Invasive Species

Invasive Species — page 1

Invasive Species — page 2 — Chapter ONE A PLAGUE OF More than a century ago a plague was unleashed on Australia Hungry animals tore up the soil chomped vegetation to the ground and caused great harm to the ecosystem Even fences could not stop the onslaught What creature was causing so much trouble European rabbits The first rabbits arrived in Australia in 1788 with the First Fleet a group of convicts and sailors sent from Europe to settle in Australia 1 Then in 1859 the Victorian Acclimatisation Society brought 24 more rabbits to Australia to provide game for hunters and remind the settlers off Rabbits burrows have damaged land in Australia 5

Invasive Species — page 3 — The Australian government built the world’s longest fence to try to keep rabbits and dingoes from spreading It is 3,488 miles 5,614 km long 6

Invasive Species — page 4 — home The rabbits quickly spread They have few predators in Australia and they reproduce quickly By the 1920s there were approximately 10 billion bunnies in Australia 2 The rabbits ate so much vegetation that native species such as wallabies and rat kangaroos did not have enough food So the bunny battle began In 1907 the government tried building three long fences to keep rabbits from spreading to other parts of the country But it was too late The bunnies had already moved in Later cats and foxes were introduced to eat the rabbits They ate some rabbits but they ate native species too causing even more stress to these species ARE INVASIVE SPECIES BAD Invasive species are not invasive everywhere In their native habitats they usually do not cause problems and may not even be very common Their natural predators competitors parasites and diseases keep them in check Invasive species only become destructive when they arrive in a new place away from these checks and balances In 1950 scientists hit on a method of biocontrol the use of organisms to control pests They introduced a rabbit virus that causes a disease called myxomatosis The disease killed up to 99 percent of the rabbits in some areas 3 However it is spread by mosquitoes which need water to reproduce So the virus was not very effective in areas with a dry climate Over time the virus weakened and some rabbits became resistant to it It started to kill fewer and fewer rabbits The rabbit population increased once again One female rabbit can have up to 30 babies per year 7

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