18.

BRYOPHYTE AND LICHEN ECOLOGY AT SWANSON. - T.C. Chambers.

H i s t o r y of the Swanson Area: This i s f u l l y discussed i n an a r t i c l e by

C.B. Trevarthen i n t h i s volume. To save unnecessary r e p e t i t i o n readers are r e f e r r e d to h i s maps. E c o l o g i c a l Nomenclature;

R.G. Robbins was the f i r s t i n v e s t i g a t o r i n N.Z. to employ q u a n t i t a t i v e as w e l l as q u a l i t a t i v e methods i n the study of our Bryophyte communities. In Europe and U.S.A. bryophytes and l i c h e n s have been in c l u d e d i n many i n v e s t i g a t i o n s on higher p l a n t comm­u n i t i e s but they have been s e r i o u s l y neglected i n N.Z. Various terms have been used by overseas i n v e s t i g a t o r s of bryophyte communities, e.g. ' s o c i e t i e s ' , ' c l a n s ' , ' c o l o n i e s ' , ' f a m i l i e s ' , ' a s s o c i a t i o n s ' , 1 a s s o c -i u l e s ' etc. Professor Lippmaa ( 1 9 3 4 - 3 5 ) introduced a new a p p r o a c h — the u n i s t r a t a l a s s o c i a t i o n concept i n which the l a y e r s (synusiae) are regarded as separate a s s o c i a t i o n s . At the Amsterdam B o t a n i c a l Cong­ress Du R i e t z and Gams proposed to name these "one-layered a s s o c i a t i o n s " - Unions - and Lippmaa accepted t h i s . The term Union admirably f i t s the bryophyte component of a p l a n t community. Sirgo (Estonia) f i r s t used t h i s term and i t has since been more e x t e n s i v e l y used by Cain and h i s a ssociated i n U.S.A. and by Robbins and B u t l e r * i n N.Z.

In the present i n v e s t i g a t i o n a Union has been looked upon as a u n i s t r a t a l community dominated by one or more species having high cover and high frequency and g e n e r a l l y being of s i m i l a r or r e l a t e d l i f e form. Methods;

The s i z e of the quadrat used i n the analyses was 0.1 sq. metres, which i s the most usual s i z e i n b r y o - e c o l o g i c a l i n v e s t i g a t i o n s . An oblong quadrat was used 20 cms. X 50 cms., which Robbins found was s l i g h t l y b e t t e r than the square f o r some of h i s work at Woodhill. AS the bryophyte community at Swanson i s f a i r l y homogeneous, due l a r g e l y to the vege t a t i v e r e p r o d u c t i o n of the moss p l a n t s , i t i s l i k e l y that the oblong quadrat would get a b e t t e r sample. Probably, any shape would be e f f i c i e n t p r o v i d i n g s u f f i c i e n t quadrats were s t u d i e d .

In the f i e l d work a species l i s t f o r the quadrat and the coverage c l a s s e s were noted as f o l l o w s :

Class X Species covering l e s s than 1% of quadrat. If 1 ti ti 1 to 5% " It 2 tt ti 5 to 25% " II 3 ti H 25 to 50% " II 4 ti ti 50 to 75$ " II 5 it it 75 to100% "

AS the quadrats were small accurate estimates of coverage were p o s s i b l e . Prom the species l i s t f o r each quadrat, besides noting coverage, frequency was a l s o c a l c u l a t e d .

The bryophytes i n the f i r s t two phanerogamic communities discussed were i n v e s t i g a t e d from both q u a l i t a t i v e and q u a n t i t a t i v e aspects. The other communities mentioned have only been considered q u a l i t a t i v e l y . 1. Leptospermum Associes on eastern s i d e of Stream:

The average height of the scrub i s about 18 f e e t and i s never l e s s than 10 f e e t , Leptospermum scoparium i s dominant with fewer p l a n t s of L. e r i c o i d e s . The most s t r i k i n g f e a t u r e of t h i s scrub i s the almost complete t e r r e s ­t r i a l carpet o f bryophytes and l i c h e n s . A s e r i e s of quadrats was made i n t h i s area and the r e s u l t s analysed.*" Dicranoloma b i l l a r d i e r i i s the dominant moss and from both s t a t i s t i c a l r e s u l t s and f i e l d observations t h i s forms a Dicranoloma b i l l a r d i e r i U n i o n — t h e major t e r r e s t r i a l bryo­phyte a s s o c i a t i o n i n the area. Very o f t e n the Dicranoloma i s assoc­i a t e d with l i c h e n s of the genus Cladonia, p a r t i c u l a r l y with 0 . f l o e r k -iana and t h i s forms the Dicranoloma b i l l a r d i e r i - Cladonia Union. In

* N.J. B u t l e r (Wellington) i n t e r p r e t e d the Union as "a homogeneous u n i s t r a t a l community with a s p e c i a l h a b i t a t preference and dominated by one or more species of the same l i f e form." * See Table I.

19.

the s m a l l hollow on the northern side of the hut, milk moss (Leucobryum candidum) plays an important part i n the bryophyte community, forming a Dicranoloma b i l l a r d i e r i - Leucobryum Union. The t e r r e s t r i a l mosses here do not form such a complete carpet as i n the p r e v i o u s l y mentioned Unions. In Great B r i t a i n a c l o s e l y r e l a t e d species, L. glaucum, i s an i n d i c a t o r of a c i d c o n d i t i o n s . I t i s p o s s i b l e that L. candidum i n N.Z. grows i n a s i m i l a r h a b i t a t . I f t h i s i s true i t might p a r t l y account f o r the poorer bryophyte cover i n t h i s area. Another f a c t o r which must be taken i n t o c o n s i d e r a t i o n i s that a number of d i c o t , shrubs have become e s t a b l i s h e d and the l e a f f a l l from these appears to r e t a r d bryophyte growth.

In the Dicranoloma - Cladonia Union the f o l l o w i n g species are l o c a l ly-dominant i n small patches and thus form f a c i e s of the Union: Ptychomnion a c i c u l a r e , Thuidium furfurosum, Hypnum cupressiforme Leucobryum >'and:,;: 11 m, Cladonia (species b ) . ~ Ptychomnion a c i c u l a r e i s more abundant i n the t e a - t r e e near the stream than around the hut. I t seems 'unlikely that t h i s i s caused by moisture c o n d i t i o n s , as i n other parts of the Waitakere Ranges t h i s moss i s often abundant i n ridge veg­e t a t i o n and probably i n these parts forms a true Ptychomnion a c i c u l a r e Union.

There seems to be l i t t l e doubt that the t e r r e s t r i a l bryophytes f u n c t i o n as a seed bed f o r regeneration of f o r e s t t r e e s . The sponge­l i k e nature of the moss carpet makes i t a great p o t e n t i a l water storage organ of the f o r e s t . 'This i s , no doubt, a b i g f a c t o r i n a s s i s t i n g the establishment of these seedlings which l a t e r i n the succession of the f o r e s t w i l l dominate the area. The f o l l o w i n g species are common i n the Dicranoloma - Cladonia Union: 1• Agathis a u s t r a l i s 2. Dacrydium cupressinum 3. P h y l l o c l a d u s trichomanoides. 4. Podoparous_totara.

bis r a m i f l o r u s . ligustrifolium.

5. M e i i c y t i s 6. Gen 3. op torn a 7• S u t t o n i a salicina. 8. S u t t o n i a a u s t r a l i s .

9. K n i g h t i a e x c e l s a . 10. O l e a r i a 1 f u r f u r a c e a . 11. 0 . cunninghamii.

•e um. 1 2. Pomaderris _e i 13• No^hopar^x aro^r 14. Pseudopanax c r a s s i f o l i u m . 1 5. Coprosma see,,

Besides those p u l a r l y BJLej3jraum hamii, Paesia 0

.ants, ferns are quite numerous s c a t t e r e d ^ p a r t i c -B. f r a s e r i . G l e i c h e n i a c i r c i n a t a , G_, cunnjng-

tendo i s a l s o The brans i t i o n from t h i s scrub to the grassy area around

the hut i s i n t e r e s t i n g (see transect),* . The Dicranoloma g r a d u a l l y gives way to Hypnum l e s s shaded par' gives way to gri

cupressiforme and Thuidium furfurosum which i n the f l e x u s which i n turn gives way to Campylopus i n t .

i ! I

f

Campylopus-grass

Campylopus i n t r o f l e x u s

B e l t t r a n s e c t showing t r a n s i t i o n from Leptospermum scrub to grassy c l e a r i n g i n f r o n t of hut.

Dicranoloma* Hypnum-Thuidium.

Open c l e a r i n g Dicranoloma b i l l a r d i e r i .

D i c r a n ­oloma . Teatree scrub

high. 10

Hypnum cupressiforme. Thuidium furfurosum. Campylopus i n t r o f l e x u s . Grasses. 3are ground.

20.

2. leptospermum associes on trio ridge at the southern end cf the property.

In contrast wi tia that around tae hut t h i s veget­a t i o n almost completely l a c k s a bryophyte f l o r a . The Leptospermum can:py i s very open. There i s a very dense herbaceous l a y e r made up mainly of Schoenus tendo, G l e i c h e n i a cunninghamii and G. c i r c i n a t a w ith scattered clumps of Gahnia xanthocarpa and Astelia t r i n e r v i a . Beneath t h i s few bryophytes can survive and probably the regeneration of phanerogams i s retarded. The moss Sematophyllum amoenum i s occasional on dead twigs, bases : f trunks and on the ground. a few small plants c f Dicranoloma are also present mainly at tae edges of t r a c k s .

a comparison of the bryophytes i n the tea-tree around the hut with those on the ridge boars out the f o l l o w i n g statement by P.W. Richards : "Owing te t h e i r small s i z e and r e s t r i c t e d growth mosses are always at a great disadvantage i n competition w i t h v a s c u l a r plants and i t i s roughly true to say that any f a c t o r which checks growth of herbaceous plants favours moss veg e t a t i o n . " I t also bears cut another of h i s statements: "That such small and comparatively slow growing plants should te able te produce important changes i n t h e i r h a b i t a t s i s mainly due to the f a c t that they are s o c i a l organ­isms and only those species w i t h well-marked s o c i a l habit have per­c e p t i b l e r e a c t i o n s . " . 3. Leptospermum-Kauri associes on the northern end c f the ridge : In complete contrast w i t h Leptospermum at the southern end of the ridge t h i s area has a bryophyte community i n some respects very sim­i l a r to that found around the hut. I t possesses an almost complete carpet of bryophytes and l i c h e n s r i g h t to the bases of the tree trunks. The k a u r i s are at the advanced r i c k e r stage and the Leptospermum i s gradually being e l i m i n a t e d . P h y l l o c l a d u s , Olearia and K n i g h t i a are a l l abundant. Together with these there i s a large w e l l - e s t a b l i s h e d population cf the a l i e n Hakea. Schoenus tendo, while f a i r l y abun­dant, i s not s u c c e s s f u l i n crowding cut tae bryophytes as on the southern end of the r i d g e .

The main t e r r e s t r i a l bryophyte community i s the Dicranoloma b i l l a r d i e r i Union. In places large cushions of Dicranoloma over 1 f t . i n depth p o s s i b l y mark the s i t s of old burnt or f a l l e n logs and stumps but there are no traces cf r o t t e n wood beneath the cush­ions to prove t h i s point. In several l o c a l i s e d patches there are large white areas where Cladonia f l o e r k i a n a has become the sole dom­inant and i n other areas i t forms a Dicraneloma-Claicnia Union l i k e that i n the Leptospermum around the nut. (see Table I I ) .

The l i t t e r on the f o r e s t f l o o r i s mainly Kauri leaves and twigs but under low growing shrubs such as Olearia furfuracea there i s more slow decaying l e a f l i t t e r ana no bryophytes or l i c h e n s at a l l . While the e x t r a shade may have some i n f l u e n c e , the presence of slew decaying leaves and p o s s i b l y t h e i r t o x i c e f f e c t as they decomposed, a l l helped to e l i m i n a t e the bryophytes although the l i s t point needs f u r t h e r i n v e s t i g a t i o n .

There are numerous seedlings growing i n the P i crane Jorna­Cladonia Union. These include Agathis a u s t r a l i s , Phyllocladus trichomanoides, Leucopogon f a s c i c u l a r i s , Olearia cunninghamii, Senecio k i r k i i , K n i g h t i a excelsa anei Hakea a c i c u l a r i s . The average depth of the bryophyte carpet i s . s i x inches - on the average 3 inches deeper than that around the hut.

an i n v e s t i g a t i o n cf an o l d and now l i t t l e - u s e d track runn­ing through t h i s area showed that the Cladonia species cannot t o l ­erate wear or hard trodden s o i l . The only species present i n any quantity are reduced forms of Leucobryum candidum and Dicranoloma b i l l a r d i e r i . 4• Mature Kaur i Po r e s t :

Here t e r r e s t r i a l bryophytes only occur i n l o c a l i s e d and g e n e r a l l y pure patches of t e n 2-3 feet across, among the mosses Mniodendron comosum, T a y l o r i a sop, Sematophyllum

Richards - "Bryophyte Ecology" i n manual of Bryology, 1932.

21 .

amo e mua, a o an t h o c I a I 1 urn extenuatum and Dicranoloma b i l l a r d i e r i occur i a t h i s manner, Growing over loose undecayed l i t t e r the e p a t i c Metzgeria, hamata occurs i n patches, while on bare s o i l L e p i d o z i a often forms a close mat. E p i p h y t i c bryophytes become more important here. Semat:phyilum amoenum i s common at the bases of the trunks, also Macromitrium i s o c c a s i o n a l l y present but t h i s l a t t e r , together with Dicnemon calycinum i s commoner higher up the trunk. On the Kauri bark F r u l l a n i a a t e r i n a var. epida and Physananthus anguiformis are very common, as i s also the algae Trentepohlia which Terms charac­t e r i s t i c reddish t u f t s , while Buzzania adnexa together with stunted Dicranoloma b i l l a r d i e r i are often present near the bases of the trunks 5. Podocarp-Dicotyledonous f o r e s t on the slopes:

The f o r e s t on the ridge i s predominantly K a u r i . On l e a v i n g the ridge there i s an immediate change i n both the f o r e s t and the associated cryptogamic vegetation. In places podocarps l i k e Rimu and Miro dominate but over most of the elope tae d i c o t . K n i g h t i a excelsa (Rewa Rewa) i s the dominant tree while a number of very large Ratas (Metrosideros robusta are also present i n s c a t t e r e d patches. Many cf the K n i g h t i a trees have clean smooth trunks but others support numerous cushions of e p i ­phytic bryophytes often together w i t h the orchid Bulbophyllum pygmaeum. Where Blechnum f r a s e r i i s present t e r r e s t r i a l bryophytes are absent as t h i s miniature t r e e - f e r n forms a dense canopy about 1 f t . above the s o i l l e v e l .

The whole f o r e s t i s c h a r a c t e r i s e d by the steep slope, heavy l e a f f a l l , dense undergrowth, wide v a r i e t y of species of shrubs, ferns and l i a n e s and the low l i g h t i n t e n s i t y . Consequently bryophytes are scattered i n discontinuous patches and a large number of species are e p i p h y t i c . a l s o , on passing from the ridge down to the stream there i s a n o t i c e a b l e general increase i n the bryophytes both epiphytic and t e r r e s t r i a l . a number cf species i n t h i s area are growing on the tangle of roots of t r e e s , others are v=ry common on lead trunks and f a l l e n branches, e.g. Sematophyilum amoenum, Dicranoloma m e n z i e s i i . The bases of the tree trunks often have a c h a r a c t e r i s t i c bryophyte f l o r a , mainly Sematophyllum amoenum, Leucobryum candidum, Sciadocladus m e n z i e s i i and Dicranoloma b i l l a r d i e r i . Clay banks are common on t h i s steep slope and ere u s u a l l y covered with Hepatics such as L e p i d o z i a c a p i l l i g e r a , B a l a n t i o p s i s d i p l o p h y l l a , Hymenophytun and P a l l a v i c i n i a as w e l l us R i c c a r d i a i n the wetter g u l l e y s .

f u r t h e r down tae slope tree ferns - Cyatnea dealbata and 0. medullaris - are more abundant and on the old f l o o d p l a i n s c r o l l s of the stream there are pure stands c f the tree f e r n Dicksonia squarrosa. In tae l a t t e r the low l i g h t i n t e n s i t y an! the numerous dead fronds exclude bryophytes w i t h the exception cf the e p i p h y t i c Hymenodon piliferus on the tree f e r n trunks. In the area above the stream banks c e r t a i n bryophytes are very abundant, e.g. Qamptcch ete arbuscula and S c h i s t o c n i l a , Hypnodendrum arcuatum, Hypo pterygium, Mniodendron and Symphogyna. 6. Stream and Stream Bank Communities;

There i s not space i n the present paper to discuss these communities i n d e t a i l . A l l species found are l i s t e d i n the annotated species l i s t accompanying t h i s a r t i c l e . a l l names of v a s c u l a r cryptogams and phanerogams are according to Cheeseman's 'Manual of N.Z. F l o r a ' , 1925.

SUMMARY. 1. Forty-one messes and twenty-five hepatics have been d e f i n i t e l y recorded from the area w i t h a f u r t h e r nineteen mosses and f i v e hepat­i c s d o u b t f u l l y present. 2. B r y o e c o l o g i c a l terminology has been b r i e f l y discussed and the term Union has been used f o r the d e s c r i p t i o n cf the bryophyte comm­u n i t i e s . 3. An attempt has been made to apply elementary s t a t i s t i c a l a n a l y s i s te the t e r r e s t r i a l bryophytes i n the Leptospermum and Leptospermum-Kauri associes.

Table I. 25 0.1 sq. metre Quadrats - Leptospermum associes between Swanson Hut ana stream.

CO ra ra o

i ra Ok M

1 . M ra o g Hi

ra ra ra o

Dicranoloma b i l l a r d i e r i Leucobryum candidum Ptychomnion a c i c u l a r e Hypnum cupressiforme Thuidium furfurosum Campylopus i n t r o f l e x u s C. clavatus Sematophyllum amoenum Bryum truncorum Mniodendron comosum Lep i d o z i a a l l i s o n i i L. c a p i l l i g e r a B a l a n t i o p s i s d i p l o p h y l l a Cladonia floerkeana Cladonia b. Lichen c. Cladonia d.

No. of species

1 2 3 4 5 6 7 8 9 10

5 5 1 2 1 2 5 - 1 -

x - -- - 3

5 -

11 12 15 14 15 16 17 18 19 20 Z1 22 23 24 25 3 5 5 5 1 2 2 4 2 - 4 2 1 1 5

x 4

Frequency Coverage

1 3

x x

1

X 3

1

- 4 4 2 -

x - - - 1 X

1 -x -1 -

1

X X X - - - - - - - - - - X

- - - - - - 1 X

2 - 3 1 - - - - x 1 X X

x 1 2 -

1 2 X 1 -X

X X

X - - 1 -- 2 2 - -

- X - X - 1

1 -- 1

X -

3 1 3 3 6 4 4 3 7 3 4 2 3 2 3 6 4 4 6 Average No. of Species per Quadrat = 3 . 6

3 4 4 6 1

Table I I . Dicranoloma b i l l a r d i e r i Leucobryum candidum Ptychomnion a c i c u l a r e Hypnum cupressiforme Thuidium furfurosum T a y l o r i a octoblepharis L e p i d o z i a Cladonia floerkeana Cladonia b. Bare ground

No. of species.

25 0.1 sq. 1 x

metre Quadrats - P i c k e r A g a t h i s , north end of Ridge, Swanson. - 3 5 5 3 3 3 2 5 4 5 4 5 2 X - 5 - 4 4 1 2 2 > _ x _ _ i - 3 2 - - - - 1 - - - - - - - - - - -

- 3 1 1

2 3 _ _ _ _ 1 1

2 1

4 1 x

2 -

x 1 -- 1

X X 1

X 2

2 4 3 1 1 1 1 2 2 1 1 Average No. of species

1 3 2 4 2 2 per Quadrat = 2 .

4 3 3

16% 36% 24%

20%

48% 36% 16%

40% 20%

51%

15%

54%

11%

4. Only the important t e r r e s t r i a l l i c h e n s have been included i n the i n v e s t i g a t i o n . 5. The e p i p h y t i c and stream bank bryophytes have only been b r i e f l y mentioned and f u r t h e r p a r t i c u l a r s of these species are included i n the annotated species l i s t . 6. The reasons f o r the great d i f f e r e n c e s i n the bryophyte component i n the d i f f e r e n t areas c f Leptospermum are d i f f i c u l t to e x p l a i n and d e t a i l e d i n v e s t i g a t i o n s i n other s i m i l a r areas i n the Waitakere Ranges are necessary. At present i t seems probable that the i n t e r f e r e n c e by man, p a r t i c u l a r l y past f i r e s , h i s introduced animals and the presence of the a l i e n Hakea, as w e l l as the surface c o n f i g u r a t i o n c f the area, are a l l c o n t r i b u t i n g f a c t o r s te the marked d i f f e r e n c e s , REFERENCES. Billings & Drew, Cain, Cain & Penfound, Cain & Sharp - 1936-38 American Midland N a t u r a l i s t , Vols. 17, 19, 20. Dixon, H.W. - 1914-28. Studies i n the Bryology of N.Z. B u l l , of N.Z. I n s t . , No. 3, p i s . 1-6. Hodgson, E.A, Hepaticae - P t s . I*VI, 1942-49. Trans. R c y l . Sec. N.Z, C l a s s i f i c a t i o n of N.Z. Hepaticae. Tuatara, V o l . I I I , Nos 1-2. Richards, P.W. 1928. The Bryophyte Communities c f a K i l l a r n e y Oakwood. Annales B r y o l o g i c i . V o l . XI. Robbins, E.G. 1949. Bryophyte Ecology at Woodhill. M.Sc, t h e s i s , A.U.C. L i b r a r y . S i r g o , V. 1935. Plant Unions of the Swamps at the mouth of the R i v e r Emajcgi. E n g l i s h summary. Acta I n s t i t u t e et H o r t j . Botanica U n i v e r s t a t i c T a r t u e n s i s . V o l . V. 1936-37. Verdoorn, P. 1932. "Manual of Bryology." A l l names of Vascular Cryptogams and Phanerogams are according te Cheeseman's "Manual c f the N.Z. f l o r a " 1925.

^nalyasis- of Table- I A n a l y s i s of Table I I . Leptospermum"associes. R i c k e r K a u r i .

'̂ 1 00% ! Coverage Frequency Coverage Frequency

Dicranoloma b i l l a r d i e r i . Ptychomnion a c i c u l a r e . Cladonia floerkeana. Cladonia 'b*

Cladonia 1 c ' Thuidium furfurosum L e p i d o z i a a l l i s o n i Leucobryum candidum. Lichen c.

Frequency Number of quadrats i n which g sp. occurs T o t a l number of Quadrate

Coverage T o t a l coverage of a species T o t a l p o s s i b l e