Holocene palynology of Whitehaven Swamp, Whitsunday Island, Queensland, and implications for the regional archaeological record

Abstract

Palynological study of Whitehaven Swamp, Whitsunday Island, provides the first Holocene palaeoenvironmental record for the Whitsunday region on the central Queensland coast. Sediment stratigraphy and radiocarbon dating indicate continuous freshwater swamp conditions since around 7000 radiocarbon years Before Present (BP). Pollen and charcoal analyses provide local and regional vegetation and fire histories for the site and surrounding area. Varying representation of swamp elements, particularly Leptocarpus and Cyperaceae, provides evidence for phases of permanent and ephemeral swamp conditions. The regional vegetation record is dominated by rainforest, sclerophyll and beach strand elements. Strongest rainforest representation occurs around the mid-Holocene, while sclerophyll elements increase from the late Holocene to present. Charcoal analyses indicate that fire has been a constant component of the Whitsunday environment throughout the period represented. Negative correlation between high charcoal and Leptocarpus pollen concentrations suggests a strong local component to the charcoal record and a history of on-site burning during ephemeral swamp phases. The vegetation reconstruction suggests moister than present conditions at Whitehaven between approximately 7000 to 4500 BP. This complies with claims for a mid-Holocene climatic optimum based on pollen records from the Atherton Tableland to the north, but contrasts with suggested mid-Holocene aridity based on a surrogate lake water level record from Fraser Island to the south. Comparisons with the regional archaeological record provide no evidence for direct links between major environmental change and archaeologically identified cultural change. In particular, claims for late Holocene population intensification are not matched by changes in the charcoal record. This may suggest that widespread vegetation burning was not a predominant feature of hunter–gatherer strategies that were focused towards marine resources, and/or that human-induced fire regimes were already well entrenched prior to intensification.