"In the Karrajia, the time of the beginning long ago, when light and life were young and learning together. In our belief if you listen, learn, understand and observe, then you will receive wisdom and knowledge. For this is the Mirning way."—Bunna Lawrie
Senior Mirning Elder and Whale Songman

This edition we focus on the lands of the Mirning people, the vast limestone Nullarbor Plain that merges with the waters of the Great Australian Bight. We thank the Mirning for sharing their world with us.

Photography by Ingvar Kenne

On a recent journey across the Nullarbor, photographer Ingvar Kenne captured epic space, beauty and the connection of land and sea for Wilderness Journal. Main image above: The Southern Ocean and Nullarbor Plain.

The southern-hairy nosed wombats' life-giving, labyrinthe burrows, carved out from under the desert, are spreading across the Nullarbor again. Wombat researcher Michael Swinbourne from the University of Adelaide discusses his work tracking the lives of southern hairy-nosed wombats. An integral part of the Nullarbor landscape, this iconic animal of South Australia is reclaiming its desert home.

What is your role and involvement with wombats?

I'm an affiliate researcher at the University of Adelaide and specialise in wombats with a particular focus on the southern hairy-nosed. I decided to study them because despite decades of research, we don't know a lot about them. A lot of the management decisions on wombats were being made in the absence of rigorous scientific information, so I thought it was about time we went out and got some.

In fact the University of Adelaide owes its very existence to the southern hairy-nosed wombat, which is also the faunal emblem of South Australia. The story goes like this: on the Yorke Peninsula back in the 1850s, there was a shepherd tending his flock, and he came across some unusual rocks outside a wombat burrow. These rocks turned out to be copper ore, and an excavation underneath the warren turned up one of the richest copper finds of all time. It led to the development of the whole area of Moonta, Wallaroo and Kadina, which became the Copper Triangle.

That original mine became known as the Wombat Mine and it is still there. Wombats became loved by miners because they would dig up copper, leading them to important finds. It led to a mining boom, which transformed the state's economy. The hotel in Kadina is still known as the Wombat Hotel and there is a memorial to wombats in the centre of Moonta. The miners protected the wombats; the first Australian animal to ever be protected was the southern hairy-nosed wombat.

Walter Watson Hughes grew wealthy from that copper find and in 1874 he donated £20,000 to establish the University of Adelaide.

The wombat has played a role in the story of South Australia, what role do they play in the environment?

Wombats are known as ecosystem engineers. They are absolutely crucial to the health of the environment and the loss of burrowing animals like the wombat, and to a smaller extent bilbies and bettongs, has really impacted soil health in a lot of places.

Wombats turn over a lot of soil and they break up the hard ground, bringing it to the surface. You can see these white mounds in the middle of patches of brown dirt in the landscape, and that is the wombats bringing up limestone. Over time it's weathered and washes down, fertilising the soil. When they dig and scratch around they make these little pits and furrows that trap nutrients and seeds, which increases germination rates for plants astronomically. If you remove these animals the ecosystem breaks down. Some of these burrows are centuries old, and you can see how they have changed the landscape.

And of course the wombats’ scats help to fertilise the landscape too. They eat grasses if they can get them, as well as saltbush and bluebush. Wombat burrows are also refuges for other animals. It’s bloody hot on the Nullarbor in the middle of summer, and so wombats live underground, but of course a lot of other animals share their burrows: snakes, lizards, insects, echidnas. We've even seen birds and wallabies living in wombat warrens.

Why were these animals on the brink of disappearing from the Nullarbor and how have they made such an impressive return?

In the late 19th and early 20th century rabbits started to spread across the country in plague numbers. It decimated the wombat population. The rabbits would compete with them for food, eating everything, and also push wombats out of their own warrens. At the time and until relatively recently, the only way to control rabbit numbers was to destroy their burrows. And as a consequence of that, wombats became collateral damage. The thinking was: ‘There is a big hole in the ground: bulldoze it, it might have a rabbit in it’... It may also have had a wombat in it, too, but that was the way it went.

Indeed, there used to be quite a sizable population of northern hairy-nosed wombats along the Murray River in the New South Wales Riverina, but back in the 1870s, they actually put a bounty on wombats to destroy their warrens so the rabbits couldn't survive. Within 15 years they wiped out the whole population. I estimate a population of twenty to thirty thousand were wiped out. We exterminated them.

The northern hairy-nosed could have gone the way of the Tasmanian tiger; it’s now one of the most critically endangered animals in the world. When they first started doing research on the northern hairy-nosed wombat back in the 1980s, there were only about 30 individuals remaining. Since then there has been a dedicated, very intense recovery programme and the numbers are up to about 250 now. But that's still very low and they are in just two protected areas, in central and southern Queensland.

Now the rabbits are under effective control, firstly with myxomatosis and more recently with calicivirus. Since the 1960s, southern hairy-nosed wombat numbers have been recovering and it really has started to bounce back in the last 20 or so years.

Are you seeing an improvement in the health of the Nullarbor as a result?

Absolutely. One of the places where we've seen the biggest change are places in the south where they've converted some old sheep grazing properties to wildlife conservation areas. And the whole ecosystem has been improving. It's much more healthy, with more animals and different species around. And the soil health is greatly improved, there is better vegetation growth as well.

Can you easily spot signs of wombats when driving across the Nullarbor?

You'll certainly see their warrens everywhere; it's hard not to see them. Once you get just west of Ceduna, all the way across the Nullarbor you'll see warrens everywhere. Bare-nosed or common wombats tend to live in single burrows, which is nothing on a scale of the southern hairy-nosed. The largest I have seen is roughly the size of the Melbourne Cricket Ground, with up to 70 entrances and there might be 20 to 30 animals living inside it.

Most people have this incorrect notion about the Nullarbor that it's just flat, but it's a fascinating landscape. It has micro-topography, which has a huge impact on where animals can and can't live. It’s an endlessly fascinating and iconic place.

Is the future looking bright for the southern hairy-nosed wombat?

It’s looking pretty good, but there is the impact of climate change. The southern hairy-nosed wombat really needs two seasons of reasonable conditions for the young to survive to maturity. In the Nullarbor droughts are becoming more frequent, which means there could be more periods where the young are not going to survive to maturity.

They'll survive because they're hardy animals, but the numbers could decline substantially in some areas. The scats can tell us a lot. I collect scats—I have freezers full of wombat poo—it’s a hobby of mine. We can look at the epithelial cells on the outside of the scats, which tells us about the genetics of the animal. We can look at the genetics of the plants they eat, what their diet is like. We want to look at the genetics between different populations to determine how they are moving across the landscape.

From all this we can determine what measures we may need to take to protect the species. We don't want them to go the way of the northern hairy-nosed wombat and get down to 30 animals before we take action. If we can get advanced ideas of what's going on, we can actually start thinking about the areas we need to protect to ensure a future for this icon of the Nullarbor.

Just below the surface of the Nullarbor lies a secret world frozen in time with the skeletal remains of the marsupial lions, thylacines and devils that once thrived here. A continued source of knowledge for the Mirning for more than 65,000 years, the caves are a window into Earth’s deep past and a glimpse into the future.
Words: Dan Down

If science is like an endless cave network of discovery, then the honeycombed limestone subsurface of the Nullarbor is metaphor made real. Beneath the desert scrub, below the wombat warrens, a wealth of scientific understanding is being brought to light. The labyrinthine caverns are a time machine that can take us millions of years into the past and even allow a sneak peek at the future, revealing what will happen to life on Earth as our climate shifts. The caves are a timeless, priceless font of knowledge that represents one of the most significant laboratories on the planet.

Jon Woodhead, a Professor of Earth Sciences at the University of Melbourne, has been studying this underworld for some 15 years. “We only know about 700 or so caves, but it is estimated that there may be many thousands, which would make this the most extensive cave network in the world,” says Prof Woodhead. “But their global scientific significance is really because of their age—most of them were formed between three and eight million years ago. And the fact that they are so remarkably well preserved is unusual. There is nowhere else on the planet with such an abundance of well-preserved ancient caves.”

The Nullarbor’s vast limestone karst formed on an ancient sea floor between 15 and 25 million years ago. This seabed was then uplifted 15 million years ago to form the Nullarbor Plain we see today. The caves stopped forming about two and a half million years ago as a wet continent dried out, leaving them frozen in time along with the remains of extinct megafauna.

Down here, the fossils of thylacine, tree kangaroos, and Thylacoleo carnifex, the marsupial lion, are a goldmine for scientists unravelling Australia’s iconic natural history. “Some passages open out into these beautiful caverns. In many cases they’re full of stalagmites and flowstones,” says Prof Woodhead. “But unlike modern caves they're not wet; they're dry and dusty because the formations here are no longer active and can be millions of years old. So it's like entering a lost world.”

How have we been able to grasp these unfathomable timeframes? “We date the caves by looking at the stalagmites and the flowstones, which contain minute amounts of uranium. This slowly decays over time to the element lead,” explains Prof Woodhead. “We use very sensitive instruments to measure tiny amounts of uranium and lead in the calcite, which allows us to determine the age. The oldest materials we've found are around 10 million years old, which likely represent the first stages of the caves’ development.”

Prof Woodhead is trying to answer how the caves formed and how the continent evolved. “Once we have the ages, we can then look at materials that are either trapped within the samples or the composition of the samples themselves to reveal what the climate was like, or reconstruct the vegetation around the cave all those millions of years ago. We do that by extracting fossilised pollen; over time pollen has been blown into the caves and become trapped in stalagmites as they're growing.”

Just as scientists study ice cores taken from the Antarctic to reveal past climates, so the Nullarbor’s caves are proving a vital record of the Earth’s pulse. “Most of these formations were formed in a period called the Pliocene, which was about two-and-a-half to five million years ago. It's a really important time in Earth's history because it's a very good analogue for future global warming,” says Prof Woodhead. “We think temperatures in the Pliocene were about three degrees hotter than today. So the Pliocene was kind of what the future world will look like, possibly as soon as the end of this century.”

And herein lies a mystery, because the Australian continent is currently drying out. “All the predictions are that southern Australia, in particular, is going to get drier and drier. But when you look at the Pliocene, it is actually very wet, so there could be a tipping point where things get wet again.” Indeed, the remains of tree kangaroos in the Nullarbor’s caves from hundreds of thousands of years ago point to a landscape once covered in lush forest.

“It just goes to show that if we just look at the land through the filter of today, then we are not really seeing the whole picture,” says Dr Liz Reed. A vertebrate palaeontologist at the University of Adelaide, she is studying the Nullarbor’s wealth of ancient animal remains, exploring the fossil record from some 20,000 years ago up to today, to see how biodiversity has responded to environmental change.

Prof Woodhead’s work has been critical in allowing her to understand the ancient climate context of sites where fossils are found, and the closer you get to today, the more sobering it becomes. “If I walk out into the Australian bush, I see a mere shadow of what the original biodiversity was like,” she says. “It is a bitter pill to swallow. We have caused devastation on a number of fronts in the short time since the European settlement, with land-use change, the introduction of domestic livestock and feral pests.

“You can drop into a cave, look at a pile of bones and see bandicoots. The Nullarbor barred bandicoot is gone; stick-nest rats: gone; bilbies: gone; mulgaras: gone. And they were so abundant on the Nullarbor; the owls were hunting these animals, bringing thousands back to the caves, coughing up pellets and leaving the bones. But now they are gone. You get quite emotional when you go into a cave and realise that what you're looking at is extinction.

“And these are recent losses, which is really sad. The Nullarbor has such a strong cultural history. I have had the opportunity to understand that perspective, that amazing relationship with Country. The exchange of information certainly helps me understand what I am looking at in the caves as I try to reconstruct the biodiversity that First Nations people lived with here for tens of thousands of years.”

The fossil record reveals the distribution of species in response to changing climates, providing a forecast of how Australia’s precious remaining fauna could respond to rising temperatures again. “We know that devils and thylacines went extinct on the mainland about 3,200 years ago; we know they were once widespread from fossils found in places like the Nullarbor,” says Dr Reed. “With the climate data and pollen from the formations we can look at what drivers led up to those mainland extinctions.

"The thylacine specimens we have from the Nullarbor are small compared to those found on the East and West coasts and Tasmania, indicating an adverse environmental change. We are now trying to find relatively young cave formations so that Prof Woodhead can decipher more about the climate around the time of the thylacine’s disappearance."

The fossil record can also be crucial when we look at rewilding or revegetating areas. "It helps us understand the original faunas and how they filled functions in the ecosystem,” says Dr Reed. “Tassie devils were recently reintroduced back to sites in New South Wales, and so a native carnivore is now fulfilling its role once again. We know they were there from the fossil record.”

The work is gathering pace. Coupled with the careful timestamping of Prof Woodhead, a complete picture is emerging of the Australian continent, its flora, fauna and climate. The underground wonderland could help us plot a path for wildlife as we enter a Pliocene-like world of our own making.

But these caves aren’t just special because of what we can learn from them, they are wonderful in their own right—for their cultural significance, the unique lifeforms they harbour, and their natural rock formations millions of years in the making. “I like to call caves the rainforests of the underground,” says Dr Reed. “They are just as biodiverse, just as delicate, just as important from a conservation perspective, they are intimately tied with groundwater. I think they really are the most fragile terrestrial ecosystems on Earth. The Nullarbor is unique. It is an important place to conserve not only for Australia, but for the world.”

We thank all the artists, photographers and scientists who've given their work to this edition. If you have anything from your own archive to share, get in touch.

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We recognise First Nations as the custodians of land and water across Australia and pay our respects to Elders past, present and emerging. We acknowledge sovereignty was never ceded.