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Red text – Aussie slang

Blue text – Lesson Vocab

AE 604.2 – Introduced Species in Australia

Alright, guys! Welcome to this Aussie English Fact episode. Today I want to talk to you about introduced species in Australia. So, I wonder if you know much about the introduced pest and feral species that are found in Australia?

So, since the arrival of the Europeans in Australia from 1770 onwards, more than 3,000 non-native species have been introduced to the shores of Australia and these species range from things like mammals, birds, reptiles, insects, parasites, to fungi, plants, mould, and many more.

You’d be hard pressed to find a single habitat or ecosystem across Australia that hasn’t actually been affected by at least one of these introduced species. And some of these species of flora and fauna are now so entrenched into their new found paradise here Down Under, that many people are clueless that the plant they’re watering in their backyard or the bird they’re feeding in their front yard is actually an unwelcome pest.

Alright, so let’s do a few definitions first before we get into some of Australia’s worst invasive feral and pest species.

Introduced species can be categorised as ‘invasive’ if the species has a tendency to spread their range into new areas or plague their range. For example: cane toads are a very invasive species in Australia.

They can be ‘feral’ if they are animals for domestic purposes, things like pets, recreational purposes, so they were introduced for hunting like foxes and rabbits or their beasts of burden for farming, you know, like cattle or goats, which have then gone wild.

And then lastly, ‘pest’ species are animals which have a direct effect on human standard of living or the environment in ecosystems in areas where they are present and they have a high rate of reproduction and are difficult to control. And these would include things like the blackberry bush or the black rat.

So, I was reading an article on the Threatened Species Recovery Hub website recently, and it was talking about new research that had just come out where they showed that invasive and pest species were a problem for more than 1,200 threatened species in Australia or about four out of every five threatened species. And the results were really surprising.

Of Australia’s 10 worst invasive species, the very worst was the European rabbit. In second place we had Phytophtora, which was a plant disease. Third place we had the feral pig, in fourth place we had the feral cat, in fifth place we had the feral goat, in equal sixth place we had the European red fox and the plant Lantana, as affecting the same number of threatened species. And then in eighth place we had the blackberry bush. In ninth place we had the black rat. And then in tenth place we had feral cattle.

And interestingly enough, if we compare European rabbits with feral cattle, number one and number 10 respectively on the list, European rabbits almost affect ten times as many species as feral cattle do, with European rabbits affecting 321 native species that are threatened and feral cattle affecting 39.

Alright. So, I thought I would go through why, when, and how some of these introduced species got to Australia, because I find it really interesting, I think, you know, the history of introducing species into a new environment, new ecosystems and then how they interact with the ecosystem, as a biologist, it’s an incredibly interesting kind of topic, you know, it’s quite often tragic because it affects negatively a lot of native species, obviously.

But on the other side of it, it tends to be a good thing for the non-native species that entered that environment, and so it’s always interesting to see and look into how introduced species change environments and affect the native species.

So, as you may know in Australia we have heaps of feral species like rabbits, foxes, cats, pigs, goats, horses, camels, cows, donkeys, but interestingly, we don’t have feral sheep.

So, before I go through the list of some of these worst culprits, I thought I would tell you this story about sheep and why we don’t have them as a feral species.

So, despite there being over 74 million sheep that are farmed in Australia, that’s three for every single human being, they aren’t feral species, and the most obvious reason for this is the thing for which they are primarily farmed, their wool, which needs to be shorn by a shearer on an annual basis as they’ve been bred not to lose their fleece naturally every single year.

So, instead, if not shorn, their fleece continues to grow in length, right? Sort of like my beard, but not the hair on my head. So, if sheep aren’t shorn, they face a number of dangers which can be lethal to the sheep including: being fly struck, which is where blowflies lay their eggs in the wool and the maggots end up eating away the animal’s flesh and skin, which leads to infection and obviously a very slow agonising death.

I actually never realised my grandfather, who had a sheep farm, he had a shotgun there on the farm and I always thought it was there for shooting foxes or rabbits, but what he actually ended up telling me was that it was for putting down fly blown sheep or sheep that had been attacked by crows and had parts of their body opened up when it rained heavily and they couldn’t move, because their wool had soaked up the water, right?

So, there you go the wool is actually quite a bit of a burden on the sheep. So, sheep can also become ‘wool blind’, which is where the fleece grows so much over their eyes and their face, that it blocks their vision and pretty much it’s sort of like pulling a beanie over your face, you can’t see anything, so it’s very hard for them to negotiate their surroundings and find things like food and water.

The fleece also traps a great deal of moisture and bacteria, weighing down the sheep and encouraging infection from microbes, and because wool can absorb so much water it becomes a dead weight on the sheep’s back making it substantially more difficult to find shelter, to eat, to move around, and to evade predators. So, some sheep that escape, skip their annual shearing, and are found barely able to walk because of this extra weight on them.

So, in short, a sheep escaping into the wild to try and live a more carefree and natural life, is actually almost certainly a death sentence to the sheep, unless he stumbled upon by someone, which is what happened to a Merino in Canberra. And this was a funny story. So, this sheep, this Merino sheep, was found in Canberra and it was given the name Chris and was found on Mulligan’s flat which was where I used to live, near where I used to live. And it was rescued by a team from the RSPCA.

So, the team got a shearer out to remove Chris’s excessive burden of wool as soon as possible, which was weighing him down and the fleece ended up weighing more than 41 kilos. So, that’s about half my body weight. He was carrying that around in fleece weight on his back. To give you context, that’s more than eight times the weight of a normal five-kilogram Merino fleece. So, he was probably out walking around in the bush for several years and it ended up smashing records. That’s the largest fleece that’s ever been shorn of a sheep.

Alright, so back to the main story. So, I thought we could go through a bunch of the worst invasive species and look at their introduction, how they got to Australia, and learn a bit more about them.

So, number one: European rabbits. European rabbits first arrived with the First Fleet in 1788. However, they weren’t intentionally introduced into Australia until halfway through the 19th century in 1859 and this was done in Victoria for the purposes of recreational hunting. So, by the year 1886, they had spread all throughout Victoria and New South Wales where they were a common sight and they were extending into the Northern Territory by the early 1900s. By 1910 they had spread throughout the majority of their present-day range, where they’re found now across the majority of Australia.

And by 1920, it was estimated that Australia was home to more than 10 billion rabbits. That’s insane. How accurate this is, no one will ever know, but more recent estimates land around the 200 million rabbit mark, which is still almost 10 rabbits for every human in Australia.

So, they’re the most disruptive introduce species in Australia, impacting more than 300 native Australian species of plant and animal through direct predation of plants and indirect competition for things like food, shelter, and water with other animals.

And on top of this, there are significant burden to farmers in Australia. As their numbers rise and ebb with the seasons, and if these numbers are left unchecked during non-drought periods with high rainfall, they can reach plague proportions and wreak absolute havoc and devastation on farmers’ crops and can compete with livestock for pasture. So, they obviously don’t just disrupt farming land, but also cause extensive damage to natural habitats in Australia and are believed to have contributed to the decline or loss of animals like the great bilby, the yellow-footed rock wallaby, the southern and northern hairy-nosed wombats, the mallee fowl and even the plains-wanderer.

It goes without saying that rabbits are impressive breeders and it’s obvious why we use the expression ‘to breed like rabbits‘ in English. And when rabbits are having a good season and their numbers are flourishing, you know that as a result feral cats and foxes are going to ride this wave of surplus rabbits and their numbers in turn are also going to increase, putting even more strain on Australian ecosystems.

Number two: Phythophtora plant disease. So, the name Phythphtora means the ‘plant destroyer’ in Greek. It was once thought to be a fungus, but it actually turns out that Phythophtora is a genus of plant damaging oomycetes or water moulds, whose member species are wreaking absolute havoc on crops and natural ecosystems worldwide.

The disease is known as ‘Phythophtora dieback’, and it’s often hard to detect and can lead to permanent damage in Australian landscapes and habitats before it’s finally identified. It can also lay in wait for prolonged periods of time, lying dormant during dry weather and in most situations it’s impossible to eradicate from infested areas. Thus, most of the fight against Phythophtora is focussed on preventing its spread from place to place, which means reducing the spread of soil, water, or plant material from location to location.

It’s such a dangerous introduced species because of its potential to rot the roots of hundreds of different plant species both native and farmed in Australia, which not only kills those plants, but has a carry-on effect by reducing the available food for animals and leading to problems like erosion of the soil.

Number three: feral pigs. So, pigs were introduced into Australia as domestic livestock from Europe, with the arrival of the First Fleet in 1788, when 49 pigs were brought to Sydney as a food source from England. The pigs were allowed to roam wild and subsequently firmly embedded themselves in the Australian environment, whereby the 1880s they were running amuck all over New South Wales. Today, they’re found all throughout Australia, except in deserts. And in 2011 there was one pig for every human in Australia.

Feral pigs grow tusks, which they then use to forage for food and dig up soil. And this behaviour leads to them causing significant damage to the environment, where large areas of land are dug up in the search for things like water and food, including: rainforest areas, monsoon forest, paperbacks, swamps, open flood lands, marsh areas, semi-arid flood lands, dry woodlands, and sub alpine grasslands and forests.

So, you can see these guys are very much generalists and are happy to live in many different environments Down Under. So, they’re foraging behaviour is the most significant problem for native species due to the extensive damage that they do whilst selectively feeding, trampling, and rooting around underground for parts of plants and for invertebrates.

They’ll also eat just about anything that they can get their tusks on including succulent green vegetation, fruit, grain, roots, bulbs, and fungi, and even animals like frogs, fish, reptiles, birds, invertebrates, and small mammals, and carrion when the chance avails itself. They’re even known to predate on lambs and the occasional newborn calf, posing a problem to farmers.

The only animals known to predate on pigs are dingoes and wild dogs, as well as large birds of prey, and they can only really manage to take out piglets before they reach adult size.

Number four: feral cats. Cats were introduced into Australia in the year 1849 from Europe as pets and many of them turned to a more liberal lifestyle in the Australian wilderness shortly after. Within less than 200 years, they’ve increased in number to the point where rough estimates suggest that there are 20 million feral cats in Australia. Nearly one for every single person and nearly five for every single pet cat in Australia.

They’re now found all throughout Australia, except in tropical rainforests, and they’re the most widely spread and invasive species of all the introduced species Down Under.

Every cat is estimated to kill around 740 animals a year, thus potentially wiping out nearly 15 billion animals per year in Australia. And cats are possibly responsible for a number of extinctions of small mammals in Australia too. They’re a major cause of decline of many native species including the bilby, bandicoot, bettong, and numbat, and have likely already caused a number of Australian native species to go extinct. Furthermore, they carry a number of infectious diseases that can be transmitted to native animals, livestock, and even humans.

Number five: feral goats. Goats were introduced into Australia with the First Fleet in 1788 as domestic livestock and they had a number of different breeds that were introduced later on in the 1800s. They’re now found throughout Australia and are a prolific feral species that eats many native species of plant and competes with many other species for things like food, water, and shelter. On top of this, there are hard-hooved ungulates and as such can break up the soil crust and destroy land that they’ve depleted of vegetation.

They also have a wide-ranging diet and they can eat just about anything and thus outlast many other native species and non-native species in times of drought, whilst also having a much more significant impact on the food supply. Lastly, they’re conduits for exotic diseases including foot and mouth disease.

Surprisingly, feral goats have a few benefits. One upside is that they’ll eat just about anything, including many weed species and, so have been introduced into some parts of New South Wales and Queensland into plantation forests in order to control the spread of weed species.

And another upside is that feral goats are now being commercially exploited by many pastoralists, leading to an industry worth now more than 29 million dollars a year, and many of these pastoralists now consider goats a significant part of their business where they round them up, capture them, and sell them as meat on the international market.

Number six: the European red fox. The European red fox was introduced into Australia in 1855 from Europe for the purpose of recreational hunting. Needless to say, the majority of foxes had other things in mind and were never actually successfully hunted. And within 100 years they’d bred and spread so prolifically, that they covered most of the Australian continent. Only in recent years have they made their way off the Mainland onto the island of Tasmania, possibly due to human release.

The foxes are a serious problem for native species, in particular ground-nesting birds, mammals, and reptiles, as in the case of feral cats, and they’re also a problem for farmers of livestock as they often hunt young calves and lambs.

If they’re not hunting you as a native rat, bilby or wallaby, they’re competing with you for food as a fellow predator, such as in the case of quolls, and they’re also spreading diseases to both native and domestic animals.

The recent decline in dingo populations on the mainland of Australia is further reason why fox numbers have increased. A final reason for their widespread success as an introduced species in Australia is their ability to live an urban lifestyle in suburbs and cities across the nation, where they feed on animals and human waste and are often free from predators.

Now, let’s go through a few plants.

Number seven: Lantana. Lantana is one of Australia’s worst invasive weed species due to its invasiveness and potential to spread, as well as its economic and environmental impacts. The plant forms dense and impenetrable thickets, which take over native bushland and pastures alike all across the eastern coast of the Continent.

Lantana often outcompetes native species for resources, whilst also reducing the productivity of pastures and forestry plantations. And it also adds extra fuel to bushfires in summer periods. And to make matters worse, it’s toxic to livestock.

Alright, the last one, number eight: blackberries or the blackberry bush. Blackberries were deliberately introduced into the countryside in New South Wales from Britain back in the 1840s due to its tasty fruits and for making hedgerows.

Needless to say, the plant had other plans and it quickly escaped into the wild, where by the 1880s it was recognised as a significant weed species. Today, it thrives in a range of different environments throughout south eastern New South Wales, invading both grazing lands and natural ecosystems.

The weed is spread via its seeds by animals like birds and even foxes, and also in waterways such as rivers and creeks. It’s a problem for native species because the plant grows in dense thickets, just like Lantana, that prevent native species from using the habitat, leading to the plant often completely dominating large swathes of land.

In its domination of the Aussie landscape, the plant also limits people’s access to places and can even alter fire regimes.

So, there you go, guys. That’s the story of some of Australia’s worst introduced plant and animal species. Whether introduced intentionally or accidentally in Australia, many foreign species find the conditions quite amenable to survival and even flourish Down Under. Once they escape into the wild, they often find an abundance of food, a lack of natural predators, and thus, a great big gaping hole in their natural ecological niches and this allows them to dominate in the Australian environment and, tragically, often at the expense of numerous native species.

So, it’s important that we do something to eradicate or at least control introduced species like these in Australia, because we need to keep our natural environment in as healthy a condition as possible for our own sake when it comes to farming livestock and crops, but also for the sake of our unique flora and fauna the majority of which is found nowhere else on Earth.

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Vocabulary:

ST = Something

SW = Somewhere

SO = Someone

A beanie – (Aussie slang) a woolen hat to keep your head warm.

A carry-on effect – an effect that “carries onwards” from one experimental condition to another.

A common sight – ST often seen.

A dead weight (on ST) – a heavy or oppressive burden.

A great big gaping hole in – a deep and wide gap in ST; an obvious absence of ST.

A great deal of ST – a lot of ST.

A wide-ranging diet – the extensive variety of things ST eats.

Alter fire regimes – change the regular occurrence of bush fires in the natural environment.

An abundance of food – more available things to eat than usual.

Around the 200 million rabbit mark – approximately 200,000,000 rabbits.

• Around the *number* mark = approximately that number

As a result – the outcome of ST you did.

At the expense of ST – so as to cause harm to or neglect of ST.

Beasts of burden – an animal, such as a mule or donkey, that is used for carrying loads.

Breed like rabbits – have many children, often rapidly.

Commercially exploited – (of a resource) used up in order to make money.

Eat just about anything that they can get their tusks on – consume anything they can acquire.

• “to do just about anything” = do nearly everything

Ecological niches – a niche is the match of a species to a specific environmental condition.

Face a number of dangers – be confronted with multiple hazards or risks.

Firmly embedded oneself (in ST) – become deeply fixed (in ST).

Flora and fauna – plants and animals.

Fly struck – infested with fly maggots.

Foot and mouth disease – a contagious viral disease of cattle and sheep, causing ulceration of the hoofs and around the mouth.

For our own sake – for our own benefit.

For the sake of ST – for ST else’s benefit.

Four out of every five – 80% of something.

Get SO out SW – cause SO to come to a location.

• Often used when calling SO to come and fix ST or help with ST as a task or work.

Give you context – give you enough information to understand what’s being said.

Go through ST – discuss or address ST thoroughly.

Go wild – (of an animal) escape into the surrounding environment and live wildly.

Grazing lands – land that is used for grazing livestock, i.e. for livestock to feed on the grasses and plants, etc.

Ground-nesting birds – birds that build their nests on the ground as opposed to in trees.

Hard pressed to do ST – if you’re “hard pressed to + do ST”, it means you’ll find doing that thing very difficult.

Hard-hooved ungulates – ungulates are mammals that have hooves, the horny and hard part of the foot, e.g. like on a horse or cow.

Have other plans – be planning to do ST different from what SO or ST else wants.

Have other things in mind – be planning to do ST different from what SO or ST else wants.

I wonder if… – used when you want to be very polite when you are asking someone to do something, or when you are asking them for their opinion or for information.

In equal sixth place – (of two things in competition with one another) to acquire the same score and both come 6^th in a competition.

In the case of ST – as a provision against something happening or being true.

In times of drought – when there’s very little rainfall.

Infectious diseases – disorders caused by organisms — such as bacteria, viruses, fungi or parasites.

Interact with ST – act in such a way as to have an effect on each other.

It goes without saying that… – needless to say that…; it’s obvious that…

Just about anything – almost anything.

Large swathes of land – vast areas of land.

Lay in wait (for ST) – to hide and wait for the right moment to make an attack.

Leave ST unchecked – leave ST unstopped or unrestrained.

Lie dormant – lying asleep or as if asleep; inactive.

Made their way SW – travel to SW.

Make matters worse – cause things to be even worse.

Needless to say – it’s obvious; it doesn’t need to be mentioned.

Negotiate one’s surroundings – move through the environment around oneself.

Non-drought periods – times when there is plenty of rain and water.

On an annual basis – occurring every year.

On the other side of ST – alternatively; on the other hand.

On top of this – furthermore.

Pose a problem (to SO) – prove to be an issue (to SO).

Predate on ST – (of an organism) eat another organism.

Present-day – today; the present.

Put ST down – euthanise ST; kill ST, usually to stop it from suffering.

Put strain on ST – burden or overload SO or ST.

Reach plague proportions – (of an organism) increase in numbers dramatically as to be a problem for the environment, other organisms, and/or people.

Recreational hunting – pursuing and killing animals for sport as a hobby.

Ride this wave of… – enjoy the advantage or benefit of a particularly successful, popular, fortunate, interesting, etc., moment or period of time.

Rise and ebb – increase and decrease.

Roam wild – live freely in nature, as opposed to in a cage or pen.

Root around – search for things in the soil.

Rough estimates – approximately.

Round ST up – capture a number of animals that are roaming freely.

RSPCA – The Royal Society for the Prevention of Cruelty to Animals

Run amuck – Behave in a frenzied, out-of-control, or unrestrained manner.

Selectively feeding – food procurement in which the animal exercises choice over the type of food being taken, as opposed to filter feeding, in which food is taken randomly.

Smashing records – beating previous records by a lot.

Soak ST up – absorb ST.

Standard of living – the degree of wealth and material comfort available to a person or community.

Take ST out – kill ST.

The bush – (Aussie slang) wild or uncultivated country.

The Mainland – the main continent island of Australia, not including Tasmania or other small islands.

The soil crust – soil surface layers that are distinct from the rest of the bulk soil, often hardened with a platy surface.

Threatened species – any species which are vulnerable to endangerment in the near future.

Three for every single human being – the number of X is 3x the number of humans.

To the point where – to the extent that.

When it comes to ST – regarding ST.

When the chance avails itself – when the opportunity occurs.

Wipe ST out – exterminate ST completely.

Worst culprits – the worst things that have done ST wrong.

Wreak absolute havoc – cause great damage.

You can see… – it’s obvious that…