Recently, the idea of resilience has started to dominate thinking about all sorts of biological and social systems. It is, in fact, quite an old idea, first introduced in 1973 by C.S. Holling, an ecologist himself. Based on his first seminal paper, Holling and others later extended the concept of resilience to a wide range of systems that include aspects of social and ecological sciences. But what is resilience? And how does it differ from stability?
Holling distinguishes resilience and stability as two opposite characteristics of ecological systems. Stability is the ability of a system to return to the same equilibrium state after a temporary disturbance. “Resilience, on the other hand, is the ability of systems to absorb change and disturbance and still maintain the same relationships between populations or state variables.”
What matters is how the system changes after a disturbance.
A diverse ecological system, such as a forest, can be very resilient and still fluctuate greatly over time, thus showing low stability. The forest persists, delivering similar ecosystem and social benefits, even though the tree species in it and their distribution may change.
Conversely, a fairly homogeneous and self-contained system, such as the Great Lakes in North America, shows low variability and hence high stability, but low resilience. Taking the fish away could trigger changes that the ecosystem could not cope with and still maintain a similar productivity.
Holling argues that the resilience and stability viewpoints yield two completely different approaches to the management of biological resources.
“The stability view emphasizes the equilibrium, aiming at a predictable world where harvesting of nature’s excess production happens with as little fluctuation as possible”.
“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 to emphasize heterogeneity”.
Today, forests are facing risks as a result of climate change. They are simultaneously perennial and dynamic systems. They evolve continuously, driven by the interplay of natural processes and human actions. In the context of global change, there are multiple uncertainties about how forests will respond to disturbance and management.
Which approach should forest scientists and managers adopt?
The interdisciplinary panel of experts that gathered at the EuroScience Open Forum in Toulouse on 10 July 2018, presented the reasons why Holling’s resilience viewpoint is best for today’s world, full of uncertainties.
Resilience thinking, applied to the forestry sector, favours adaptive management strategies to cope with uncertainty and keep options open. By contrast, stability thinking fixes a target objective and assumes minimum uncertainty. Resilience implies using diverse forest management practices, and forest governance that encourages diversity rather than ‘one solution fitting all’.
Resilience thinking allows and encourages experimentation, because as much as the science is rapidly moving forward, we do not know what will work under all circumstances.
If resilience thinking is to guide forest management, we need to encourage experimentation and open-mindedness. And for that, we need to recognise the many benefits of forests to people and the key role of forest managers in providing those benefits.
The ESOF session ‘Resilience and adaptation of forest social-ecological systems in the context of global change’ on 10 July 2018 was organized by François Lefèvre, INRA National Institute for Agricultural Research, France; with Teresa Baiges Zapater, CPF Catalonia Centre de la Propietat Forestal, Spain; Davide Pettenella, TESAF University of Padova, Italy; Georg Winkel and Ewa Hermanowicz, EFI European Forest Institute, Germany.
Holling (1973) Resilience and Stability of Ecological Systems, Annual Review of Ecology, Evolution and Systematics 4:1-23.
INFORMED project (Integrated research on forest resilience and management in the Mediterranean)