[Paleopsych] NYT: The Origin of Invasive Species
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Thu Sep 15 01:37:15 UTC 2005
The Origin of Invasive Species
New York Times, 5.6.12 (note date)
By Richard Conniff
OUT OF EDEN
An Odyssey of Ecological Invasion.
By Alan Burdick.
Illustrated. 324 pp.
Farrar, Straus & Giroux. $25.
FOR the past few years, I have been engaged in hand-to-hand combat
with a 10-foot-tall alien -- growing thick as toothpicks in a box,
just outside my door. Late in summer, I thrash through the marsh to
coat the blades of the phragmites reed with herbicide. (Some
environmentalists endorse this; others abhor it.) In midwinter, I
attach a rope to each end of a board and use it to trample down the
dead stalks. (Politically correct, but Bruegelesque, or possibly
Chaplinesque.) Sometimes, when I lurch out of the grass, sweating,
muddy and in a spirit of high ecological dudgeon, my dog, Maggie,
backs away growling. (''Who is this and what is he doing in my
Phragmites, a handsome European reed with a feathery crimson plume,
got dumped on the coast of New England in heaps of 19th-century ship
ballast. It has choked almost every wetland east of the Mississippi.
But in my little pocket of coastal marsh, I have opened up the
landscape again and made room for the native grasses and cattails I
remember from childhood. I have also made room for nesting mute swans,
another invader. (Should I coddle the eggs and stop them from
reproducing? Please do not advise.) I am also acutely aware that if I
lay off for a season or two, the phragmites will come booming back.
The natural world has gone wildly astray, through the kindness of
human beings, and there isn't any good way to put it right again.
Should we even bother trying? It turns out there are lots of people
who are obsessed, dismayed and perhaps also occasionally made demented
by invasive species. Often, they fight noble battles they know they
are doomed to lose. In ''Out of Eden,'' the science writer Alan
Burdick travels the world to chronicle their intriguing, undervalued
lives, and those of the species that trouble them.
''The greatest threat to biological diversity is no longer just
bulldozers or pesticides but, in a sense, nature itself,'' Burdick
writes. Since its accidental introduction to Guam, the Australian
brown tree snake has extirpated nine native bird species, sending
three to extinction. One of the last remaining pairs of another
species hangs on only because the nest is now barricaded behind
electric wires, with branches pruned back to keep snakes from creeping
in from nearby trees: ''The couple looked trapped in its safety, like
those people in Manhattan who secure their apartments with eight locks
on the front door.'' Alas, the couple also suffered from ''sexual
disharmony,'' and small wonder: one night, researchers with traps
caught seven snakes at the door.
Because of its knack for hitchhiking in freight containers and
aircraft landing gear, the brown tree snake may yet set up shop in
Hawaii or San Diego or even South Florida.
Thousands of other invasive species, many of them of more benign or
even beautiful varieties, already surround us. They herald an era of
''creeping sameness,'' called by one scientist ''the Homogecene.''
Tourists freshly escaped from the howling depths of winter may delight
in the birdsong and the tropical vegetation in Honolulu. But
everything around them, another scientist tells Burdick, ''is
introduced'': ''Not a single plant, none of the lowland birds in
Hawaii are native.'' We are turning the world into ''a McDonald's
ecosystem,'' with the same species living roughly the same way
Burdick is best describing the minute details of this change: how does
the onslaught of new species affect Hawaii's native forests? The
answer comes partly from studying fruit fly species and obscure soil
dwellers like springtails and mites that also date back as far as the
forests. We meet Hawaiian drosophilists who ritually stopper specimen
vials with torn aloha shirts, to distinguish themselves from
mainlanders who still use telltale cotton balls. We encounter a
parasitologist who ''would be more comfortable . . . doing pretty much
anything other than talking. If he were a bird, he might be a night
heron . . . liable to stand there blinking in the illumination of a
flashlight, then dart away.''
We go underground with a burly entomologist, Frank Howarth, who
listens to the distinctive love songs sent out by different native
species of the tiny insects called plant hoppers, which dwell in caves
and lava tubes. (Howarth once discovered a new species on the property
of Loretta Lynn and named it Oliarus lorettae, after her.) The plant
hoppers tap out their songs along the rootlets of a native tree;
Burdick likens them to human lovers making a crosstown phone call.
Unfortunately, that tree is being supplanted by an invasive tree
species with different roots, resulting in something like a
subterranean silent spring: ''The singers are growing mute,'' Burdick
writes, ''each one marooned on the island of itself, unable to
communicate, to mate, to sustain its end of evolutionary
A KIND of unnatural selection at the hands of introduced species is
apparently commonplace, with the luckier native species managing to
survive through accelerated evolution. In 1968, before introduced
mosquitoes caused a malaria pandemic, some native birds in Hawaii used
to sleep any which way, leaving themselves exposed to mosquito bites.
By 1986, those birds had been weeded out, leaving only birds that
slept with their legs tucked under their bodies, their bills and faces
buried in the fluffed feathers on their backs. In Australia, toxic
cane toads introduced from the Americas have favored the proliferation
of snakes with mouths too small to swallow them.
Burdick tries to make the case that nature is adaptable enough to
handle the changes in our topsy-turvy world. When scientists figure
out how to isolate the problem and interpret all the variables, it
appears, for instance, that even having 500-pound feral pigs rooting
through the forests of Hawaii may not do the permanent damage
conservationists fear. Instead of causing local extinctions, he
writes, ''most successful invaders simply blend into the ecological
woodwork. . . . To the local eye, biological diversity seems to have
increased. Isn't that a good thing?''
Maybe Burdick is simply trying to avoid the hazards of environmental
alarmism, but surely this goes too far. It doesn't square with the
evidence he has diligently accumulated: What about the Australian tree
spreading rapidly through the Everglades that ''draws in so much water
through its roots that it essentially converts open marsh habitats . .
. into . . . dry land''? What about the European green crab, which
''single-leggedly crushed the soft-shell clam industry north of Cape
Cod''? And how about, shortly after a cholera epidemic in South
America in 1991, ships dumping ballast water that released the same
strain of cholera bacteria into oyster beds at Mobile Bay in Alabama?
The argument that many, or even most, invasive species cause no harm
risks encouraging a ''What, me worry?'' attitude in a public already
too complacent about environmental change.
Henry David Thoreau once defined weeding as the business of ''making
invidious distinctions with the hoe.'' But in the science of
''invasion biology,'' the distinctions about what to keep in and what
to weed out sometimes really matter. Burdick's account of the
researchers who struggle with this largely thankless work is graceful
and inviting. He would have written a better book, though, if he had
made a more cogent case for why, every now and then, we need to cough
up the money to buy those workers a better hoe.hAndrew Solomon's
''Noonday Demon'' received a National Book Award in 2002. He is
currently writing a book about families grappling with traumatic
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