Table Of ContentSelbyana 14: 71-74
DIFFERENTIAL COLONIZATION BY EPIPHYTES ON
NATIVE (CIBOTIUM SPP.) AND ALIEN
(CYATHEA COOPERI) TREE FERNS IN A
HAWAIIAN RAIN FOREST
A. C. MEDEIROS, L. L. LoOPE, AND S. J. ANDERSON
Haleakala National Park, P.O. Box 369, Makawao, Hawaii 96768
In Hawaiian rain forests, many species grow METHODS
as epiphytes either exclusively or in addition to
a terrestrial habit. Two types of sites are favored The immediate vicinity of the main Cyathea
by epiphytes: 1) the bryophyte mats that form coop eri population was chosen as the study area.
on the branches and trunks of forest trees, and All individuals of the two native tree ferns, Ci
2) trunks of tree ferns. The predominant group botium chamissoi and C. glaucum, that exceeded
of native tree ferns is in the genus Cibotium 1.5 m in height were located and sampled. Cy
(Dicksoniaceae), known in Hawai'i as hapu'u. athea cooperi was much more common in the
Five endemic Cibotium species occur in the Ha area and was sampled only within fixed study
waiian Islands (Wagner 1990), three within Ha plots used in assessing stand structure. For all
leakala National Park-Co chamissoi Kaulf., C. three species, only large individuals (> 1.5 m
glaucum (J. E. Smith) Hook. & Am., and C. height) were selected. For each tree fern, all vas
splendens (Gaud.) Krajina ex Skottsb. (Medeiros cular plant epiphyte species were listed and the
and Loope unpubl. ms.). number of individuals of each species recorded.
An alien tree fern, Cyathea cooperi (Hooker
ex F. von Mueller) Domin in the family Cy
RESULTS
atheaceae, native to eastern Australia, has locally
invaded native forests on the Hawaiian islands Eleven of 16 tree ferns (66%) of the native
of Kaua'i, O'abu, and Maui (Medeiros et al. Cibotium glaucum surveyed had populations of
1992). In 1987, well established populations were epiphytes, all with native species and three (18%)
discovered in the remote rain forests ofKipabulu , with alien species. Nineteen of 21 (91 %) tree ferns
Valley, within Haleakala National Park, proba of the native Cibotium chamissoi had popula
bly originating through wind blown spores from tions of epiphytes; all with native species, none
plant nurseries on the coast near the settlements with alien species. Twenty of 50 tree ferns (40%)
of Hana and Nahiku, 12 km distant. The largest of the alien Cyathea coop eri had populations of
population of Cyathea coop eri in the valley oc epiphytes, 12 with native species (24%) and 12
curs in native Metrosideros polymorpha and Aca (24%) with alien species.
cia koa rain forest at 730 m elevation and com Thirty-four species of vascular plants were re
prises over 800 individuals. Based on the height corded as epiphytes on the three species of tree
of the largest individuals (4 m) and the extent of ferns at the study site (TABLE 1). Of these, 18
the population, colonization probably began in species were pteridophytes (in 13 families), three
the 1970's. Numerous smaller understory trees, species were monocots (3 families), and 13 were
shrubs, herbs, and pteridophytes at the site form dicots (11 families). Of these, 28 species (82%)
a diverse assemblage of native species, including were native and six were alien (18%). Of the
local endemics. native species, 10 species were indigenous (34%),
As biologists with Haleakala National Park, 17 were endemic (60%), and one taxa unidenti
one of our major objectives is to detect newly fied to the species level (Huperzia sp.) was clas
invading species capable of damaging native plant sified as native only.
and animal populations and/or ecosystem prop Of the six non-native species, there were two
erties before they become widespread, so that ferns (Athyriopsis japonica and Cyathea cooperz),
chances for control are maximized. An expedi one grass (Paspalum conjugatum), one sedge,
tion in April 1991 was devoted entirely to ex (Rhynchospora caduca) and two dicots (Agera
amining the status and impact of C. coop eri in tina adenophora and Rubus rosi/olius). All are
Kipahulu Valley. In conjunction with an effort invasive species in Hawaiian rain forests, with
to assess the stand structure of the population of P. conjugatum recognized as one of the worst
this Australian tree fern in fixed plots, we com weed species in native Hawaiian habitats (Smith
pared the epiphyte populations on native and 1985). All six alien species were classified as
alien tree fern species. mostly terrestrial but also epiphytic.
71
72 SELBYANA [Volume 14
TABLE 1. List of vascular plant species recorded as TABLE 1. Continued.
epiphytes on Cibotium chamissoi, C. glaucum, and
Cyathea cooperi, Kipahulu Valley, Hawaiian Is Primarily found as epiphyte.
lands. The rough categories of frequency are "rare Found rarely on Cibotium chamissoi only.
ly" (occurring on 1-2 tree ferns), "sparingly" (oc
Hymenophyllaceae
curring on 3-4 tree ferns), and "commonly"
(occurring on more than 4 tree ferns). Vandenboschia davallioides (Gaud.) Copel.
Endemic to main Hawaiian Islands
Found mostly as an epiphyte, but also occurs terres
Pteridophytes
trially.
Aspleniaceae
Found rarely on Cibotium glaucum only.
Asplenium contiguum Kaulf.
Lycopodiaceae
Indigenous
Common both terrestrially and as epiphyte. Huperzia sp.
Found sparingly on Cyathea cooperi, common on Native to the Hawaiian Islands
Cibotium glaucum and Cibotium chamissoi. Found mostly as an epiphyte, but also occurs terres
trially.
Athyriaceae
Found sparingly on Cyathea cooperi and rarely on
Athyriopsis japonica (Thunb.) Ching Cibotium chamissoi.
Alien: native to Asia
Found mostly terrestrially but also as an epiphyte. Lycopodium cernuum L.
Indigenous: pantropical
Found sparingly on Cyathea cooperi only.
Common both terrestrially and as epiphyte.
Cyatheaceae Found rarely on Cibotium chamissoi only.
Cyathea cooperi (Hook. ex F. Muell.) Dom.
Lycopodium phyllanthum Hook. & Am.
Alien: native to eastern Australia
Indigenous: India to main Hawaiian Islands
Found mostly terrestrially but also as an epiphyte.
Found mostly as an epiphyte, but also occurs terres
Found rarely on Cyathea cooperi only.
trially.
Dicksoniaceae Found rarely on Cibotium glaucum and Cibotium
Cibotium glaucum (J. E. Smith) Hook. & Am. chamissoi only.
Endemic to main Hawaiian Islands Nephrolepidaceae
Found mostly terrestrially but also as an epiphyte.
Nephrolepis cordifolia (L.) Pres!'
Found sparingly on Cibotium glaucum only.
Indigenous: pantropical
Elaphoglossaceae Found mostly as an epiphyte, but also occurs terres
Elaphoglossum hirtum (Sw.) C. Chr. var. micans trially.
(Mett.) C. Char. Found rarely on Cibotium chamissoi only.
Indigenous: pantropical, variety endemic to Hawai Ophioglossaceae
ian Islands
Ophioglossum pendulum L. subsp. falcatum (Presl.)
Primarily found as epiphyte.
Clausen
Found rarely on Cibotium glaucum only.
Indigenous: pantropical; subspecies found on Pacific
Gleicheniaceae islands
Dicranopteris linearis (Burm.) Underw. Primarily found as epiphyte.
Indigenous: Japan, India, New Zealand to main Ha Found sparingly on Cibotium chamissoi only.
waiian Islands Polypodiaceae
Found mostly terrestrially but also as an epiphyte.
Pleopeltis thunbergiana Kaulf.
Found rarely on Cibotium glaucum only.
Indigenous
Grammitaceae Found mostly as an epiphyte, but also occurs terres
Adenophorus hymenophylloides (Kaulf.) Hook. & trially.
Grev. Found rarely on Cyathea cooperi and Cibotium
Endemic to main Hawaiian Islands glaucum.
Primarily found as epiphyte. Psilotaceae
Found rarely on Cibotium chamissoi only. Psi/otum nudum (L.) Beauv.
Indigenous: pantropical and subtropical
Adenophorus pinnatijidus Gaud.
Found mostly as an epiphyte, but also occurs terres
Endemic to main Hawaiian Islands
trially.
Primarily found as epiphyte.
Found sparingly on Cibotium glaucum and com
Found rarely on Cibotium glaucum only.
monly on Cibotium chamissoi only.
Adenophorus tamariscinus (Kaulf.) Hook & Grev.
Endemic to main Hawaiian Islands Monocotyledons
Primarily found as epiphyte. Cyperaceae
Found commonly on Cibotium glaucum and spar
Rhynchospora caduca Elliott
ingly on Cibotium chamissoi.
Alien: native to the southern U.S.
Grammitis tenella Kaulf. Found mostly terrestrially but also as an epiphyte.
Endemic to main Hawaiian Islands Found rarely on Cibotium glaucum only.
1993] MEDEIROS ET AL.: EPIPHYTE COLONIZATION ON TREE FERNS 73
TABLE 1. Continued. TABLE 1. Continued.
Pandanaceae Endemic to the Hawaiian Islands of Kaua'i, O'ahu,
Freycinetia arborea Gaud. Moloka'i, Lana'i, and Maui
Indigenous: Polynesia, Samoa, New Caledonia and Found mostly terrestrially but also as an epiphyte.
main Hawaiian Islands Found rarely on Cibotium chamissoi only.
Found mostly as an epiphyte, but also occurs terres Piperaceae
trially.
Peperomia cookiana C. DC.
Found sparingly on Cibotium chamissoi only.
Endemic to the Hawaiian Islands of Kaua'i, Molo
Poaceae ka'i, Maui, and Hawai'i
Paspalum conjugatum Berg. Common both terrestrially and as an epiphyte.
Alien: native to tropical America Found commonly on Cyathea cooperi, and sparingly
Found mostly terrestrially but also as an epiphyte. on Cibotium glaucum and Cibotium chamissoi.
Found commonly on Cyathea cooperi and rarely on Rosaceae
Cibotium glaucum.
Rubus rosifolius Sm.
Alien: native to Asia
Dicotyledons
Found mostly terrestrially but also as an epiphyte.
Araliaceae
Found commonly on Cyathea cooperi only.
Cheirodendron trigynum (Gaud.) Heller
Rubiaceae
Endemic to main Hawaiian Islands
Found mostly terrestrially but also as an epiphyte. Coprosma ochracea Oliver
Found commonly on Cibotium glaucum and Cibo- Endemic to the Hawaiian Islands of O'ahu, Molo-
tium chamissoi. ka'i, Lana'i, Maui, and Hawai'i
Found mostly terrestrially but also as an epiphyte.
Asteraceae
Found rarely on Cibotium chamissoi only.
Ageratina adenophora (Spreng.) King and Robinson
Hedyotis ajJinis (Hook. & Am.) Wagner and Herbst
Alien: native to Mexico
Endemic to main Hawaiian Islands
Found mostly terrestrially but also as an epiphyte.
Common both terrestrially and as epiphyte.
Found rarely on Cyathea cooperi only.
Found rarely on Cibotium glaucum only.
Campanulaceae
Rutaceae
Clermontia arborescens (Mann) Hillebr.
Pelea c/usiifolia Gray
Endemic to Hawaiian Islands of Moloka'i, Lana'i,
Endemic to main Hawaiian Islands
and Maui
Found mostly terrestrially but also as an epiphyte.
Common both terrestrialJy and as epiphyte.
Found commonly on Cibotium glaucum and Cibo-
Found sparingly on Cibotium glaucum and rarely on
tium chamissoi.
Cibotium chamissoi.
Ericaceae
Vaccinium calycinum Sm.
Endemic to main Hawaiian Islands
Common both terrestrially and as epiphyte. The two native Cibotium species supported
Found sparingly on Cibotium glaucum and com- more individual epiphytes than did trunks of Cy
monly on Cibotium chamissoi. athea coop eri ofc omparable size. On the 16 plants
of Cibotium glaucum, there were an average of
Fabaceae
20.2 individuals of native epiphyte species. On
Acacia koa Gray
the 21 individuals of Cibotium chamissoi, there
Endemic to main Hawaiian Islands
Found mostly terrestrially but also as an epiphyte. were 11.4, and on Cyathea coop eri (N = 50) an
Found rarely on Cibotium chamissoi only. average of 1.1 individuals of native epiphyte spe
cies.
Hydrangeaceae
Four ofthe six alien epiphyte species were re
Broussaisia arguta Gaud. corded only on the non-native Cyathea tree ferns.
Endemic to main Hawaiian Islands
One alien species and 23 native species (82% of
Found mostly terrestrially but also as an epiphyte.
native species) were recorded only on native Ci
Found rarely on Cyathea coop eri and on Cibotium
botium tree ferns.
chamissoi.
Of the 28 native epiphyte species, six (21 %)
Myrtaceae
are exclusively epiphytes, six (21 %) are predom
Metrosideros polymorpha Guad. inantly epiphytes but can be found terrestrially,
Endemic to main Hawaiian Islands
six (21 %) are common both epiphytically and
Found mostly terrestrially but also as an epiphyte.
terrestrially, and 10 species (36%) are mostly ter
Found commonly on Cibotium glaucum and Cibo-
restrial species, but can occur epiphytically. The
tium chamissoi.
six species that were found only as epiphytes
Syzygium sandwicensis (Gaud.) Nied.
were all small-sized ferns and fern allies. Ten
74 SELBYANA [Volume 14
TABLE 2. Average number of epiphytes of native and The tendency for many species of Hawaiian
alien vascular plant species per trunk of native plants to occur both rooted in soil and as epi
(Cibotium spp.) and alien (Cyathea cooperz) tree phytes is characteristic of island rain forests
ferns. Means that do not differ at a 0.01 confidence
(Mueller-Dombois & Howarth 1981). In Kipa
level based on the t-test are indicated by a com
mon superscript (A, B, q. hulu Valley, occurrence of primarily terrestrial
plant species as epiphytes has been important in
Average no. of maintaining biological diversity locally when
plants per trunk there is substantial and frequent ground distur
bance due to feral pig rooting.
Native Alien
Cibotium glaucum (N = 16) 20.2A 0.25C
Cibotium chamissoi (N = 21) 11.4A OC
Cibotium (both spp.) (N = 37) 15.8A O.lc CONCLUSIONS
Cyathea cooperi (N = 50) l.lB O.5c Cyathea coop eri, though undocumented until
recently as invasive, is an aggressive species that
has established in native forests on several is
native species could be classified as species that
lands in the 1970's and is rapidly spreading
are normally large statured and whose growth as
(Medeiros et al. 1992). In addition to impacts
an epiphyte will result in long-term survival only
such as aggressive competition for space and light,
if the roots eventually contact the soil.
the evidence presented here demonstrates that
Cyathea coop eri appears to support more in
the alien tree fern supports fewer epiphytes than
dividuals of the alien epiphyte species than do
the two native Cibotium tree ferns.
the native tree ferns. Cibotium chamissoi had no
alien epiphyte species and Cibotium glaucum av
eraged 0.25 individuals ofa lien epiphyte species.
However, C. coop eri averaged 0.5 individuals of ACKNOWLEDGMENTS
alien epiphyte species per trunk. Compared to We thank Betsy H. Gagne for assistance in
the total number of individuals on each plant, gathering data and Sabine Jessel and William
the percentage of alien species is 0% for Cibotium Minyard for field assistance. We thank Greg
glaucum, 1.7% for Cibotium chamissoi, and Westcott for sharing his observations on Cyathea
31.3% for Cyathea coop eri (TABLE 2). coop eri under nursery conditions.
DISCUSSION
LITERATURE CITED
Why should there be more epiphytes on Ci
botium tree ferns than on Cyathea coop eri tree MEDEIROS A. C., L. L. LooPE, T. FLYNN, S. J. ANDERSON,
ferns? We could generate two possible reasons. L. W. CuDDIHY, AND K. A. WILSON. 1992. Notes
First, Cyathea coop eri is much faster growing on the status of an invasive Australian tree fern
than Hawaiian tree ferns (Cibotium); therefore, (Cyathea cooperz) in Hawaiian rain forests. Amer
ican Fern Journal 82(1): 27-33.
large plants of Cyathea may be relatively young,
while a comparable sized individual of Cibotium MUELLER-DOMBOIS D. AND F. G. HOWARTH. 1981.
Life-form integration in island communities. Pp.
is likely to be of considerable age. A second rea
337-364 in D. MUELLER-DoMBOIS, K. W. BRIDG
son may be that the trunks of Cyathea coop eri ES, AND H. L. CARSON, eds., Island ecosystems.
are in some fashion (mechanically or chemically) Hutchinson Ross Publ. Co., Stroudsberg, Penn
resistant to establishment of epiphytes. A hor sylvania.
ticulturist on Maui reported that, when orchids SMITHC. W. 1985. ImportofalienplantsonHawaii's
and other plants were attached to Cyathea trunks native biota. pp. 180-250 in C. P. Stone and J.
in cultivation trials, the epiphytes did very poor M. Scott, eds., Hawaii's terrestrial ecosystems:
preservation and management. Univ. Hawaii Press
ly and seemed to be harmed by the aerial roots
for Univ. Hawaii Cooperative National Park Re
of Cyathea (G. Westcott pers. comm.). In con
sources Studies Unit, Honolulu.
trast, the broken fibers ofthe Hawaiian tree ferns
WAGNER W. H., JR. 1990. Hawaii's Satchel-Sorus
Cibotium are widely used as planting media for Tree Ferns, Cibotium species: what is their taxo
orchids. It is likely that both factors are opera nomic status? Bull. Amer. Fern. Soc. (Fiddlehead
tive. Forum) 17(1): 7-8.
