Lichenologist 35(2): 137–146 (2003)
doi:10.1016/S0024-2829(03)00017-3
The lichen genus Ramalina Ach. (Ramalinaceae) on the outlying
islands of the New Zealand geographic area
J. M. BANNISTER and D. J. BLANCHON
Abstract: The diversity of species of Ramalina occurring on the outlying islands of the New Zealand
geographic area is linked to their methods of dispersal and the origin and principal climatic features
of the islands themselves. It appears that species of Ramalina have reached these islands by
transoceanic, wind-borne dispersal of ascospores and soredia, not necessarily in the direction of the
prevailing winds. Species have become established on the islands only if both climatic and habitat
requirements have been met.
2003 The British Lichen Society. Published by Elsevier Science Ltd. All rights reserved.
Key words: species of Ramalina, New Zealand geographic area, emergent oceanic islands,
wind-borne dispersal.
Introduction
The genus Ramalina in Australia was revised
by Stevens (1987), but the occurrence
of species on Lord Howe, Norfolk and
Macquarie Islands was not documented.
Subsequently the species occurring on
Norfolk Island were documented by Elix
et al. (1992). Blanchon et al. (1996) revised
the genus in New Zealand with distribution
being based on herbarium collections. Recently the distribution of species of Ramalina on the main islands of New Zealand
has been recorded and mapped more
intensively (P. Bannister, J. M. Bannister &
D. J. Blanchon, unpublished).
The study reported here includes the
species of Ramalina occurring on the outlying islands of New Zealand’s geographic
area (Fig. 1): the Kermadec Islands, the
Chatham Islands, the Bounty Islands, the
Snares Islands, the Antipodes and Auckland
J. M. Bannister: Department of Botany, University of
Otago, P.O. Box 56, Dunedin, New Zealand.
D. J. Blanchon: Resource Management Research
Group, School of Landscape and Plant Science,
UNITEC, Private Bag 92025, Auckland, New
Zealand.
0024-2829/03/020137+10 $30.00/0
Islands and Campbell Island. This study
also includes Norfolk Island, Lord Howe
Island and Macquarie Island. Although they
are Australian territory, biogeographically
they have very close links to New Zealand
(Wardle, 1978; Orchard 1994). In terms of
climate, these islands range from subtropical
to subantarctic. The Snares and Bounty
Islands consist of basement rock (granite)
and are part of the original New Zealand
continental landmass (Turnbull 1999),
while the other islands have arisen in isolation, by volcanic or tectonic activity. The
presence of various species of Ramalina on
the emergent islands implies both successful
dispersal from other islands, or from mainland sites in New Zealand or Australia, and
climatic conditions that allow establishment
of the thallus and its subsequent growth and
reproduction. The distribution of species on
these geologically recent islands provides
an interesting case study of long-distance
dispersal.
Material and Methods
Synoptic climatic and other information, summarized
in Table 1, was collated from a variety of sources (De
Lisle 1965; Fineran 1969; Elix & Streimann 1989;
2003 The British Lichen Society. Published by Elsevier Science Ltd. All rights reserved.
138
THE LICHENOLOGIST
Vol. 35
30°N
Norfolk Id.
Kermadec Is.
Three Kings Is.
Lord Howe Id.
Australia
North Island
Sydney
Auckland
Tasman Sea
40°
Wellington
South Island
Christchurch
Chatham Is.
Dunedin
Stewart Island
Tasmania
Snares Is.
Bounty Is.
Antipodes Is.
50°
Auckland Is.
Campbell Id.
Macquarie Id.
Pacific
Ocean
180°E
F. 1. The New Zealand archipelago and surrounding islands.
Selkirk et al. 1990; Wardle 1991; Kantvilas & Seppelt
1992; Archer & Elix 1994; Atkinson 1996; O’Connor
1999; Turnbull 1999; West & Rance 1999; Sykes
et al. 2000; and others) and the records of the
National Institute of Water and Atmospheric Research
(NIWA).
Literature reports of species of Ramalina have
been checked and only those that have been
confirmed from herbarium specimens are included in
this study. Collections were borrowed from the following herbaria: ADT, AK, AKU, BM, CANB,
CANU, CHR, FH, HO, MEL, MSC, O, OTA,
WELT and the private collection of P. N. Johnson
(Dunedin).
Nomenclature is based on the taxonomic revisions
of the genus in Australia (Stevens 1987) and New
Zealand (Blanchon et al. 1996). Ramalina subfraxinea
var. leoidea (Nyl.) G. N. Stevens and R. nervulosa var.
luciae (Molho et al.) G. N. Stevens are currently re-
ferred to as R. leoidea (Nyl.) Nyl. and R. luciae Molho
et al. in the Australian checklist (McCarthy 2002). Two
new species have been described since these revisions,
R. stevensiae Elix (Elix et al. 1991) and R. meridionalis
Blanchon & Bannister (Blanchon & Bannister,
2002).
The accepted names of Ramalina species in the study
area are as follows: R. australiensis Nyl., R. canariensis
J. Steiner, R. celastri (Spreng.) Krog & Swinscow,
R. erumpens Blanchon, Braggins & A. Stewart bis,
R. exiguella Stirt., R. geniculata Hook. f. & Taylor,
R. inflata (Hook. f. & Taylor) Hook. f. & Taylor,
R. leoidea (Nyl.) Nyl. (syn.: R. subfraxinea var. leoidea
(Nyl.) G. N. Stevens), R. luciae Molho, Bodo, W. L.
Culb. & C. F. Culb. [syn.: R. nervulosa var. luciae
(Molho et al.) G. N. Stevens], R. meridionalis Blanchon
& Bannister, R. cf. microspora Kremp., R. pacifica
Asah., R. peruviana Ach., R. stevensiae Elix and
R. unilateralis F. Wilson.
2003
Ramalina on o#shore islands of NZ—Bannister & Blanchon
139
T 1. The outlying islands of New Zealand showing latitude, area, age, maximum elevation (ME), mean annual
temperature (MAT), mean annual rainfall (MAR) and total number of vascular plant taxa (VAS)
Island
Latitude
Area (km2)
Age (Ma)
ME (m)
MAT ((C)
MAR (mm)
VAS
Norfolk
Kermadecs
Lord Howe
Chathams
Bounty
Snares
Antipodes
Auckland
Campbell
Macquarie
28(58#S
29(30#S
31(33#S
44(00#S
47(05#S
48(01#S
49(41#S
50(30#S
52(35#S
54(30#S
35
33
17
950
1·3
2·6
21
625
113
128
3
1·6
7
2·5
–
–
1·05
10
6
1·7
316
518
875
287
70
130
366
668
569
434
18·5
18·9
19
11
–
9·8*
–
8·5
6
4·5
1313
1500
1675
800
–
1482*
–
1520–2160
1400
895
445
265
459
472
0
21
72
233
212
45
(–) No information available.
*Based on limited information.
Study area
Norfolk Island
Norfolk Island is situated on the submarine Norfolk
Ridge which extends from New Zealand to New
Caledonia. It lies 1610 km NE of Sydney (Australia),
1100 km NNW of New Zealand and 670 km S of New
Caledonia. Volcanic in origin, the island has been
emergent since the late Pliocene. The climate is subtropical, rainfall occurs throughout the year but can be
variable and short droughts may occur. Humidity is
moderate, RH 72–81%, and the prevailing winds are
from the west to south-west in winter, and from the
north-east to south-east in the summer.
The vascular flora is similar to that of Lord Howe
Island and is more closely related to New Zealand than
Australia (Orchard 1994). The vegetation consists
of remnant rainforest, open Araucaria heterophylla
(Salisb.) Franco woodland, pasture with isolated trees
or small stands of Araucaria and weedy forest of Psidium
littorale Raddi and Olea africana Mill. (Elix & Streimann
1989).
Kermadec Islands
The Kermadec Islands, 976 km NE of New
Zealand, rise from a volcanically active submarine
ridge, the Kermadec Ridge, that extends NE from the
Taupo Volcanic Zone in the North Island of New
Zealand. This is part of the subduction zone between
the Australian and Pacific tectonic plates and two
islands, Raoul (Sunday Island) and Curtis, remain
actively volcanic. The climate is subtropical, with a
mean average temperature of 18·9(C. In winter the
winds and ocean currents are from the south-west,
while in summer the prevailing winds and currents are
from the north-east (Sykes et al. 2000).
There are dry forests at low altitude (below 244 m)
and wet forests at higher altitudes and in more moist
habitats. The dominant tree in both forest types is
Metrosideros kermadecensis W. R. B. Oliver. There are
also areas of coastal scrub or low forest. The vascular
flora is more closely related to that in New Zealand
than it is to Norfolk Island and Lord Howe Island
(Wardle 1991; Sykes et al. 2000).
Lord Howe Island
Lord Howe Island is situated on the Lord Howe
Rise, an undersea volcanic plateau extending from New
Zealand to a point between Queensland and New
Caledonia. The island is the emergent part of a sea
mount which is a remnant of a large shield volcano.
Lord Howe Island has been above sea level since the
late Miocene. It lies 700 km NE of Sydney and
1250 km NW of New Zealand. The climate is subtropical and humidity is moderate (RH 70–78%); prevailing
winds in winter are westerlies, while in summer they
come from the east.
The vascular flora is similar to that of Norfolk Island
and, like that flora, is more closely related to New
Zealand than Australia (Orchard 1994). Three types of
forest are found on the island: lowland exposed areas
with a dry Drypetes/Cryptocarya forest with thickets of
Howea spp.; lowland sheltered forests with Drimys
howeana F. Muell., Cleistocalyx fullageri (F. Muell.)
Merrill & Perry, Atractocarpus stipularis (F. Muell.)
Puttock ex P. S. Green and Chionanthus quadristaminea
F. Muell.; and, at higher altitudes, a cloud forest of
Hedyscepe canterburyana H. Wendl. & Drude, Lepidorrachis mooreana (H. Wendl. & Drude) Burret,
Dracophyllum fitzgeraldii F. Muell. and Negria rhabdothamnoides F. Muell. occurs (Archer & Elix 1994;
Orchard 1994).
Chatham Islands
The Chatham Islands are situated on the Chatham
Rise, part of the Campbell Plateau, a submerged portion of the New Zealand subcontinental landmass. The
islands, 870 km E of Christchurch, have been formed
by volcanic eruptions over a long period of time,
accompanied by uplift and changes in sea level. The
present landmass has been emergent for at least 2·5
million years. Summer droughts can occur, but there
140
THE LICHENOLOGIST
Vol. 35
are frequent rain showers and spray-laden gales. Conditions are often overcast with high humidity, and frosts
are infrequent. The prevailing winds are from the
south-west.
The original broad-leaved forest has been extensively
fragmented by agriculture. The most abundant tree is
Corynocarpus laevigata J. R. Forst. and G. Forst., but
many other broad-leaved trees are present. Tree-heath,
dominated by Dracophyllum arboreum Cockayne, occurs
on drier peats, and scrub and fern-dominated communities occurs in coastal areas, upland sites and on peat
domes. The islands lie near the subtropical convergence
and although the climatic zone is cool-temperate, some
of the vascular plants show a$nities with warmtemperate species (Wardle 1991; Atkinson 1996).
on Campbell Island, these volcanoes were eroded by
glaciation occurring from 1 million to 15 000 years ago.
The temperatures are cool and equable, and while
levels of sunshine are low, there are more hours of
bright sunshine than on Campbell Island (estimated
960 h). Humidity is high with frequent rain (over 300
days a year). The prevailing strong winds are westerly
and north-westerly (De Lisle 1965).
The vegetation shows a distinct altitudinal zonation,
with tussock grassland, forests of Olearia lyallii, dwarf
forest of Metrosideros umbellata Cav., subalpine shrubland (Cassinia and Dracophyllum spp.) with herb moor
and an alpine region dominated by mosses. The plant
species are closely related to those in New Zealand
(Wardle 1991; West & Rance 1999).
Bounty Islands
Campbell Island
Situated on the Campbell Plateau, 624 km E of
the southernmost point on the South Island of New
Zealand, these small granite islands are part of the
original New Zealand continental landmass. They are
drenched by sea spray and support dense populations of
seals and sea birds. There are no available climatic data,
but cloudy, overcast conditions can be surmised with
prevailing winds from the south-west.
The Snares
These small, granite islands are part of the New
Zealand continental landmass, situated 209 km S of
New Zealand. Little climatic information is available,
but it appears that the climate is comparable to that of
South West Cape on Stewart Island, with a high
rainfall, over 200 rain days per year, and predominantly
westerly winds (NIWA 2002, unpublished data).
Tree-heath, comprising three woody species, Olearia
lyallii Hook. f., Brachyglottis stewartiae (J. B Armstr.) B.
Nordenstam and Hebe elliptica Pennell, covers most of
Main Island, with tussock grassland in more exposed
areas (Wardle 1991; West & Rance 1999).
Antipodes Islands
The Antipodes Islands are situated on the Campbell
Plateau 872 km SE of New Zealand. They are volcanic
in origin, and while detailed climatic information is not
available, it has been suggested that the rainfall is
probably only half that of the Auckland Islands
(O’Connor 1999).
The islands are peat-covered and there is no forest,
the vegetation consisting of tussock grasslands with
patches of shrubs and fern gullies (West & Rance
1999).
Auckland Islands
The Auckland Islands are situated on the Campbell
Plateau 465 km S of New Zealand and are the eroded
remnants of two shield volcanoes. Volcanic activity
took place from about 20 to 10 million years ago, and as
Campbell Island is situated on the Campbell Plateau, 700 km S of New Zealand. The Auckland Islands
are 300 km to the north-west and Macquarie Island is
700 km to the south-west. Campbell Island is a glacially
eroded remnant of a shield volcano that was active 11
to 6 million years ago. The climate is cloudy with
uniformly cool temperatures and a narrow daily temperature range. The number of sunshine hours average
660 per year, and the island is moist, with over 300 rain
days a year, and windy, with strong, persistent westerly
and north-westerly winds (De Lisle 1965).
The vegetation is similar to that on Auckland Island,
but the forest is even more dwarfed. Metrosideros umbellata is absent and the dominant and tallest tree is
Dracophyllum longifolium (J. R. Forst. and G. Forst.) R.
Br. with a subcanopy of Myrsine divaricata A. Cunn.
There are tussock grasslands, subalpine shrubs and a
higher alpine area of rushes and cushion-forming plants
(Wardle 1991; West & Rance 1999).
Macquarie Island
Macquarie Island is an emergent part of the
Macquarie Ridge that extends 900 km SSE from
Fiordland, New Zealand. The ridge formed as a result
of sea floor spreading rather than volcanic activity c. 27
million years ago, and it forms part of the boundary
between the Australian and Pacific plates. Islands may
have emerged and foundered repeatedly along the crest
of the ridge. One view is that the high points of the
island were raised between 200 000 and 90 000 years
ago (Hnatiuk 1993). However, sea level fluctuations
and downward movements over the last 2 million years
may mean that the island has been submerged for part
of that time. The island may not have been glaciated,
and its oceanic position and the fact that it lies north of
the Antarctic convergence (the sharp boundary between the cold Antarctic waters and warmer subantarctic waters) ameliorates the temperature slightly. The
climate is uniformly cool, cloudy (with only 850 h
sunshine per year) and windy (the prevailing winds are
westerly and north-westerly). Rain falls on more than
300 days per year and the relative humidity is 89%.
Macquarie Island lacks trees and shrubs, the vegetation consisting of tall tussock grassland, short grassland
2003
Ramalina on o#shore islands of NZ—Bannister & Blanchon
141
T 2. Occurrence of species of Ramalina on the outlying islands of New Zealand and the presence of these species in
Australia and New Zealand.
Species
R.
R.
R.
R.
R.
R.
R.
R.
R.
R.
R.
R.
R.
R.
R.
Nor
How
Ker
Cha
Ant
Auk
Cam
Mac
+
australiensis
canariensis
celastri
erumpens
exiguella
geniculata
inflata
leoidea
luciae
meridionalis
cf. microspora
pacifica
peruviana
stevensiae
unilateralis
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
Total
+
+
+
+
+
+
NZ
+
+
+
+
AU
+
+
+
+
+
+
+
+
+
6
4
8
+
4
+
+
1
1
1
+
+
+
+
+
2
10
10
Key to locations: Norfolk Island (Nor), Lord Howe Island (How), Kermadec Islands (Ker), Chatham Islands
(Cha), Antipodes Islands (Ant), Campbell Island (Cam), Auckland Islands (Auk), Macquarie Island (Mac),
Australia (AU), New Zealand (NZ).
with herbs on upper slopes and fellfield covering about
45% of the plateau uplands (Selkirk et al. 1990). A
greater proportion of the vascular flora is shared with
New Zealand than Australia (Wardle 1978). Lichen
communities are found on cli#s and rocks in the coastal
area, in herbfield and on vegetation, peat and rock in
the fellfield (Selkirk et al. 1990; Kantvilas and Seppelt
1992).
Results
Species of Ramalina
Norfolk Island
The most important lichen habitats are
rainforest, open Araucaria woodland, exposed rock surfaces inland and on the foreshore, and fenceposts (Elix et al. 1992).
The most recent Australian checklist
(McCarthy 2002) lists six species of Ramalina: R. arabum, R. exiguella, R. leiodea, R.
pacifica, R. peruviana and R. stevensiae.
While earlier lists had also included R. australiensis, R. canariensis, R. celastri and R
glaucescens, Elix et al. (1992) were unable to
examine specimens and verify these names.
We have examined specimens of those taxa
listed in the Australian checklist in AK,
CANB, CHR, HO and MEL (Table 2).
Blanchon & Bannister (2002) have referred
specimens previously named R. arabum to
the newly described and mainly corticolous
R. meridionalis.
Kermadec Islands
Ramalina australiensis, R. celastri, R. exiguella, R. geniculata, R. luciae, R. pacifica
and R. peruviana have been identified from
specimens in AK, AKU, CHR and WELT
(Table 2). Specimens with inflated thalli,
previously labelled R. microspora, are R.
geniculata, while a few in AK, CHR and
WELT, originally labelled R. geniculata,
are tentatively identified as R. cf. microspora. Ramalina microspora Kremp. s. str.
appears to be restricted to coastal habitats
in the Hawaiian Islands. Elix & McCarthy
(1998) listed two other species, R.
farinacea (L.) Ach. and R. fastigiata
(Pers.) Ach. We identified as R. pacifica a
specimen collected by W. R. B. Oliver in
1908, sent to Kew and determined as R.
farinacea (AK 20267). Another specimen
collected by Oliver and labelled R. fastigiata, was found to contain divaricatic acid
and may belong to R. cf. microspora.
Ramalina fastigiata contains evernic acid
and does not occur in Australia or New
Zealand.
142
THE LICHENOLOGIST
Lord Howe Island
The main lichen habitats are found in the
three types of forest, on exposed rock surfaces and on isolated trees in pasture. While
Elix & McCarthy (1998) listed R. complanata (Sw.) Ach., R. leiodea and R. peruviana
from Lord Howe Island, Archer & Elix
(1994) corrected R. complanata to R. subfraxinea, without confirming its identity
from specimens. It is probable that this
name refers to R. leoidea (syn.: R. subfraxinea
subsp. leiodea Nyl.).
Specimens in CANB have been determined by us as R. leiodea, R. meridionalis,
R. pacifica and R. peruviana (Table 2;
Blanchon & Bannister 2002). Ramalina leiodea and R. peruviana were collected from
basalt and shrubs, R. meridionalis was found
only on rock and R. pacifica only on shrubs.
Chatham Islands
There are only a few specimens of Ramalina in CHR, HO, OTA, WELT and hb P.
Johnson, with few habitat details provided.
The species are R. canariensis, R. celastri,
R. erumpens and R. peruviana (Table 2).
Bounty Islands
There are no vascular plants on these
islands, the vegetation consisting of algae
and crustose lichens (Wardle 1991). No
species of Ramalina have been recorded
(Table 2).
The Snares
Although lichens have been collected on
the Snares as well as on the Mutton Bird
Islands and Codfish Island (o# the coast
of Stewart Island), once again Ramalina
appears to be absent (Fineran 1969)
(Table 2).
Antipodes Islands
Specimens in CHR, HO, MSC and O
indicate that R. erumpens is the only species
of Ramalina found on these islands (Table
2). It has been found growing on rock and
shrubs of Coprosma spp.
Auckland Islands
The Auckland Islands are the type locality
for R. inflata, and this is the only species of
Vol. 35
Ramalina found there (Table 2). It grows
epiphytically on shrubs including Dracophyllum and Myrsine spp. and on the small trees
of Metrosideros umbellata. There are specimens in BM, MSC, OTA and WELT.
Campbell Island
Ramalina inflata (on Dracophyllum and
Myrsine spp.) is the only species in MSC
and OTA (Table 2).
Macquarie Island
The Australian checklist (McCarthy
2002) includes four species: R. banzarensis,
R. farinacea, R. inflata and R. unilateralis.
Specimens in ADT, BM, CANB, FH and
MEL were determined as R. erumpens and
R. unilateralis (Table 2). Specimens of R.
erumpens had been previously determined as
R. banzarensis C. W. Dodge or R. farinacea.
Bannister & Blanchon (2002) have placed
R. banzarensis incertae sedis, suggesting that it
was impossible to determine whether the
name referred to R. erumpens, R. unilateralis
or possibly R. inflata, although no specimens
of R. inflata have been found on the island.
One packet from FH labelled R. inflata var.
gracilis was found to be a specimen of Leifidium tenerum (Laurer) Wedin. Indeed it is
highly unlikely that R. inflata is present on
Macquarie Island as there are no suitable
woody plants for this corticolous species.
The specimens of R. erumpens and R. unilateralis have been collected mainly from rock,
but also from timber, peat on rock and one
specimen of each has been collected from
the base of small perennial plants.
Discussion
The biota of emergent, oceanic islands
becomes established by long-distance,
transoceanic dispersal. New arrivals are successful only if they reach suitable substrata
and microclimates, and colonization takes
place in spite of the fact that the chances of
successful dispersal and survival for an organism are low. The outlying, emergent
islands around New Zealand (except the
Bounty Islands and the Snares) are all
geologically comparatively young, and the
2003
Ramalina on o#shore islands of NZ—Bannister & Blanchon
T 3. Types of propagule produced by species of
Ramalina found on the islands
Species
australiensis
canariensis
celastri
erumpens
exiguella
geniculata
inflata
leoidea
luciae
meridionalis
cf. microspora
pacifica
peruviana
stevensiae
unilateralis
Ascospores
Soredia
++
–
+++
–
+++
+++
+++
+++
+
++
+++
+
++
+++
+
–
+++
–
+++
–
–
–
–
+++
–
–
+++
+++
–
+++
–, propagule not known; +, propagule found only
rarely; ++, some thalli do not produce the propagule;
+++, typically all specimens produce large numbers
of propagules.
species of Ramalina found on the islands
have arrived presumably from Australia,
Tasmania, New Zealand or other older
islands by transoceanic dispersal.
Lichens can be dispersed by thallus fragments, and some species of Ramalina produce short, fragile branches or long, fine
branches that may break from the parent
thallus and be dispersed. Büdel &
Scheidegger (1996) considered that long,
Usnea-like Ramalina thalli are torn and dispersed by strong winds. Species of this type
include R. australiensis and R. meridionalis,
but it is not known whether these fragments
could be dispersed over long distances.
Most species of Ramalina produce either
ascospores or soredia, although both propagules may be present in some species
(Table 3 ). Ascospores are ellipsoidal,
straight or slightly curved, one-septate, colourless and thin-walled (Blanchon et al.
1996). Lichen ascospores are liberated when
the contents are ejected from a mature ascus
which bursts apically after a build-up of
hydrostatic pressure (Ingold 1965). In
Ramalina the contents are discharged as
packets of six to eight ascospores, for a
distance of 4–10 mm (personal observation). Ascospores are shot into turbulent
143
air above the 1–2 mm deep boundary layer
of still air that covers the surface of the
apothecia, thus allowing dispersal by air
currents. Soredia are liberated passively
from soralia by water, abrasion by small
invertebrates or birds, but wind provides
more successful long-distance dispersal by
lifting the soredia from dry soralia into
turbulent air (Bailey 1976).
Successful dispersal can occur only if
propagules remain viable during transportation, and ascospores are considered to be
resistant to long-distance aerial transport
(Galloway & Aptroot 1995). Desiccation
and sunlight are thought to harm some
ascospores, although thick-walled and pigmented ascospores are thought to have a
better chance of survival (Pedgley 1982).
Ramalina ascospores are both thin-walled
and hyaline (Blanchon et al. 1996), but as
the ascospores are liberated only when the
apothecia are wet, they may be dispersed in
cloudy conditions or rainy weather, and this
may allow for a greater rate of survival. Nine
species producing only ascospores occur on
the islands (Table 3).
Following dispersal, an ascospore must
germinate on a suitable substratum where it
must resynthesize the lichen thallus with an
appropriate photobiont. In Ramalina, the
photobiont is a species of Trebouxia (Purvis
& James 1992), and although it is rarely
found outside lichens and is thought to be
a poor competitor (Honegger 2001), there
is evidence that Trebouxia exists in the
free-living state (Galun 1988; Sanders &
Lücking 2002). Sanders & Lücking (2002)
present evidence to show early stages of
lichenization in foliicolous lichens where
ascospores have reassociated with algal symbionts after germination. The abundance of
species lacking vegetative diaspores indicates that lichenization must be a common
process (Galun 1988). Murtagh et al. (2000)
found evidence of self-fertilization in lichens, indicating that a population could
develop from a single dispersed ascospore.
Following dispersal, soredia do not have the
problem of lichenization as the photobiont is
already enclosed in the fungal hyphae, but
they still have to establish a thallus on a
144
THE LICHENOLOGIST
suitable substratum. If dispersal by thallus
fragments occurs, the fragments must develop a holdfast for attachment prior to the
lichen thallus becoming re-established. It is
not known whether any species of Ramalina
are able to re-attach a fragment to a substratum. However, we have observed that
thalline branches of the Hawaiian species
R. microspora and the Australasian species
R. australiensis and R. inflata can form new
holdfasts.
Various methods of transoceanic dispersal of lichen propagules have been
suggested, including animals, flotation or
rafting and air currents. Bailey (1976)
considered that wind was the most likely
agent for long-distance dispersal, and
Louwho# (2001) has suggested that winddispersal is more influential than the combined e#ects of bird-dispersal and rafting
for Pacific Parmeliaceae.
There is little direct evidence for transoceanic dispersal by animals. Small invertebrates are often associated with lichens, and
some feed on ascospores, fungal hyphae or
algal cells. The possibility of long-distance
dispersal of propagules arises when the invertebrates are themselves dispersed. Tardigrades, in an anabiotic condition, have been
reported as being wind-dispersed together
with small lichen propagules (Gerson &
Seaward 1977). Many mites feed exclusively
or occasionally on lichens, and they occur
on subantarctic islands, having previously
been dispersed from island to island
or from the southern tips of landmasses
(Gressitt 1967). Several species of mites
found on Macquarie Island also occur in
New Zealand (Sømme 1985).
It has often been suggested that birds
contribute to long-distance dispersal by carrying lichen propagules on their feathers or
feet. One, often quoted, example is of a
Royal Albatross on the Auckland Islands,
that had soredia and thallus fragments
washed from its feet after it was forced to
run through scrub (Bailey & James 1979).
This information presumably led Purvis
(2000) to suggest that birds such as the
Royal Albatross may transport lichen propagules over very long distances. However,
Vol. 35
dispersal in this way is highly unlikely as
albatrosses spend the time between breeding
seasons in the air or on the sea surface; they
do not touch land until they return to the
same island breeding colony (McClelland
1999). Smith (1995), in a study of Hawaiian
lichens, also considered it unlikely that birds
were responsible for the dispersal of lichens
to the islands.
Marine currents are unlikely to disperse
lichen fragments or thalli of species of
Ramalina. Experimental work on immersion
of coastal lichen thalli in sea water showed
that while certain thalli could withstand immersion for several days, thalli of R. siliquosa
(Huds.) A. L. Sm., a xeric-supralittoral
species, do not survive immersion (Fletcher
1976). Both R. australiensis and R. meridionalis can grow in the splash zone and might
be transported by seawater if their thalli
could survive immersion. In fact, the occurrence of R. meridionalis on rocky islands
and peninsulas in northern New Zealand
(Blanchon & Bannister 2002; P. Bannister,
J. M. Bannister & D. J. Blanchon, unpublished.) suggests this might occur. Although ascospores of marine ascomycetes
survive in sea water, there appear to be
no published records indicating that ascospores of lichenized ascomycetes can survive
immersion.
Most lichen propagules are probably
transported by wind as ascospores and soredia are small and light and are thus wellsuited for long-distance dispersal by air
currents (Bailey 1976; Wedin 1995). The
length of Ramalina ascospores varies between 10 and 20 µm (Blanchon et al. 1996)
and soredia are roughly spherical and 25–
50 µm in diameter (personal observation).
These dimensions are similar to those of
small (10–25 µm) and medium-sized pollen
grains (25–50 µm) (Moar 1993). Air sampling traps have recorded cryptogam spores,
pollen grains, mites and wingless insects
over land and oceans including those at
polar latitudes and up to an altitude of
3–6 km (Pedgley 1982). Spores of rust
fungi and aphids are recorded as having
crossed the Tasman Sea in air currents from
Australia, and these organisms have become
2003
Ramalina on o#shore islands of NZ—Bannister & Blanchon
established in New Zealand (Close et al.
1978). Evidence of wind-dispersal from
Australia and New Zealand comes from
modern pollen rain studies on Campbell
Island (McGlone & Meurk 2000), the
Antipodes Islands (Moar 1969) and the
Chatham Islands (Dodson 1976). Aphids
on Campbell Island are thought to have
dispersed from New Zealand (Close et al.
1978). For successful dispersal to the islands, propagules need be airborne for only
a few days as some winds can carry airborne
organisms 1000 km or more in a day
(Pedgley 1982). Thus, trans-Tasman crossings might take only 2–3 days (Close et al.
1978).
It is not surprising that current distributions of Ramalina species on these islands
appear to confirm that dispersal of airborne
organisms mainly takes place in the direction of the prevailing winds. Norfolk Island
and Lord Howe Island have winds from the
direction of Australia in winter, and from
New Zealand in summer, and both have
mixtures of New Zealand and Australian
Ramalina species. The Kermadec Islands
have winds from the direction of New
Zealand in the winter and from the Pacific
(the north-east) in summer, with six species
of Ramalina in common with New Zealand
and two additional Pacific species. The
Chatham Islands receive winds from southern New Zealand and the Subantarctic, and
have species in common with both. The
Auckland Islands and Campbell Island receive westerly and north-westerly winds and
have one species, which is also found in
Australia, to the north-west.
However, the direction of plant dispersal
to the subantarctic islands only partly conforms to the prevailing winds. For example,
the flora of Macquarie Island is derived
largely from that of New Zealand despite the
infrequency of favourable winds (Wardle
1978). Moreover R. erumpens occurs on
Macquarie Island, but it does not occur in
Tasmania or mainland Australia. It presumably has dispersed from New Zealand where
it is confined to the south-eastern part of the
South Island (P. Bannister, J. M. Bannister
& D. J. Blanchon, unpublished). This
145
species has also reached the Chatham
Islands and the Antipodes Islands.
In conclusion, we suggest that the species
of Ramalina occurring on the outlying islands
of the New Zealand geographic area have
arrived by transoceanic transport, winddispersal of either ascospores or soredia, not
necessarily in the direction of the prevailing
winds, and that species have only become
established on the islands if both climatic and
habitat conditions have been met.
We thank Peter Johnson and the curators of the herbaria listed for loans of specimens and for providing
other information, Daphne Lee for discussing the geological ages with J.M.B., Peter Bannister, David
Galloway, Mel Galbraith and Mark Large for constructive criticism of the draft manuscript, NIWA for
climatic information, Matt McGlone for use of the map
in Fig. 1 and two anonymous referees for helpful
comments.
R
Archer, A. W. & Elix, J. A. (1994) The lichens of Lord
Howe Island. 1. Introduction and the genus Pertusaria (Pertusariaceae). Telopea 6: 9–30.
Atkinson, I. (1966) Major habitats. In The Chatham
Islands (I. Atkinson et al., eds): 49–61. Christchurch:
Canterbury University Press.
Bailey, R. H. (1976) Ecological aspects of dispersal and
establishment in lichens. In Lichenology: Progress and
Problems (D. H. Brown, D. L. Hawksworth &
R. H. Bailey, eds): 215–247. London: Academic
Press.
Bailey, R. H. & James, P. W. (1979) Birds and the
dispersal of lichen propagules. Lichenologist 11: 105.
Bannister, J. & Blanchon, D. J. (2002) The typification
and status of the name of Ramalina banzarensis
Dodge. Australasian Lichenology 51: 14–16.
Blanchon, D. J. & Bannister, J. (2002) Ramalina meridionalis, a new species from New Zealand, Norfolk
Island and Lord Howe Island. Australasian
Lichenology 51: 17–19.
Blanchon, D. J., Braggins, J. E. & Stewart, A. (1996)
The lichen genus Ramalina in New Zealand. Journal
of the Hattori Botanical Laboratory 79: 43–98.
Büdel & Scheidegger, C. (1996) Thallus morphology
and anatomy. In Lichen Biology (T. H. Nash III,
ed.): 37–64. Cambridge: Cambridge University
Press.
Close, R. C., Moar, N. T., Tomlinson, A. I. & Lowe,
A. D. (1978) Aerial dispersal of biological material
from Australia to New Zealand. International Journal
of Biometeorology 22: 1–19.
De Lisle, J. F. (1965) The climate of the Auckland
Islands, Campbell Island and Macquarie Island.
Proceedings of the New Zealand Ecological Society 12:
37–44.
146
THE LICHENOLOGIST
Dodson, J. R. (1976) Modern pollen spectra from
Chatham Island, New Zealand. New Zealand
Journal of Botany 14: 341–347.
Elix, J. A., Din, L. B. & Samsudin, M. W. B. (1991)
New species of Ramalina (lichenized Ascomycotina)
from Australasia and Malaysia. Mycotaxon 40: 41–44.
Elix, J. A. & McCarthy, P. M. (1998) Catalogue of the
lichens of the smaller Pacific islands. Bibliotheca
Lichenologica 70: 1–361.
Elix, J. A. & Streimann, H. (1989) The lichens of
Norfolk Island. 1: Introduction and the family
Parmeliaceae. Proceedings of the Linnaean Society of
New South Wales 111: 103–121.
Elix, J. A., Streimann, H. & Archer, A. W. (1992) The
lichens of Norfolk Island. 2: The genera Cladonia,
Pertusaria, Pseudocyphellaria and Ramalina. Proceedings of the Linnaean Society of New South Wales 113:
57–76.
Fineran, B. A. (1969) The flora of the Snares Islands,
New Zealand. Transactions of the Royal Society of
New Zealand, Botany 3: 237–270.
Fletcher, A. (1976) Nutritional aspects of marine and
maritime lichen ecology. In Lichenology: Progress and
Problems (D. H. Brown, D. L. Hawksworth & R. H.
Bailey, eds): 359–384. London: Academic Press.
Galloway, D. J. & Aptroot, A. (1995) Bipolar lichens: a
review. Cryptogamic Botany 5: 184–191.
Galun, M. (1988) Lichenization. In Handbook of
Lichenology, Vol. 3 (M. Galun, ed.): 153–169. Boca
Raton: CRC Press.
Gerson, U. & Seaward, M. R. D. (1977) Licheninvertebrate asociations. In Lichen Ecology (M. R. D.
Seaward, ed.): 69–119. London: Academic Press.
Gressitt, J. L. (1967) Introduction. In Entomology in
Antarctica (J. L. Gressitt, ed.): 1–27. Washington:
American Geophysical Union.
Hnatiuk, R. J. (1993) Subantarctic Islands. Flora of
Australia 50: 53–62.
Honegger, R. (2001) The symbiotic phenotype of
lichen-forming ascomycetes. In The Mycota IX,
Fungal Associations (R. Hock, ed.): 165–188. Berlin:
Springer Verlag.
Ingold, C. T. (1965) Spore Liberation. Oxford:
Clarendon Press.
Kantvilas, G. & Seppelt, R. D. (1992) The lichen flora
of Macquarie Island: introduction and an annotated
checklist of species. ANARE Research Notes 87: 1–20.
Louwho#, S. H. J. J. (2001) Biogeography of Hypotrachyna, Parmotrema and allied genera (Parmeliaceae)
in the Pacific islands. Bibliotheca Lichenologica 78:
223–246.
McCarthy, P. M. (2002) Checklist of Australian Lichens.
Canberra: Australian Biological Resources Study,
http://www.anbg.gov.au/abrs/lichenlist.
McClelland, P. (1999) Birds. In New Zealand’s Subantarctic Islands (T. O’Connor, ed.): 58–72.
Auckland: Reed Books.
McGlone, M. S. & Meurk, C. D. (2000) Modern pollen
rain, subantarctic Campbell Island, New Zealand. New
Zealand Journal of Ecology 24: 181–194.
Vol. 35
Moar, N. T. (1969) Pollen analysis of a surface sample
from Antipodes Island. New Zealand Journal of
Botany 7: 419–423.
Moar, N. T. (1993) Pollen Grains of New Zealand Dicotyledonous Plants. Lincoln: Manaaki Whenua Press.
Murtagh, G. J., Dyer, P. S. & Crittenden, P. D. (2000)
Sex and the single lichen. Nature 404: 564.
O’Connor, T. (ed.) (1999) New Zealand’s Subantarctic Islands. Auckland: Reed Books.
Orchard, A. E. (ed.) (1994) Flora of Australia. Oceanic
Islands 1 Vol. 49. Canberra: Australian Government
Publishing Service.
Pedgley, D. (1982) Windborne Pests and Diseases.
Chichester: Ellis Horwood Ltd.
Purvis, O. W. & James, P. W. (1992) Ramalina
Ach. (1910). In The Lichen Flora of Great Britain
and Ireland (O. W. Purvis, B. J. Coppins, D. L.
Hawksworth, P. W. James & D. M. Moore, eds):
524–529. London: Natural History Museum
Publications.
Purvis, W. (2000) Lichens. London: The Natural
History Museum.
Sanders, W. B. & Lücking, R. (2002) Reproductive
strategies, relichenization and thallus development observed in situ in leaf-dwelling lichen
communities. New Phytologist 155: 425–435.
Selkirk, P. M., Seppelt, R. D. & Selkirk, D. R. (1990)
Subantarctic Macquarie Island: Environment and
Biology. Cambridge: Cambridge University Press.
Smith, C. W. (1995) Notes on long-distance dispersal
in Hawaiian lichens: ascospore characters. Cryptogamic Botany 5: 209–213.
Sømme, L. (1985) Terrestrial habitats—invertebrates.
In Antarctica (W. N. Bonner & D. W. H. Walton,
eds): 106–117. Oxford: Pergamon Press.
Stevens, G. N. (1987) The lichen genus Ramalina in
Australia. Bulletin of the British Museum (Natural
History), Botany Series 16: 107–223.
Sykes, W. R., West, C. J., Beever, J. E. & Fife, A. J.
(2000) Kermadec Islands Flora, Special edn. Lincoln:
Manaaki Whenua Press.
Turnbull, I. (1999) Geology. In New Zealand’s Subantarctic Islands (T. O’Connor, ed.): 25–34.
Auckland: Reed Books.
Wardle, P. (1978) Origin of the New Zealand mountain flora, with special reference to trans-Tasman
relationships. New Zealand Journal of Botany 16:
535–550.
Wardle, P. (1991) Vegetation of New Zealand.
Cambridge: Cambridge University Press.
Wedin, M. (1995) The lichen family Sphaerophoraceae
(Calicales, Ascomycotina) in temperate areas of
the Southern Hemisphere. Symbolae Botanicae
Upsalienses 31(1): 1–102.
West, C. J. & Rance, B. (1999) Vegetation. In New
Zealand’s Subantarctic Islands (T. O’Connor, ed.):
25–34. Auckland: Reed Books.
Accepted for publication 12 February 2003