New Zealand Journal of Botany abstracts
A 6000-year palaeoenvironmental record from Harataonga, Great Barrier Island, New Zealand
M. Horrocks
Centre for Archaeological Research
University of Auckland
Private Bag 92 019
Auckland, New Zealand
S. L. Nichol
Department of Geography
University of Auckland
Private Bag 92 019
Auckland, New Zealand
P. A. Shane
Department of Geology
University of Auckland
Private Bag 92 019
Auckland, New Zealand
Abstract
A pollen, sediment, and tephra record from a drained swamp at Harataonga contains a history of the local coastal environment from the Mid Holocene. This commences c. 6000 cal yr BP in a freshwater environment with swamp forest composed mainly of Laurelia
, Leptospermum
, Ascarina
, and Cyathea
spp. Dodonaea
and Cyperaceae grew on margins of this forest. Forest on the hills surrounding the wetland comprised mainly Metrosideros
, with emergent Dacrydium
and Libocedrus
. Ascarina
, Rhopalostylis
, and Cyathea dealbata
type were a significant part of the understorey of the hillside forest. Around the time of deposition of the 5550 cal yr BP Whakatane tephra, a freshwater lake developed at the site. Extensive Cyperaceae swamp developed on the fringes of the lake. Shortly after c. 2900 cal yr BP, Dacrycarpus
briefly invaded swamp forest, possibly as a result of storm disturbance, and the site made the final transition to swamp. Myrsine
and then Hebe
shrubs invaded fringes of the swamp as the water table fell, possibly as a result of a change to drier conditions in the Late Holocene. Polynesian deforestation, as indicated by the presence of abundant charcoal and Pteridium
spores, is recorded in this core as occurring shortly after deposition of the c. 600 cal yr BP Kaharoa tephra.
Keywords
palynology; Holocene; anthropogenic disturbance; Whakatane tephra; Kaharoa tephra; Great Barrier Island
B01024 Received 30 May 2001; accepted 7 December 2001
New Zealand Journal of Botany, 2002, Vol. 40
: 123–135
0028–825X/02/4001–0123 $7.00 © The Royal Society of New Zealand 2002
PDF file of entire paper: Print-quality (337K)
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