213

BOTANICAL NOTES ON THREE HIGH PEAKS OVERLOOKING THE

by Lucy B. Moore*

SUMMARY

Mt. Hobson (622 m), Hauturu (723 m) and Moehau (892 m), the highest points of , and Peninsula respectively, all support predominantly woody vegetation to their highest levels. Moehau offers the widest range of habitats, including cushion bog, and changes there since the author's observations began in 1929 are outlined. Floristically the three peaks show resemblances to and differences from one another, and selected species are listed in groups according to their occurrence here, and on other high land of the district.

INTRODUCTION

Auckland's north-eastern skyline boasts three mountain peaks, Hauturu (723 m), 75 km distant on Little Barrier Island, Mt Hobson (622 m), a dim 75 km away on Great Barrier Island, and Moehau (892 m, Te Moehau of earlier maps) some 69 km off on (Fig. 1). The latter, botanically, is about as much on an island as the other two. Cockayne (1928 p. 382) included all these places in the Thames Subdistrict (of his South Auckland Botanical District), the land boundary of which follows the southwards almost to its source and then runs ("obviously a quite arbitrary boundary") roughly northeast to about Te Puke. Within this subdistrict, as is shown here, there is considerable diversity from south to north; long ago Adams (1885) was impressed by the difference between the vegetation of Te Aroha Mountain and that of the dividing range east of the town of Thames, and he gave contrasting lists of species characteristic of the two florulas. When later he made the first ascent of Moehau, his report (1889) was so preoccupied with the unforeseen montane element of the florula there that he failed to mention the absence of certain important species, which he had noted as.characteristic of the Thames Range, and which Kirk (1869) had recorded on Great Barrier further north. The of Little Barrier were listed (in Hamilton 1961) by Hamilton and Atkinson who, like Cockayne, found more ecological and floristic resemblances to the Coromandel Peninsula than to the adjacent mainland to the west. They drew attention to the unexpected absences, and recorded the presence of some species only as young plants, and the very local occurrence of others, but little of this is directly relevant to the higher altitudes. The following discussion of the vegetation and flora of the three mountain tops is based in part on direct observations on Little Barrier Island in 1942, on Great Barrier in August 1972, and on Moehau during ten visits between 1929 and 1934, totalling some 20 days on various parts of the range, supplemented by one day in 1939 and another in 1971.

*c/o Botany Division, Department of Scientific & Industrial Research, Christchurch. 214

Location map 215

VEGETATION

On each mountain there is a definite zonation, with some species dropping out and new ones appearing as altitude increases, and it is by the presence of these upland plants that upper levels are recognized for the present discussion. Many species, common in the lowlands, extend to even the highest tops or reappear there after being absent on intervening slopes. With the change in species there is an alteration in the structural character of the vegetation the trees finally becoming short, mostly many-trunked and thickly draped with bryophytes, though I saw no very good example of this mossy forest on Mt Hobson. On or near each summit outstanding rocks offer sites suitable for small, light-demanding plants, but only on Moehau is there extensive, well-developed peat with a low covering of cushion plants and/or sphagnum moss. All the tops have been altered to some extent. On Hauturu the disturbance has been least; surveyors made a clearing about the trig station and the few tracks have been trampled by many human feet. Mt Hobson has at least two tracks to the summit, one of them much used. The remains of a high dam at about 550 m testify to the extensive activities of bushmen over a number of years. Here stray cattle, sheep, goats, wild pigs and rabbits (all absent from Little Barrier) have access to the top but any effect they have on the vegetation is not immediately obvious. Opossums appear to be absent. The highest part that I saw, near the dam, showed little sign of having been burnt at any recent date; scrub 3-4 m tall on a narrow ridge included a mixture of high-level and lowland plants, the surrounding forest on steep slopes being dominated by Dacrydium intermedium. Moehau presents quite another picture, though one of its insular character• istics is that opossums still appeared to be absent in December 1971. Adams (1889) considered that there was nothing upon the mountain to support life — neither bird nor beast - "so that, after a few expeditions have been made to fully explore the summit for plants, Te Moehau will probably be left undisturbed except for the wind". How wrong he was! Maclaren (1899) wrote of "tracks worn into mud by the wild cattle that abound on Moehau" and settlers told us of long-haired aggressive beasts that had been on the mountain "since Adam and Eve were boys", but we saw no signs of their presence on the many high ridges we explored in the 1930's (Moore and Cranwell, 1934). We saw numbers of goats, and noted how well the line cut by surveyors served them as a route along the top of the main ridge through thick wind-scrub. From our own experience we could easily believe tales of animals being bailed up here for killing, as if in a fenced race. Pigs we heard often and their wallows were numerous, but not towards the real summits. Later Mason and Chambers (1950) recorded wild sheep in kamahi forest. A boggy slope on the eastern face of the trig peak had obviously been burnt; we were told by Mr Bronlund, who had lived within sight of it at Stony Bay since about 1895, that the only fire he had ever seen there was one "lit by Bill Wharfe in a dry summer" about 1899. In more recent years visitors to the tops have been relatively numerous, and observers with specific projects have maintained camps there. During the last 35 years there have been great changes. In 1971 goats were seen in mobs right to the top, droppings gave good evidence that cattle 216 frequented the upper levels, and in full daylight two large pigs wandered about the broad open slope below and to the east of the trig peak. Photographs show that the area of open ground increased there as trees died, and that extensive grassland developed. Even the previously impenetrable short scrub on the main ridge between the trig and the rocky peak has been opened up and, though still mostly woody, it is now easily traversed in any direction by man or beast. On the south side, immediately under the rocky peak, there is an undamaged remnant of the tightly interlaced mossy forest that was once much more extensive. Below the rocky peak in the direction of the top of the Hope ridge the area of open wet bog has expanded greatly. New landslips have occurred and one of them below the bog that occupies the head of the Ongohi stream, may have taken with it the only of Cordyline indivisa that we ever saw on the mountain. In contrast to all this down-graded vegetation, a new forest, with Libocedrus bidwillii as the vigorous dominant, is growing up on the rounded eminence of the trig peak, partly on the sunny, boggy slope amongst cushions of , and partly within the area of the old burn on the eastern side.

FLORISTICS

The following list sets out some of the striking contrasts between the species to be found on the upper levels of the three mountains, and indicates more general distributions. Records were assembled from the published papers listed below and from field notes (principally those of Cranwell and Moore 1929-1934 from Moehau, confirmed to a large extent by a list compiled by A.E. Esler in 1971), and by reference to herbarium specimens. Collections at Botany Division, Department of Scientific and Industrial Research, made by A.P. Druce in recent years, have added much useful information about the plants of the Thames and Kaimai Ranges, but the numerous specimens brought from Great Barrier to the Auckland Museum by R.C. Cooper between 1960 and 1970 have been by no means fully investigated. The Pirongia records of Gudex (1955) were supple• mented by others from R.I. Bell. A provisional checklist of the plants of Great Barrier Island, lowland as well as upland, has been prepared, using the more obvious published sources (chiefly Kirk, 1869) and also some herbarium specimens; this may be consulted at Botany Division. The list of selected species presented here is not rigidly critical. It is offered as a basis for checking by botanists and in the hope that it may stimulate comparisons by workers in other groups. An obvious example concerns frogs of the Leiopelma, which have not been found on the Barrier islands (Stephenson, 1961). The whole "main axial elevation of the Hauraki Peninsula, an elevation that has its northern termination in the Great Barrier Island" (Maclaren, 1899) presents many problems for discussion by biogeographers and biohistorians. 217

SELECTED SPECIES LIST

On Moehau but not on Great or Little Barrier Islands. A. Species here reaching their northern limit and not known elsewhere on Coromandel, Thames, Kaimai, Hunua or Pirongia Ranges: far removed from other occurrences and all low-growing plants of open places, either peat bogs or rock. (a) Confined to the rocky peak (Little Moehau): Dacrydium biforme; Podocarpus nivalis, originally a single plant recorded on cytological grounds (Hair & Beuzenberg 1958, n = 18) as a natural hybrid between P. nivalis and P. hallii, on the basis of a layered transplant grown on at Otari Gardens, Wellington for about 25 years, the count to be checked on cuttings direct from Moehau, now rooted at Botany Division, Lincoln; Drapetes dieffenbachii; Aporostylis bifolia. (b) Almost confined to the three highest peaks: Celmisia incana, represented also by one plant established on the bank of a streamlet much lower, and flourishing there for ten years at least; Oreobolus pectinatus, in closed cushion bog and also colonising burnt boggy ground; Notodanthonia setifolia; Carpha alpina, also colonising disturbed boggy ground. (c) Extending along the main ridge to the north; Pentachondra pumila; Cyathodes empetrifolia. B. Species here reaching their northern limit but known elsewhere on Thames and/or Kaimai Ranges, including Te Aroha; also on Pirongia Range, but none recorded from . (a) Confined to high levels: Ourisia colensoi, on rocky peak and colonising slip. (b) Found in many places along the and most also extending down into forest: Phyllocladus alpinus; Libocedrus bidwillii; foetidissima; C. banksii; C. colensoi; Pseudopanax simplex var. sinclairii; Luzuriaga parviflora. (c) Species at or approaching their northern limit: Cordyline indivisa, a single plant, now presumed dead, the species also recorded from Thames Range (Adams, 1884), Te Aroha, and Hunua and Pirongia Ranges; Astelia nervosa, known from Thames, Kaimai and Pirongia Ranges, and one plant found in Waitakere Range.

On Great Barrier Island, but not on Moehau or Little Barrier: Olearia allomii, extending almost to top of Mt Hobson, endemic to Great Barrier but a plant from near (CHR 168127, R.I. Bell, 1965) approaches it; patens, grows high on Mt Hobson, recorded also from Thames Ranges; Dacrydium kirkii, a northern species, reaching almost to summit of Mt Hobson, known from Thames Ranges but not recorded from Kaimai, Hunua or Pirongia Ranges; Leptospermum sinclairii, extending almost to top of Mt Hobson, listed as endemic to Great Barrier, but recorded (Hynes, 1950) from Poor Knights. Should be critically compared with the low-growing plants from North Cape from which the cultivar 218

Leptospermum scoparium 'Wairere' was derived (Mole, 1967); Epacris pauciflora var. sinclairii, extending almost to top of Mt Hobson, also on Thames Ranges, forming a shrubby bush.

III. On Little Barrier and on Moehau, but apparently absent from Great Barrier. A. Elsewhere northern as well as southern, and mostly also from two or more of the Thames, Kaimai, Hunua and Pirongia Ranges: Griselinia littoralis; Ascarina lucida; Elytranthe tetrapetala; Collospermum microspermum; Hymenophyllum lyallii.

B. Elsewhere only further south; on Thames and Pirongia Ranges, but not recorded from the Hunua Ranges: Dracophyllum pyramidale, earlier recorded as D. traversii and doubtfully distinct; Pseudopanax colensoi var. colensoi.

IV. On Great Barrier and on Moehau, not recorded on Little Barrier: Dacrydium intermedium, abundant at high levels on Great Barrier, very rare on Moehau. Recorded also on Thames and Kaimai Ranges.

V. On Little and Great Barrier Islands but not on Moehau: Pseudopanax discolor, local endemic, extending as far south as Te Aroha; Archeria racemosa, local endemic, found on Thames Ranges and to the Bay of Plenty and eastwards, but not southwards; Metrosideros parkinsonii, elsewhere only on the northern part of the west coast of the .

VI. At higher levels on Little and Great Barrier Islands and on Moehau. A. Local endemic: Coprosma dodonaeifolia (including C. lucida var. angustifolia), also on Thames to Kaimai Ranges. B. Mostly further north: Metrosideros albiflora, also on Thames Ranges; Pittosporum kirkii, noted above 760 m but not to summit of Moehau, also on Te Aroha and Hunua Ranges; Corokia buddleioides, also on Thames and Hunua Ranges; Weinmannia silvicola var. betulina, so determined by Wardle (1966) and placed with collections from Thames, Kaimai and Hunua Ranges, and a few localities in eastern north Auckland and the North Cape area; Alseuosmia macrophylla, also on Thames, Te Aroha, Hunua, and Pirongia Ranges. C. Only further south: Metrosideros umbellata, also Thames and Pirongia Ranges; Pseudowintera colorata, so determined in herbaria, but Vink (1970) placed some such specimens as P. axillaris x colorata and his maps show only P. axillaris, in one form or another, on Little and Great Barrier Islands, and in the Thames and Kaimai areas. D. Common constituents of upland forest in the Auckland Province, mostly here reaching summits, but extending downwards into forest also: Phyllocladus glaucus; lxerba brexioides; Quintinia acutifolia, with leaves resembling those of Westland plants; Senecio kirkii; Myrsine salicina; Pseudowintera axillaris; Astelia trinervia; Libertia pulchella; Gahnia pauciflora. 219

VII. Lowland species found almost to the top of Mt Hobson: Lygodium articulatum; Loxoma cunninghamii; Phyllocladus trichomanoides; Phebalium nudum; Rhabdothamnus solandri; Cyathodes fasciculata, with large juvenile leaves.

VIII. Notable absences: Dacrydium colensoi, recorded from Moehau by Adams, apparently in error for D. biforme, and by Kirk from Great Barrier, apparently later distinguished as D. intermedium; Lycopodium fastigiatum and Hymenophyllum malingii both recorded from Te Aroha but not found on Moehau ,Astelia linearis and Arthropodium cirratum recorded by Adams as growing on the peak of Moehau but not since seen there.

ACKNOWLEDGEMENTS

To Lucy M. Cranwell, a good companion on Coromandel expeditions, partly under a Duffus Lubecki Scholarship; to high winds that providentially extended a day visit to Little Barrier into a whole week; to Mr A.E. Esler for arranging the 1971 trip to Moehau, and for drawing the map; to Auckland University Field Club for its invitation to join the Fiftieth Anniversary Scientific Camp at Great Barrier.

REFERENCES

Adams, J. 1884: On the Botany of the Thames Goldfields. Trans. N.Z. Inst. 16: 385-94. Adams, J. 1885: On the Botany of Te Aroha Mountain. Trans. N.Z. Inst. 17: 275-87. Adams, J. 1889: On the Botany of Te Moehau Mountain, Cape Colville. Trans. N.Z. Inst. 21: 32-41. Barton, I.L. 1972: On the Vegetation of the Hunua Ranges, Auckland. N.Z. Jl. Bot. 10: 8-26. Cockayne, L. 1928: "The Vegetation of ." W. Engelmann, Leipzig. Cranwell, L.M.; Moore, L.B. 1936: The Occurrence of Kauri in Montane Forest on Te Moehau. N.Z. Jl. Sci. Tech. 18: 531-43. Edwards, J.; Bieleski, R. 1952: Hunua Species List. Tane 5: 56-60. Gudcx, M.C. 1955: The Native Bush Flora of Pirongia Mountain. Trans. R. Soc. N.Z. 83: 303-11. Hair, J.B.; Beuzenberg, E.J. 1958: Contributions to a Chromosome Atlas of the New Zealand Flora X.N.Z.Jl. Sci. 617-28. Hamilton, W.M. 1961: Little Barrier Island (Hauturu). Bull. N.Z. Dept. Sci. Ind. Res. 137. 198 pp. Hynes, P. 1950: Great Barrier Island. Auck. Bot. Soc. Newsletter 8: 4 - 7. Kirk, T. 1869: On the Botany of the Great Barrier Island. Trans. N.Z. Inst. 1: 144-157. Kirk, T. 1870: On the Botany of the Thames Goldfields. Trans. N.Z. Inst. 2: 89-100. Maclaren, J.M. 1899: On the Geology of Te Moehau..7>aws. N.Z. Inst. 31: 494-98. Mason, G.W. 1951: Some Notes on the Vegetation of Great Barrier Island. Tane 4: 25-7. Mason, G.W. 1951: The Vegetation of the Hunua Ranges. Tane 4: 27-9. 220

Mason, G.W.; Chambers, T.C. 1950: Vegetation of North-east Coromandel (Cape Colville Peninsula) with special reference to Mt. Te Moehau. Tane 3: 69-71. Mason, G.W.; Preest, D.S. 1954: Notes on the Vegetation Types of Little Barrier. Tane 6: 91-8. Mole, R.M. 1967: Leptospermum scoparium 'Wairere'. N.Z. Plants and Gardens 7: 153. Moore, L.B.; Cranwell, L.M. 1934: Induced Dominance of Microlaena avenacea (Raoul) Hook. f. in a New Zealand Rain Forest Area. Rec. Auckland Inst. Mus. 1: 219-38. Stephenson, E.M. 1961: New Zealand Native Frogs. Tuatara 8: 99-105. Vink, W. 1970: The Winteraceae of the Old World 1. Pseudowintera and Drimys -- Morp• hology and . Blumea 18: 225-354. Wardle, P. 1966: Biological Flora of New Zealand 1. Weinmannia racemosa Linn. f. (Cunoniaceae). Kamahi.A'.Z Jl Bot. 4: 114-31. Wardle, P. 1968: The Taxonomy and Distribution of the Stipulate Species of Pseudopanax in New Zealand. N.Z. Jl Bot. 6: 226-36.