Environmental Engineering Reference
In-Depth Information
CHAPTER 2
NEW WORLDS
Australia is the world's biggest island. Virtually cut off from the rest of the terrestrial world for millions
of years, it was a place of evolutionary throwbacks like marsupials and the egg-laying duck-billed platy-
pus, a creature so strange to outsiders that the first specimens taken back to Europe were dismissed as a
hoax.
1
Until the first human Australians arrived there from South Asia more than forty thousand years
ago, the island was home to giant emus, marsupial lions that could stand on their back legs, a spiny
anteater the size of a pig, a horned tortoise, its own giant lizard, and two-ton wombats. The reason for
the demise of these bizarre mega-creatures is disputed, though the early migrants are generally blamed.
Some of the animals may have been hunted down, while others probably succumbed to the massive fires
that the humans are believed to have set as they pursued and corralled their prey and burned grassland
to encourage regrowth.
This is not the place for a detailed history of Australia's ecology, but three introduced animals em-
body many of the profound changes that have accompanied recent human influences on the Australian
landscape and ecology: the dingo, the sheep, and the rabbit. Their stories tell an important truth about
what happens when we take species around the world. We expect those species to transform our new
habitats into replicas of the worlds we left behind, and when they are not so obliging, we blame them.
When ecosystems change dramatically or simply fail to deliver our needs, we look for scapegoats and
usually blame our alien companions. The truth is always more complex. In the melting pot landscapes
that usually follow human mass migrations, almost everything changes. There are usually more species
than before. New arrivals far outnumber any resulting extinctions. Local biodiversity increases. We may
mourn what is lost, but there is no going back.
The dingo (
Canis lupus dingo
), Australia's wild dog and the country's largest land predator, was ori-
ginally not so wild and not so Australian. It is the oldest animal that we know with any certainty to have
been introduced by humans. It probably arrived aboard seafarers' ships from Asia some five thousand
years ago, initially as a domesticated companion. Aborigines adopted it to help with hunting, but it also
took off into the wild, where it prospered.
2
It was soon top dog, seeing off rival native carnivores like
the thylacine, often called the Tasmanian tiger. The thylacine was finally confined to exile on the island
of Tasmania, where humans eventually hunted it close to extinction, before the last dog died in a Hobart
zoo in 1936.
Nobody seems quite sure whether to regard the dingo as alien or honorary native. It touches a raw
nerve in Australia. Some love the animal and believe it can do no harm. That resulted in a famous mis-
carriage of justice. Lindy Chamberlain was convicted of killing her child at a remote outback camping
site in 1980 because the court believed expert assertions that her cries that “a dingo's got my baby” had
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