Our panarchic future: a theory that explains the evolution of ecosystems may apply to civilizations as well--and it says we're approaching a critical phase.

Buzz Holling, one of the world's great ecologists, is a kind and gracious man, with a shock of white hair and a warm smile. Born in Toronto and educated at the University of Toronto and the University of British Columbia, he worked for many years as a research scientist for the government of Canada, where he pioneered the study of budworm infestations in the great spruce forests of New Brunswick. Later, as an academic researcher and eventually as director of the International Institute for Applied Systems Analysis in Austria, he created powerful mathematical models to explain the ecological phenomena he saw in the field. Using these models, he achieved major breakthroughs in understanding what makes complex systems of all kinds--from ecosystems to economic markets--adaptive and resilient.


Since the early 1970s, Holling's research has attracted attention in disciplines ranging from anthropology to economics. His papers have been distributed like samizdat through the Internet, and Holling himself has become something of a guru for an astonishing number of very smart people studying complex adaptive systems. Some of these researchers have coalesced into an international scientific community called the

Resilience Alliance, with over a dozen participating institutions around the world. Although Holling is now retired from his last academic position at the University of Florida, he's still terrifically vigorous and focused on furthering the Resilience Alliance's work.

Holling and his colleagues call their ideas "panarchy theory"--after Pan, the ancient Greek god of nature. Together with anthropologist and historian Joseph Tainter's ideas on complexity and social collapse, this theory helps us see our world's tectonic stresses as part of a long-term global process of change and adaptation. It also illustrates the way catastrophe caused by such stresses could produce a surge of creativity leading to the renewal of our global civilization.

Dangerous Efficiency

Panarchy theory had its origins in Holling's meticulous observation of the ecology of forests. He noticed that healthy forests all have an adaptive cycle of growth, collapse, regeneration, and again growth. During the early part of the cycle's growth phase, the number of species and of individual plants and animals quickly increases, as organisms arrive to exploit all available ecological niches. The total biomass of these plants and animals grows, as does their accumulated residue of decay--for instance, the forest's trees get bigger, and as these trees and other plants and animals die, they rot to form an ever-thickening layer of humus in the soil. Also, the flows of energy, materials, and genetic information between the forest's organisms become steadily more numerous and complex. If we think of the ecosystem as a network, both the number of nodes in the network and the density of links between the nodes rise.

During this early phase of growth, the forest ecosystem is steadily accumulating capital. As its total mass grows, so does its quantity of nutrients, along with the amount of information in the genes of its increasingly varied plants and animals. Its organisms are also accumulating mutations in their genes that could be beneficial at some point in the future. And all these changes represent what Holling calls greater "potential" for novel and unexpected developments in the forest's future.


As the forest's growth continues, its components become more linked together--the ecosystem's "connectedness" goes up--and as this happens it evolves more ways of regulating itself and maintaining its stability. The forest develops, for example, a larger number of organisms that "fix" nitrogen--converting the element from its inert form in the air to forms that plants and animals can use--in the specific amounts and in the specific places needed. It becomes home to more worms, beetles, and bacteria that break down the complex organic molecules of rotting plants into useful nutrients. And it produces more negative feedback loops among its various components that keep temperature, rainfall, and chemical concentrations within a range best suited to life in the forest.

Over time as the forest matures and passes into the late part of its growth phase, the mechanisms of self-regulation become highly diverse and finely tuned. Species and organisms are progressively more specialized and efficient in using the energy and nutrients available in their niche. Indeed, the whole forest becomes extremely efficient--in a sense, it effectively adapts to maximize the production of biomass from the flows of sunlight, water, and nutrients it gets from its environment. In the process, redundancies in the forest's ecological network--like multiple nitrogen fixers--are pruned away. New plants and animals find fewer niches to exploit, so the steady increase in diversity of species and organisms slows and may even decline.

This growth phase can't go on indefinitely. Holling implies--very much as Tainter argues in his theory--that the forest's ever-greater connectedness and efficiency eventually produce diminishing returns by reducing its capacity to cope with severe outside shocks. Essentially, the ecosystem becomes less resilient. The forest's interdependent trees, worms, beetles, and the like become so well adapted to a specific range of circumstances--and so well organized as an efficient and productive system--that when a shock pushes the forest far outside that range, it can't cope. Also, the forest's high connectedness helps any shock travel faster across the ecosystem. And finally, the forest's high efficiency makes it harder for it to realize its rising potential for novelty. For instance, the extra nutrients that the forest ecosystem has accumulated aren't easily available to new species and ecosystem processes because they're fully expropriated and controlled by existing plants and animals. Overall, then, the forest ecosystem becomes rigid and brittle. It becomes, as Holling says, "an accident waiting to happen."

So in the late part of the growth phase of any living system like a forest, three things are happening simultaneously: the system's potential for novelty is increasing, its connectedness and self-regulation are also increasing, but its overall resilience is falling. At this point in the life of a forest, a sudden event such as a windstorm, wildfire, insect outbreak, or drought can...

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