late quaternary palynology of the southern ruahine range north island, new zealand

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Late quaternary palynology of thesouthern Ruahine Range North Island, NewZealandCynthia M. Lees aa Department of Soil Science , Massey University , Palmerston North,New ZealandPublished online: 05 Dec 2011.

To cite this article: Cynthia M. Lees (1986) Late quaternary palynology of the southernRuahine Range North Island, New Zealand, New Zealand Journal of Botany, 24:2, 315-329, DOI:10.1080/0028825X.1986.10412680

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New Zealand Journal qf Botan)', 1986, ~bl. 24:315-329 315 0028-825X/86/2402-031552.50/0 �9 Crown copyright 1986

Late Quaternary palynology of the southern Ruahine Range North Island, New Zealand

CYNTHIA M. LEES Depar tment of Soil Science Massey University, Palmerston Zealand

North, New

Abstract Aranuian (post-glacial) pollen diagrams are presented from five sites in the southern Ruahine Range within an alt i tudinal range of 80- 1050 m. The pollen spectra indicate that podocarp-broadleaf forest was well established in the foothills as early as 12 900 + 200 yr B.P. The dom- inance of PrunznopiO's tax~/blia and absence of Daco'dium cupressinum suggest a climate cooler and drier than at present. By 10 350 _+ 100 yr B.P. Daco'dium cupressinum is abundant in the profile indicating a warmer, wetter climate. The frost- and drought-tender species Ascarina lucida increased and then declined about 3400 yr B.P. and is almost absent from the region at present. Some information on the occurrence ofAscarma, Quintinia, and l! 'emmamzia pollen is given. (Generally, the results support the findings of other workers in this field).

Keyuords Aranuian; southern Ruahine Range: pollen diagrams; climatic change; podocarp-broadleaf forest; Ascarina; Fl'einmannia: Quintinia

I N T R O D U C T I O N

The intention of this study was to examine post- glacial pollen sites from various altitudes in that part of the Ruahine Range bounded on the north by the headwaters of the Pohangina River and Takapari Ridge (1259 m) and on the south by the Manawatu Gorge. This area was of particular interest because of recent acceleration in the observed rates of erosion. There are no published data on fossil pollen sites in this area, although further north in the Ruahine Range, peat bogs have been investigated by Moar (1956, 196 I, 1967). Moar

Recetved 23 Marc/z 1984, accepted 7 December 1985

used Taupo Pumice and Waimihia Formation for dating the deposits and found a slow rise in the Nothofagus pollen curves in all cases. The occurrence of pollen of species not now present at the sites was attributed by Moar (1967) to the upward drift of pollen from forests at lower altitudes. In the present study five sites spanning the last 14 000 years were sampled and three new radiocarbon dates were obtained. The locations of the sites are given in Fig. 1 and the grid references, altitudes, and radiocarbon dates obtained for the sites are listed in Table 1.

Vegetation Elder (1965) observed several notable features of the vegetation on the southern Ruahine Range; .Vothqfagus is almost completely absent, the present tree-line dominated by Libocedrus bidwillii and Daco'dimn bi/brme was formerly at a higher altitude. and there is now a very' extensive area of sub- alpine scrub dominated almost exclusively by Olearia colensoi. Four species, Olearia colensoi, Daco'dium cupressmum, Libocedrus bidwillii, and It'einmamzia racemosa have a smaller alti tudinal range than they do in the central and northern Ruahine Range.

Vegetation surveys conducted by the New Zealand Forest Service in the Southern Ruahines record damage to vegetation by introduced animals (Cunningham 1962, James & Beaumont 1971, Cuddihy 1977). Weinnzannia racemosa appears to have been the most seriously affected by the brush- tailed possum (1)'ichosurus vulpecula), and in some areas dead trees are prominent. Strand (1977). however, considered several factors were involved, one of which is that H'eim~Tamzia racemosa tends to be even-aged and old, and the observed decline ma3 thus be due to natural causes. A similar con- clusion has been reached by Stewart and Veblen (1982) for 31etrosideros um[~ellata and II'eimnan- nia racemosa forests in central Westland. They concluded that these trees establish on slips following a catastrophe such as an earthquake and will reach senescence at approximately the same time, and are more likely to die as a consequence of some detrimental influence such as possum browsing.

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316 New Zealand Journal of Botany, 1986, Vol. 24

Fig. 1 Location of study sites in the southern Ruahine Range.

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Lees- -Southern Ruahine Ra. Quaternary palynology

Table 1 Fossil pollen sites in the Southern Ruahine Range.

317

Location Map ref.* Alt. (m) NZI4C No. Age yr B.P. Dated material

West 333239 100 NZ4651 A 12 9000 Metrosiderost Ballantrae _+ 200 wood 81/3 NZ4651 B 13 000

_+ 200

East 333239 80 NZ5320 A 10 350 Leptospermum Ballantrae +_ 100 wood 81/9 NZ5320 B 10 650

_+150

Delaware 348266 1 0 5 0 NZ5274 A 8160 Compositae Ridge _+ 120 wood Road NZ5274 B 8 400 80/1&81/6 + 130

Manawatu 329241 300 NZ5231 A 3 430_+ 80 Daco'diurn Gorge NZ5231 B 3 530_+80 cupressinurn 81/5 NZ5231 C 3 770_+90 wood

West 268253 500 NZ4547 A 790_+60 Pittosporurn Tamaki NZ4547 B 810_+ 70 wood River NZ4547 C 770_+ 60 80/2

*Map references NZMS series 1. Wood specimens identified by R. N. Patel, Botany Division, DSIR, Lincoln. + Identified by R. A. Cresswell and Dr E. O. Campbell.

Climate

No complete study of the climate for the southern Ruahine Range is available although some partial reports exist (Coulter 1973, Searell 1974, Neale & Thompson 1978, Marden 1981). These suggest high precipitation rates varying from 1150 mm per annum at the lowest altitudes to 2500 mm per annum along the crest of the Range. Cloudbursts occur and 150 mm of rain may fall in one day at any t ime of the year. Cloud frequently covers the upper slopes; fog and drizzle also occur. Winds are predominant ly westerly, frequently strong. Mean daily temperatures range from 10.5~ to 4.5~ depending on altitude, with maxima of 15~ and 8.5~ and min ima of 6~ to 0~

Erosion

Widespread concern by workers at acceleration of the rate of erosion in the Range during the last two decades and its possible effect on valuable farm- land led to intensive study of the West Tamaki catchment in the south-eastern Ruahines (Hubbard 1978: Hubbard et al. 1979; Hubbard & Neall 1980; Marden 1977, 1981). Grant (1977, 1981) also stud- ied "erosion periods" over the entire Ruahine Range. Their conclusions indicate four important factors are involved in the erosion process in this

region. The presence of faults and associated earthquakes, and the steepness of bedding planes together with intensive rainfall patterns and steepland soils make the region very vulnerable to mass movement. Hubbard and Neall (1980) saw this mass movement as due to a natural cyclic process of erosion frequently triggered by intense rainstorms or earthquakes.

M E T H O D S

As all sites were open-faced, a monoli thic sample was taken at each and a representative sub-sample removed from the 50 m m section for use in pollen analysis. On the pollen diagrams the histogram bars are located in the centre of each 50 mm depth interval, (100 mm at the West Tamaki site). Stand- ard processing methods were used (Faegri & Iver- sen 1975). Counts for total pollen were usually of 500 grains per sample. Where pollen sums were of woody ta• only, a min imum of 150 grains was counted.

A statisical analysis of the percentage data was made to standardise the interpretation of.changes occurring within the pollen profile. An estimation of the true proport ion (p) of a pollen type within

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318 New Zealand Journal of Botany, !986, Vol. 24

Table 2 Stratigraphy of the West Ballantrae site 81/3.

Depth (m) Deposit Comment

0.00-1.50 Colluvium derived from loess 1.50-2.50 Gravelly sandy silts, iron

stained, with fine sandy lenses

2.50-2.55 Predominantly sand with two thin carbonaceous layers

2.55-2.60 Sandy silt 2.60-2.70 Alternating layers silt/sand,

carbonaceous. 2.70-2.75 Carbonaceous silty sands 2.75-2.85 Carbonaceous silty sands 2.85-2.90 Base of silty sands

Unconformity > 2.90 Pliocene mudstone

Some angular fragments also rounded gravel

More carbonaceous Wood 5 cm diam.

Many pieces of wood Wood 2 cm diam. Melrosideros wood dated at 12 900 yr B.P.

the pollen sum is made using the ratio x/n where x - the number of grains of the pollen type and n = the pollen sum, where n > 150. Using the equation developed by Mosimann (1965) the confidence interval at the 95% confidence level can be calculated. Any overlap of the intervals indicates, that adjacent samples came from the same population.

S ITES AND RESULTS

Ballantrae sites (Fig. 2, 3) Two sites, the West Ballantrae and the West Tamaki , had previously been dated and the West Tamaki site is described by Hubbard & Neall (1980). Hubbard (1978) has also described the Delaware Ridge site. The two Ballantrae sites lie, one on each side of the Mohaka Fault, in the foothills of the Range to the west of Woodville. West Ballantrae is now about 19 m above the East Bal- lantrae site as a result of tectonic movement on the fault and is exposed in a cutting on a farm road. The stratigraphy of the oldest site, West Ballantrae, is given in Table 2. The depth of colluvium is greater at the East Ballantrae site but both deposits are thought to have accumulated in cut-off mean- ders or as back swamp deposits of the Mangopapa Stream now lying further to the east. The two Bal- lantrae sites are now in pastureland. The carbonaceous silts from 2 .50-2 .90m depth were sampled and the fossil pollen extracted. Above 2.50 m the site appears to have been overwhelmed by flood deposits. The pollen diagram (Fig. 2a) is dominated by Leptospermum which is obviously of local origin. Prumnopitys taxifolia is the most important tree pollen and Dacrvdium cupressinum

is represented by only minor occurrences. Phyllo- cladus pollen is present in small amounts throughout the spectrum. By excluding Leptospermum (Fig. 2b), when counting woody taxa only, the domi- nance of P. taxfolia is confirmed. The stratigraphy suggests a cut-off meander subsequently overwhelmed by flood deposits. The pollen spectra con- firms this as Leptospermurn is a very successful coloniser of alluvium. Lowland podocarp-broadleaf forest surrounded the site but it was almost totally lacking in D. cupressinum. East Ballantrae site is a stream bank exposure (Table 3).

Delaware Ridge Road sites The Delaware Ridge site is a roadside cutting exposure in Takapari peaty loam on the crest of the Range. The site has been described by Hubbard & Neall (1980) and their data are presented in Table 4.

Wood lying on top of the greywacke at the 80/1 location was found to have a radiocarbon date of 8400 + 130 yr B.P. The present vegetation is almost entirely Olearia colensoi with small patches of tus- sock. Species identified were Chionochloa pallens, Aslelia trinerva, Pratia macrodon, an Epilobium species, and a Hydrocotyh,. Macro-fossils from the undecayed material at the base were identified as Sphagnum and Polytrichum juniperinum. Moat (1961) describes several tarns containing Sphag- num on the Mokai Patea Range in the north- western Ruahine Range.

At this altitude, the pollen of taxa not now present at the site has been carried by updraft (Moar 1967). All tree pollen must therefore be regarded as regional since these sites are above both the

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Lees--Southern Ruahine Ra. Quaternary palynology 319

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Table 3 Stratigraphy of the East Ballantrae Site 81/9.


0.00-2.00 Colluvium derived from loess 2.00-3.70 Medium gravels

3.70-4.10 Grey carbonaceous silts as follows:

3.70-3.75 Grey brown sandy silt 3.75-3.80 Grey brown silt/

olive sand 3.80-3.85 Olive sand with iron stain 3.85-3.90 Olive sand with organically

enriched streaks, slightly greasy

3.90-3.95 As above plus iron staining

3.95-4.05 Olive sand, minor iron staining, grey mottles

4.05-4.10 Greyish brown sand with iron staining

> 4 . 1 0 Medium gravels

Some angular fragments among rounded gravels

Organic material at base

Many roots

Marked organic layer top 2-3 mm thick.

Leptospermum wood 10 350_+ 100 yr B.P. 0.5 m to river level

Table 4 Profile description of the Delaware Ridge Road sites 80/1 & 81/6 (after Hubbard & Neall, 1980).

Depth (mm) Zone Description

0-160 Ha 1 Dark reddish brown peaty loam, slightly sticky plastic, moderately developed fine crumbs, abundant fine- coarse roots

160-550 Ha 2 Dark brown peaty loam, slightly plastic, moderately developed medium blocky, many fine roots.

550 Taupo pumice 1819_+ 17 yr B.P. 550-870 Dark brown, slightly peaty loam, sticky

plastic with greasy feel, moderately developed coarse blocky

870 Pocketing 3440_+ 70 yr B.P.

870-1070

Marker lapilli Ha 3

Waimihia Formation

Ha 4

1100 R

Dark brown peaty loam, sticky plastic with greasy feel, weakly developed, medium blocky On weathering greywacke

Note: At 80/1 and 81/6 Taupo pumice was found at 545-555 mm. The Waimihia Formation was not located in the present study.

present tree-line and also what appears to have been an older and higher tree-line. The pollen spectrum is dominated by Podocarpaceae but the curve of Nothqflagus fusca-type rises steadily from the base to the top of the profile. Ascarina is present in small quantities throughout the profile but reaches a small maximum between the Waimihia and Taupo eruptions. Olearia-type pollen increases only towards the top of the profile. There is close agreement of the pollen spectra from the two sites which were

only 100 mm apart. The pollen spectrum from site 80/1 is presented in Fig. 4.

Manawatu Gorge site The Manawatu Gorge site lies in the bank of a small stream in the Manawatu Gorge railway reserve. Downstream of the site the stream curves in a wide loop which encircles a swamp before it plunges over the rim of the gorge. The stratigraphy and possible

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Lees - -Sou the rn Ruah ine Ra. Quaternary palynology 321

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Lees- -Southern Ruahine Ra. Quaternary palynology

Table 5 Stratigraphy of the Manawatu Gorge site 81/5.


0.00-0.40

0.40-0.90

0.90-1.08 1.08-1.38

Free draining silt, yellow brown in colour Strongly mottled imperfectly draining silt. Leached, with reddish brown mottles Blue, gleyed silty sand Carbonaceous silty sands

1.38 Silts and gravels

Base Greywacke gravels

Overbank deposits

Intermittent flooding as stream channel changes Water possibly stagnant Organic debris accumulated in slow flowing water, possibly in subsidiary channel, backwater or lag at edge of bog An event caused uprooting of trees and damming of the stream. Dacrvdium cupressinum wood dated at 3430_+80 yr B.P.

323

development of the deposit are given in Table 5. The carbonaceous silty sands were sampled and the pollen extracted. Lowland podocarp-broadleaf forest surrounds the site, although it is rather degraded. Beilschmiedia tawa and Melio,tus rami- [lorus are abundant and dense entanglements of Ripogonum scandens occur. Sites with a more open canopy are occupied by tree ferns, mainly Dick- sonia and the large grass Cortaderia.

The pollen spectrum (Fig. 5) is dominated by Cyathea spores and Gramineae pollen with D. cupressinum as the most abundant of the Podo- carpaceae. The Ascarina curve increases from the base reaching a maximum of 12% in the uppermost sample. Again, this site developed following a disturbance, possibly windthrow, followed by diver- sion of the stream. Cyathea and grass, possibly Cortaderia, were the colonising species and there was some Dicksonia; this genus often being under- represented in pollen spectra (Macphail & McQueen 1983). Podocarp-broadleaf forest surrounded the site with Ascarina a prominent component.

West Tamaki River site

The youngest site, West Tamaki, has been exposed by the downcutting of the northern branch of an eastern tributary to the West Tamaki River. An erosional event described by Hubbard & Neall (1980) deposited a large alluvial fan from the Whi- teywood creek on the west. The fan filled the main channel and dammed the eastern tributary. A Cor- taderia and Ct,athea swamp, of a type now rarely seen in the Manawatu region (Esler 1978),

developed to partially fill the valley floor of the eastern tributary. Lowland podocarp-broadleaf forest covers the hillside. Weinmannia racemosa in the vicinity of the site is only of pole size but the more distant hills carry the dead trunks of larger trees. Logs of D. cupressinum lie close to the stream where they have been undermined, but on the valley sides mature trees with full, rounded crowns are vigorous. Other species present are Podocarpus totara, Knightia excelsa, Pseudowintera colorata, a Hoheria sp., Pennantia corvmbosa, Metrosideros df~itsa, Lycopodium sp., Pteris macilenta, Hypo- lepis tenufolia, Rumohra adiantformis, and Urtica ~'rox. Nolhofagus occurs on ly at the head of the main West Tamaki valley. Wood from the base of the deposit has been dated at 770 _+ 60 yr B.P. and 2.6 m of organic silt accumulated prior to downcutting by the stream. This gives a very rapid aver- age sedimentat ion rate of 3 . 4 m m yr ~. The stratigraphy of the West Tamaki site is shown in Table 6. The grey sand strata are interpreted as being flood deposits. The corroded nature of the pollen grains below the 1.20 m level suggests remo- bilisation and redeposition: the pollen diagram therefore covers only the upper 1.20 m.

The most conspicuous feature of the pollen spectrum (Fig. 6) is the rise of f{Wnmannia racemosa pollen and the small decline in the upper samples. D. cupressinum is again the most abundant of the Podocarpaceae. Ascarina occurs sporadically but only in small amounts, usually < 1%. Pinus pollen occurs above the 0.40 m level. This is a compar- atively young site and most taxa observed in the vicinity of the site are represented in the pollen spectrum.

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Lees--Southern Ruahine Ra. Quaternary palynology 325

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Table 6 Slratigraphy of the west Tamaki River site 80/2.


0.00-0.12 Roots/litter 0.12-0.28 Gravel Downcutting of stream 0.28-0.35 Grey sand Flood prior to downcutting 0.35-0.54 Brown organic silt 0.54-0.57 Grey sand Flooding 0.57-0.83 Brown organic silt 0.83-0.85 Grey sand Flooding 0.85-1.24 Brown organic silt 1.24-1.27 Grey sand Flooding 1.27-1.74 Brown/black organic silt 1.74-1.77 Grey sand Flooding 1.77-2.40 Brown/black organic silt 2.40-2.45 Grey sand Flooding 2.45-2.60 Black organic silt Pittosporum wood

dated 770_+60 yr B.P.

D I S C U S S I O N

Vegetation

These five sites provide disjunct information which spans the last 13 000 years, i.e., the post-glacial period, in the southern Ruahine Range. Although they are at different altitudes this does not really obscure the general pattern of vegetation that emerges. It is clear that during this period podo- ca rp-broad leaf forest has been the main vegetative cover in this part of the Range. There is no evidence to suggest that Nothofagus forest covered the area during the last 13 000 years. At present beech forest occurs to the north of the study area and the slow rise of the pollen curves of this taxa at the Delaware sites is in accord with the findings of Moar for the western and northern Ruahines (1956, 1961, 1967).

Podocarp-broadleaf forest appears to have been present at all sites and to have had a similar com- position with Dacrydium cupressinum dominant for the last 10 000 years. The West Ballantrae site, however, clearly shows that at about 13 000 yr B.P. D. cupressinum was exceedingly rare and Prum- nopitys taxfo/ia was the dominant podocarp. The Delaware sites lie above the present tree-line and also above what appears to be an earlier tree-line at a higher altitude. The field evidence for this statement presented by Elder (1965) is supported by the pollen data at the Delaware sites. Moar (1961) discusses the climatic implications of the conclusions reached by Elder (1959). Both sites show a rise in Olearia and 81/6 has a coincident decline of dacrydioid, probably Daco,dium bforme, pollen. The dacrydioid curve fluctuates somewhat at 80/1.

The small tree Ascarina lucida is rarely recorded in the area to-day. In a separate study of pollen rain

in the Kahuterawa Valley to the south of the Man- awatu Gorge Ascarina pollen was found in two moss polsters (Lees unpubl.). A small plant of this species has recently been found in the same area by R. M. Greenwood (pers. comm. 1981). The tree has also been recorded in the Akatarawa and Tar- arua Ranges (pers. comm. 1981 R. A. Creswell). Fossil pollen of this species is usually < 1% of the total pollen sum. At the Manawatu Gorge site sometime after 3430 yr B.P. it reached 12% of the woody taxa count. Between the Waimihia (3420 yrs B.P) and the Taupo eruptions (1819 yrs B.P.) it was up to 4% at one Delaware site. Quintinia was not recorded by Elder in his 1965 survey but the pollen was found at all sites except the most recent one, the West Tamaki.

Climate

On the basis of results obtained from these studies it is considered that the ameliorat ion of the climate was quite rapid in the immediate post-glacial period with podocarp-broad leaf forest well established by 12 900 yrs B.P. This forest was, however, dominated by (Prumnopitys taxfolia) unlike that which succeeded it at 10 350 yr B.P. This later forest, dominated by Daco,dium cupressinum, remained until about 5000 yrs B.P. and indicates a warmer, moister climate. These results are in keeping with those found by McGlone & Topping (1977). Since about 4000 yrs ago there has been a slow decline in the pollen ofpodocarps and a rise in Nothofagus pollen, which may merely reflect the spread of this slow coloniser into less favourable areas. During this period a fluctuation in climatic conditions occurred and the frost- and drought-tender species Ascarina was able to extend its range. This period lasted about 2000 years and occurred between 3430

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Lees--Southern Ruahine Ra. Quaternary palynology

Table 7 Climatic changes in the southern Ruahine Range.

Date Change Vegetation Evidence

12 900 Warmer than before Podoearp-broadleaf West Ballantrae yr B.P. Prumnopilys tax~)lia

dominant 10 350 Warmer and moister Podocarp-broadleaf

yr B.P. D. cupressimml dominant

3400-1800 Frost and Ascarma increases Manawatu Gorge yr B.P. drought free Delaware

post 1800 Decline of Ascarina Delaware yr B.P. Absence of Quintinia West Tamaki

300- More cloudy Olearia increases Delaware present and stormy at 1050 m

East Ballantrae

327

and 1819 yrs B.P. These dates support the work of McGlone & Moat (1977). Quintinia pollen declines towards the upper part of the Delaware site and is entirely absent from the West Tamaki. The present distribution of Quintinia aculfolia in the North Island (Allan 1961) suggests it also requires an equ- able climate. Its absence from the area during this period together with the decline of Ascarina indicate that frosts and droughts are far more frequent since 2000 years ago. During the last 300 or so years calculated on the sedimentation rate of 0.003 mm yr + there has been an increase in Olearia pollen and a decrease in D. bforme, a timberline shrub species, which must indicate an extension in the range of the sub-alpine scrub into lower altitudes. Wardle (1971) states that Oh,aria colensoi is a plant requiring very heavy, well distributed precipitation, usually > 2500 mm yr ', also that it survives under frequent cloud cover and high winds. He noted that on either side of the Manawatu Gorge it lies at an altitude which normally supports forest elsewhere in the Tararua and Ruahine Ranges. Zotov (1938) mentions the influence of fog on tree- line altitudes in the Tararua Range and Wardle (1965) has discussed the anomalous xerophytic features of Olearia colensoi. He concluded that these were adaptations to low radiation. These facts, and the evidence put forward by Elder (1965) for a low- ered tree-line, suggest that the climate at these altitudes may be more cloudy now than that of former times. These comments have been summarised in Table 7.

E r o s i o n

Four of the five sites examined have developed subsequent to disturbance which altered the geo- morphology and hence the edaphic conditions at the site. It would appear that the causative events were predominantly storms. Windthrow occurred at the Manawatu Gorge site and flooding at the

Ballantrae and West Tamaki sites. Hubbard and Neall (1980) regarded the Delaware site as stable for the last 4600 years. The new radiocarbon date obtained extended this back to 8000 yrs and the macrofossil evidence suggests an origin in a sub- alpine bog. They attributed this stability to the neg- ligible mass movement on the relatively flat sum- mit plateau. This contrasts with the steepness of the valley sides at the Manawatu and West Tamaki locations, a causative factor in erosion named by Marden (1977). It is possible that the recent deterioration in climate outlined above, which led to the replacement of the upper forest by Olearia colensoi scrub, may have reduced the ability of the vegetative cover to protect and stabilise the soil, making the area more prone to mass movement. Coupled with the increased frequency of high intensity rainstorms advocated by Grant (1979, 1981) and the nature of the steepland soils (Hub- bard et al. 1979) these factors could well be respon- sible for the accelerated rate of erosion which has been commented on by many observers.

It is not possible to say from the data obtained whether the introduction of the possum and the observed decline of l/I'einmannia racemosa are connected. The rapid rise of the Weinmannia curve at the West Tamaki site suggests it records the establishment of the species on newly exposed ground. In such a situation Stewart and Veblen (1982) found that an even aged stand so established would be particularly vulnerable to the depreda- tions of this animal when the stand reached senescence. All that can be said here is that the curve does show the very first onset of a decline.

ACKNOB~LEDGMENTS This study formed part of the work for an M.Sc. degree at Massey University, Palmerston North, New Zealand. I wish to thank Dr J. P. Skipworth of the Department of Botany and Zoology, Dr M. J. Shepherd and J, L.

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328 New Z e a l a n d Jou rna l o f Botany, 1986, Vol. 24

McArthur of the Department of Geography, and Dr V. E. Neall of the Department of Soil Science, all of Massey University, for their advice and assistance with this study. Thanks are also due to Dr N. T. Moat and the staff of the Palynological Laboratory, Botany Division, DSIR, Lincoln for their training, advice, and encouragement. I am grateful to Mr R. N. Patel, also of the Botany Divi- sion, DSIR, Lincoln for identifying the wood samples for me, and to the Radiocarbon Dating Laboratory for pro- viding me with three new radiocarbon dates. Dr E. O. Campbell, Department of Botany and Zoology at Massey University assisted with the identification of macrofos- sils. I would also like to thank the unknown referee for patience and valuable help in the correction of this manuscript.

R E F E R E N C E S

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Cuddihy, M. J. 1977: Forest, grasslands and animals of the southern Ruahine Range. Unpublished NZFS FRI Forestry Division Report No. 151.

Cunningham, A. 1962: Catchment condition in the Ruahine Range (Unpublished) NZFS FRI Protec- tion Forestry Report No. 23.

Elder, N. L. 1959: Vegetation of the Kaweka Range Transactions of the Royal Socieo~' q/'New Zealand 87 : 9-26.

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Esler, A. E. 1965: Botany of the Manawatu District of New Zealand Wellington, Government Printer.

Faegri, K.; Inversen, J. 1975: Textbook of pollen analysis (3rd Ed.) Munksgaared.

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James, I. L.; Beaumont, P. E. 1971: Report on a surve) of vegetation of the Southern Ruabine Range. NZFS Protection Foresto Branch Report No. 80.

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Macpbail, M. K.: McQueen, D. R. 1983: The value of New Zealand pollen and spores as indicators of Cenozoic vegetation and climates Tuatara 26 : 37- 59.

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McGlone, M. S.; Moar, N. T. 1977: The Ascarina decline and post-glacial climatic change in New Zealand. New Zealand journal of botany 15: 485-489.

McGlone, M. S.; Topping, W. W. 1977: Aranuian (post- glacial) pollen diagrams from the Tongariro region, North Island, New Zealand. New Zealand journal c~/'botany 15: 749-760.

Moar, N. T. 1956: Peat on the Mokai Patea, Ruahine Range, North Island, New Zealand. New Zealand journal of science and technology, A 37: 419-426.

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Moore, L. B.; Edgar, E 1970: Flora of New Zealand Vol. II Wellington, Government Printer.

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Neale, A. A.; Thompson, G. H. 1978: Rainfall distribution near the Manawatu Gorge in simple westerly weather and northwesterly airstreams. New Zealand Meteorological Service Technical Note 233.

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L e e s - - S o u t h e r n R u a h i n e Ra. Q u a t e r n a r y pa lynology 329

- - ( e d . ) 1981: Erosion in the Ruahines. Inter- national Conference on soils with variable charge. 1981. Massey University, Palmerston North.

Searell, Pamela 1975: Ruahine Forest Park. New Zealand's nature heritage Vol. 5:777-1782.

Strand, S. 1977: The vegetation and management of the West Tamaki catchment In: Neal, V. E. (ed.) Field Excursion to Southern Ruahine Range. New Zealand Society of Soil Science 25th Jubilee Con- .~rence : 21-26.

Stewart, G. H.; Veblen, T. Y. 1982: Regeneration patterns in southern rata (Metrosideros umbellata)-kamahi

(Weinmannia racemosa) forest in central West- land. New Zealand journal of botany 20: 55-72.

Wardle, P. 1965: Significance of xeromorphic features in humid sub-alpine environments in New Zealand. New Zealand journal of botany 3 : 342-34.

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late quaternary palynology of the southern ruahine range north island, new zealand

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