xiv Resilience theory (Walker and Salt 2006) was developed by ecologists over the
past three decades to explain surprising and nonlinear dynamics of complex adaptive systems (Gunderson and Holling
2002, Walker et al. 2004). Moreover, resilience theory is the basis for adaptive management, which embraces uncertainty
of complex resource systems (Holling 1978, Walters 1986, 1997).
xiv Development of ecological resilience theory began in the 1960s with attempts to mathematically model
dynamic ecosystems.
xix The dynamics of complex adaptive systems following large-scale disasters... present problems of predictability
for management... Yet planning and management require some estimate of future conditions.
xx Adaptive management acknowledges the deep uncertainties of resource management and attempts to
winnow those uncertainties over time by using management actions as experiments to test policy... Developers of adaptive
management approaches... acknowledged the complex multidimensionality of natural resource issues but focused on analytic approaches
primarily in the ecological and economic domains from a systems perspective.
xxi The purpose of this volume is to synthesize the key scientific papers that led to our current
understanding of resilience... Our focus is specifically on ecological resilience. The concept of ecological resilience
is often applied to social-ecological systems, but the foundations are in ecology.
p.4 Systems have a capacity to absorb disturbance, but this capacity has limits and bounds, and
when these limits are exceeded the system may rapidly transform. Holling was the first to recognize the significance
of thresholds in ecological systems, and the importance of avoiding them.
p.5 resilience is defined as a measure of a system's persistence and its ability to absorb change
and disturbance but still maintain the same relationships among population or state variables.
p.7 Holling (1996) also begins to formulate a model of the relationship among ecological
diversity, resilience, and scale (formally conceptualized in Peterson et al. 1998). He notes that resilient systems
have multiple controls that are most efficient on different scales, and that the distribution of diversity
within and across scales is what matters.
p.41 Resilience determines the persistence of relationships within a system and is a measure of
the ability of these systems to absorb changes of state variables, driving variables, and parameters, and still persist.
In this definition resilience is the property of the system and persistence or probability of extinction is the result.
p.46-47 A management approach based on resilience, on the other hand, would emphasize the need to
keep options open, the need to view events in a regional rather than a local context, and the need to emphasize heterogeneity.
Flowing from this would be not the presumption of sufficient knowledge, but the recognition of our ignorance;
nor the assumption that future events are expected, but that they will be unexpected. The
resilience framework can accommodate this shift of perspective, for it does not require a precise capacity
to predict the future, but only a qualitative capacity to devise systems that can absorb and accommodate future events in
whatever unexpected form they may take. [JLJ - application for game theory]
p.53 Ecosystems are moving targets, with multiple potential futures that are uncertain and unpredictable.
Therefore management has to be flexible, adaptive, and experimental at scales compatible with the scales of critical
ecosystem functions (Walters, 1986).
p.64 There are indeed strong suggestions that management and institutional regimes can be designed
to preserve or expand resilience of systems as well as provide developmental opportunity. It is a central issue that
only now is beginning to be the focus of serious scholarship and practice.
p.121 The new perspective recognizes that resilience can be and has been eroded and that the self-repairing
capacity of ecosystems should no longer be taken for granted (Folke 2003, Gunderson 2000). The challenge
in this new situation is to actively strengthen the capacity of ecosystems to support social and economic development.
It implies trying to sustain desirable pathways and ecosystem states in the face of continuous change (Folke
et al. 2002, Gunderson & Holling 2002).
p.121 Here, we define resilience as the capacity of a system to absorb disturbance and reorganize
while undergoing change so as to retain essentially the same function, structure, identity, and feedbacks (Walker
et al. 2004). The ability for reorganization and renewal of a desired ecosystem state after disturbance and change will strongly
depend on the influences from states and dynamics at scales above and below (Peterson at al. 1998)... Hence, resilience
reflects the degree to which a complex adaptive system is capable of self-organization (versus lack of organization
or organization forced by external factors) and the degree to which the system can build and increase the capacity
for learning and adaptation (Carpenter et al. 2001b, Levin 1999).
p.154 To a large extent this is a consequence of the fact that organisms and their
environments are connected by a complex web of interrelations and feedbacks that are non-linear, and contain lags and discontinuities,
thresholds, and limits (Kay 1991, Costanza et al. 1993).
p.161 Being adaptive means, among other things, being able to respond to environmental feedbacks
before those effects challenge the resilience of the entire resource base and the economic activities that depend on it.
That is, it is necessary to frame the level of economic activity in a way that minimizes the risk of irreversible damage to
the system on which human activity depends (Perrings and Opschoor 1994).
p.188 We argue that ecosystems are usefully
considered not as fixed objects in space, but as interacting, self-organized sets of processes and structures that
vary across scales.
p.303 In contemporary times, resilience is considered a component of complex systems of both people
and nature (Walker et al. 2004, Walker and Salt 2006), but such thinking took decades to develop.
p.335 A conceptual framework for policy design is meaningless unless a cohesive methodology links
it to the constraints and realities of actual management practice.
p.338 the first requirement is to develop an effective and validated dynamic description of the
ecological constraints of the problem. In practice, this means a simulation model which can be used as a
kind of "laboratory world" with some confidence that it will be responsive to the exploration of a variety of different
policies and their consequences.
p.339 An ecological policy design program must be based on a generalizable description of the underlying
biology if it is to be usefully responsive to inevitable but unpredictable changes in the decision environment and if it is
to meet the requirements of transferability across a wide range of decision problems.
p.339 The Modeling Problem
Myth: The descriptive model should be as comprehensive as possible.
Any model represents an abstraction of reality. The problem is not whether, but what to leave
out.
Ecosystem management problems are comprised of an immense array of interacting variables, conflicting
objectives and competing actions. Attempts to comprehensively model such complexities are futile... Our experience
has suggested the opposite course: to be as ruthlessly parsimonious and economical as possible while still retaining responsiveness
to the management objectives and actions appropriate for the problem. The variables selected for system description must be
the minimum that will capture the system's essential qualitative behavior in time and space.
The initial steps of bounding the problem determine whether the abstract model will usefully represent
that portion of reality relevant to policy design. Key decisions must be made regarding the policy domain, the ecosystem variables,
the temporal horizon and resolution, and the spatial extent and resolution to be modeled.
p.340 The policy domain can be defined, or bounded, by specifying the range of acts and indicators to which
the dynamic model will be responsive... Objectives are descriptions of desired system behavior... Acts are
the physical weapons in the manager's arsenal. They are the actual things which he can do... policies are the rules
or plans by which acts are applied to the system in order to obtain its desired behavior... policies are prescriptions for
action
p.349 some of the major advances in coping with the unexpected and unknown have applied the techniques
of adaptive management (Walters and Hilborn, 1976).
p.364 The first responsibility of policy design is to generate and explore a strategic range of alternative
approaches to the management problem. Subsequent efforts can seek to evolve a satisfactory or, more ambitiously, an optimal
policy from this initial range.
p.434 Adaptive capacity has been defined in the ecological literature as the ability to manage resilience
(Gunderson 2000, Walker et al. 2004)... humans do manage for adaptive capacity. Those management actions can be categorized
as those that are aimed at buffering the impact of disturbances (Berkes and Folke 1998, 2002), those that
accelerate recovery and renewal, and those that attempt to choose and manage transitions among alternative regimes.
