Social-ecological systems appear to share attributes by which resilience can be characterized and assessed. We have investigated which system attributes relate specifically to the ecological definition of resilience, asking, “What attributes reflect whether a system will be able to continue to function and retain its identity in the face of existential challenges?” We considered attributes for all types of systems, including natural and manmade, physical and institutional, small and large, simple and complex. A number of researchers have defined various attributes of system resilience.
2.1. Previous Efforts to Move from Theory to Application
In his seminal work on the subject, Holling examined the concepts of resilience and stability and described how diversity and connectivity contribute to system resilience [1
]. Several years later, in examining the vulnerability of the American energy system, Lovins advanced the concept of managing for resilience by proposing an approach to a design science for resilience, wherein he delineates a set of key attributes for system resilience associated with both engineered and biological systems [22
]. These attributes, the descriptions of which focus on a national energy system, included: fine-grained, modular structure; early fault detection; redundancy and substitutability; optional interconnection; diversity; standardization; dispersion; hierarchical embedding; stability; simplicity; limited demands on social stability; accessibility, and reproducibility. With these attributes, Lovins made significant strides in articulating terms of resilience common to both natural and human-designed systems.
Lee examined the essential contribution of adaptive management, the capacity for institutional learning, and the requirements for leadership and collaboration. Adaptive management, in particular, was advanced by Lee, with agencies and organizations implementing adaptive management widely in various forms [23
Becker and Ostrom examined a series of case studies to formulate general principles for organizing the types of institutions that successfully manage resources in a sustainable manner [24
]. They identified eight principles: clearly defined boundaries (for both resources and resource users); proportional equivalence between benefits and costs (rules specifying resource allocation are based on local conditions); collective-choice arrangements (affected participants can influence the rules); monitoring (of resources and user behavior by accountable monitors); graduated sanctions; conflict resolution mechanisms; minimal recognition of rights to organize (outside authorities do not challenge local institutions), and nested enterprises. Becker and Ostrom differentiated the institutional rule sets required for managing renewable versus
single use resources.
Walker et al.
examined the relationships between three related attributes of SESs that appear to determine the future trajectory of an SES: resilience, adaptability, and transformability [14
]. Regarding resilience, they described four key aspects: latitude—the maximum amount a system can be changed before it breaches a threshold and loses its ability to recover its identity; resistance—the ease or difficulty of changing the system; precariousness—how close the current state of the system is to the threshold; and panarchy—the resilience of the system at one scale is dependent on system dynamics at other scales “above” and “below.” Walker et al.
also discussed the concepts of Stability and Balance in regards to system resilience.
Revisiting that line of research, Folke et al.
examined how adaptability captures the capacity of a SES to combine experience and knowledge to learn [25
]. Folke et al.
described how “resilience is often associated with diversity” [4
]. Discussing the importance of adaptive management (and co-management), they maintained that management actions that build resilience are flexible and open to learning and collaboration.
Folke et al.
examined ecosystems undergoing change and described the importance of maintaining functional-group diversity and functional-response diversity for the conservation of biodiversity and ecosystems [10
Walker et al.
asked “When does it make sense to build resilience and what is the best way to do it for a particular SES?” In answer, they proposed a “resilience analysis and management approach” [11
]. They discuss the importance of collaboration among stakeholders in the system to ensure the legitimacy of the effort.
Walker et al.
advanced a series of concepts about resilience, several of which were proposed as attributes of resilient systems [5
]: adaptability (including functional diversity, response diversity, redundancy, social capacity including leadership, social networks, trust, innovation and skills); linkages; institutions for self-determination; capital reserves (natural, social, financial, infrastructure), and learning, memory, and adaptive co-management.
Ostrom’s Institutional Analysis and Development (IAD) Framework provided a means for assessing how institutional traits and characteristics and the leadership capacities (and limitations) of key actors at multiple levels within any system can influence system resilience [26
]. She discussed the importance of learning capacity in the context of institutional structure. She also cautioned that differences between individual institutions may be so great as to confound simple comparison. This observation may argue for the development of system-specific resilience metrics based on generalized resilience attributes, as is discussed in this article. Ostrom also provided additional explanation of the role of leadership in [27
], showing that when some members of a group possess entrepreneurial skills and are respected locally, self-organization to manage resources is more likely. She also addressed the role of norms for reciprocity in building trust that supports collaborative efforts.
Berkes examined the relationship of resilience and vulnerability in regards to natural hazard evaluation [28
]. He identified a series of factors relevant to building resilience: learning to live with change and uncertainty; nurturing various types of diversity (ecological, social, political); developing learning capacity; promoting self-organization and autonomy; strengthening local institutions; building cross-scale linkages, and building problem-solving networks. Berkes described the concept of false subsidies, the need for tight coupling of monitoring and response, as well as how adaptive capacity is strengthened by adaptive management and institutional learning.
Examining the relationship between sustainability and resilience, Fiksel described strategies for enhancing ecological resilience including [2
]: broaden knowledge sources; increase human ability to cope with change and uncertainty; introduce adaptive management practices; build networks (social and scientific).
In Resilience Thinking
, Walker and Salt (2006) described a series of key attributes of resilience, including: Functional Diversity, Response Diversity, Modularity, Redundancy, Tightness of Feedbacks, Reserves, and Collaboration [3
]. In Resilience Practice
, Walker and Salt developed a framework for assessing general resilience that is focused on Adaptive Capacity, and specifically the attributes: Diversity, Openness, Reserves, Tightness of Feedbacks, Modularity, Leadership, Social Networks, Trust, and Levels of Capital Assets [6
Olsson et al.
examined a series of case studies across the globe, comparing the outcome of various management actions employed as an SES is transformed [29
]. They found that leadership and shadow networks are key components for preparing for and effecting such transformations. Leadership functions include: spanning scales of governance; building knowledge; orchestrating networks; communicating understanding and reconceptualizing issues; reconciling problems; recognizing or creating windows of opportunity; promoting and stewarding experimentation as smaller scales; and promoting novelty by combining different networks, experiences, and memories.
Thomas and Kerner described the resilience enhancing potential of adaptive management and collaboration, as well as the negative influence of false subsidies, for energy security policies and programs [30
Biggs et al.
examined the current literature to identify seven principles for enhancing resilience of ecosystem services [12
]: maintain diversity and redundancy (addressing response diversity, balance, and disparity); manage connectivity (including modularity and nestedness); manage slow variables and feedbacks; foster an understanding of SESs as complex adaptive systems; encourage learning and experimentation (addressing adaptive management); broaden participation, and promote polycentric governance systems (conveying modularity and functional redundancy). The first three of these principles address general SES properties and processes, while the remaining four focus on governance of the SES. The authors state that this is not a definitive set of principles, but one advanced to stimulate further discussion and refinement. They write: “there is a pressing need for a better understanding of how the principles can be operationalized.”
In examining the related concepts and appropriate management context of robustness, resilience, and sustainability, Andries et al.
discuss how incorporating the principles of managing for robustness can add rigor to managing for resilience [31
]. They discuss a number of key attributes for resilient systems: adaptive capacity and response diversity; adaptive management and the capacity to learn; transformability; understanding cross-scale interactions and feedback systems, and collaboration.
Stokols et al.
discussed how resilience theory relates to social-ecological systems theory [32
]. They described the core principles of social ecology and how these contribute to community resilience. They presented a detailed description of the forms of capital available to and necessary for SESs to function. This includes Material Resources: economic/financial capital—financial assets for attaining productivity; natural capital—resources produced through natural processes; human-made environmental capital—physical resources designed and built; and technological capital—machinery, equipment, digital/communications devices. It also includes Human Resources: social capital—relationships among people that facilitate action; human capital—capacities of persons, including skills and information; and moral capital—investment of personal and collective resources toward justice/virtue.
2.2. Stakeholder Analytical Constraints
All resilience analysis methodologies are hampered by a limited knowledge about the system in question and the spatial, temporal, and contextual (environmental, socio-cultural, regulatory, and related) circumstances within which it functions. Figure 1
depicts different levels of knowledge a stakeholder might have about their SES.
Extent of knowledge about SES.
Extent of knowledge about SES.
Note: Different system stakeholders have different levels of knowledge concerning the system, its components, and adjacent systems.
Given the complex, adaptive, and stochastic nature of an SES, even a slight difference in system insight could yield a significantly different understanding of the system’s dynamics, and therefore resilience, in the face of shocks and perturbations. These limits inherently constrain even the most comprehensive of analyses. As such, an incremental approach to resilience assessment may prove most productive, beginning with examining a system’s resilience-specific attributes to develop a baseline understanding of the system’s “resilience posture”; this in turn supports deeper investigations of resilience phenomena for which information beyond the normal purview of the stakeholder must be pursued. Moreover, the availability of common analytical terms supports better coordination in the further development of resilience theory.
It should also be noted that the varying degrees of stakeholder knowledge about a system, which may arise for a number of reasons, point to the importance of cooperation in order to work comprehensively within the system.
2.3. The Synthesis of Practical Resilience Attributes
From the above examination of the literature, we can develop an understanding of key traits of resilient systems as conceived by researchers from diverse academic and practicing fields, including ecology, wildlife and fisheries management, water resource management, various branches of engineering, hazard mitigation, risk management, operations research, and institutional analysis.
As stated, our efforts are focused on making theory serviceable to the practitioner, namely the stakeholder seeking to understand and affect the resilience of a system. This requires consideration of certain factors: First, stakeholders usually know their systems best. An outsider may offer new ways of examining a system, but the stakeholder will have both the broadest and the most intimate knowledge about that system. Second, stakeholders have limited time and resources. The perceived value of additional analyses and actions will be weighed against more pressing requirements. And third, stakeholders pay the most attention to that which they believe can most affect their systems. Concern about other possible influences, internal or external, tends to fall off with a decrease in the perceived likelihood and consequence of that influence.
To accommodate these factors, we have sought to develop, derive, and compile resilience analysis terms that: are stated in the language of stakeholders; address easily-assessed system attributes without extensive knowledge of new theory; and promote the ready consideration of the broadest range of factors that could affect system resilience. Prior efforts have tended to yield theory-oriented terms that suit the resilience theoretician; we have sought to provide systems-oriented terms that favor the stakeholder involved in resilience analysis.
In addition to meeting stakeholder needs in their own vocabulary, there is another pragmatic reason for this approach: It is much harder to recognize, understand, and characterize the tremendous variety of systems from the resilience perspective than it is to recognize, understand, and characterize resilience concepts from those systems’ perspective. Put another way, the world of possible systems is harder to delineate in resilience-theory terms than resilience theory is to delineate in systems terms.
Expanding on the terms employed by Lovins [22
] and addressing open systems (i.e.
, SESs), and drawing on the authors’ own research as well as that of others (as cited above and in the discussion of the individual resilience attributes below), we derived or synthesized from basic resilience theory literature the specific attributes associated with a system’s resilience. We identified resilience concepts already expressed in terms stakeholders could easily use to measure or characterize their system, then crafted additional system-oriented terms to capture those concepts not yet described in stakeholder-friendly language, with the focus remaining on what a stakeholder can readily measure or characterize about their system. The resilience literature was revisited to ensure system attributes had been included that would support an assessment of each resilience concept. Finally, several iterations were made to combine like terms under single headings if it could be done without losing pertinent, independent system attributes. The terms are intentionally generic to support a wide variety of systems, with the understanding that stakeholders will employ them in a manner and language aligned with their unique systems.
To meet typical stakeholder needs, we focus on system traits that can be construed from information commonly available within the system, or easily obtained by those stakeholders. The terms form a baseline for resilience analysis, providing a snapshot of the system’s resilience posture that could be retaken on a regular basis as part of an adaptive management strategy to maintain and enhance system resilience.
The attributes also form the basis for the first part of an iterative approach to assessing system resilience. Others have sought to capture all aspects of resilience theory in their attempts to postulate metrics, but they require analytical approaches that are not administratively and economically realistic for many system managers. Instead, an understanding of more nuanced aspects of resilience, such as panarchy, latitude, or precariousness, can then be built on the baseline these terms afford.
Finally, stakeholders are the ones who will ultimately decide whether to assess the resilience of their systems, and this hinges on their understanding of the value of these concepts. In many cases, it is best for system stakeholders to apply concepts in order to learn them, as opposed to learning concepts in order to apply them. The availability of user-friendly terms for straightforward system resilience analyses best suits this objective.
Taken together, these attributes are intended to provide the terms that are necessary and sufficient to describe the resilience posture of any system. Care was taken to develop terms that reflect system resilience rather than a desired end-state or system output. While there is significant overlap between the attributes, each term has been found adequately unique to stand as a separate trait. Note that certain attributes will play a more prominent role than others in any given situation, but the entirety of the list is intended to provide a firm foundation for assessing and managing resilience.
The resilience attributes and their definitions are provided in Table 1
. They are grouped into categories of Stability, Adaptive Capacity, and Readiness.
|Single Points of Failure||Singular features or aspects of the system, the absence or failure of which will cause the entire system to fail.|
|Pathways for Controlled Reductions in Function||Whether the functionality of a system, operation, or capability can be reduced in a manner that avoids the overwhelming effects of an unconstrained failure.|
|Resistance||The insensitivity of the system to stresses of a given size, duration, or character.|
|Balance||The degree to which a system is not skewed toward one strength at the expense of others.|
|Dispersion||The degree to which the system is distributed over space and time.|
|Adaptive Capacity Category|
|Response Diversity||The variety and disparity of steps, measures, and functions by which an operation can carry out a task or achieve a mission.|
|Collaborative Capacity||The capacity to act through coordinated engagement.|
|Connectivity||How readily resources and information can be exchanged to ensure continued functionality.|
|Abundance/Reserves||The on-hand resource stores (capital) upon which a system can rely when responding to stress.|
|Learning Capacity||The ability to acquire, through training, experience, or observation, the knowledge, skills, and capabilities needed to ensure system functionality.|
|Situational Awareness||How well system, component, and functional capabilities are monitored. How readily emerging stresses or failures can be detected.|
|Simplicity/Understandability||How well system functions and capabilities can be understood.|
|Preparedness||The level of preparation in plans, procedures, personnel, and equipment for responding to system perturbations.|
|False Subsidies||Whether inputs, outputs, or internal processes receive incentives disproportionate or unrelated to their value.|
|Autonomy||A system manager’s authority to select and employ alternate actions, configurations, and components in response to stress.|
|Leadership and Initiative||The ability to motivate, mobilize, and provide direction in response to disruptions, as well as the ability to assume responsibility and act.|
The attributes are sorted into the three categories (Table 2
) to provide an easy cognitive basis for organizing the resilience attributes. It should be noted, however, that the attributes do not arise from the categories, but the categories instead arise from a convenient grouping of the attributes. Each of the attributes in fact features some degree of all three categories.
Categories of Resilience Attributes.
The categories do, however, offer a useful functional construct. Put simply, managers need to know if the system as currently structured and resourced can survive a challenge (Stability), have the ability and options to respond if necessary (Adaptive Capacity), and understand if there are factors that help or hinder that response (Readiness).