Archaeoecology in Southwestern Australia Part 1: What can animal bones tell us about Aboriginal land management practices?

This post is the first in a series I’ll be posting this week, discussing some of the key aspects of my PhD research. This series corresponds with the final week of our crowdfunding campaign, which will help us understand how the Amangu and Yued people manipulated landscapes and ecosystems of the northern Swan Coastal Plain and Lesueur sandplains. Please share this campaign (here: How nature and nurture created biodiversity in south-western Australia) with your friends and colleagues, and help send us back to the field this year!

In recent months, it has become something of a ritual aspect of any social gathering. I meet someone new, or start to chat with a friend I’ve not seen in a while, and the topic of my PhD research inevitably arises. As anyone who’s ever pursued a PhD can tell you, attempts to explain your research are often met by a complicated combination of facial expressions. The raising of eyebrows in surprise. A polite smile. The faintly perplexed glazing-over of eyes. But in my experience, these initial responses are often quickly followed by a single, important question:

“How can you learn about past Aboriginal land management practices by looking at animal bones?”

It’s a great question, and like many great questions, it doesn’t have a simple answer.

Historic records show that Aboriginal people across Australia modified the landscape and ecology to change the availability of plants and animals. But while that gives us a bit of an understanding of cultural landscapes and practices in the 18th and 19th centuries, it doesn’t tell us anything about how (or when) these activities began, or how they have changed through space and time. Did ‘fire-stick farming’ serve the same purpose in the tropical north as it did in the cool, wet forests of the southwest? Was vegetation managed in the same way in southwestern and southeastern Australia? How did past environments change when more or fewer Aboriginal groups lived in an area? And what does this variation mean for our understanding of “traditional land management practices”, or how we employ them in modern land management?

One of the more difficult aspects of this research is developing a way to identify Aboriginal impacts on landscapes and ecosystems. In lieu of a time machine, archaeologists and palaeontologists typically use “proxy data“: things that we can observe in the archaeological or palaeontological record, which we can then use to infer events, activities and systems that are not directly observable. Proxy records can be anything from charcoal (used to look at fire frequency and intensity), pollen (changes in plant species distribution, which can indicate environmental and cultural changes), to sediment and soil (environmental and depositional processes), and much more. Animal remains, including bones and teeth, eggshell, horns and antlers, shells, and fish otoliths, are some of the more commonly used proxy records. They tell us about past environments, diets, and the relationships we have with other species.

During excavation, sediment is sieved and is collected. The material being sorted here includes bones, teeth, fragments of eggshell and charcoal.

During excavation, sediment is sieved and the sieve remnants collected. The material being sorted here includes bones, teeth, fragments of eggshell and charcoal.

But how can animal remains tell us about the ways in which people have influenced the ecosystems in which they live? The most widespread and significant cultural land management practice employed by Aboriginal peoples across Australia was probably the use of fire to clear vegetation: it opened up landscapes, changed the distribution of communities in different fire succession stages, and impacted on plants and animals that required specific habitat niches to survive.

Animals like quokkas, kangaroos, possums and bandicoots all formed an important part of the diets of people living in southwestern Australia. By managing vegetation, it was possible for Aboriginal people to manipulate animal populations. Kangaroos are attracted to areas with fresh, young growth. Brushtail possums need nesting hollows (usually created by fire), as well as the flowers and shoots of trees like Eucalyptus. Quokkas live in dense thickets and woodland, and seem to prefer a combination of vegetation that has been recently burnt (in the last 10 years) and long unburnt (at least 10 years post-fire). When these animals appear in the archaeological or palaeontological record, we can be reasonable sure that they were living nearby. By understanding their specific habitat niches and needs, we can reconstruct the surrounding environments and begin to infer the ways in which natural and cultural systems might have influenced the availability of these habitats.

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Animals like the Western Grey Kangaroo are often drawn to the fresh young growth that sprouts after fire [Image credit: David Burton, Flickr]

My PhD research tests the hypothesis that Aboriginal people maintained or increased food resource diversity and availability over time, as management practices (like burning) intended to stabilise resource accessibility created a mosaic of interconnected communities in different fire succession stages. This modification of ‘natural’ communities would likely have been associated with cultural changes, particularly those linked to the transfer of Traditional Ecological Knowledge, seasonal patterns of mobility and changes in the structure of cultural groups.

One of the ways we can look for this is by exploring changes in biodiversity over time (particularly the period of initial European colonisation and post-European changes to floral and faunal diversity), testing the hypothesis that management of the landscape by Aboriginal people resulted in changes to resource structures and availability. Biodiversity that is high and stable (or increasing) through time would support this interpretation, particularly if it is accompanied by archaeological evidence of cultural changes, indicating a link between changes in biodiversity and patterns of cultural resource management.

The first panel of Ensign Robert Dale's panorama of King George Sound shows an Aboriginal camp in the foreground, with fires burning in the dense vegetation that surrounds the cleared lands occupied by Europeans.

The first panel of Ensign Robert Dale’s panorama of King George Sound shows an Aboriginal camp in the foreground, with fires burning in the dense vegetation that surrounds the cleared lands occupied by Europeans. [Image via National Library of Australia]

Research like this has been undertaken in other parts of the world (like this study in the Quiroste Valley, California), demonstrating the potential to shed light on the processes behind the development of cultural landscapes, and how people responded to major transition events like climatic changes. By combining the macro (ecosystem/landscape biodiversity) and micro (individual species, which I will talk about in the next post) scales of analysis, together with the archaeological record, we can begin to look at how plant and animal communities responded to environmental and cultural activity.


We need your help!

We’re so close to reaching our funding goal. Learn more about our project, and how you can help, here.

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