S. Anna Florin, University of Wollongong; Andrew Fairbairn, The University of Queensland; Chris Clarkson, The University of Queensland; James Shulmeister, University of Canterbury; Nicholas R Patton, University of Canterbury, and Patrick Roberts, Max Planck Institute for the Science of Human History
Archaeological research provides a long-term perspective on how humans survived various environmental conditions over tens of thousands of years.
In a paper published today in Nature Ecology and Evolution, we’ve tracked rainfall in northern Australia’s Kakadu region over the past 65,000 years. We wanted to know how major changes in rainfall may have affected the region’s Aboriginal communities through time.
Our findings suggest the Kakadu region wasn’t as prone to dry spells as surrounding areas — and it likely functioned as a place of refuge for early Australians as they struggled through harsh and arid conditions.
To generate a rainfall record spanning 65,000 years, we used ancient food waste left behind by the First Australians living at Madjedbebe, a rock shelter on Mirarr country in the Kakadu region.
This site boasts the earliest known evidence of humans living in Australia. It also boasts plenty of Pandanus spiralis, a native plant commonly called “pandanus” or “screw pine”.
This plant, known as “anyakngarra” to the Mirarr people — the Traditional Owners of Madjedbebe — is very important to them.
Its leaves are used for weaving, its trunk to create dye, its fruit flesh is used in a drink and its nuts (the seed kernels within the fruit) are consumed as a rich source of fat and protein.
Anyakngarra’s nuts were also eaten by the First Australians 65,000 years ago. Discarded nut shells have been preserved as burned fragments, disposed of in fireplaces over time.
These small remnants have proven hugely useful for our research team, which includes archaeologists, environmental scientists and Traditional Owners.
By analysing the isotopic composition in ancient anyakngarra nutshells, we could track rainfall at Madjedbebe. Specifically, we detected how much water (and therefore rainfall) was available to anyakngarra plants in the past.
This analysis is possible due to photosynthesis – the process by which plants convert carbon dioxide in the air into sugars. Anyakngarra plants absorb two isotopes of carbon from the atmosphere: ¹²C and ¹³C. Isotopes are different types of atoms within a chemical element that have the same number of protons but a different number of neutrons. Chemically, the isotopes of carbon are the same, but each has a different atomic “weight”.
Explainer: what is an isotope?
When environmental conditions are favourable, an anyakngarra plant will preferentially absorb more ¹²C than ¹³C. But if a plant is stressed by its environment, such as when it’s waterlogged due to seasonal flooding, it begins to absorb more ¹³C.
The isotopic composition (the ratio of ¹²C to ¹³C) is recorded in the sugars used by the plant for new tissue growth, including for the seasonal growth of nuts.
A higher proportion of ¹³C in a nutshell indicates that the plant it came from was waterlogged during its growth season. From this, we can conclude it likely experienced higher levels of rainfall.
Over the past 72,000 years, humans have lived through an ice age in which there were two particularly cold periods called “stadials”. During stadials, glaciers extended to cover parts of North America, northern Europe, northern Asia and Patagonia (in South America).
The height of the second stadial in this ice age was called the Last Glacial Maximum. While this occurred 22,000 to 18,000 years ago, intense cold and dry conditions in Australia started as early as 30,000 years ago.
During this time, water availability was the main challenge in arid northern Australia (rather than low temperatures). The country’s arid zone expanded dramatically and parts of central Australia may have been temporarily abandoned by Aboriginal people.
Yet the “palaeoclimatic” record we generated for Madjedbebe indicates that, although glacial stages did lead to less rainfall, the Kakadu region remained relatively well-watered during these periods.
Our records show that for as long as people have been around, rainfall at Madjedbebe is unlikely to have dropped below current levels. Thus, this area would have helped early Australians survive during long dry spells and may have also attracted others from surrounding areas.
Our findings are supported by other archaeological evidence from Madjedbebe. For instance, our research has revealed more stone tools were left at this site during the glacial periods. This implies more people gathered there at these times.
Also, because the Kakadu region was still drier during glacial periods as compared to inter-glacial periods, people had to travel further for food and other important resources.
This is supported by evidence of an increased number of tools being brought to the site from further away. This points to increased mobility and new social arrangements being made as people adjusted to life in a harsher environment.
Notably, over the past 65,000 years the driest time in the Kakadu region was not during the Last Glacial Maximum. It is today.
Rather than being the result of less rainfall occurring, this is likely due to higher evaporation caused by warmer inter-glacial temperatures. Aboriginal communities currently living in the Kakadu region are experiencing unprecedented aridity.
These difficult conditions are exacerbated by the threat of invasive plants and animals and disruption to cultural practices of landscape management, such as vegetation burning.
While the people of Kakadu have spent thousands of years adapting to environmental change, the scale and intensity of today’s anthropogenic impacts on regional climates and local landscapes poses an altogether different challenge.
S. Anna Florin, Research fellow, University of Wollongong; Andrew Fairbairn, Professor of Archaeology, The University of Queensland; Chris Clarkson, Professor in Archaeology, The University of Queensland; James Shulmeister, Professor, School of Earth and Environmental Sciences, University of Canterbury; Nicholas R Patton, Ph.D. Candidate, University of Canterbury, and Patrick Roberts, Research Group Leader, Max Planck Institute for the Science of Human History
In recent months, three humpback whales were spotted in the East Alligator River in the Northern Territory’s Kakadu National Park. Contrary to its name, the river is full of not alligators but crocodiles. And its shallow waters are no place for a whale the size of a bus.
It was the first time humpback whales had been recorded in the river, and the story made international headlines. In recent days, one whale was spotted near the mouth of the river and scientists are watching it closely.
The whales’ strange detour threw up many questions. How did they end up in the river? What would they eat? Would they get stuck on the muddy river bank?
And of course, there was one big question I was repeatedly asked: in an encounter between a crocodile and a humpback whale, which animal would win?
The humpback whales were first spotted in September this year by marine ecologist Jason Fowler and fellow scientists, during a fishing trip. Fowler told the ABC:
I noticed a big spout, a big blow on the horizon and I thought that’s a big dolphin … We were madly arguing with each other about what we were actually seeing. After four hours of raging debate we agreed we were looking at humpback whales in a river.
The whales had swum about 20 kilometres upstream. Fowler photographed the humpback whales’ dorsal fins as evidence, and reported the unusual sighting to authorities and scientists.
Thankfully, two whales returned to sea on their own, leaving just one in need of help. There was concern it might become stranded in the shallow, murky tidal waters. If this happened, it might be attacked by crocodiles – more on this in a minute.
Experts considered a variety of tactics to encourage the whale back out to sea. These included physical barriers such as nets or boats, and playing the sounds of killer whales – known predators of humpback whales.
But none of these these options was needed. After 17 days, the last whale swam back to sea on its own.
The whale that spent two weeks in the river has recently returned and been spotted swimming around the mouth of the river. It appears to have lost weight – most likely the result of migration. It is now being monitored nearby in Van Diemen Gulf.
Questions are now being raised about the health of the animal, and why it has not headed south for Antarctic feedings waters.
There are various theories as to why they swam into the East Alligator River. Humpback whales are extremely curious, and may have entered the river to explore the area.
Alternatively, they may have made a navigation error – also the possible reason behind September’s mass stranding of pilot whales in Tasmania.
Long-term, a humpback whale’s chances of surviving in the East Alligator River are slim. The lower salinity level may cause them skin problems, and they may become stranded in the shallow waters – unable to move off the muddy bank. Here the animal might die from overheating, or its organs may be crushed by the weight of its body. Or, of course, the whale may be attacked by crocodiles.
In this case, my bet would be on the whale – if it was in relatively good condition and could swim well. Humpback whales are incredible powerful creatures. One flick of their large tail would often be enough to send a crocodile away.
If a croc bit a whale, their teeth would likely penetrate the whale’s skin and thick blubber. But it would take a lot more to do serious harm. Whale skin has been shown to heal after traumatic events, including the case of a humpback whale cut by a boat propeller in Sydney 20 years ago. Dubbed Bladerunner, it survived but still bears deep scars.
The whale sighting continues to fascinate experts. Scientists are hoping to take poo samples from the whale in Van Diemen Gulf, and could also collect whale snot to learn more about its health. However, the best case scenario would be to see the whale swim willingly to offshore waters.
This unusual tale will no doubt go down in Australian whale history. If nothing else, it reminds us of the vulnerability – and resilience – of these marine giants.
The author would like to thank Northern Territory Government whale expert Dr Carol Palmer for her assistance with this article.
Western Arnhem Land, Northern Territory, has a remarkable range and number of rock art sites, rivalling that of Europe, southern Africa and various parts of Asia. Several thousand sites have been documented and each year new discoveries are made by various research teams working closely with local Aboriginal communities.
Today, in the journal Australian Archaeology, we and colleagues introduce an important previously undescribed rock art style. Consisting of large human figures and animals, the style is primarily found in northwest Arnhem Land, and has been named Maliwawa Figures by senior Traditional Owner Ronald Lamilami.
We recorded 572 Maliwawa paintings at 87 rock shelters over a 130-kilometre east-west distance, from Awunbarna (Mount Borradaile) to the Namunidjbuk clan estate of the Wellington Range, a region home to unique and internationally significant rock art of various types.
Maliwawa Figures consist of red to mulberry naturalistic human and animal forms shaded with stroked lines. Occasionally they are in outline with just a few strokes within. Almost all were painted but there is one drawing.
The figures are often large (over 50 cm high), sometimes life-size, although there are also some small ones (20–50 cm in height). Various lines of evidence suggest the figures most likely date to between 6,000 to 9,400 years of age.
In the Maliwawa paintings, human figures are frequently depicted with animals, especially macropods (kangaroos and wallabies), and these animal-human relationships appear to be central to the artists’ message. In some instances, animals almost appear to be participating in or watching some human activity.
Another key theme is a male or indeterminate human figure holding an animal, often a snake, or another human figure or an object.
Such scenes are rare in early rock art, not just in Australia but worldwide. They provide a remarkable glimpse into past Aboriginal life and cultural beliefs.
Maliwawa animals are usually in profile. Some macropods are shown in a human-like sitting pose with paws in front, resembling a person playing a piano. Depictions of animal tracks (footprints) and geometric designs are rare.
Macropods, birds, snakes and longtom fish are the most frequent animal subjects, comprising three quarters of total fauna. But, more generally, mammals are most common.
There are seven depictions of animals long extinct in the Arnhem Land region, consisting of four thylacines and three bilby-like creatures. At one Namunidjbuk site there is a rare depiction of a dugong.
A third of human depictions were classified as male because they have male genitalia depicted. Females, identified because breasts were shown, are rare, comprising only 5% of human depictions. Almost 59% of human figures could not be determined to be either male or female because they lack sex-specific characteristics.
Human figures generally have round-shaped or oval-shaped heads; some have lines on the head suggestive of hair. 30% of human figures are shown with headdresses, of which there are ten different forms. The most common is a ball headdress, followed by oval, cone and feather.
Maliwawa males are usually in profile and often have a bulging stomach above a penis. A few Maliwawa females are also shown with an extended abdomen.
Most Maliwawa Figures are in accessible or visible places at low landscape elevations rather than hidden away, or at shelters high in the landscape. This suggests they were meant to be seen, possibly from some distance. Often, Maliwawa Figures dominate shelter walls with rows of figures in various arrangements.
We first found some of these figures during a survey in 2008-2009 but they became the focus of further field research from 2016 to 2018.
In Australia, we are spoiled with rock art — paintings, drawings, stencils, prints, petroglyphs (engravings) and even designs made from native beeswax in rock shelters and small caves, on boulders and rock platforms. Often in spectacular and spiritually significant landscapes, rock art remains very important to First Nation communities as a part of living culture.
There are as many as 100,000 sites here, representing tens of thousands of years of artistic activity. But even in 2020, new styles are being identified for the first time.
What if the Maliwawa Figures were in France? Surely, they would be the subject of national pride with different levels of government working together to ensure their protection and researchers endeavouring to better understand and protect them.
We must not allow Australia’s abundance of rock art to lead to a national ambivalence towards its appreciation and protection.
The Maliwawa Figures demonstrate how much more we have to learn from Australia’s early artists. And who knows what else is out there waiting to be found.
Alyson Stobo-Wilson, Charles Darwin University; Brett Murphy, Charles Darwin University; Graeme Gillespie, University of Melbourne; Jaana Dielenberg, The University of Queensland, and John Woinarski, Charles Darwin University
Only a few decades ago, encountering a bandicoot or quoll around your campsite in the evening was a common and delightful experience across the Top End. Sadly, our campsites are now far less lively.
Northern Australia’s vast uncleared savannas were once considered a crucial safe haven for many species that have suffered severe declines elsewhere. But over the last 30 years, small native mammals (weighing up to five kilograms) have been mysteriously vanishing across the region.
The reason why the Top End’s mammals have declined so severely has long been unknown, leaving scientists and conservation managers at a loss as to how to stop and reverse this tragic trend.
Our major new study helps unravel this longstanding mystery. We found that the collective influence of feral livestock — such as buffaloes, horses, cattle and donkeys — has been largely underestimated. Even at quite low numbers, feral livestock can have a big impact on our high-value conservation areas and the wildlife they support.
In 2010, Kakadu National Park conducted a pivotal study on Top End mammals. It found that between 1996 and 2009, the number of native mammal species at survey sites had halved, and the number of individual animals dropped by more than two-thirds. Similar trends have since been observed elsewhere across the Top End.
Given the scale and speed of the mammal declines, the need to find effective solutions is increasingly urgent. It has become a key focus of conservation managers and scientists alike.
The list of potential causes includes inappropriate fire regimes, feral cats, cane toads, feral livestock, and invasive weeds.
With limited resources, it’s essential to know which threats to focus on. This is where our study has delivered a major breakthrough.
We looked for patterns of where species have been lost and where they are hanging on. With the help of helicopters to reach many remote areas, we used more than 1,500 “camera traps” (motion-sensor cameras to record mammals) and almost 7,500 animal traps (such as caged traps) to survey 300 sites across the national parks, private conservation reserves and Indigenous lands of the Top End.
We found most parts of the Top End have very few native mammals left. The isolated areas where mammals are persisting have retained good-quality habitat, with a greater variety of plant species and dense shrubs and grasses.
This habitat provides more shelter and food for native mammals, and has fewer cats and dingoes, which hunt more efficiently in open areas. In contrast, sites with degraded habitat have much less food and shelter available, and native mammals are more exposed to predators.
Across northern Australia, habitat quality is primarily driven by two factors: bushfires and introduced livestock, either farmed or feral.
Our surveys revealed that areas with more feral livestock have fewer native mammals. This highlights that the role of feral livestock in the Top End’s mammal declines has previously been underestimated.
Even at relatively low densities, feral livestock are detrimental to small mammals. Through overgrazing and trampling, they degrade habitat and reduce the availability of food and shelter for native mammals.
Frequent, intense fires also play a big role. Australia’s tropical savannas are among the most fire-prone on Earth, but fires that are too frequent, too hot and too extensive remove critical food and shelter.
Yet, even if land managers can manage fires to protect biodiversity, for example by reducing the occurrence of large, intense fires, the presence of feral livestock will continue to impede native mammal recovery.
Cats have helped drive more than 20 Australian mammals to extinction. So it’s not surprising we found fewer native mammals at our sample sites where there were more cats.
However, our results suggest the best way to manage the impact of cats in this region may not be to simply kill cats, which is notoriously difficult across vast, remote landscapes. Instead, it may be more effective to manage habitat better, tipping the balance in favour of native mammals and away from their predators.
The combination of prescribed burning to protect food and shelter resources, and culling feral livestock, might be all that’s needed to support native mammals and reduce the impact of feral cats.
Many scientists have suggested dingoes could also be part of the solution to reducing cat impacts — as cats are believed to avoid dingoes. With this in mind, we explored the relationship between the two predators in this study.
We found no evidence dingoes influenced the distribution of feral cats. In fact, survey sites with more dingoes had fewer native small mammals, suggesting a negative impact by dingoes.
But, unlike cats, culling dingoes is not an option because they provide other important ecological roles, and are culturally significant for Indigenous (and non-Indigenous) Australians.
Our study suggests an effective way to halt and reverse Top End mammal losses is to protect and restore habitat. For example, by improving fire management and controlling feral livestock through culling.
It is also very important to conserve the environments that still have high-quality habitat and healthy mammal communities, such as the high-rainfall areas along the northern Australian coast. These areas provide refuge for many of our most vulnerable mammal species.
While there’s more research to be done, it’s crucial we start managing habitat better, before we lose more of our precious mammal species.
The authors would like to gratefully acknowledge the support from many Indigenous ranger groups, land managers and Traditional Owners. This includes the Warddeken, Bawinanga, Wardaman and Tiwi rangers, the Traditional Owners and land managers of Kakadu, Garig Gunak Barlu, Judbarra/Gregory, Litchfield and Nitmiluk National Parks, Djelk, Warddeken and Wardaman Indigenous Protected Areas, and Fish River Station and was facilitated by the Northern, Tiwi and Anindilyakwa Land Councils.
Alyson Stobo-Wilson, Postdoctoral Research Associate, Charles Darwin University; Brett Murphy, Associate Professor / ARC Future Fellow, Charles Darwin University; Graeme Gillespie, Honorary Research Fellow, University of Melbourne; Jaana Dielenberg, Science Communication Manager, The University of Queensland, and John Woinarski, Professor (conservation biology), Charles Darwin University
Barry Judd, Charles Darwin University; Amanda Kearney, Flinders University; Chris Hallinan; Christine Schlesinger, Charles Darwin University; Joseph M. Cheer, Wakayama University, and Keir James Reeves, Federation University Australia
Last weekend marked 34 years since the land title to Uluru was handed back to the local Yankunytjatjara-Pitjantjatjara peoples. It was also when joint management of the Uluru-Katja-Tjuta National Park began between the traditional owners (Anangu people) and Parks Australia.
The arrangement recognised Anangu title to the land and ensured the direct involvement of Anangu in the development of tourism in the area.
The agreement also coincided with the relocation of tourism facilities from the southeast base of Uluru to the purpose-built resort town of Yulara. The old hotels and other tourist sites were discarded and became the base for the Anangu community of Mutitjulu.
However, if joint management aimed to deliver improved economic and social outcomes for Anangu residents, it has proven to be a spectacular failure.
Today, Yulara and Mutitjulu stand in stark contrast. Yulara is filled with cashed-up, bucket-list travellers from all over the world, while Mutitjulu is an outpost of lingering disadvantage where overcrowding, underemployment, poverty, high rates of suicide and preventable diseases remain pervasive problems.
Mutitjulu was also the epicentre of the controversial Northern Territory National Emergency Response in 2007, commonly referred to as the intervention, when the federal government took control over more than 70 Indigenous communities in response to allegations of child sexual abuse.
Mutitjulu is emblematic of what academic Jon Altman refers to as the persistent need to reestablish trust between Indigenous Australians and the institutions that for so long failed to ensure their basic human rights were protected.
The end of climbing at Uluru provides an opportunity to reset the relationship between the traditional owners and the tourism sector, and look for new ways for Anangu to be integrated into the industry.
Central to this is how the Anangu can meaningfully develop their cultural assets within the park to ensure the long-term benefit of their people, particularly through direct employment.
There would appear to be ample opportunities for the people in Mutitjulu to take advantage of the 1,000-plus tourism jobs in Yulara, which are currently staffed largely by Indigenous and non-Indigenous people from outside the community.
The closure of Uluru to climbing also necessitates the development of alternate visitor experiences, particularly more educational and immersive experiences that would entail learning from and interacting respectfully with traditional owners.
Yet, structural impediments prevent this from becoming a reality at Uluru, as well as other remote parts of Australia.
These obstacles include a lack of education and training options specific to Indigenous needs to help them set up and run their own businesses. Another issue is that land rights and native title claims have tended to benefit a few legally recognised landowners and haven’t been conducive to whole-of-community development.
Both the Anangu and key tourism stakeholders in central Australia, including Voyages Indigenous Tourism and Tourism NT, are keenly aware of the need to reform the local tourism industry.
Enabling greater access to commercial bank loans is critical to Indigenous business development, as is collaborative planning between Indigenous groups and the government. Likewise, scientific and traditional Indigenous knowledge could be combined in new ways to drive tourism growth in areas like land and wildlife management.
The Anangu must also be empowered to start micro-enterprises grounded in Knowledge of Country that would strengthen their community, culture and language. One example of this is the Indigenous Ranger and Protected Area program, which involves Indigenous rangers managing their own lands based on traditional cultural practice.
Another approach that has shown promise is embracing Indigenous knowledge systems as part of the tourist educational experience. This is gaining currency in the NT as remote community arts centres seek to become visitor destinations in their own right.
These approaches to bottom-up initiatives have the greatest potential for growth and long-term empowerment in Uluru.
A major tourism rethink also requires addressing the structural impediments that prevent Indigenous peoples from starting businesses.
For example, new incentives could be built into the Australian tax code for those who invest in businesses on Aboriginal-owned land. However, such measures will only succeed if they are supported by bespoke educational and training programs for Anangu wanting to work in tourism.
The closure of Uluru to climbing should not simply focus on the limits the Anangu have imposed on visitors, but rather on the new possibilities this presents to leverage tourism for a more sustainable and resilient future.
This could also provide a model for traditional owners elsewhere who want to reclaim decision-making authority over tourism and other cultural activities on their lands.
And it signals to the broader Australian public that a greater respect for the rights of Indigenous people might just be the catalyst that helps drive a brighter Indigenous future.
Barry Judd, Professor, Indigenous Social Research, Charles Darwin University; Amanda Kearney, Matthew Flinders Fellow, Professor of Australian and Indigenous Studies, Flinders University; Chris Hallinan, Research Associate; Christine Schlesinger, Senior Lecturer in Environmental Science and Ecology, Charles Darwin University; Joseph M. Cheer, Professor in Sustainable Tourism, Wakayama University, and Keir James Reeves, Professor of History, Federation University Australia