The Song of the Dodo: Island Biogeography in an Age of Extinctions

Christian Century, Sept 24, 1997 by Debra Bendis

There's nothing more romantic than biogeography," confides scientist Edward Wilson to David Quammen, who confesses that "in the spell of the moment, by God, I almost believe him." Quammen's book is scientific journalism at its best: entertaining, erudite and impassioned. A primer of evolutionary theory, it is also studded with adventure stories.

The reader accompanies 19th-century biologist Alfred Wallace as he fends off mosquitoes, pirates and squalls to explore the Malay Archipelago; follows myrmecologist (ant expert) Wilson to Florida mangrove islands for a study of anthropods ("[The mud] sucked at their ankles like bathtub caulk. They sank . . ."); and shares the author's jaunts to isolated islands -- Angel de la Guarda, east of the Baja peninsula; Mauritius, on the east coast of Africa; Komodo, in central Indonesia.

After a few days with the Galapagos iguana, Quammen decides that the creature is not "hideous," as Charles Darwin claimed, but only "homely." He trails herpetologists in Guam as they check traps for a brown tree snake that may have caused the sudden extinction of the island's bird population. Here the arachnophobic author stumbles into "prune-bodied spiders" of "ungodly abundance" in "huge communal webs." He glimpses the rare Hapalemur aureus (golden lemur) of Madagascar, then describes an epic moment in this "romantic adventure":

When the rain begins drumming

more steadily, I raise the hood of

my parka. . . . I hunker. The golden

bamboo lemurs hunker. I gape at

them and, every so often, they

glance pityingly down at me. An

hour creeps by. . . . A few leeches

come inchworming up my legs,

thirsty for blood. I flick them away

without malice.

Quammen describes the forces that control life on islands as "antic," and the results as "wild and crazy fauna." There are species that exist, or once existed, nowhere else: carnivorous parrots, legless skinks, giant monitor lizards, pigmy hippopotamuses, flightless crickets, 1,000-pound birds. Yet the same isolated conditions that give rise to these rare and spectacular species also spell their doom, for island species face a greater likelihood of extinction than continental species.

It is here that Quammen's challenge begins -- to teach the science of biogeography to nonscientists. And part of his success comes because he never forgets to acknowledge his readers. Quammen received the National Magazine Award for essays in Outside magazine, and his informal style easy empathy with readers serve him well. Even the most resistant student learns the meaning of "sympatric speciation" and "phyletic evolution," as Quammen stealthily weaves instruction around and through his travel stories, then adds maps (by wife, Kris Ellingsen) and a glossary. The author respects the reader's limits: one glossary entry, for example, reads: "Logarithm. A mathematical thing. Never mind," while in another entry he gently chides the reader who doesn't take him seriously: "Biogeography. Come on, you've read the book."

Biogeography is concerned with where a species lives and where it doesn't live. Because island species are geographically isolated and consequently exist in small numbers, they are vulnerable to inbreeding, to catastrophic events, to decline of habitat. Over time, for example, they lose defensive adaptations: rattlesnakes lose rattles; lizards lose protective coloring and thus become vulnerable to any new predator or disease. Seventeenth-century travelers to Mauritius killed the flightless dodo bird by the dozens because the birds didn't run away; they had lost inherent wariness, a basic defensive adaptation.

Sightings of these exaggerated, flamboyant and rare creatures lead Quammen to discuss global extinction. As ecologist Michael Soul says, "Scores of birds, mammals and flowering plants have suddenly become extinct, particularly on oceanic islands, during the last 100 years. It is as if some epidemic were raging among these species. . . . Now the disease appears to be spreading to the continents."

Quammen believes that what we learn about island extinction will explain ecological decay elsewhere. Most wild animal habitats are fragmented, isolated and deteriorating. He calmly understates the urgency of our education: "Maybe you stand among those well-informed people for whom the notion of catastrophic worldwide losses of biological diversity is a serious concern. Chances are, still, that you lack a few crucial pieces of full picture."

Quammen speaks for endangered species one species at a time. How about the indri, he asks, the big lemurs of Madagascar that sail through space, sometimes leaping 20 or 25 feet between trees? Their howls are "eerie but beautiful, like a cross between the call of a humpback whale and a saxophone riff by Charlie Parker. . . . Imagine them with the face of a jackal, yellow brown eyes, black-and-white fur like a giant panda's. Imagine you know them as babakoto. They sing. Imagine that the last 80 live in a little forest reserve called Analamazaotra."