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III. T H E ESTABLISHMENT OF PERMANENT

VEGETATION QUADRATS

By Barbara S. Parris*

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

In 1963 grazing animals were eliminated from the park reserve on Cuvier Island. Since then the vegetation, once checked by grazing and occasional fires, has been allowed to regenerate freely.

At present that part o f the island which is a reserve is largely covered by pohutukawa forest (Metrosideros excelsa) with occasional Dysoxylon spectabile, Vitex lucens, Planchonella novo-zelandica, Brachyglottis repanda, Melicytus ramiflorus, Macropiper excelsum, Nestigis apetala, Pseudopanax lessonii, Corynocarpus laevigatus, Melicope ternata etc. reaching to the canopy, and else­where forming a subcanopy. There are also some areas covered with grasses, rushes, bracken (Pteridium aquilinum), Muehlenbeckia complexa, Clematis paniculata, and occasionally Sicyos angulata, which do not appear to be regener­ating to forest through the usual sequence of Leptospermum scrub. These areas may have been opened up by fires, or by man, and kept clear by the grazing of goats and other animals. After the removal of animals from the reserve the density and length of grass and bracken in these areas was probably too great to allow seedling establishment to take place. Any regeneration in these areas seems to be around the edges, or from small 'islands' of forest vegetation, in much the same way as on Rangitoto Island where pohutukawa paves the way for the advent of other species. Here the shade of the trees, mainly pohutukawa, at the edges of the grassed areas either kills the grasses etc. or thins them to such an extent that seedling establishment is able to take place.

Five quadrats were set up on the island, in a variety of vegetation types, to determine the speed and sequence of regeneration. They wi l l provide an interest­ing comparison with the two permanent quadrats on Little Barrier Island, which were set up in 1954 (Bellingham & Percy, 1954) and re-examined in 1958 (Percy, 1958), 1963 (English & Brock, 1964) and 1967 (Parris & Keen, 1968), and the eight permanent quadrats set up in grassland, adjacent to bush, at Swanson in 1968 (Parris & Rae). It is hoped that all of these quadrats wi l l be sampled at regular intervals. It would also be appreciated i f the next party to examine the quadrats on Cuvier Island would take some lengths of galvanised pipe to mark the corners of the quadrats as only wooden pegs were available at the time and they wi l l not last indefinitely. Location of the quadrats is shown in Fig. 1 — Beaver et al. (1969).

•Department of Botany, Auckland University.

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M E T H O D O F S A M P L I N G

The method of sampling is that used by English & Brock (1964) and Parris & Keen (1968) on the Little Barrier quadrats, with the addition of an approxi­mate recording of the relative abundance of seedlings of the various species. Quadrats 2, 3 and 4 were sampled in this way. Quadrats 1 and 5 do not contain any forest tree or shrub species yet, but should be sampled in this way when such species appear in them.

The vegetation is divided as follows:-

1. Poles. Greater than 4 inches D . B . H . (diameter breast height).

2. Saplings. Between 1 and 4 inches D . B . H . which are further subdivided into

A. 1 2 inches D . B . H . B. 2- 3 inches D . B . H . C. 3 - 4 inches D . B . H .

3. Striplings. Less than 1 inch D . B . H . and higher than 12 inches. These are further subdivided into height classes

A. 1 - 5 feet B. 5 - 1 0 feet C. 10-15 feet D. 15-20 feet

4. Ground Cover. Phanerogams and cryptogams less than 12 inches in height. Frequency and density of plants in this category are not recorded because of their erratic occurrence.

Each quadrat is 10 yards square, and is divided into 6 foot square plots which are sampled separately as above. The results are expressed as frequencies and densities, with the various height and D . B . H . classes, as well as seedling occurrence, also recorded.

Frequency and density are calculated as follows:

„ plots in which species occurs F = m rT~* x 1 0 0

total no. of plots _ _ total no. individuals of a given species

total area of quadrat (in sq.yards)

Ferns and dicotyledons are as in 'Flora of New Zealand' by H . H . Allan, monocotyledons are as in 'New Zealand Flora' by T .F . Cheeseman (1925) and adventive species are as in 'Handbook of the Naturalised Flora of New Zealand' by H . H . Allan (1941).

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Q U A D R A T 1.

This is situated near the highest part of the island at an altitude of approx­imately 750', in an area which was probably cleared for the siting of the old radar station. A tall pole may be seen near the old scanner, and seven feet from here on a bearing of 3 3 5 ° is the southwest peg of the quadrat. The northwest and southeast pegs are at bearings of 3 4 3 ° and 7 3 ° respectively from this peg.

The ground here slopes to the southeast. The vegetation within the quadrat is typical of that on the summit of the island. There is dense bracken, cocksfoot (Dactylis glomerata), Muehlenbeckia complexa and some Scirpus nodosus. It seems unlikely that this area will regenerate to forest in the near future as it is not near any 'islands' nor the main edge of the forest from which colonisation can take place. There are no seedlings of tree or shrub species in this dense plant cover. Areas similar to this occur on many parts of the island, although Clematis and sedges may be more common elsewhere, and there are often more ferns, especially on the rocky slopes above Northwest Bay.

Q U A D R A T 2.

The southwest corner of this quadrat is situated one hundred and twenty-six feet from the northwest corner of the living quarters of the old radar station, on a bearing of 1 5 6 ° . From this peg the northwest peg is at 3 1 8 ° , the southeast peg at 1380.

The ground slopes to the southwest. The quadrat is almost completely surrounded by trees, but there are none taller than five feet within the quadrat. The surrounding vegetation consists of pohutukawa, Dysoxylon, Pseudopanax lessonii, Macropiper, Melicytus, Geniostoma, Brachyglottis, Coprosma macrocarpa and Gahnia lacera, while Entelea arborescens and Pseudopanax crassifolium are rare. Important species in the ground cover surrounding the quadrat, apart from seedlings of the above species, are Doodia media, Oplismenus undulatifolius and Dichondra repens.

Within the quadrat the only trees above one foot in height are Pseudopanax lessonii and Macropiper excelsum (see Table 1).

Many Dysoxylon and a few Pseudopanax lessonii seedlings occur on the southern side of the quadrat where shade from an overhanging Dysoxylon has hindered grass growth. This suggests that the future mode of regeneration will be by the establishment of seedlings under the spreading shade of mature trees, and hence greatest change is expected on the northern and southern sides of the quadrat where solitary trees and the main forest are developed respectively.

Quadrat 2 may show the greatest change in the shortest time of any of the

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five quadrats and wil l be most important in determining the speed at which the forest regenerates. At present the quadrat is largely covered by Clematis, Muehlenbeckia and an unidentified sedge, with some Oplismenus under the over­hanging Dysoxylon.

Q U A D R A T 3.

Like quadrats 1 and 2, this is situated near the summit of the island. Ninetynine feet up on the left hand side of the concrete path, leading from the living quarters to the scanner,is a galvanised marker pole. Twentyseven feet from this at a bearing of 3 2 0 ° is the southeast peg. From this the northeast peg is at 4 9 ° , the southwest peg at 3 1 9 ° .

The ground slopes to the north west. The canopy in this area is of pohutukawa, estimated as being between twentyfive and thirty feet high, with a subcanopy mainly of Dysoxylon with some Melicytus and Brachyglottis approximately twenty to twenty five feet in'height. These three subcanopy species, and Macropiper, produced multiple trunks of which only the largest was measured. The vegetation is light and open in character.

Apart from seedlings, which are listed in Table 2, the ground cover consists of Doodia, Polystichum richardii, Adiantum cunninghamii, Asplenium lucidum, Oplismenus, Clematis, Dichondra, Gahnia lacera, at least two species of unidentified sedges and an unidentified grass. The last three are uncommon.

Near the quadrat is a large tree of Knightia excelsa and a large Cyathea dealbata, both atypical of the vegetation of this area. Seedlings of Planchonella occur near the quadrat, and both Pteris comans and Carmichealia cunninghamii are common close to the quadrat although they do not occur within it. Epiphytes are absent in this area.

Dysoxylon is by far the most abundant species in the quadrat and probably always will be dominant in this area. Although Coprosma macrocarpa and Pseudopanax lessonii are also fairly abundant they lack the great numbers of seedlings of Dysoxylon here, and Macropiper does not appear to be regen­erating as there are very few striplings of this species in comparison with the numbers of older plants (see Table 2).

Q U A D R A T 4.

This is situated further down the main track to the summit of the island, at an altitude of approximately 500 feet. On climbing up the track a galvanised marker pole may be found on the left hand side by a large fallen pohutukawa tree which blocks the trail. Twenty one feet from this at a bearing of 2 2 2 ° is the southeast corner of the quadrat and from here the southwest peg is at 2 0 2 ° , the

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northeastern at 2 2 ° .

The ground slopes to the west. The canopy here is also of pohutukawa, estimated to be about thirty five feet high, with a subcanopy of Dysoxylon and Melicytus approximately thirty feet high. The vegetation is denser than in Quadrat 3.

Apart from seedlings, listed in Table 3, the ground cover of the quadrat consists of Polystichum, Doodia, Asplenium lucidum, Phymatodes diversifolium, Arthropteris tenella, Cyathea dealbata, Oplismenus, Uncinia australis, Carex dissita (?), Rhopalostylis sapida, Pterostylis alobula and Parsonsia heterophylla.

Near the boundaries of the quadrat, but not within it, are the following species: Hymenophyllum dilatatum, Blechnum filiforme, Asplenium falcatum. Clematis, pohutukawa, Pittosporum tenuifolium, Coprosma rhamnoides and C. 'cunninghamii'.

The only epiphytes present are Arthropteris and Phymatodes diversifolium.

There is a greater variety of species in this quadrat than in quadrat 3. The trees and shrubs are larger and the vegetation is more dense and less wind­swept than on the higher site. The large pohutukawa on the southern side of the quadrat appears to be the home of a pair of pigeons. These pigeons may be responsible for the introduction of species, bearing berries, not found as mature trees nearby. Although Dysoxylon is still important in this quadrat it is far less so than in Quadrat 3. This species, together with Brachyglottis and Melicytus, does not seem to be regenerating well (see Table 3). These three species, which are common as members of the subcanopy over most of the island, may eventually be replaced here by other species, such as Pseudopanax lessonii, Macropiper, Nestegis, Hedycarya arborea and Corynocarpus laevigatus.

Q U A D R A T 5.

This is also on the main track, not far above the boundary fence between the lighthouse farms and the reserve, on the site of an old orchard, which was burnt in January, 1968 (Merton, 1968). There is an old concrete trough on this burnt area and the northeast corner of the quadrat is six feet, at a bearing of 157° , from the southwest corner o f this trough. From this peg the southeast corner is at 101° , the north western at 2 8 1 ° .

The ground slopes to the south. There are no seedlings of forest tree or shrub species in this quadrat.

Doodia, bracken and Scirpus nodosus appear to have regenerated from root stocks or rhizomes in this area after burning. Other species present are

so

Cirsium lanceolatum, Sonchus asper, Erechtites scaberula, Erigeron canadense, Lotus sp., Trifolium sp., Geranium dissectum, Rumex sp., Euphorbia peplus, Plantago sp., Phytolacca octandra, Solanum nigrum and Albizzia lopantha.

This area may regenerate in time to the surrounding coastal dicotylous forest, or it may become covered in Albizzia, of which there are only a few seedlings present. It was not seen elsewhere on the island.

A C O M P A R I S O N O F T H E L I T T L E B A R R I E R A N D C U V I E R I S L A N D Q U A D R A T S

The sequence of forest regeneration on both islands appears to be quite different. On Little Barrier, which is a larger island and thus not so influenc­ed by the sea as Cuvier, the vegetation is similar to that on the mainland. The climax forest in Quadrat I is not yet obvious; that of Quadrat II will probably be kauri-beech. (Parris & Keen, 1968). The vegetation on Cuvier is far more coastal in character, as the pohutukawa forest, extending over most of the island at present, is apparently being slowly replaced by a coastal dicotylous forest. The vegetation of the islands is similar in that podocarp species are unimportant. Few species are common to the quadrats on both islands (only Quadrats 3 and 4 being considered for Cuvier here), with no species important in the quadrats on both islands. Table 4 shows the three most important species in each of the four quadrats, arranged in order of density.

T A B L E 4. A C O M P A R I S O N O F T H E T H R E E M O S T I M P O R T A N T SPECIES IN T H E Q U A D R A T S O N L I T T L E B A R R I E R A N D C U V I E R I S L A N D S , A R R A N G E D IN O R D E R O F D E N S I T Y .

Little Barrier Cuvier

Q U A D R A T I. Q U A D R A T 3.

Myrsine australis Dysoxylon spectabile

Coprosma arborea Pseudopanax lessonii

Melicytus ramiflorus Coprosma macrocarpa

Q U A D R A T II. Q U A D R A T 4.

Neopanax arboreum Macropiper excelsum

Coprosma spathulata Pseudopanax lessonii

Pittosporum tenuifolium Nestegis apetala

Comparison of the numbers in each class, as a percentage of the total number of plants in each quadrat, shows that Little Barrier has a larger proportion of mature trees, while Cuvier has a very high proportion of young trees. This may be attributed to the cessation of grazing on the latter island,

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and the proportion of young trees should become much less as the present trees grow. A t the time of analysis the regeneration gap between the canopy and subcanopy trees and the dense undergrowth of vigorous young trees was most noticeable. Pseudopanax lessonii shows the greatest apparent increase in numbers of young plants in comparison to the numbers of old plants (see Tables 2 and 3). Although it was the second most abundant species in both quadrats 3 and 4, all the plants counted were less than ten feet high.

C O N C L U S I O N

Further sampling at regular intervals is desirable to determine the sequences of regeneration in these quadrats and to provide comparisons with other types of regeneration studied by Field Club, i.e. the permanent quadrats established on Little Barrier in 1954 and at Swanson in 1968.

A C K N O W L E D G E M E N T S

The author wishes to thank Misses Rosalie Lambert and Alison Smith, and Mr I. Johnstone for assistance in setting up the quadrats.

R E F E R E N C E S

Studies on the vegetation of Cuvier Island I. The plant communities and a vascular plant species list. Tane 15.

Permanent vegetation quadrats in Leptospermum communities o f Little Barrier Island. Tane 6: 110-115.

A further examination of the permanent quadrats on Little Barrier Island. Tane 10: 79-83.

Cuvier Island. 25 January 1968. Official unpublished report to the Conservator of Wildlife, Dept. Internal Affairs, Wellington. (Dept. Internal Affairs file 46/14/7.)

A further examination of the permanent quadrats on Little Barrier Island. Tane 14: 83-92.

The establishment of permanent quadrats in pastureland at Swanson. 1969 (in press).

Examination of the permanent quadrats on Little Barrier Island. Tane 8: 106-109.

B E E V E R , R . E . ; 1969 P A R R I S , Barbara S; B E E V E R , Jessica E .

B E L L I N G H A M . N . O . 1954 P E R C Y , C . A .

E N G L I S H , D . A . 1964 B R O C K , J . L .

M E R T O N , D . V . 1968

P A R R I S , Barbara S; 1968 K E E N , Lynn R.

P A R R I S , Barbara S; R A E , W.J.

P E R C Y , C . A . 1958

T A B L E 1. Species found in Quadrat 2 arranged in order of density.

Density Frequency Poles j

A Sapling

B 5S

C St

A riplin;

B C Seedlings

Pseudopanax lessonii 0.05 4 5 rare

Macropiper excelsum 0.02 8 2 rare

Dysoxylon spectabile X X locally abundant

Numbers in each class as a percentage of the total number. 100

X = not recorded

T A B L E 2. Species found in Quadrat 3 arranged in order of density.

Density Frequency Poles S;

A ipling;

B C Stri

A plings B C

Seedlings

Dysoxylon spectabile 1.37 92 4 3 1 118 10 1 abundant

Pseudopanax lessonii 0.67 84 65 2 sparse

Coprosma macrocarpa 0.32 68 26 6 none

Macropiper excelsum 0.27 56 13 2 7 5 locally abundant

Brachyglottis repanda 0.06 20 2 4 sparse

Melicytus ramiflorus 0.02 8 1 1 sparse

Geniostoma ligustrifolium 0.02 8 1 1 none

Metrosideros excelsa 0.01 4 1 none

Coprosma rhamnoides 0.01 4 1 one

Knightia excelsa X X two

Numbers in each class as a percentage of the total number 2.16 6.47 2.16 0.36 79.78 8.66 0.36

X - not recorded

T A B L E 3. Species found in Quadrat 4 arranged in order of density 1

Density Frequency Poles Sa

A pling

B C Str

A plings

B C Seedlings

Macropiper excelsum 0.95 92 81 14 common

Pseudopanax lessonii 0.61 76 55 6 common

Gymnelaea apetala 0.28 52 28 common

Dysoxylon spectabile 0.21 52 3 1 1 2 13 1 common

Brachyglettis repanda 0.18 52 7 2 7 2 common

Coprosma macrocarpa 0.18 48 9 9 sparse

Hedycarya arborea 0.16 44 16 common

Coryaocarpus laevigatus 0.12 28 12 sparse

Melicope ternata 0.05 16 5 common

Melicytus ramiflorus 0.04 12 1 1 1 1 sparse

Neopanax arboreum 0.03 12 3 sparse

Table 3 continued

Density Frequency Poles Sap

A dings

B C Strij

A >lings B C

Seedlings

Vitex lucens 0.02 8 2 sparse

Carmichealia cunninghamii 0.02 8 2 none

Ploachonella novo-zelandica 0.01 4 1 sparse

Entelea arborescens 0.01 4 1 one

Geniostoma ligustrifolium 0.01 4 1 one

Knightia excelsa 0.01 4 1 none

Numbers in each class as a percentage of the total number 1.38 2.76 1.38 1.03 80.96 12.45 0