Posted : July 2009
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Pigs were introduced in most regions of the world through livestock farming.
All well and good, but a lot of them got out, and they eat like, well, pigs.
They tear up huge chunks of land rooting around for food, which screws up local
plants and hurts the native species that rely on the plants for food. They also
love farmed cropland, causing millions of dollars of damage a year. In some
places, they eat native species’ eggs or destroy their habitat with their
rooting. On Santiago
Island, for example, they
dramatically reduced sea turtle and tortoise numbers by eating their eggs.
The Rattus Rattus is native to India,
but it has spread to almost everywhere in the world. This rat has directly
caused, or contributed to, the extinction of multiple wildlife species
including a variety of birds, plants and other small mammals. They’re blamed
for the incredible decline in seabirds on several islands, including many
Hawaiian species.
3. Zebra Mussels - North America, Europe
It’s not often that a tiny relative of the clam can strike fear in anyone’s
heart, but these bad boys have caused millions upon millions of dollars of
damage, especially in the Great Lakes region.
The zebra mussel, native to western Asia, spread to most of Europe
starting in the 1700s. It was most likely introduced in North America in the
mid-80s by a European cargo ship that released ballast water into the Great Lakes. They have caused loads of damage, especially
to water intake pipes that they colonize and then clog. They also compete with
native species for food, dramatically reducing the native populations. They
also cause loads of trouble for boats in areas they colonize.
2. The Cane Toad - US, Australia, others
At some point in the 20th century, someone had an amazingly bright idea. They
had heard of these toads from Central America
that ate almost any type of insects. Of course, they thought, we can introduce
them into our fields, especially sugar cane fields, and they’ll naturally
reduce the insect population. Boy did they. The Cane Toad thrived in its new
locations in Hawaii, Florida,
Australia,
and other places. At some point though, someone realized they were doing a
little better than native species, and a lot of predatory animals were dying.
It turns out the cane toad competes pretty well with native species for food,
and they are extremely toxic to predators, including pets. They’re also
incredibly hard to get rid of. Oops. At least we know they also suffer back pain
when they spread.
1. The European Rabbit - Everywhere except Asia and
Antarctica
Most places have their fair share of invasive species, but Australia is on
another level altogether. It’s not so much that their invasive species are
worse, but they introduced so many of them on purpose, especially in the 19th
century, and they’ve had a massive impact on the environment. The European
rabbit has had an impact on many places, but especially in Australia.
Rabbits are partially blamed for the extinction of almost an eighth of mammal
species in Australia.
They cause millions of dollars in agricultural damage a year, and cause serious
soil problems. They also contribute to the flourishing of other non-native
species, specifically foxes and feral cats, which cause further damage to the
Australian ecosystem. The first rabbits were reportedly brought by the First
Fleet in 1778, but the current massive infestation of rabbits is traced back to
the release of just 24 animals by a man named Thomas Austin in 1859. Austin was an avid hunter while living in England, and when he moved to Australia
decided the country could do with a few rabbits to shoot on weekends. While
other farmers later released rabbits into the wild, Austin appears to be the first and the one
most responsible for the infestation today. Before we get too harsh on Austin, however, let’s remember that this was an age where
very little was known about the effect of invasive species on the environment,
and Australia
was a place where people were willing to experiment heavily with the natural
ecosystem. If you’ve ever read Bill Bryson’s excellent book on the country, you
may remember a man who wanted to introduce monkeys into the country to amuse
people.
~Blog Admin~
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