ARCHIPELAGO EARTH
We think we can preserve nature on little islands scattered in an ocean of human dominion. It won't work. It's not enough.
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BY DAVID QUAMMEN
Forget about Marshall McLuhan's global village. Although it may have been a prescient idea as applied to electronic communication, from an ecological perspective it's diametrically wrong. McLuhan foresaw unity of culture and consciousness, but the defining trend among earth's ecosystems is the opposite: fragmentation. So far as nature is concerned, we live in a global archipelago. To say it more plainly, a world of islands.
As we humans have spread across earth's surface, asserting ourselves as the most devastatingly successful species in the history of life, we have transformed the great continental landscapes in two ways--by shrinking them overall and by dividing the remnants into pieces. Those pieces constitute ecological islands in an ocean of human dominion. The dominion takes many forms--crop fields and highways, forest clear-cuts and urban sprawl--but the effect is as chilling as sea water. The fragmentation grows worse each passing year. The islands are green, beleaguered and dwarfed by the immensity that surrounds them.
Some of them are familiar: Yellowstone, Yosemite, Royal Chitwan, Serengeti. Others are uncelebrated but glorious patches of forest, savanna or wetland. Many of their animal and plant populations are as inescapably marooned as the finches of the Galapagos or the lemurs of Madagascar. A grizzly bear in Yellowstone Park can't wander to Canada in search of a mate--not without running a deadly gauntlet through the ranches and suburbs of late-20th century Montana. A tiger in Royal Chitwan, near Nepal's southern border, likewise can't make its way to a tiger refuge in India. Insularity entails geographical constraint, but the prospects of survival and perpetuation for these species are constrained too. As the waters of (what we euphemistically call) civilization rise, the green islands become smaller, and the implications grimmer.
Why grim? Because of a phenomenon that I call the island syndrome. It's the gloomy half of a good-news-bad-news deal that has made islands especially interesting to biologists over the past 162 years. The good news is that islands are conducive to the evolution of new and revealingly peculiar species--as Charles Darwin himself discovered, during his 1835 stopover in the Galapagos. The bad news is that islands are deathtraps for many of the same wondrous creatures to which they give birth.
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