Environmental Engineering Reference
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the whole was greater than the sum of the parts. Ecosystems were “super-organisms.” The natural world
had a metabolism. From here springs our idea of rain forests as systems rather than just collections of
trees—and on a global scale, of a “biosphere” comprising conjoined ecosystems. The British independ-
ent scientist James Lovelock went even further in the 1970s and proposed that the biosphere maintained
the planet's atmosphere and oceans in ways fit for life to thrive. Neatly fulfilling Botkin's observation
that all these ideas go back to classical times, Lovelock called this super-organism Gaia, after the Greek
Earth goddess.
8
This all-embracing ecological orthodoxy has long been attacked by dissident scientists, who see it as
romantic or even religious flummery with no scientific basis. In his time, Clements's great critic was
Henry Gleason. A contemporary of Clements, Gleason also grew up in the Midwest collecting wild
plants, but he drew very different conclusions. Nature was not composed of climatically determined as-
sociations of species, he said. Nature was primarily “individualistic.” Species did their own thing, ac-
cording to their genes and physiology, unconstrained by any higher purpose or super-organism strait-
jacket. “Every species of plant is a law unto itself, the distribution of which in space depends on its
individual peculiarities of migration and environmental requirements,” Gleason wrote in 1926. Far from
forming discrete and exclusive associations, species “grow in company with any other species of similar
environmental requirements, irrespective of their normal associational affiliations.” There were no ex-
clusive clubs of species maintaining a natural balance within their ecosystems. Ecosystems were open.
Any species could join. They might be recently native to that ecosystem, or they might be aliens brought
by happenstance or human hand. The distinction was of no consequence.
9
This was heresy. Gleason had an uphill battle to get his ideas heard, let alone discussed. “To ecolo-
gists I was anathema,” he later complained. “Nobody would even argue the matter. I was an ecological
outlaw.” It took until the 1940s for him to initiate a debate. But by doing so, he had fired the opening
shots in a battle for the soul of ecology that has raged ever since. Michael Barbour of UC Davis summed
it up: “Where Clements saw predictability, uniformity, cooperation, stability and certainty, Gleason saw
only individualism, competition, a blur of continuous change and probability.”
10
By the 1950s and 1960s, mainstream ecology was becoming more sophisticated, adopting mathem-
atical theories about how systems work. The University of Georgia's Eugene Odum and others said that
ecosystems could be examined according to their nutrient and energy flows.
11
Odum became a key fig-
ure in the emerging environmental movement in the 1960s. He argued that ecological thinking about the
balance of nature could help resolve a growing crisis caused by “man's conflict with nature.”
12
Other
ecologists followed this path, making big claims for the perfectibility of ecosystems. Of today's gen-
eration, Gretchen Daily of Stanford University famously compared ecosystems to airplanes. You can
remove one rivet from the wing, perhaps a few rivets, without evident harm, she said. But eventually, if
you move one too many, the wing falls off and the plane crashes.
13
New ecological science and old ideas about the balance of nature seemed for a while inseparable.
But in the 1970s, established systems theory was upset by the arrival of chaos theory. This said systems,
including ecological systems, were not necessarily stable at all. They could be nonlinear, subject to ab-
rupt jumps between different stable states, or have no stable states at all. There was no balance of nature.
One of the pioneers was Australian zoologist Robert May, who later became chief scientist for the Brit-
ish government and president of the Royal Society in London.
14
He was, like Charles Elton half a cen-
tury before, a specialist in population dynamics and saw how species went on orgies of boom and bust
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