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The tourist brochures are right – Australia is a country like no other. Our fair brown land is home to a whopping one million native species, and of these more than 80 per cent of our mammals, reptiles and frogs, most of our freshwater fish and almost half of our birds can be found nowhere else on Earth.
But our diverse fauna is fast disappearing. Australia has 782 threatened animals on the International Union for the Conservation of Nature red list, second only to the USA which has 914 critically endangered, endangered
or vulnerable species.
Twenty per cent of Australian mammals are threatened and 18 Australian mammal species have become extinct in the last two centuries – almost half of all mammal extinctions worldwide over the past 200 years.
“Some of the main contributing factors are introduced species like foxes and feral cats, in combination with habitat destruction, loss of protective ground cover due to livestock and feral grazers and widespread killing of dingoes to protect livestock, which has taken the pressure off cats and foxes, allowing them free rein,” says Martin Taylor, a conservation scientist from WWF Australia.
Northern hairy-nosed wombat
One of three species of wombats, the population of northern hairy-nosed wombats has hovered close to extinction for over 40 years. Competition with livestock and feral animals like rabbits for food is the major threat – wombats are a grazing bunch who munch on native roots and grasses – but the small population could easily die off in a freak flood, fire or disease outbreak.
“The last 30 northern hairy-nosed wombats were saved from extinction in the late 1970s by the creation of the Epping Forest National Park in central Queensland,” says Taylor. “The population has slowly climbed back to about 150 at present, allowing a new colony to be started in a new protected area, the Richard Underwood Nature Refuge in Queensland near the NSW border, where two babies were born recently.”
Resembling a possum with large white spots, the northern quoll inhabits only small pockets of the Northern Territory and Queensland, having once roamed right across the northern half of Australia.
“The biggest threats to quolls are forest clearing or logging and exotic animals especially cats, foxes and cane toads, which poison quolls that try and eat them,” says Taylor. Rebecca Spindler, from Taronga Conservation Society Australia, agrees that cane toads pose the biggest threat to the health of northern quoll populations.
“The quoll is impacted most by the cane toad, which is poisonous, so when bitten by the quolls emits a poison that kills the quoll,” she says. “Quoll populations have shrunk in direct correlation with the expansion of the cane toad population since they were introduced in 1935.”
Carnaby’s black cockatoo
A resident of southwest Western Australia, the Carnaby’s black cockatoo can live to the ripe old age of 50. But populations have declined by over 50 per cent in the last 45 years, largely due to a reduction in habitat.
“The destruction of key habitat mainly for agriculture means that there simply aren’t enough habitat patches for this highly mobile species to move from one area to another to meet its foraging needs,” says
Spindler. “Plus, the limited number of nesting hollows means reproduction is rapidly decreasing.”
Scientists are working on habitat protection and a captive breeding program to save the species from extinction.
Fifteen years ago, Tasmanian devils were abundant on the Apple Isle with numbers reaching around 150,000. Fast forward to 2008 and 90 per cent of the population was wiped out in certain geographical areas of Tasmania by devil facial tumour disease.
“It is thought to be passed from devil to devil by scratching and biting,” says Emily Dunstan from Zoos Victoria. “The disease starts out as small lumps on the face and quickly grows into big tumours. Many of the devils are dying within six months of contracting the disease, often from starvation.”
Because they feed on dead animals, Tasmanian devils help reduce disease and recycle vital nutrients in the wild – so their dwindling numbers are a major concern to conservationists. Spindler says the building of healthy, disease-free insurance populations in zoos and animal parks is helping to maintain the valuable genetic diversity of the species into the future.
By turtle standards, loggerheads are relatively small – they are typically less than a metre long and will rarely tip the scales at more than 150 kg. Their primarily Western Australian habitat is threatened by fishing gear, boats and human occupation of beaches, says Taylor.
The species is heavily impacted by climate change and warmer ocean temperatures as it’s classified as having ‘temperature dependent sex determination’ – where warmer temperatures result in the hatching of more female turtles.
But progress is being made. “There is a federal marine turtle recovery plan as well as actions to lessen the
impact of by-catch and understand the changes in nesting and reproduction as a result of climate change,” says Spindler.
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