Ancient and recent Australian desert hunter‐gatherer responses to climatic variability

In this thesis I examine the ethnographic record of recent arid-zone Australian hunter-gatherers to consider how prehistoric populations may have responded to climate change in similar climatic and ecological settings. The archaeological record of population presence and absence indicates that pulses of territorial abandonment and reoccupation correspond with periods of significant climatic variability, with the Last Glacial Maximum (LGM) and the on-set of modern El Niño-Southern Oscillation (ENSO) cycles during the mid-Holocene being identified as significant periods of increased environmental stress and associated habitat abandonment. However modelling such population processes at a fine-grained level is constrained by the differential preservation of archaeological material, dating limitations, issues with chronological control at some sites, and differences in research intensity. As a result the archaeological record is unclear as to whether such population processes involved...Show moreIn this thesis I examine the ethnographic record of recent arid-zone Australian hunter-gatherers to consider how prehistoric populations may have responded to climate change in similar climatic and ecological settings. The archaeological record of population presence and absence indicates that pulses of territorial abandonment and reoccupation correspond with periods of significant climatic variability, with the Last Glacial Maximum (LGM) and the on-set of modern El Niño-Southern Oscillation (ENSO) cycles during the mid-Holocene being identified as significant periods of increased environmental stress and associated habitat abandonment. However modelling such population processes at a fine-grained level is constrained by the differential preservation of archaeological material, dating limitations, issues with chronological control at some sites, and differences in research intensity. As a result the archaeological record is unclear as to whether such population processes involved habitat tracking to more favourable areas, or alternatively resulted in extinction of local groups in areas that became unviable for continued occupation. My thesis addresses this lack of clarity by relating recent hunter-gatherer drought responses to prehistoric population process evident from the archaeological record. I start with an examination of the Arandic and Western Desert societies to provide a background for establishing how desert hunter-gather groups responded to serious drought in the recent past. I look at the cultural and economic strategies developed by these tribal groups in response to distinct but connected environments, and discuss how differences in social organisation between groups occupying distinct ecological regions shaped drought responses. I investigate the socio-cultural and behavioural mechanisms of desert hunter-gatherers that facilitated habitat tracking and develop a framework based on behavioural ecology models to consider how subsistence and mobility strategies enabled range shifts to neighbouring areas during periods of resource depletion. Where drought forced local group extinction is evident, I identify the constraining factors acting on populations that limited their capacity to respond to changing environmental conditions. I argue that water availability is the major constraint to occupation of arid environments, with access to reliable water sources and foraging areas available from water points being a precondition of occupation for both recent and prehistoric arid-zone hunter-gatherers and the main factor limiting population distribution. I propose that extensive social and economic networks linking groups, who were dependent on one another for access to water and resources, were crucial for successful occupation of the Australian desert during the historical period and relied on critical population size, particularly during periods of climatic instability. While the precise social organisation and subsistence strategies employed by prehistoric hunter-gatherer groups is invisible in the archaeological record, I hypothesise that such social and economic networks were likely equally crucial to the survival of prehistoric hunter-gatherers. In the event that critical population size dropped below the threshold for maintaining such networks, continued occupation of marginal environments was unviable.Show less

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Ancient and recent Australian desert hunter‐gatherer responses to climatic variability