The myth of the optimal state: adaptive cycles and the birth of resilience thinking

By David Salt

Being sustainable, is tough. So far, we (as in humanity) are failing at the task miserably. My contention is that a big part of the problem is our inability to deal with the complexity of the systems around us, that we are a part of. Rather than acknowledging this complexity, we impose framings on these systems treating them as simple. (I discussed these ideas in complicated vs complex.)

Command and control

Simple systems can be managed and controlled, and held in an optimal state for as long as needed. Complex systems, on the other hand, self-organise around our efforts to control them. They can’t be held in an optimal state.

The notion of an ‘optimal sustainable yield’ was a widespread idea in natural resource management last century. The belief was that if you knew a little about what drives a natural resource (say reproductive capacity in fish stocks or forest trees), you could harvest that system removing an optimal amount of that resource forever as it would always replace itself. It’s a command-and-control approach that left countless collapsed fisheries and degraded landscapes in its wake.

‘Command and control’ involves controlling aspects of a system to derive an optimized return. The belief is that it’s possible to hold a system in a ‘sustainable optimal state’.

However, it’s not how the world actually works. Yes, we can regulate portions of the system, and in so doing increase the return from that portion over a short time frame, but we can’t do this in isolation of the rest of the system. If we hold some part of the system constant, the system adapts around our changes, and frequently loses resilience in the process (ie, loses the capacity to recover from a disturbance).

While we can hold parts of the system in a certain condition, the broader system is beyond our command. Indeed, no one is in control; this is a key aspect of complex adaptive systems.

Resilience thinking is an alternate approach to working with these systems, an approach that places their complexity front and centre. And the origins of this approach are entwined with an early realisation that a command-and-control approach to harvesting natural systems will always strike problems eventually. (The following example is based on a discussion that appears in the book Resilience Thinking.)

Of budworms and social-ecological systems

Spruce fir forests grow across large areas of North America, from Manitoba to Nova Scotia and into northern New England. They are the base of a highly valuable forestry industry.

Among the forests’ many inhabitants is the spruce budworm, a moth whose larvae eat the new green needles on coniferous trees. Every 40 to 120 years, populations of spruce budworm explode, killing off up to 80% of the spruce firs.

Following World War II, a campaign to control spruce budworm became one of the first huge efforts to regulate a natural resource using pesticide spraying (thanks in part to new technologies emerging from the war).

Initially, the pest control proved a very effective strategy, but like so many efforts in natural resource management that are based on optimizing production, it soon ran into problems.

In a young forest, leaf/needle density is low, and though budworms are eating leaves and growing in numbers, their predators (birds and other insects) are easily able to find them and keep them in check. As the forest matures and leaf density increases the budworms are harder to find and the predators’ search efficiency drops until it eventually passes a threshold where the budworms break free of predator control, and an outbreak occurs.

While the moderate spraying regime avoided outbreaks of budworms, it allowed the whole forest (as distinct from individual patches) to mature until all of it was in an outbreak mode. Outbreaks over a much greater area were only held in check by constant spraying (which was both expensive and spread the problem).

The early success of this approach increased the industry’s dependence on the spraying program, intensified logging and spawned the growth of more pulp mills.

Now there was a critical mass of tree foliage and budworms. The whole system was primed for a catastrophic explosion in pest numbers. The managers in this system were becoming locked into using ever increasing amounts of pesticide because the industry wouldn’t be able to cope with the shock of a massive pest outbreak. The industry had little resilience, and yet the continued use of chemicals was only making the problem worse. They had created a resource-management pathology.

Adaptive cycles

The industry acknowledged the looming crisis and engaged ecologists (including CS ‘Buzz’ Holling) to see how they might tackle the problem from a systems perspective. In 1973, Holling proposed a new analysis of the dynamics of the fir forests, one based on what he described as ‘adaptive cycles’.

Forest regions exist as a patchwork of various stages of development. The cycle for any one patch begins in the rapid growth phase, when the forest is young. The patch then proceeds through to maturity, and eventually, following some 40 to 120 years of stable and predictable growth (referred to as the ‘conservation phase’), the cycle tips into the release phase. The larvae outstrip the ability of the birds to control them, larvae numbers explode, and the majority of forest trees in that patch are killed. Their rapid demise opens up new opportunities for plants to grow, and during the reorganization phase the forest ecosystem begins to re-establish itself. The cycle then repeats.

With this understanding of the cycle and the key changing variables that drive the system, the forest managers were able to fundamentally modify the manner of their pest control. Rather than continually using low doses of pesticide over wide areas they switched to larger doses applied less frequently at strategic times over smaller areas. They re-established a patchy pattern of forest areas in various stages of growth and development rather than keeping wide areas of forest primed for a pest outbreak.

The forest industry also changed through the process, moving to regional leadership with a greater awareness of the ecological cycles that underpinned the forest’s productivity.

From budworms to resilience thinking

The case study of the spruce budworm and the fir forest is important on many levels as it was in part the genesis of what has become resilience thinking. During his investigations, Holling proposed that the key to sustainability was an ecosystem’s capacity to recover after a disturbance, not the ability to hold it in a notional optimal state.

He also recognized that the ecosystem and the social system had to be viewed together rather than analyzed independently, and that both went through cycles of adaptation to their changing environments. Adaptive cycles don’t just happen in nature, they happen in communities, businesses and nations, it’s feature of complex adaptive systems.

His proposal catalyzed the thinking of ecologists and researchers (with an interest in systems) all over the world because similar patterns were being identified everywhere social-ecological systems were being studied.

One key insight that grew out of an understanding of adaptive cycles is that bringing about change/reform in a social-ecological system is always difficult. However, windows of opportunity do open when a system goes into a release phase, although the window doesn’t open for long. You need to be prepared to seize the opportunity while it’s there.

A basic lesson I draw from the notion of adaptive cycles is that systems get locked into themselves over time and become rigid. There’s no such thing as a sustainable optimal state because even if the system is managed into a condition deemed desirable, it then progressively loses its capacity to learn, innovate or keep its flexibility (often in the name of efficiency). Efficiency is important but is never the complete answer. Efficiency is not the key to sustainability.

Over the decades since Holling first described adaptive cycles, the models and the thinking associated with managing for resilience has gone through much refinement but the two core ideas remain at its heart: the fact that social-ecological systems constantly move through adaptive cycles over many linked scales, and that they can exist in different stable states. I’ll discuss this second building block in my next blog.

Banner image: Spruce fir forests provide valuable timber. However, efforts to optimise these systems last century with the widespread application of pesticide almost destroyed the industry. Uncovering what was going wrong became the origins of resilience thinking. (Image by Reijo Telaranta from Pixabay.)