Out of Eden: An Odyssey of Ecological Invasion
By Alan Burdick
Farrar, Straus and Giroux, 2005
Reviewed by Jason Van Driesche
It is not often that a book presents a contradiction before you even open the cover. But such is the case with Out of Eden.
At the heart of the matter lies a well-worn question: What is nature? If one takes the book’s title at face value, Burdick seems to be saying that nature is Eden — a state of perfect balance that exists only in our absence and is therefore unknowable and unrecoverable. “We all hurry to see it, only to discover that it departed immediately with our arrival,” he writes. “Always there is a worm in the apple, and the worm is us.”
This kind of setup left me worried. Didn’t he know that the “balance of nature” idea went out the window decades ago? Was this just one more superficial recitation of the familiar tragedies of a homogenizing world? Thankfully, Burdick is far more interested in good ideas and good writing than in assembling a uniformly grim case with which to beat the reader over the head. The result is a book defined much more by its subtitle — An Odyssey of Ecological Invasion — than by its title. This is a journey through some of the world’s more devastated ecosystems in the company of a tour guide whose sense of curiosity is matched only by his blazing intellect.
A chapter or two into the book, Burdick has already launched into a headlong exploration of the complexity and contradiction of the natural world as it is — not as we think it might once have been. And no better place to start than with the island of Guam, where the depredations of the brown tree snake have resulted in an ecosystem nearly devoid of birds. Burdick’s approach to this well-trodden ground is at once brilliant and exceedingly audacious: he sets out to explore a scene of ecological havoc from the point of view of the perpetrator thereof. What does it mean, he asks, to think like a brown tree snake?
Above all, he answers, it requires an unswerving focus on what motivates a snake — not on what motivates us to dislike it. Calling the snake an opportunist, Burdick contends, is nothing more than a “post-hoc explanation masquerading as a noun.” The snake is simply an ecological force — a novel and devastating force, but one without a shred of malice. He compares the snake to the AIDS epidemic — “a kind of contagion, surreptitious yet virulent” — and argues that combating it effectively requires a deep understanding of the snake’s own reasons for doing what it does. So Burdick spends a chapter with a researcher who designs snake-proof exclosures by parsing in minute detail the behavior of trapped snakes. He spends another chapter following a scientist who himself tracks his quarry’s every move, tracing 240-m-long threads whose leading ends are tied around the necks of captured-and-released snakes. “If I thought like a snake, this would be easy,” the researcher says. Would that it were.
The second section moves to Hawaii, where Burdick plunges into the murky world of invasion ecology with an uncommon intellectual rigor and enthusiasm. He offers a finely nuanced exploration of the ecological concepts — refuge, niche, competitive exclusion — that form the backbone of our understanding of invasions. In the process, he cuts every one of these concepts loose from its moorings, setting them adrift in a world where everything changes — and not just because we’re stirring the pot. “To introduce niche theory is to propose a koan,” he says. “Does an ecological niche exist before an invader arrives to fill it?” The answer: there is no such thing as an “empty niche” — just a swirling mess of opportunities and threats, the ownership of which shifts with each new addition to or deletion from the system.
This leads to the central question of the Hawaii chapters and, really, of the whole book. If nature is always changing, on what basis do we claim that changes wrought by invasives are bad? A Hawaiian ‘apapane (Himatione sanguinea) doesn’t care if its kind goes extinct; native or nonnative, all creatures save humans are (as best we can tell) concerned only with their own individual survival and reproduction. Burdick’s core argument is that ecological homogenization is bad only in the eyes of a creature able to understand the concepts involved — and that this is reason enough to combat invasions. “It is a disarming notion,” he says, “that the strongest argument for preserving biodiversity might rest on something so mercurial, so subjective, so intimate as a personal desire to live in a world drenched in biological richness.”
And there it is again: a longing for Eden. How does one reconcile the apparent contradiction between an all-too-human desire for something familiar and the ecological reality of constant change? By developing an intimate understanding of and a deep appreciation for the process of change itself — and then using that knowledge to make change biodiversity’s engine rather than its destroyer. “Stability is not an end result,” Burdick says. “It is a state that nature is forever falling into.”
I wish I had written this book. I am glad, at least, to have found it. Burdick’s writing exhibits an intelligence and a resonance that few nature writers since Aldo Leopold have managed to master. I will be returning to Out of Eden again and again, and each time, I suspect, I will find something new.