Steve Packard set out to extend the habitat of authentic
prairie. On the way he resurrected a lost ecosystem, and perhaps
acquired the assembly instructions for a savanna. Working in an ocean of
water instead an ocean of grass, David Wingate in Bermuda set out thirty
years ago to nurse a rare species of shorebird back from extinction. On
the way, he recreated the entire ecology of a subtropical island, and
illuminated a further principle of assembling large functioning systems.
The Bermuda tale involves an island suffering from an unhealthy, ad
hoc, artificial ecosystem. By the end of World War II, Bermuda was
ransacked by housing developers, exotic pests, and a native flora
wrecked by imported garden species. The residents of Bermuda and the
world's scientific community were stunned, then, in 1951 by the
announcement that the cahow -- a gull-size seabird -- had been rediscovered on
the outer cliffs of the island archipelago. The cahow was thought to be
extinct for centuries. It was last seen in the 1600s, around the time
the dodo had gone extinct. But by a small miracle, a few pairs of
breeding cahows hung for generations on some remote sea cliffs in the
Bermuda archipelago. They spent most of their life on water, only coming
ashore to nest underground, so they went unnoticed for four centuries.
As a schoolboy with a avid interest in birds, David Wingate was
present in 1951 when a Bermudan naturalist succeeded in weaseling the
first cahow out of its deep nesting crevice. Later, Wingate became
involved in efforts to reestablish the bird on a small uninhabited
island near Bermuda called Nonsuch. He was so dedicated to the task that
he moved -- newly married -- to an abandoned building on the uninhabited,
unwired outer island.
It quickly became apparent to Wingate that the cahow could not be
restored unless the whole ecosystem of which it was part was also
restored. Nonsuch and Bermuda itself were once covered by thick groves
of cedar, but the cedars had been wiped out by an imported insect pest
in a mere three years between 1948 and 1952. Only their huge white
skeletons remained. In their stead were a host of alien plants, and on
the main island, many tall ornamental trees that Wingate was sure would
never survive a once-in-fifty-year hurricane.
The problem Wingate faced was the perennial paradox that all whole
systems makers confront: where do you start? Everything requires
everything else to stay up, yet you can't levitate the whole thing at
once. Some things have to happen first. And in the correct order.
Studying the cahows, Wingate determined that their underground
nesting sites had been diminished by urban sprawl and subsequently by
competition with the white-tailed tropicbird for the few remaining
suitable sites. The aggressive tropicbird would peck a cahow chick to
death and take over the nest. Drastic situations require drastic
measures, so Wingate instituted a "government housing program" for the
cahow. He built artificial nest sites -- sort of underground birdhouses. He
couldn't wait until Nonsuch reestablished a forest of trees, which tip
slightly in hurricanes to uproot just the right-sized crevice, too small
for the tropic bird to enter, but just perfect for the cahow. So he
created a temporary scaffolding to get one piece of the puzzle going.
Since he needed a forest, he planted 8,000 cedar trees in the hope
that a few would be resistant to the blight, and a few were. But the
wind smothered them. So Wingate planted a scaffold species -- a
fast-growing non-native evergreen, the casuarinas -- as a windbreak around
the island. The casuarinas grew rapidly, and let the cedars grow slowly,
and over the years, the better-adapted cedars displaced the casuarinas.
The resown forest made the perfect home for a night heron which had not
been seen on Bermuda for a hundred years. The heron gobbled up land
crabs which, without the herons, had become a pest on the islands. The
exploded population of land crabs had been feasting on the succulent
sprouts of wetland vegetation. The crab's reduced numbers now allowed
rare Bermudan sedges to grow, and in recent years, to reseed. It was
like the parable of "For Want of a Nail, The Kingdom Was Lost," but in
reverse: By finding the nail, the kingdom was won. Notch by notch,
Wingate was reassembling a lost ecosystem.
Ecosystems and other functioning
systems, like empires, can be destroyed much faster than they can be
created. It takes nature time to grow a forest or marsh because even
nature can't do everything at once. The kind of assistance Wingate gave
is not unnatural. Nature commonly uses interim scaffolding to accomplish
many of her achievements. Danny Hillis, an artificial intelligence
expert, sees a similar story in the human thumb as a platform for human
intelligence. A dexterous hand with a thumb-grasp made intelligence
advantageous (for now it could make tools), but once intelligence was
established, the hand was not as important. Indeed, Hillis claims, there
are many stages needed to build a large system that are not required
once the system is running. "Much more apparatus is probably necessary
to exercise and evolve intelligence than to sustain it," Hillis wrote.
"One can believe in the necessity of the opposable thumb for the
development of intelligence without doubting a human capacity for
thumbless thought."
When we lie on our backs in an alpine meadow tucked on the perch of
high mountains, or wade into the mucky waters of a tidal marsh, we are
encountering the "thumbless thoughts" of nature. The intermediate
species required to transform the proto-meadow into a regenerating
display of flowers are now gone. We are only left now with the thought
of flowers and not the helpful thumbs that chaperoned them into
being.
continue...
|