Environmental Engineering Reference
In-Depth Information
earthworms now occur in every region in all but the driest or coldest habitat types on Earth.”
14
Their ef-
fects can be regarded as good and bad, aerating soils but also changing soil chemistry and ecology. They
travel accidentally in soil or more deliberately through the surprisingly large global trade in fishing bait.
Canadian exports of fish bait alone are worth $20 million a year—that is a lot of worms—and more bait
comes from Europe, Japan, and Vietnam.
Among the most unruly of the accidental migrants have been diseases and pests. European travelers
returning from Asia in the fourteenth century brought home black rats that carried the bubonic plague,
ultimately killing some seventy-five million people. The first colonists of the Americas wiped out most
of the native inhabitants with smallpox, measles, and other alien diseases that they carried. It was “the
worst human holocaust the world has ever witnessed,” University of Hawaii historian David Stannard
argues.
15
But those travelers going back to Europe didn't return empty-handed. They brought syphilis.
People-trafficking to provide labor for the British Empire carried hookworm from India to the Carib-
bean and cholera to the Far East. A North American fungus,
Phytophtora infestans
, infected the Irish
potato crop in the 1840s and, with the help of British administrative heartlessness, killed a million Irish
people in the subsequent famine. A decade later, the American vine aphid
Phylloxera
reached the vine-
yards of France, almost wrecking the wine industry until someone thought of grafting European vines
onto American rootstock resistant to the pest. And, as the century closed, Italian troops took to East
Africa cattle that carried rinderpest, an Asian virus similar to canine distemper, which changed the con-
tinent's ecology forever, as we shall see in
chapter 8
.
Some journeys by pests defy prediction. European airport arrival halls often carry warnings about
bringing in the Colorado beetle. In the seventeenth century,
Leptinotarsa decemlineata
was living
quietly in central Mexico, eating the seeds of the Mexican burweed (
Solanum rostratum
). Then Spanish
conquistadors brought in cattle, which they drove north to sell in Texas. The animals carried burweed
seeds caught in their coats, and the beetles came too. Liking the lay of the land, burweed and the attend-
ant beetle moved north again into the Great Plains.
In Colorado the beetle encountered fields of potatoes, which also had made a long journey to get
there. The vegetable had been taken from the Andes to Europe, and subsequently it was introduced in
the United States in the early eighteenth century. The beetle swiftly developed such a taste for the potato
that it switched hosts. Finding potato fields everywhere, it moved east across the United States before
making it to Europe via US military bases set up near Bordeaux in France after the First World War.
In the early 1950s, Soviet-occupied potato-eating East Germany became heavily infested with the
Colorado beetle, leading to charges—probably erroneous—that the “Yankee beetle” was being dropped
from US planes as a biological weapon. The Cold War briefly threatened to become a hot potato war.
Tempers cooled, but the beetle became established in the Soviet Union by 1955 and is to this day heav-
ily quarantined to keep it out of western European countries.
16
For Europeans, there was both commercial zeal and scientific curiosity in the desire to move stuff
around the world. In the 1680s, Hans Sloane, the personal physician of Lord Albemarle, the British
governor of Jamaica, returned home with the embalmed remains of his deceased employer. Also in his
packing cases was a huge collection of forest goods from the Caribbean, including eight hundred plants
and a seven-foot yellow snake, subsequently shot by Lady Albemarle after it escaped from a pot. Sloane
took more care of his cacao (cocoa) plants, however, turning them into a new career. Having seen Ja-
maicans prepare a drink made from cocoa, honey, and pepper, he came up with the idea of mixing the
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