Stockwell_B_Understanding the role of disturbance in peri-urban
Understanding the role of disturbance in
peri-urban agricultural systems and
New concepts and principles to guide strategic
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
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).
• 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
• Most of the traditional definitions of the zone are overly
deterministic (e.g. Walker, 1987; Burnley and Murphy,
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
Complex Systems Approach
• "A 'complex system' is a system consisting of a large
number of agents that interact with each other in various
• 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).
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).
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.
Theoretical construction of the peri-urban
zone, derived from a biomimicry framework
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
• Devise principles and strategies which mimic those used by
ecosystem restoration ecologists in these peri-urban
ecosystems to enhance resilience to repeated disturbance.
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).
• 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 zone can be characterised as a
spatially and temporally patchy community
which is ‘disturbance dominated’.
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.
• A typical example of peri-urban communities within an
• 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)
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,
• 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
• 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
• 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.
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
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.
If the contrary is true, i.e. a perturbation occurs in
an area with:
• ageing farmer population;
• low global commodity price; and
• 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.
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
Dynamic 2 ‐ Refugia, dispersal and colonisation characteristics
determine the adaptability of peri‐urban communities
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
• These network hubs cab drive innovation after disturbance
• Colonisation can involve expanding production over
multiple properties (colonising gaps through ownership or
• 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).
• 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
Analogous Peri-urban Attributes
• There are several characteristics of wallum communities
analogous to the dynamics of peri-urban economies. For
• 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.
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.
Dynamic 3 – Initial post-disturbance conditions will
determine the transformation pathway of
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.
• Wallum ecosystems have adapted to disturbance by
featuring a mix of species with different vital life-stage
• 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.
Dynamic 4 – Diverse vital attributes determine the resilience
of peri-urban communities
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
• 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
• 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
• Dynamics of ‘ecotonal’ peri-urban agriculture systems are
very similar to that described previously for wetland and
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’.
patterns of social and
economic behaviours can
be explained by five
dynamic principles which
mimic patch dynamics in
waterways and wallum
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
5. Ecotonal patchiness facilitates peri‐urban diversity and
• The challenge of reconfiguring agriculture systems in periurban zones is to understand and influence successional
processes within social, economic and agri-ecological
• 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
• 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,