Ecological resilience for ecologists Benjamin Planque, Grégoire Certain, Raul Primicerio, Kathrine Michalsen, Lis Lindal Jørgensen, Michaela Aschan, Padmini Dalpadado, Mette Skern-Mauritzen, Edda Johannesen, Susanne Kortsch, Magnus Wiedmann Read title + BarEcoRe project + co-authors

BarEcoRe: Resilience of the Barents Sea ecosystem to climate and fishing what does resilience mean?

the ability to absorb disturbance and maintain structure and function

The multiple facets of resilience adaptability functional diversity robustness adaptive cycles functional redundancy social-ecological systems amplitude complex adaptive systems hysteresis stability identity sustainability complexity inertia taxonomic diversity cross-scale redundancy maleability tipping points marble metaphor transformability early warning signals modularity variability ecosystem services panarchy viability elasticity regime shifts vulnerability engineering resilience resilience thinking resistance foodweb topological structure return rate BarEcoRe project = study of the resilience of the Barents Sea ecosystem. We thought we knew what resilience meant but we faced a plethora of terms related to resilience and this resulted in a fair amount of confusion and arguments. How to put a little bit of order into all this?

What do these concept mean? Can we use them in quantitative ecology? Structural properties Normative Conceptually vague trans-disciplinary Descriptive Conceptually precise Quantitative ecology Well, we have not found the ultimate solution but rather a useful way to clarify the meaning of many of these concepts, and in particular whether they are useful and applicable in quantitative ecology. The poster shows two axes of classification of concepts: first an axis which separate terms that are descriptive, conceptually precise and can be used in quantitative ecology, from those that are more useful in a trans-disciplinary context but which can be conceptually vague, normative and not quantitative. Second, on the right part of the map we separate concepts that describe structural properties of ecosystems from those that relate to the dynamic properties. Dynamic properties

The poster is an interactive support for discussion The poster is an interactive support for discussion. You can come and test your knowledge about resilience related concepts and place the words on the conceptual map.

There is no unique way to define resilience Vague terminology promotes creative thinking Being precise ensure testability of concepts Clarify ‘specific’ concept and the associated measures & metrics Make sure these are applicable to a given system/data/model

Holling 1973 “I propose that the behavior of ecological systems could well be defined by two distinct properties: resilience and stability. 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. Stability, on the other hand, is the ability of a system to return to an equilibrium state after a temporary disturbance… In this definition stability is the property of the system and the degree of fluctuation around specific states the result.”

Westmann, 1978 Elasticity: rapidity of restoration of a stable state following disturbance. Pimm, 1984 Resilience: how fast the variables return towards their equilibrium following a perturbation. Resilience is not, therefore, defined for unstable systems.

Engineering vs. ecological resilience: the marble metaphor Ecological Resilience ~ probability of staying in the valley Engineering resilience ~ rate of return to the bottom of the valley I will start with the correspondence between the observation of temporal changes in ecosystems and ecosystem resilience. Resilience is often defined as the ability to maintain structure and function. If we refer to the marble metaphore, illustrated here by Peterson et al 1998, the ecosystem state at a given time can be represented in a landscape and tends to maintain itself close to equilibrium, i.e. in a valley. If the ecosystem state crosses a critical point no either side of the valley, it is interpreted that the structure and function of the system has changed and resilience has been lost. This is why the substantial changes in structure and function and generally interpreted as lack of resilience. Peterson et al., 1998

Walker et al., 2004 Resilience is the capacity of a system to absorb disturbance and reorganize while undergoing changes so as to still retain essentially the same function, structure, identity and feedbacks. Cumming et al., 2005 We equate resilience with the ability of a system to maintain its identity, where system identity is defined as a property of key components and relationships (networks) and their continuity through space and time. Levin and Lubchenko, 2008 the notion of resilience is sometimes interpreted in the general literature in the narrower sense of recovery from disturbance, and at other times in the broader sense of the maintenance of functioning in the face of disturbance. Within this article, we adopt the broader definition, and we do not distinguish it from robustness.

Derissen et al., 2011 Some authors explicitly define or implicitly understand the notions of resilience and sustainability such that they are essentially equivalent. Levin et al (1998) claim in general that “resilience is the preferred way to think about sustainability in social as well as natural systems”, thus also suggesting an equivalence of resilience and sustainability.