4 Reorganization Decay Healing Rebuild

1) Exploitation: rapid expansion, e.g., population grows.

2) Conservation: population reaches carrying capacity and stabilizes for a time.

3) Release: population declines due to a competitor, or changed conditions

4) Reorganization: certain members of the population are selected for their ability to survive despite the competitor or changed conditions that triggered the release.

Four stages of adaptive cycle

Adaptive cycle: four stagesr K

Ωα

r

K

Ωα

Three properties of adaptive cycle

Potential: the number and kinds of future options available (e.g. high levels of biodiversity provide more future options than low levels)

Connectedness: the degree to which a system can control its own destiny through internal controls, as distinct from being influenced by external variables

Resilience: how vulnerable a system is to unexpected disturbances and surprises that can exceed or break that control. The adaptive cycle is the process that accounts for both the stability and change in complex systems.

There are ‘discontinuities’ in variables of interestDiscontinuities determine dominant scales

Adaptive cycles occur at multiple discontinuous scales in natural ecosystems

Tem

pora

l sca

le

Spatial scale

Panarchy

• A term adopted to better represent complex adaptive systems than ‘hierarchy’

• Hierarchy describes “top-down rule”

• Panarchy refers to a specific form of governance or rule (archy) that would encompass (pan) all others

What is panarchy?

“The term [panarchy] was coined as an antithesis to the word hierarchy (literally, sacred rules). Our view is that panarchy is a framework of nature's rules, hinted at by the name of the Greek god of nature, Pan.”

Lance Gunderson and C. S. Holling, Panarchy: Understanding Transformations in Systems of Humans and Nature, Island Press, p.21, 2001.

Panarchy: all-encompassing nested set of adaptive cycles operating at discrete scales

(Gunderson and Holling 2001).

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These cycles connect with cycles ‘above’ and ‘below’ them in the hierarchy:

“Revolt" – this occurs when fast, small events overwhelm large, slow ones, as when a small fire in a forest spreads to the crowns of trees, then to another patch, and eventually the entire forest

“Remember" – this occurs when the potential accumulated and stored in the larger, slow levels influences the reorganization. For example, after a forest fire the processes and resources accumulated at a larger level slow the leakage of nutrients, and options for renewal draw from the seed bank, physical structures and surrounding species that form a biotic legacy.

Panarchy predicts discontinuities in adaptive cycles across scales

Allen, Craig R., et al. "Panarchy: Theory and Application." Ecosystems 17.4 (2014): 578-589.

Three Core Properties of Complex Systems that follow Panarchy Theory

Cup-and-ball model: changes to new stability domain through shift in variables or parameters

e.g., variable=species composition e.g., parameter=climate

Mann et al.

Chapman and Walsh

Global to arctic

Polaramplification

Permafrost is thawingin many places,

not just southern margins

Four mechanisms affect permafrost thaw:

a)Active layer thickeningb)Talik formationc)Erosiond)Thermokarst development

Schuur et al. 2008

Positive feedback to atmospheric GHGs

Schuur et al. 2008

Frozen peat, Canada, SiberiaCryoturbated soil, thin peat, AlaskaMineral deposit, Siberia

Melting permafrostHudson Bay, CanadaScience Daily, Sept 2, 2008

Both the variables and the parameters are changing in the Arctic

e.g., variable=species composition e.g., parameter=climate

IPCC FAR projected global warming

Mean Annual Temperature and Precipitation Predictions for BC

Four Impacts to Forests

1. Reduced snow pack

2. Increased forest fires

3. Forest dieback and species migrations

4. Forests shifted from net CO2 source to sink

1. Dramatic decline in snowpack by 2040

http://www.ipcc.ch/publications_and_data/ar4/wg1/en/ch11s11-5-3-5.html

2. Increasing area burned annually in Canada2. Increasing area burned annually in Canada

http://cfcg.forestry.ubc.ca/projects/climate-data/climatebc-and-bioclimatic-envelope-modelling/

3. Massive shifts in forest composition3. Massive shifts in forest composition

4. Changed from CO2 sink to source

New study shows declining productivity and carbon sequestration in Canadian boreal forest

NASA, Dec. 2011Pan, PNAS, 2012 28

1. Increased forest fire frequency and severity due to warming and drying.

2. Increased disturbances due to insects and disease.

3. Potential ranges of species will move northward and upward in elevation.

4. New assemblages of species will occur in space and time.

5. Species may be unable to move into areas of suitable climate due to barriers to movement, slow migration rates, unsuitable growing substrate or lack of habitat.

Potential Impacts of Climate Change in ForestsBC Ministry of Forests

Summary• Complex adaptive systems are inherently stable• Stable systems change but are homeostatic, like a dancer• Stables systems have resistance, where small disturbances are

contained, and resilience, where the system returns to the same stability domain

• Complex systems change through adaptive cycles• Adaptive cycles and panarchy are stabilizing characteristics• Positive feedbacks and crossing tipping points can lead to loss of

stability• Climate change could cause instability • Maintaining complexity will be crucial