Environmental Engineering Reference
In-Depth Information
Fear of alien plants can turn to hatred of alien animals, especially recent arrivals. The signal crayfish
(
Pacifastacus leniusculus
) was brought to Britain from North America in the 1970s to be farmed. It is
bigger and tastier than native crayfish. But it is also more aggressive, breeds earlier, lays more eggs,
tolerates dirtier water, eats a wider variety of food, and carries a fungus that latches onto locals but to
which it is itself immune. It can walk on land and burrow into riverbanks, causing them to collapse.
With that skill set, it may be no surprise that it soon escaped and set about colonizing its new home.
In little more than three decades, it has virtually supplanted native crayfish in lowland England and by
2006 had made it onto a UK list of “most wanted foreign species” compiled by the UK government's
Environment Agency. “Wanted” as in “wanted dead.”
29
Succumbing to crude xenophobia, the agency says that the crayfish have “taken advantage of Bri-
tain's welcoming living conditions” and “overstayed their environmental visa.” Their “crimes” include
“out-muscling native competition and spreading disease.” Echoing a complaint first made by British
males about US forces stationed in Europe during World War II, they are “over-sized, over-sexed and
officer eager to capture tabloid headlines. But they were only one step removed from the racism of the
British National Party, which in a rare foray into ecology called the signal crayfish “the Mike Tyson of
crayfish . . . a diseased, psychotic, evil, illegal immigrant colonist [that] totally devastates the indigen-
ous environment.”
31
As with another fast-spreading, riverbank-burrowing but tasty alien crustacean, the
Chinese mitten crab (
Eriocheir sinensis
), the best solution might just be to eat more of it. Celebrity chef
Gordon Ramsay is a fan.
32
Alien creatures seem to bring out the worst in even the most apparently animal-friendly people.
“There is a war going on in the parks, ponds, rivers and greenhouses of Britain,” wrote Lucy Siegle in
her ethical-living column in the
Observer
. It is a war she evidently approves of. She served up a photo-
fit list of “our top 10 unwanted non-native invasive species,” with the top two places occupied by the
signal crayfish and the gray squirrel.
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Many of the species appeared for no other reason than that they were “fast-growing, aggressive and
voracious.” They certainly didn't get the benefit of the doubt. The muntjac deer (
Muntiacus reevesi
)
from China made number three even though “scientists are not yet sure about the extent of the small
deer's impact.” The worst crime of parakeets, at number four, was that they represented “potential com-
petition for nest sites with some native birds.” The terrapin, released after the craze created by the TV hit
Teenage Mutant Ninja Turtles
in the 1980s, made number five even though “we do not know the extent
to which it is reproducing.” Actually, all the evidence is that British waters are too cold for terrapins to
breed at all.
Cuter alien animals may get a pass into public affection. The edible dormouse (
Glis glis
) is so named
because, fattened up with almonds and chestnuts, it was a favorite snack food of the Romans. It was un-
known in Britain until 1902, when a few of them were inducted to the private menagerie of Walter (later
Lord) Rothschild in Hertfordshire. From there, some escaped and have since been tracked, almost vil-
lage by village, on a steady odyssey across the Chiltern Hills of South East England. They now number
upwards of ten thousand and, most unusually for an alien species, have protection under wildlife legisla-
tion passed in 1981.
34
Not everyone is happy at this legislative anomaly. As the ever-grumpy
Daily Mail
put it in 2006: “They live in your loft, breed like rabbits, go bump in the night, gnaw through wiring,
strip fruit trees in your garden—and you can't touch them because they're a protected species.”
35
But
the edible dormouse is nonetheless an honorary Brit.
The European rabbit appears in many places round the world but is endangered in its native Iberia.
36
In fact, its spread may have been its making. The first rabbits to show up in Britain a millennium ago
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