Journal of the Royal Society of New Zealand abstracts
Late Pleistocene and Holocene vegetation history, Central Otago, South
Island, New Zealand
M. S McGlone1, A. F. Mark2, and D. Bell
3
Pollen diagrams from upland blanket bogs and mire-pool complexes on the
southern Garvie Mountains and the Old Man Range, and from a sag pond mire on
the slopes of the Kawarau Gorge, record the vegetation history of the last
12 000 years in Central Otago, the driest region of New Zealand. During
the late-glacial/early Holocene these subalpine sites supported
grassland/shrubland vegetation. Trees or tall scrub were absent. Tree ferns
became increasingly common in the early Holocene, most likely as small stands
in damp, sheltered locations. At 7500 yr B.P. a coniferous forest of
Prumnopitys taxifolia,
Dacrycarpus dacrydioides and
Podocarpus abruptly replaced the previous grassland communities at lower
altitudes, while a coniferous scrub of
Phyllocladus alpinus and
Halocarpus bidwillii formed the upper treeline. The reafforestation of
Central Otago and adjacent regions was completed 2000 years after
podocarp-dominant forest began to occupy coastal regions. The delay is
attributed to drier climates in the interior of the southern South Island
during the early Holocene. From 6000 yr B.P.
Nothofagus menziesii began
to spread through the higher altitude forest, and shortly after 3000 yr B.P.
N. fusca type forest began to replace the previous treeline dominants,
Phyllocladus and
Halocarpus. Treeline may have risen slightly in
the mid to late Holocene. From 600 yr B.P., repeated fires destroyed both
lowland and upland forest and tall scrub communities. First bracken, and then
grassland, replaced the burnt forest. These fires were a consequence of Maori
exploitation of the Otago hinterlands.
Keywords: Climatic change, pollen record, fire, Polynesian settlement,
treeline, peatlands, vegetation history.
(c) Journal of The Royal Society of New Zealand,
Volume 25, Number 1, March 1995, pp 1-22
PDF file of entire paper: medium quality (1711K); (scanned from paper original: notes about this process)
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