Monday 18 February 2013

Man’s  stupidity with respect to the environment (Part I)

I never fail to be surprised when I learn of Man’s stupidity when it comes to trying to do something right and when the efforts invariably bring about disastrous results.  I am presenting to my readers the first part of this series and it deals with Australia.

Macquarie Island is a 34km by 5km island halfway between Australia and Antarctica. Cats and rabbits were introduced in 1860s in Tasmania to provide food if sailors were shipwrecked.  Overtime, the two species formed a balance with each other.

That balance was interrupted in the 1950s when the myxomatosis virus was introduced by scientists to control the influx of rabbits. Each time a virus outbreak decimated rabbit populations, the cats started hunting native birds. In the 1990s, scientists gained $500,000 in funding to eliminate a population of only around 500 cats that had been on the island for almost a century and a half. When the final cat was removed in 2000, rabbit numbers had then increased and were somewhere between 4,000 and 20,000. Within 6 years, the population of rabbits had reached 130,000 and Macquarie Island's vegetation was being eaten to extinction.

Then the scientists decided to poison the rabbits to get rid of them. Later the scientists conceded that the collateral damage of their recent rabbit control programs included a significant number of the local bird population that either ate the baits or the poisoned bodies of the dead rabbits. When the same control programs were inflicted on the mainland, collateral damage also included the quolls, (looks like a small squirrel) birds and goannas that eat rabbits. Even when the predators were not poisoned by the bodies of the dead rabbits, they were deprived of a food source. Collateral damage then expanded to include the various marsupials that would not have been hunted by large populations of starving cats, foxes, eagles, quolls and goannas (lizards) if the rabbits were still around.

Rabbits were introduced to Australia in the 18th century when they were brought with the first eleven ships that left Great Britain, bound for Australia, on 13 May 1787 with their boats crammed with prisoners and their families. There were only six rabbits that were brought ashore. Now as everyone knows, they breed like there is no tomorrow. .

Now there are millions upon millions of rabbits in Australia. The rabbits are considered one of the most damaging and destructive introduced animals ever brought to Australia.

Rabbits cause Soil Erosion and Land Degradation. These long-eared pests cut away the bark of trees in a ring around the tree and thereby killing the trees.  They also eat the seedlings therefore giving the plant species no way of growing back.  The rabbits also compete with native animals for habitat and food, and as such, the Greater Bilby (small, rat-like marsupial) is now endangered.

The rabbits also add to the rate of decline of native fauna. Rabbits and Goats have eaten out the Phillip Island Hibiscus (Hibiscus insutaris). Only 2 clumps remain. Rabbits, sheep, cattle, goats, horses and camels are just as bad as foxes and cats when it comes to the effect these animals have on the delicate ecosystems of Australia except there are millions of rabbits eating native flora.

Not only do these animals affect the native flora, but they have a huge effect on the populations of other native animals. This feral monster competes with small animals, such as the Greater Bilby and the Brush-tailed Bettong, which were once found all over Australia.

These animals, just like the rabbit, are burrowing animals. When the rabbit population gets so bad that there is no food left for the other animals, they start to die off. As soon as this starts to happen, the rabbits go in and take over the native animal’s burrow. This resulted in reduced habitat for the animals.

These two little, native marsupials were at the brink of extinction due to the combined effort of foxes, feral cats and rabbits. There have been massive campaigns to save these two little marsupials, which have been successful, but there is still the threat. This is why they decided to eradicate feral animals.

Rabbits cost the Australian economy millions of dollars each year due to the competition with livestock for food. They eat the most nutritious grasses and leave none for the livestock with the result of the animals dying. This decrease costs the economy millions and causes soil erosion and land degradation.

Native to Central and South America, sugar cane toads were introduced to Australia from Hawaii in June 1935 by the Bureau of Sugar Experiment Stations in an attempt to eradicate the native cane beetles. 

The cane toads bred immediately when in captivity, and by August 1935 more than one hundred and two young toads were released in areas around Cairns, Gordonville and Innisfail in northern Queensland. More toads were released around Ingham, Ayr, Mackay and Bundaberg. Since their release, toads have rapidly multiplied in population and now number over 200 million and have been known to spread diseases affecting local bio-diversity.

Unfortunately, the introduction of the toads has not only caused large environmental detriment, but there is also no evidence that they have had an impact on the cane beetles they were introduced to predate. The toads have steadily expanded their range through Queensland, reaching the border with New South Wales in 1978 and the Northern Territory in 1984. The toads on the western frontier of their advance have evolved larger legs; this is thought to be related to their ability to travel farther.

They are causing the depletion of native species that die eating cane toads; the poisoning of pets and humans; depletion of native fauna preyed on by cane toads; and they have reduced prey populations also.

This is what happens when scientists come up with ideas as to how to solve problems without first determining if their ideas will bear fruit or bear thorns.

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