Isotopic evidence of human mobility and diet in a prehistoric/protohistoric Fijian coastal environment (c. 750-150 BP).

OBJECTIVES: Bourewa, on the southwest coast of Viti Levu in Fiji, is a multi-period site that contained burials dated to the later Vuda Phase (750-150 BP), a period of climatic fluctuations that potentially impacted the availability of food resources. We aim to investigate diet and movement at this site during a time of possible ecological pressure and political change. MATERIALS AND METHODS: We analyzed δ(13) C, δ(15) N, and (87) Sr/(86) Sr of these Vuda Phase individuals (n = 25) interred at the site. By analyzing dentin and bone, both childhood diet and the diet within the past few years of adults' lives were examined. RESULTS: The paleodietary results suggested that adult diets consisted largely of low trophic level marine organisms. Dentin and bone isotopic values differed significantly: childhood diet involved consumption of more higher trophic level terrestrial foods. Most individuals displayed (87) Sr/(86) Sr ratios expected of people living along a marine coastline. However, a few individuals displayed (87) Sr/(86) Sr ratios and paleodietary values (δ(13) Cdentin , δ(15) Ndentin ) suggestive of living further inland or consuming a more terrestrial-based childhood diet. DISCUSSION: The results are compared with past studies of sites from Fiji and nearby archipelagoes, placing our interpretations into a wider regional context. The Bourewa community appears to have consumed more low trophic level marine foods than any nearby site, possibly because terrestrial foods were more difficult to acquire. Interpreting the childhood diet is challenging due to the paucity of ethnohistoric literature on Fijian childhood; small meals outside of communal mealtimes or feeding children terrestrial animal protein as a means of cultural buffering are potential explanations.

Assessing human diet and movement in the Tongan maritime chiefdom using isotopic analyses.

The rise of stratified societies fundamentally influences the interactions between status, movement, and food. Using isotopic analyses, we assess differences in diet and mobility of individuals excavated from two burial mounds located at the `Atele burial site on Tongatapu, the main island of the Kingdom of Tonga (c. 500 - 150 BP). The first burial mound (To-At-1) was classified by some archaeologists as a commoner's mound while the second burial mound (To-At-2) was possibly used for interment of the chiefly class. In this study, stable isotope analyses of diet (δ13C, δ15N, and δ34S; n = 41) are used to asses paleodiet and 87Sr/86Sr ratios (n = 30) are analyzed to investigate individual mobility to test whether sex and social status affected these aspects of life. Our results show significant differences in diet between burial mounds and sexes. Those interred in To-At-2 displayed lower δ13C values, indicating they ate relatively more terrestrial plants (likely starchy vegetable staples) compared with To-At-1 individuals. Females displayed significantly lower δ15N values compared with males within the entire assemblage. No differences in δ34S values were observed between sexes or burial mound but it is possible that sea spray or volcanism may have affected these values. One individual displayed the strontium isotopic composition representative of a nonlocal immigrant (outside 2SD of the mean). This suggests the hegemonic control over interisland travel, may have prevented long-term access to the island by non-Tongans exemplifying the political and spiritual importance of the island of Tongatapu in the maritime chiefdom.