Adaptive cycle and Panarchy. Gunderson & Holling 2002 Adaptive cycle of recovery (succession) after...
-
Upload
lynne-potter -
Category
Documents
-
view
217 -
download
7
Transcript of Adaptive cycle and Panarchy. Gunderson & Holling 2002 Adaptive cycle of recovery (succession) after...
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).
7/10
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