The application of ecological models and trophic analyses to archaeological marine fauna assemblages: towards improved understanding of prehistoric marine fisheries and ecosystems in tropical Australia

Peck, Helene (2016) The application of ecological models and trophic analyses to archaeological marine fauna assemblages: towards improved understanding of prehistoric marine fisheries and ecosystems in tropical Australia. PhD thesis, James Cook University.

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Abstract

This project focuses on the high-resolution analysis of archaeological marine fauna assemblages, using methodologies situated in an evolutionary ecology theoretical framework. These assemblages come from eight Kaiadilt archaeological sites across the South Wellesley Archipelago, which are a valuable dataset to examine not just dietary composition of foragers in the islands but also long-term patterns in the temporal and spatial availability of subsistence resources. This study also represents the first Australian investigation that applies trophic level analysis to archaeological marine fauna assemblages in order to explore anthropogenic effects on prehistoric fisheries (e.g. Bourque et al. 2008; Reitz et al. 2009; Quitmyer and Reitz 2006).

Located in the southern Gulf of Carpentaria, in the central north of Australia the study area for this project focuses on Bentinck, Sweers and Fowler Islands, three of the largest islands in the South Wellesley Archipelago and the traditional home of Kaiadilt people. A three phase cultural chronology spanning the past c. 3,500 years is suggested for the study area, based on a comprehensive suite of 128 radiocarbon dates collected from cultural deposits, combined with results from linguistic studies (see Memmott et al. 2016).

This archaeological research undertaken in collaboration with the Kaiadilt Aboriginal community has resulted in the recording of cultural places on their lands. Community engagement has been an integral part of this research and ultimately has contributed to the success of the project. At a regional level this thesis contributes to the discourse about Aboriginal subsistence practices in northern Australia for the late Holocene. The project provides a large dataset similar with those of other studies conducted internationally, and is therefore able to inform other research based within an ecological theory framework.

This research aims to (1) identify evidence for human subsistence strategies, in particular the diversity of marine species types exploited (diet-breadth) and patterns of habitat (patch) exploitation through time; (2) characterise temporal changes in the biomass contribution and population structure of particular species through development of taxa size/age profiles, which identifies, for example, declining efficiencies in marine exploitation and human harvest pressure on resources; and (3) identify and assess changes in marine trophic levels exploited and explore potential evidence of trophic cascades in the local ecosystem in order to determine anthropogenic impacts on local ecologies.

The project addresses these aims using methodologies based within an evolutionary ecology framework including the Diet-Breadth Prey Choice Model (MacArthur and Pianka 1966), the Patch Choice Model (Charnov and Orians 1973) and the Central-Place Forager Model (Metcalfe and Barlow 1992). All data are grouped into chronological units of 250-year intervals. While these units offer a broad temporal resolution that may obscure some fine-grained variances in individual datasets, they provide a method for characterising local assemblages in a way that they can be compared across the region (e.g. Ulm 2006).

Archaeological evidence indicates that marine shellfish, fish and invertebrates substantially contributed to diet in the South Wellesley Islands. A total of 124.3kg of marine faunal remains are examined for this study. People's foraging strategies were broad-based in terms of both range of habitats accessed and diversity of species collected. 62 molluscan taxa were identified in the study. Hiant venus clam (Marcia hiantina), rock oyster (Saccostrea glomerata), turban snails (Lunella cinerea) and longbums (Telescopium telescopium) were the main molluscs consumed. There is evidence for a long-term trend in changing habitat preferences that could reflect changing cultural preferences and/or changing environments affecting resource availability. From two locations on Bentinck Island we have signals that clearly imply changes in diet-breadth c. 500 cal BP, which were likely a response to an environmental event impacting mangrove habitats and therefore changing taxa abundances available for exploitation.

The study characterises the population structure of M. hiantina (the dominant species) through development of the taxon's profile and reviews temporal changes in densities and sizes. Although M. hiantina specimens exhibit some short-term reductions in mean size during seasonal bouts of intensive foraging, temporal patterns indicate that foraging efficiency was not compromised in the long-term.

A minimum of 15 species of fish, 1 species of shark and 1 species of turtle were identified from skeletal remains. There is also evidence throughout most periods at most sites of crustacea being foraged although it is difficult to determine numbers. Based on known habitats for the specimens identified (e.g. catfish, grass sweetlip, rockcod, mullet, longtom, whiting, wrasse) much of the fish would have been obtained from hunting in nearshore waters, either from around rocky/coral reefs, intertidal mangroves, estuaries or in the numerous constructed stonewalled intertidal fishtraps. The Central-Place Forager Model was used to explain disparity between ethnographic reports of fishing and hunting activities and the low quantities of fish and vertebrate bones identified in the analysed materials. I contend it is likely dugong, turtle and some fish were processed and consumed at the beach closer to the location of procurement, rather than returned to residential camps (see Tindale 1960:48, 71).

Trophic level analysis was used to establish the average trophic level for each 250-year period's marine biomass catch. Faunal data suggest that people targeted primarily the low trophic level shellfish during the early periods of occupation, before shifting their economic focus to a broader-based diet-breadth incorporating more fish, which in turn raised the mean trophic level of all site assemblages. A review of temporal changes in the mean trophic level of exploited resources indicates that hunter-gatherers had little long-term impacts on the overall fishery of the South Wellesley Islands.

Item ID: 48929
Item Type: Thesis (PhD)
Keywords: archaeoichtyology, archaeology, Australian Aboriginal archaeology, Australian Indigenous archaeology, coastal and island archaeology, fish remains, Gulf of Carpentaria, human adaptation, prehistoric fisheries, prehistoric foraging, shell mounds, shellfishing, Wellesley Islands, zooarchaeology
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Additional Information:

Publications arising from this thesis are available from the Related URLs field. The publications are:

Chapter 6: Tomkins, Helene, Rosendahl, Daniel, and Ulm, Sean (2013) Tropical archaeology research laboratory comparative fish reference collection: developing a resource for identifying marine fish remains in archaeological deposits in tropical Australasia. Queensland Archaeological Research, 16. pp. 1-13.

Chapter 2 and Chapter 15: Rosendahl, Daniel, Ulm, Sean, Tomkins, Helene, Wallis, Lynley, and Memmott, Paul (2014) Late Holocene changes in shellfishing behaviors from the Gulf of Carpentaria, northern Australia. Journal of Island and Coastal Archaeology, 9 (2). pp. 253-267.

Date Deposited: 14 Jun 2017 21:52
FoR Codes: 21 HISTORY AND ARCHAEOLOGY > 2101 Archaeology > 210101 Aboriginal and Torres Strait Islander Archaeology @ 70%
21 HISTORY AND ARCHAEOLOGY > 2101 Archaeology > 210102 Archaeological Science @ 30%
SEO Codes: 95 CULTURAL UNDERSTANDING > 9505 Understanding Past Societies > 950503 Understanding Australias Past @ 100%
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