Species clustering and New Zealand quaternary climate

Harris, W. F.; Darwin, J. H.; Newman, M.J.

doi:10.1016/0031-0182(76)90016-x

Cited by 5 publications

(6 citation statements)

References 7 publications

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“…The areas around the greater Wellington area covered by previous palynological investigations are Wallaceville (Harris 1951;Harris & Mildenhall 1980, 1984Mildenhall 1994), Haywards Hill (Harris 1959;Mildenhall 1986a), Porirua and Pauatahanui (Mildenhall 1979(Mildenhall , 1983(Mildenhall , 1993aPillans et al 1993), Hutt Valley (Harris 1959;Harris & Norris 1972;Mildenhall 1973a, in press;Harris et al 1976;Harris & Mildenhall 1980, 1984McQueen & Mildenhall 1983b), Wainuiomata (Mildenhall 1993c), Ohariu Valley (Harris in Grant-Taylor & Hornibrook 1964;Mildenhall et al 1977), Wellington City (Lewis & Mildenhall 1985;Mildenhall 1986cMildenhall , 1992aMildenhall , 1993b, and Turakirae Head (Mildenhall & Moore 1983), as well as other scattered sites around the region south of Plimmerton in the west and Kaitoke in the east (McQueen 1973;Mildenhall 1978Mildenhall ,1986bMildenhall , 1992bHarris et al 1981;McQueen & Mildenhall 1983a).…”

Section: Previous Palynological Studiesmentioning

confidence: 99%

“…These changes, and the arrival or increase of Knightia excelsa (Mildenhall 1979), have been interpreted as a result of a climatic deterioration (McGlone et al 1984a, c;McGlone 1988) involving decreasing temperatures, increasing drought and frosts, and more frequent and stronger southerly and southwesterly winds. Although the present sampling intervals are not detailed enough to determine climate change to a finer resolution, should the opportunity present itself, and given an adequate thickness of fossiliferous Postglacial sediments, discriminant function analyses could be carried out on pollen counts to elicit finer detail (Harris et al 1976;Mildenhall in press).…”

Section: Postglacial Palynostratigraphy and Paleoenvironmentsmentioning

confidence: 99%

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Palynostratigraphy and paleoenvironments of Wellington, New Zealand, during the last 80 ka, based on palynology of drillholes

Mildenhall

1994

New Zealand Journal of Geology and Geophysics

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About 20 pollen profiles from the Wellington area are correlated and zoned according to their pollen characteristics. Sequences from many of the larger sedimentary deposits are shown to contain little or no sediment of late Last Glacial and early Postglacial age, while late Postglacial sedimentation is restricted to a few localities. Sediments of middle and early Last Glacial age are well represented and widespread over the Wellington area. Pollen diagrams from Last Glacial and Postglacial sediments are zoned as follows: Zone A, 80 000-60 000 yr B.P. (lower end of range more likely) and provisionally correlated with oxygen isotope stages 5a and basal 4; Zone B, 70 000-50 000 yr B.P. (lower end of range more likely), provisionally correlated with upper oxygen isotope stages 4 and basal stage 3; Zone C, a short zone just beyond the range of radiocarbon dating at the top of Zone B of 60 000-50 000 yr B.P., correlated with the middle of oxygen isotope stage 3; Zone D, 50 000-10 000 yr B.P., with a major period of nondeposition or erosion between c. 18 000 and 10 000 yr B.P., correlated with the upper part of oxygen isotope stages 3 and all of 2; Zone E, 10 000-1000 yr B.P. (Postglacial); Zone F, last 1000 years (human occupation zone). During this time the vegetation changed from a beech forest (Zone Al) to a shrub/grassland, with pollen from the dominant tree taxa being Nothofagus fusca type (Zone A2), N. menziesii with Phyllocladus (Zones B, C), Phyllocladus with N. menziesii (Zone D), Dacrydium cupressinum (Zone E), and Nothofagus fusca with D. cupressinum (Zone F).Climatic conditions during the Last Glaciation were generally colder, drier, and stormier relative to the present day. The virtual absence of sediment of this age suggests widespread nondeposition or erosion under unstable conditions. Zones B-D represent the harshest conditions, with temperatures averaging up to 5°C less than the present day. Basal Postglacial conditions were the reverse, with higher rainfall and temperatures averaging up to 2°C higher than the present day. From sometime before 5000 yr ago, conditions deteriorated towards the present day with increased frostiness and droughts.Tephras were deposited in the Wellington area during previous glacial episodes. The Rangitawa Tephra was deposited during the mid middle Pleistocene (early Haweran) C94007Received 21 February 1994; accepted 26 July 1994 at a time when the region was covered in a low subalpine scrubland and climatic conditions were similar to that of the Last Glaciation. During the early middle Pleistocene (Okehuan) an unnamed tephra was deposited during a period of similarly cold, dry conditions and onto a similar vegetation.

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Section: Previous Palynological Studiesmentioning

confidence: 99%

Section: Postglacial Palynostratigraphy and Paleoenvironmentsmentioning

confidence: 99%

Palynostratigraphy and paleoenvironments of Wellington, New Zealand, during the last 80 ka, based on palynology of drillholes

Mildenhall

1994

New Zealand Journal of Geology and Geophysics

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“…Two studies (Harris & Norris 1972, Harris et al 1976) have applied quantitative techniques to New Zealand pollen data in order to reconstruct past climates. In these studies discrirninant analysis was used to identi~ groups of pollen taxa with apparently similar climate requirements.…”

Section: Introductionmentioning

confidence: 99%

“…In these studies discrirninant analysis was used to identi~ groups of pollen taxa with apparently similar climate requirements. In this way objective, but non-quantified indices of climate change were developed and applied to a Holocene pollen core (Harris et al 1976). Although these studies demonstrated the existence of strongly correlated groups of pollen types, they were based entirely on fossil data.…”

Section: Introductionmentioning

confidence: 99%

Quantitative analyses of modern pollen-climate relationships in New Zealand indigenous forests

Norton

McGlone²,

Wigley

1986

New Zealand Journal of Botany

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Modern arboreal pollen data from 161 sites throughout New Zealand were collated and then analysed by means of principal components and cluster analyses to identify sites with common assemblages of pollen taxa. These pollen assemblages are directly comparable with the main associations of tree species. Simple correlation coefficients calculated between the modern pollen and climate data from the same sites show some significant relationships, particularly with precipitation. Multiple regression analysis was used to calibrate transfer functions linking the pollen data and three climate variables: mean summer temperature, annual temperature range, and the logarithm of mean annual precipitation. The regressions were verified on independent data, but those for mean summer temperature and annual temperature range failed to verify significantly. The log-precipitation transfer function performs best, with the pollen data explaining 55% of the precipitation variance in calibration, and 46% in verification. The explained variance values are lower than those obtained in eastern North America. However, it appears that with a denser, and more selective set of modern pollen sites, transfer functions could be developed in New Zealand which would make possible quantitative reconstructions of postglacial climates.

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“…The aim of the present study is to use those statistically selected pollen types to reconstruct the sequence of past vegetation types from Mt Hauhungatahi and elsewhere by way of linear discriminant function analysis (LDF) of fossil pollen data. A similar type of analysis was carried out by Harris et al (1976), who used discriminant function analysis on fossil pollen data to indicate the comparative temperatures under which Quaternary sediments accumulated in several locations in New Zealand. Our primary aim is methodological, assessing LDF as a method for reconstructing past vegetation and looking at its potential, rather than providing a detailed ecological interpretation of the fossil pollen records from the sites sampled.…”

Section: Introductionmentioning

confidence: 99%

An assessment of linear discriminant function analysis as a method of interpreting fossil pollen assemblages

Horrocks

Ogden

2003

New Zealand Journal of Botany

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Linear discriminant function analysis (LDF) is assessed as a method of interpreting fossil pollen assemblages from Mt Hauhungatahi, Tongariro National Park, and Ohakune-Horopito, central North Island, New Zealand. Pollen types selected by stepwise discriminant analysis were used in LDF to predict the vegetation type (forest, dense scrub, open fernland, or open tussockland) and canopy type (closed or open) represented by fossil pollen assemblages from an array of sites. Chisquare Goodness-of-fit tests were used to test prediction made by LDF against the vegetation type suggested by the common "standard" method of assessment of the fossil pollen spectra, which is carried out by visual inspection of stratigraphic pollen diagrams. Some sites showed highly significant differences, with many samples obviously misclassified by LDF, especially those from montane forest vegetation. This misclassification occurred mainly because the montane forest samples were so different from the remainder that they were excluded from the prediction set, so that the pollen types most likely to be predictors were not employed. Overall, however, more sites showed no significant differences. The LDF method is confirmatory rather than providing a clear improvement, and its validity will depend strongly on the correct choice of discriminators.

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Species clustering and New Zealand quaternary climate

Cited by 5 publications

References 7 publications

Palynostratigraphy and paleoenvironments of Wellington, New Zealand, during the last 80 ka, based on palynology of drillholes

Palynostratigraphy and paleoenvironments of Wellington, New Zealand, during the last 80 ka, based on palynology of drillholes

Quantitative analyses of modern pollen-climate relationships in New Zealand indigenous forests

An assessment of linear discriminant function analysis as a method of interpreting fossil pollen assemblages

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