RESILIENCE IN THE ANTHROPOCENE - Rethinking Invasion Ecologies from the Environmental Humanities - page 47

C. S. Holling and resilience
Resilience was defined as an ecological concept in 1973 by C. S. (Buzz) Holling,
an animal ecologist and evolutionary biologist interested in mathematical models
of predator-prey relations. His 1973 definition, still frequently cited, was that
resilience was a measure of 'the persistence of systems and their ability to absorb
change and disturbance' (Holling, 1973: 14). Holling contrasted resilience with
stability , 'the ability of a system to return to an equilibrium state after a temporary
disturbance' (ibid.: 14) The value of the concept of resilience in ecology was that
it described the system as it responded to a changing world whether there was
equilibrium or not. It theorised the relationship between the shocks and the system,
and was suitable for assessing the effects of the activities of people on natural
systems.
A resilient system keeps absorbing successive shocks and adapting without
dramatically altering the relationships between its parts. But at some point this
resilient character passes a limit and beyond this, 'the system rapidly changes to
another condition' (ibid.: 7). The example Holling gave was of a small Italian lake
whose limnology was unchanged for a very long period, even though the
catchment around it changed from steppe to grassland to forest. Then, suddenly,
the hydrography of the lake changed and it became eutrophied (rich in nutrients).
What had changed? The eutrophication corresponded to the building of the
Roman road, the Via Cassia, about 171 BC . The surrounding landscapes could have
very little cover or whole forests without changing what could or could not live
in the lake. But a hard Roman road and people using it suddenly altered the way
water flowed into the lake. It was the anthropogenic change that altered and
decided which animals and plants could survive there.
Resilience is the stretch of the system, what it can absorb and adapt to, but it is
not an infinite property. It has limits (ibid.: 7). Limits were very much in vogue in
the 1970s. The famous report, Limits to Growth (Meadows et al ., 1972) was
published the year before this paper. The language has changed. In the 1970s and
1980s, people spoke of 'abrupt change' or 'flips' in the system (Broecker, 1987:
125). Now, more commonly, we hear terms like 'threshold levels', 'tipping points'
or 'planetary boundaries' (Lindsay and Zhang, 2005; Rockström et al ., 2009,
Bhatanacharoen et al ., 2011). The scale is more often global, but the idea of focusing
on the system (even the whole Earth) under stress, has gathered pace since Holling's
original resilience paper. Resilience enabled ecologists to think about which
properties of a system maintained its essence , and which forced a system to shift from
one state to another.
Ecology has moved away from the idea of natural balance. Resilience is one of
the concepts it has developed to describe interactions between dynamic natural
systems, and increasingly between natural and social systems (Egerton, 1973).
Resilience is also a key metaphor in business and medicine, particularly psychiatry,
the study of the psyche under stress (Luthar, 2006). Indeed, it sometimes works
near the nodes of connections between ecology, business and medicine (sustainable