For 65,000 years, Bininj – the local Kundjeihmi word for aborigines – have been returning to the Madjedbebe Rock Shelter in Mirarr Land in the Kakadu Region (in the Northern Territory).
In this immense period of time, the environment around the rock shelter has changed dramatically.
Our paper, published last week in Reviews of the Quaternary Sciencesuses ancient remains of plant foods that were once charred in the site’s hearths to study how the Aboriginal communities camping at the site responded to these changes.
These cooking scraps tell a story of resilience in the face of changing climate, sea levels and vegetation.
A changing environment
The 50 meter long Madjedbebe Rock Shelter lies at the base of a huge sandstone outcrop. The site has a dark, ashy floor from hundreds of bonfires in the past and is strewn with stone tools and grindstones.
The back wall is decorated with vibrant and colorful rock art. Some images – such as horsemen with broad-brimmed hats, ships, cannons and decorated hands – are quite recent. Others are probably many thousands of years old.
Today the site is on the edge of the Jabiluka Wetlands. But 65,000 years ago, when sea levels were much lower, it sat on the edge of a vast savannah plain that linked Australia and New Guinea in the Sahul supercontinent.
At that time, the world was experiencing an Ice Age (referred to as Marine Isotope Stage 4, or MIS 4). And while Kakadu would have been relatively well-watered compared to other parts of Australia, the monsoon vine forest vegetation common at other times would have receded.
This ice age would eventually subside, followed by an interglacial period and then another ice age, the Last Glacial Maximum (MIS 2).
Cut to the Holocene (10,000 years ago) and the weather became much warmer and wetter. Monsoon vine forest, open forest and forest vegetation increased and the sea level rose rapidly.
7,000 years ago Australia and New Guinea were completely separated and the sea approached Madjedbebe to a high plateau only 5km away.
What followed was the rapid transformation of the Kakadu region. At first the sea receded slightly, the river systems near the site became estuaries, and mangroves etched the lowlands.
4,000 years ago these were partially replaced by freshwater wetlands. And 2,000 years ago, today’s iconic Kakadu Wetlands emerged.
Our research team, made up of archaeologists and traditional owners of Mirarr, wanted to find out how people lived in this changing environment.
To do this, we searched for an unlikely archaeological treasure: charcoal. It’s out of the question for the average camper, but when a fireplace is lit, many of its components — like twigs and leaves or food thrown into it — can later turn into charcoal.
Under the right conditions, these charred remains will survive long after campers have moved on. This has happened many times in the past. Bininj, who lived in Madjedbebe, left a number of food remains, including charred and fragmented fruits, nuts, palm stalks, seeds, roots and tubers.
Using powerful microscopes, we compared the anatomy of these lumps of charcoal to plant foods still harvested in Mirarr country today. In this way, we learned about the foods people ate in the past, the places they collected them from, and even the seasons when they visited the site.
From the earliest days of camping in Madjedbebe, people gathered and ate a wide range of anme (the Kundjeihmi word for “plant food”). These included plants such as pandan nuts and palm hearts, which require tools, labor, and detailed traditional knowledge to gather and make edible.
Tools used included edge-ground axes and whetstones. These were all found in the oldest strata at the site – making them the oldest axes and the earliest whetstones in the world.
Our evidence shows that during the two drier glacial phases (MIS 4 and 2), communities in Madjedbebe relied more on these more difficult-to-process foods. Because the climate was drier and food was likely more dispersed and less plentiful, people would have had to make do with foods that took longer to process.
Esteemed anme like karrbarda (long yam, Dioscorea transvera) and annganj/ankanj (water lily seeds, nymph spp.) were important dietary components at times when monsoon vine forest and freshwater vegetation moved closer to Madjedbebe—such as during wetland formation in the last 4,000 years and earlier wet periods. However, they were also searched for in drier times from more distant places.
A change of seasons
The greatest change in Madjedbebe’s plant-based diet occurred with the formation of freshwater wetlands. About 4,000 years ago, not only did Bininj start incorporating more freshwater plants into its diet, they also returned to Madjedbebe at a different time of the year.
Instead of coming to the rock shelter when local fruit trees like andudjmi (green plum, Buchanania obovata) bore fruit, from Kurrung to Kunumeleng (September to December), they began visiting from Bangkerrang to Wurrkeng (March to August).
This is a time of year when resources found at the edge of the wetlands, now near Madjedbebe, become available as the flood waters recede. With the emergence of patchy freshwater wetlands 4,000 years ago, communities changed their diets to make the most of their surroundings.
Today, the wetlands are culturally and economically important to the Mirarr and other Bininj people. A selection of seasonal animal and plant-based foods is offered for dinner, including magpie geese, turtles and water lilies.
The burning question
It is likely that the first Australians not only reacted to their environment but also shaped it. In the Kakadu region, Bininj today are changing their landscape mainly through cultural burning.
Fire is a cultural tool with a variety of functions – such as hunting, creating plant growth, and clearing trails and campsites.
One of its most important functions is the steady reduction of biomass during the wet season which, if left unchecked, becomes fuel for dangerous bushfires in Kurrung (September to October) at the end of the dry season.
Our data show the use of a range of plant foods at Madjedbebe during Kurrung, during most of the site’s settlement between 65,000 and 4,000 years ago.
This indicates an ongoing practice of cultural burning, as it suggests that communities are managing fire-sensitive crop varieties and reducing the likelihood of high-intensity bushfires by practicing low-intensity cultural burning ahead of the hottest time of the year.
Today the Mirarr return to Madjedbebe. Your knowledge of local anme will be passed on to new generations who will continue to shape this incredible cultural heritage.
Acknowledgments: We would like to thank the Gundjeihmi Aboriginal Corporation, the Mirrar and especially our co-authors May Nango and Djaykuk Djandjomerr.
Anna Florin, Research Fellow, University of Cambridge; Andrew Fairbairn, Professor of Archaeology, The University of Queensland and Chris Clarkson, Professor of Archaeology, The University of Queensland.
This article was republished by The Conversation under a Creative Commons license. Read the original article.