Doctor of Philosophy
School of Geosciences
Atchison, Jennifer, Continuity and change: a late Holocene and post contact history of Aboriginal environmental interaction and vegetation process from the Keep River region, Northern Territory, Doctor of Philosophy thesis, School of Geosciences, University of Wollongong, 2000. http://ro.uow.edu.au/theses/1967
Australian Aboriginal and hunter-gatherer impacts on the environment have been widely debated in anthropological and scientific circles. At one extreme hunter-gatherer impacts have been viewed as non-existent or unintentional, at the other they have been viewed as significant agents of extensive change. Wherever Aboriginal people are considered as agents of change, fire is considered to be the primary and most important method. The way in which vegetation responds to fire and other factors influences our perception of the nature and degree to which Aboriginal people live within, impact upon, manage or construct their environment. Non-equilibrium ecology provides a useful framework for examining vegetation change by identifying disturbance regimes and individual species response.
Ecological processes and Aboriginal environmental interactions from the Keep River region of the Northern Territory are examined in this thesis using three methods: biogeographic, archaeobotanical and ethnoecological analysis. The results cover two main time periods, the late Holocene and the recent post contact period. Rock outcrops are a visual, cultural and ecological focus in the predominantly savanna environment of the Keep region. They provide key habitats for mixed savanna assemblages and for monsoon rainforest assemblages and were important traditional and post European camping places for local Aboriginal people.
Analysis of tree demographics and spatial pattern of savanna plants around rock outcrops identifies significant differences in spatial distribution and plant density. Many of the differences in seedling regeneration, sapling recruitment and tree survival are associated with regional differences in fire regime. Significantly, edible fruit species, in particular Persoonia falcata, are identified as marginal under current conditions at all of the sites considered, except one re-occupied and managed by the Marralam Aboriginal community since the late 1980's.
Archaeobotanical material from archaeological excavations indicates Persoonia falcata and Buchanania obovata seeds were processed and eaten at various times across the Keep River region from about 3500BP up until the post contact period. The chronology is derived by directly dating seed remains using AMS 14C and suggests both spatial and temporal variation in deposition. Fruit seed use and sustained rock shelter occupation in the Keep Region is associated with dry climatic phases in the late Holocene identified from other evidence elsewhere in northern Australia. Significantly, cultural deposition of fruit seeds declines to total absence in the post European levels. The decline in cultural fruit seed deposition and the contemporary disparity in fruit species viability across the region can be explained by a significant shift in fire regimes and Aboriginal occupation since European arrival.
Monsoon rainforest patches and yam species are examined through the memory of traditional Aboriginal custodians. Keep River rainforest patches are small and isolated on dolomite outcrops. Yams are gathered by removing significant quantities of dirt and rock, resulting in large holes and depressions across the forest floor. Dioscorea transversa has disappeared from at least one site within the living memory of local custodians. Contemporary yams are severely degraded by cattle trampling. Isolated rainforest trees in the surrounding savanna suggest that the contemporary patches have been more extensive than present. The recent change in distribution and abundance of important traditional food plants has significant consequences for Aboriginal attachments to country.
In this thesis I illustrate a complex picture of continuity and change in Aboriginal interaction with the environment of the Keep region over the past 3500 years. I argue that Aboriginal people have in the past, and where possible, continue today to creatively manage the vegetated landscape.