Panarchy

 

What is Panarchy? 

Panarchy is a conceptual framework to account for the dual, and seemingly contradictory, characteristics of all complex systems – stability and change. It is the study of how economic growth and human development depend on ecosystems and institutions, and how they interact.  It is an integrative framework, bringing together ecological, economic and social models of change and stability, to account for the complex interactions among both these different areas, and different scale levels (see Scale Levels). 

Panarchy’s focus is on management of regional ecosystems, defined in terms of catchments, but it deals with the impact of lower, smaller, faster changing scale levels, as well as the larger, slower supra-regional and global levels. Its goal is to develop the simplest conceptual framework necessary to describe the twin dynamics of change and stability across both disciplines and scale levels.

 

The development of the panarchy framework evolved out of experiences where “expert” attempts to manage regional ecosystems often resulted in considerable degradation of those ecosystems (Gunderson and Holling, 2002). Regional management efforts are generally linear in nature, targeting the maintenance of certain variables – forest growth rates, river clarity, fish harvest rates, etc. 

 

It was noted that focusing on managing a single variable, usually one of economic interest, generally resulted in other variables in the system changing, sometimes abruptly, and eventually degrading the entire ecosystem.  It was also noted that the changes triggered by attempting to sustain a particular variable were changes that occurred so slowly (over decades or more), that they often went unnoticed until they in turn triggered an abrupt change (e.g. the forest became infested, the river became polluted, or the fish stock collapsed).

 

Basic Concepts in Panarchy

 

Ecosystem Characteristics   

Empirical evidence of natural, disturbed and managed ecosystems identifies four key characteristics:

• Change is neither continuout and gradual, nor continuously chaotic. It is epicodic, regulated by interactions between fast and slow variables
• Different scale levels concentrate resources and potential in different ways, and non-linear processes reorganize resources across levels
• Ecosystems do not have a single equilibrium; multiple equilibria are common. Ecosystems have processes that maintain stability in terms of productivity and biogeochemical cycles; as well as processes that are destabilizing, which provide diversity, resilience and opportunity
• Management systems must take into account these dynamic features of ecosystems and be flexible, adaptive and experiment at scale levels compatible with the levels of critical ecosystem functions.

Stages of the Adaptive Cycle: Basic Ecosystem Dynamics

Panarchy identifies four basic stages of ecosystems, represented in the Figure below: exploitation, conservation, release and reorganization.  All ecosystems, from the cellular to the global level, are said to go through these four stages of a dynamic adaptive cycle (see below).

• The exploitation stage is one of rapid expansion, as when a population finds a fertile niche in which to grow.
• The conservation stage is one in which slow accumulation and storage of energy and material is emphasized as when a population reaches carrying capacity and stabilizes for a time.
• The release occurs rapidly, as when a population declines due to a competitor, or changed conditions
• Reorganization can also occur rapidly, as when certain members of the population are selected for their ability to survive despite the competitor or changed conditions that triggered the release.

Adaptive Cycles   

The four stages of the adaptive cycle described above (analogous to birth, growth and maturation, death and renewal), have three properties that determine the dynamic characteristics of each cycle:

• Potential sets the limits to what is possible - the number and kinds of future options available (e.g. high levels of biodiversity provide more future options than low levels)
• Connectedness determines the degree to which a system can control its own destiny through internal controls, as distinct from being influenced by external variables (e.g. temperature regulation in warm blooded animals, which involves five different physiological mechanisms, is an example of high connectedness)
• Resilience determines how vulnerable a system is to unexpected disturbances and surprises that can exceed or break that control (see below for more details).

The adaptive cycle is the process that accounts for both the stability and change in complex systems.  It periodically generates variability and novelty, either internally such as through genetic mutations or adaptation, or by accumulating resources that change the internal dynamics of an ecosystem.  These changes are the triggers for experimentation. In the reorganization stage various experiments are tested and resources are reorganized in new configurations, some of which enter a new exploitation stage to repeat the cycle.

 

Interconnectedness of Levels 

Panarchy places great emphasis on the interconnectedness of levels, between the smallest and the largest, and the fastest and slowest.  The large, slow cycles set the conditions for the smaller, faster cycles to operate. But the small, fast cycles can also have an impact on the larger, slower cycles. There are many possible points of interconnectedness between adjacent levels; however, two specific points are of particular interest with respect to sustainability:

• “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.

 

The fast levels invent, experiment and test; the slower levels stabilize and conserve accumulated memory of past, successful experiments.  Sustainability in this framework is the capacity to create, test and maintain adaptive capability.  Development becomes the process of creating, testing and maintaining opportunity.

 

Resilience

Resilience is the capacity of an ecosustem to tolerate disturbances without collapsing into a qualitatively different state.  The greater the resilience is in a particular ecosystem the more it can resist large or prolonged disturbances.  If resilience is low or weakened, then smaller or briefer disturbances can push the ecosystem into a different state, where its dynamics change.

 

According to this model, after a disturbance, ecosystems evolve through time as ecological niches fill in (increasing connectedness), biomass accumulates (increasing potential) and more successful species outcompete less successful species (decreasing resilience). This makes ecosystems vulnerable to exogamous shocks that they cause a release of resources and a period of rapid reorganization.

 

Once resilience is overwhelmed and an ecosystem enters a new state, restoration can be complex, expensive, and sometimes even impossible. Research suggests that to restore some systems to their previous state requires a return to environmental conditions well before the collapse.

 

Resilience can be degraded by a large variety of factors which largely depend on underlying, slowly changing variables such as climate, land use, nutrient stocks, human values and policies. Resilience is a characteristic of natural systems.  When resilience is weakened it is sometimes possible to restore it. Diversity is believed to be a key issue in restoring resilience – both biological and social diversity are important to the extent they contribute functional redundancy (i.e. similar services can be provided by some element in the diversity). But as biological diversity is lost, or as human systems and institutions become homogenous and rigid, then the likelihood of restoring lost resilience declines.

 

The ability to anticipate and plan for the future is a unique characteristic of human systems, and has the potential to increase their resilience.

 

Strengths of Panarchy

Panarchy is a complex and controversial framework for describing ecosystem and human system dynamics and interactions, and it is beyond the scope of this overview to provide a thorough critique.  Despite its broad sweep it does have the advantage of relative simplicity in terms of the basic concepts used to describe an array of complex phenomena.  This framework developed over several years, is solidly based in empirical research across a broad range of ecosystems, and continues to develop conceptually and generate policy relevant research.

 

Panarchy is a sophisticated attempt to connect ecosystem functioning with economic activities and human institutions for managing the relation between the two. It is an evidence-based approach that forces us to think in non-linear terms about complex systems, while providing the conceptual tools to understand the complexities involved.

 

Limitations

Panarchy remains a hypothesis, despite the many empirical studies it has generated. It's broad sweep requires more empirical testing.  While it proports to be an integrative model of ecological, economic and social dynamics, it's focus is primarily ecological. There are competiting attempts at integration,¹ which may also account for the observed phenomena. There are also different ways of thinking about resilience (e.g. Fraser et al, in press). Despite these limitations, the panarchy framework continues to stimulate constructive debate and guide empirical studies.

 

Relation to Sustainable Scale   

Many of the conclusions and observations made within the Panarchy framework are congruent with those regarding sustainable scale. There is recognition that:

• due to the inherent instability of ecosystems it is extremely difficult to detect or predict transitions to new ecosystem equilibria (e.g. when maximum scale might occur, see Considerable Uncertainty)
• sustainability is about retaining capabilities to continue contributing ecosystem services (i.e. natural income does not deplete natural capital, see  Natural Capital and Income)
• resilience, the ability to resist disturbances, is a key characteristic of ecosystems (e.g. when throughput exceeds regeneration, resilience is reduced, see  Sustainable Or Unsustainable)
• uncertainty is an inherent characteristic of the adaptive cycle and must be a key factor in any ecosystem management activity
• both uncertainty and risk increases with scale (i.e. problems at the global scale pose the greatest risks)
• precautionary policies are necessary to limit surprises (surprises increase as more natural income is used than is regenerated, see Wisdom in Precaustion in Visions For A Sustainable Future)
• the interaction of different time cycles is important, and that by the time efforts to keep fast variables within desired limits (e.g. GHG emissions) are recognized, it may be too late to avoid a major system change (e.g. climate stability) (see Climate Change)
• science uses uncertainty to drive inquiry, while vested interests use and foster uncertainty to maintain the status quo
• biodiversity is an important component of resilience, and is therefore important even if the types of biodiversity have no market value (see Biodiversity)
• new institutions are needed that gather better information on the slow variables, place greater emphasis on the future, maintain social flexibility for adaptive response, and which maintains and restores ecosystem resilience (see Institutions for a Sustainable Future)
• economic globalization contributes to simplification of ecosystems (as well as to their degradation), reducing resilience.

Panarchy is not a way of measuring sustainable scale. It does provide some interesting and challenging conceptual tools to assist in our understanding of how ecosystems and economic activities and institutions interact. It also identifies a variety of practical approaches to restore and conserve ecological sustainabilty.

 

References

 

Fraser, E., Figge, F., and W. Mabee. "A framework for assessing the vulnerability of food systems to future shocks," Futures (2004). 

 

Fraser, E. "Social vulnerability and ecological fragility: building bridges between social and natural sciences using the Irish potato famine as a case study," Conservation Ecology, 7.2 (2003): 9.

 

¹Fraser, E. "Social vulnerability and ecological fragility: building bridges between social and natural sciences using the Irish potato famine as a case study," Conservation Ecology, 7.2 (2003): 9.

 

Gunderson, Lance and C. S. Holding. Panarchy: Understanding Transformations in Human and Natural Systems. Washington: Island Press, 2002.

 

"Resilience Alliance Home page." Resilience Alliance. www.resalliance.org