Stockwell_B_Understanding the role of disturbance in peri-urban


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Beyond the Edge: Australia's First National Peri-Urban Conference
La Trobe University
Oct 2013

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Stockwell_B_Understanding the role of disturbance in peri-urban

  1. 1. Understanding the role of disturbance in peri-urban agricultural systems and communities New concepts and principles to guide strategic intervention Brian Stockwell
  2. 2. Fragticulture: Reconfiguring agricultural systems to enhance resilience and sustainability in fragmented coastal peri-urban catchments Relevant Research Question Are there different conceptual constructs derived from the application of complexity, chaos and network theory that can guide the prioritisation and design of interventions seeking sustainable futures for peri-urban agriculture?
  3. 3. Resilience The capacity of a system to absorb disturbance and re-organise so as to retain essentially the same function, structure and feedbacks (Walker) The capacity of a system to buffer change, learn and develop (Folke et al., 2002).
  4. 4. Definitional Problem • The majority of research has, at least implicitly, been conducted with the predominant conception of the zone as a geography undergoing predictable, lineal and sequential change in response to movements in urban and rural residential populations. • Most of the traditional definitions of the zone are overly deterministic (e.g. Walker, 1987; Burnley and Murphy, 1995; Theobald,2001).
  5. 5. Driver for Re-Conceptualisation • In my experience the conceptualisation of the peri‐urban space as a lineal system undergoing progressive and unidirectional change has underpinned flawed policy, planning & intervention. • This stimulated interest in reconceptualising peri-urban zone from a complex chaotic systems approach.
  6. 6. Complex Systems Approach • "A 'complex system' is a system consisting of a large number of agents that interact with each other in various ways. • Such a system is 'adaptive' if these agents change their actions as a result of the events in the process of interaction." (Vriend, 1994, p1).
  7. 7. Chaos Theory Chaos theory deals with the changing relationship between order and disorder in the behaviour of natural and social systems which are typified by four main elements: • nonlinearity but self‐similarity of systems dynamics; • qualitative transformations to new dynamical states; • progressively more complex outcomes; as well as • the appearance of new forms of order out of even the most chaotic regimes (Kauffman 1993, Levy 1994, Warner 2001, Young and Keil 1994).
  8. 8. Kauffman (1993) applied the concept of ‘dynamical attractors’ to explain pattern emergence in natural systems (i.e. organs, organisms, species and ecosystems) and postulated that networks poised on the edge of chaos can perform the most complex tasks.
  9. 9. Theoretical construction of the peri-urban zone, derived from a biomimicry framework
  10. 10. Biomimicry - Eureka moment circa 2005 • Use chaos and complex systems theory as the tools to understanding within a biomimicry framework. • Develop a socio-ecological conceptualisation of the periurban zone based on mimicking the natural patterns and process observed in the local landscapes in response to disturbance • Devise principles and strategies which mimic those used by ecosystem restoration ecologists in these peri-urban ecosystems to enhance resilience to repeated disturbance.
  11. 11. Biomimicry is the study of nature, and its models, systems, processes and elements with an aim to imitate or take creative inspiration from nature in order to solve human problems in a sustainable manner (Benyus, 1997).
  12. 12. Biomimicry • Two natural ecosystem types on the Sunshine Coast were mimicked using the theoretical constructs of chaos theory and patch dynamics to characterise peri‐urban zones. • Particularly looking at ecosystem dynamics post disturbance – succession in coastal stream and wetland habitats and wallum ecosystems. • Five dynamic principles which characterise socio‐economic as well as ecosystem processes are postulated which may help to guide successional pathways for agriculture in peri‐urban zones.
  13. 13. Peri-urban zone can be characterised as a spatially and temporally patchy community which is ‘disturbance dominated’.
  14. 14. Post-Disturbance Succession I posit that • Shocks and perturbations such as changes to planning schemes, climatic conditions, water availability and macroeconomic or supply chain characteristics can create spaces where non-agricultural activities or new agricultural enterprises can establish. • In a similar process to healthy coastal wetlands and waterways, and wallum ecosystems succession after disturbance in peri-urban attributes can enhance the coexistence and diversity of agricultural systems.
  15. 15. Source: Mackenzie, Whelan and Oliver
  16. 16. • A typical example of peri-urban communities within an industrialised society • Coastal waterway, wetland and floodplain ecosystems have adapted to highly variable flow regimes and frequent spates and hydrological disturbance • Close to the coast a complex ‘wallum’ ecosystem, exhibits high species diversity in low nutrient coastal plains with periodic fire playing a major role in the structure of the community (McFarland, 1988)
  17. 17. Wetland –Peri Urban Analogy • Wetlands occupy the transitional zone between permanently wet and generally dry environments. They share characteristics of both environments, yet cannot be classified exclusively as either aquatic or terrestrial. • A perception of patchiness is vital in understanding the freshwater ecology of these systems. • Peri‐urban areas encompass a fragmented mixing of urban and rural worlds in a complex mosaic of human and natural subsystems (Allen 2003; Lerner & Eakin 2011; Maxey 2006, Walker 1987).
  18. 18. Patch Dynamics • Hypothesis that disturbance at a range of scales provides the driver that creates patches of different ages and different sizes, resulting in a mosaic of natural habitats. • Disturbances initiate succession - the suite of changes observed in an ecological community following a perturbation that opens a gap. • Frequently resulting in a sequential replacement of assemblages i.e. explaining spatial and temporal variability.
  19. 19. • Disturbances generate space do not always empty cells completely but may selectively remove particular species. The dynamics of such communities is described as relictcontrolled (Townsend, 1989). • There is a mix of localised outcomes with certain patches being controlled by dominant residual species and others controlled by mobile ‘founder’ species. • For example, patch types featuring an abundance of less mobile species are likely to continue to be dominated by these species if the disturbance/flow event is less extreme; • post-disturbance community is likely to be dominated by in-moving ruderal (invasive) species where disturbance is more severe and existing species more sessile.
  20. 20. Dynamic 1 – disturbance regimes determine ‘Founder’ or ‘Relict’ controlled peri-urban zones The timing & intensity of shocks is critical in determining the socioeconomic trajectory of peri-urban agricultural areas
  21. 21. Relict-controlled If a shock such as economic recession hits an area: • which has a young farmer demographic, • while commodity prices are high; and • rainfall above average, then • the disturbance is unlikely to create many new patches where other land uses can establish.
  22. 22. Founder Controlled If the contrary is true, i.e. a perturbation occurs in an area with: • ageing farmer population; • low global commodity price; and • drought • then even minor disturbances may have a major impact; such as • opening relatively large spaces or gaps where new community and industry structures can establish.
  23. 23. Wetland & Waterway Refugia & Colonisation • Refugia (e.g billabongs) play a critical role as sources of recolonisation after spates of inundation, and therefore buffer against disturbance • Most streams species are ruderal, i.e. highly mobile, reproduce rapidly and recolonise swiftly • A well-connected wetland system also retains species diversity over drought periods through a process of dispersal and colonisation from critical refugia • In a similar way, a resilient peri-urban production system will feature diverse and connected social networks and core community hubs that enhance their resilience to disturbance.
  24. 24. Dynamic 2 ‐ Refugia, dispersal and colonisation characteristics determine the adaptability of peri‐urban communities
  25. 25. Refugia & Colonisation • Industry organisations, community groups or institutional arrangements, act like refugia and enable a community to withstand shocks (e.g. major change to funding arrangements) • These network hubs cab drive innovation after disturbance • Colonisation can involve expanding production over multiple properties (colonising gaps through ownership or leases) • Dispersal can involve diversifying income streams (dispersing into different parts of the value chain or colonising different parts of the local economy, e.g. value adding, tourism and off-farm employment).
  26. 26. Wallum ecosystem – peri-urban analogy
  27. 27. Wallum Characteristics • Wallum is a name for the flat to undulating country with a high water table on coastal dunes and plains that features wet an dry heathland and shrubland • Small changes in hydrology and elevation lead to a distinctive spatial mosaic in wallum landscapes. • Wallum communities, like wetland ecosystems, are characterised by their patchiness. Temporal patchiness in this community is related to the adaptive mechanisms that wallum plants have evolved to cope with fire. • Initial Floristic Composition Model (Egler) and vital attributes theories (Noble and Slatyer, 1980) explain the post fire succession
  28. 28. Analogous Peri-urban Attributes • There are several characteristics of wallum communities analogous to the dynamics of peri-urban economies. For example: • Disturbance leads to high level of diversity; • Small changes in terrain result in different community mixes and a modular ecosystem structure in terms of connectivity at a landscape scale. • Adaptation to reasonably harsh transitional environments is required for survival.
  29. 29. Importance of Initial Conditions – Chaos theory link • Species composition immediately after fire determines the succession of vegetation in wallum communities • It is hypothesised that the range of likely future scenarios for agriculture will be heavily dependent on the make up of individuals, enterprises and production systems in existence after disturbance • This will be true whether pre-existing individuals or industries have withstood the shock or others in-movers have rapidly colonised gaps. • Like natural systems, the adaptability and resilience of this mix of ‘species’ will determining how agri-ecosystems and institutions innovate or transform to meet new conditions.
  30. 30. Dynamic 3 – Initial post-disturbance conditions will determine the transformation pathway of peri-urban agriculture
  31. 31. Understanding Potential Trajectories • These attributes of peri-urban systems suggest planners, policy makers and agricultural extension officers should make greater use of scenario-based planning processes • Scenario thinking leads to a more organic complex systems approach that can devise ‘agile’ interventions using the initial conditions as the starting point for future outcomes. • Tactical responses can be modelled for a range of different future scenarios based on the understanding that the unpredictability of timing and scale of future shocks will lead to varied future trajectories and recovery pathways.
  32. 32. Vital Attributes • Wallum ecosystems have adapted to disturbance by featuring a mix of species with different vital life-stage attributes. • E.g. some short-lived plants seed profusely after fire, some regenerate from root-stock after intense fire and others resprout after cooler burns. • It is posited that agricultural systems in peri-urban zones will be more resilient if a conscious effort is made to build analogous attributes into local landscapes and enterprises.
  33. 33. Dynamic 4 – Diverse vital attributes determine the resilience of peri-urban communities
  34. 34. Vital attributes that might be designed/encouraged include: • enterprises which feature a diversity of commodities and market segments and the creation of different niche attributes which act as a buffer from shocks in one part of a market • diversity in the life-stage of principal players in the production system including: – the retention of mature, traditional farmers with intergenerational tacit knowledge of the landscape and shocks – middle age ‘sea/tree changers’ who bring more professional life experience who can apply a cross-disciplinary approach – a suite of first, second and third generation young innovative farmers with the capacity to ‘resprout’ and adapt to disturbance
  35. 35. Ecotonal Diversity • Ecological literature suggests the form and functions of patch edges have powerful effects on the movements of individuals, resources and processes across them, and • That diversity is high in ecotonal communities (transition zones). • Dynamics of ‘ecotonal’ peri-urban agriculture systems are very similar to that described previously for wetland and wallum ecosystems.
  36. 36. Dynamic 5 – Ecotonal patchiness facilitates peri-urban diversity and innovation
  37. 37. On the Edge of Chaos • Complex systems produce their most inventive displays in the region of behaviour on `the edge of chaos. • Systems operating in the vicinity of the edge exhibit wild bursts of creativity and produce new and novel behaviours at the level of the whole system • Communities and economies in the transition between urban and rural areas display many of the characteristics of a system ‘on the edge of chaos’.
  38. 38. In Summary Recurring underlying patterns of social and economic behaviours can be explained by five dynamic principles which mimic patch dynamics in peri-urban wetlands, waterways and wallum ecosystems.
  39. 39. Five Dynamics 1. Disturbance regimes determine ‘founder’ or ‘relict’ controlled peri‐urban zones 2. Refugia, dispersal and colonisation characteristics determine the adaptability of peri‐urban communities 3. Initial post disturbance conditions will determine the transformation pathway of peri‐urban agriculture 4. Diverse vital attributes determine the resilience of peri‐urban communities 5. Ecotonal patchiness facilitates peri‐urban diversity and innovation
  40. 40. Conclusion • The challenge of reconfiguring agriculture systems in periurban zones is to understand and influence successional processes within social, economic and agri-ecological systems. • Applying biomimicry from natural ecosystems reveals insights about adaptation to disturbance that may aid this reconfiguration process and enhance the longer term resilience of peri-urban agricultural systems. • Application of the 5 dynamic principles by practitioners may help create agricultural systems that are adapted to repeated disturbance and resilient to future shocks
  41. 41. REFERENCE • Stockwell, B. 2011. Understanding the role of disturbance in peri‐urban agricultural systems and communities: new concepts and principles to guide strategic intervention. Int. J. Innovation and Sustainable Development, Vol. 5, No. 4,