Biology Reference
In-Depth Information
distributed in the sub-Antarctic islands (Clayton
1994
). These regions share a
considerable number of cold-temperate species, e.g., the brown alga
Adenocystis
utricularis
, the red alga
Iridaea cordata
and
Gigartina skottsbergii
, however, some
endemic Antarctic species such as
Himantothallus grandifolius
and
Ascoseira
mirabilis
do not inhabit the sub-Antarctic islands (Luning
1990
; Clayton
1994
).
The distribution of the endemic Antarctic rhodophyte
Palmaria decipiens
just
extends to Macquarie Island (Wiencke and Clayton
2002
). On the other hand, the
circumpolar kelps
Macrocystis pyrifera
and
Lessonia
spp
.
as well as the large
intertidal fucoid
Durvillaea antarctica
are absent from the Antarctic (John et al.
1994
; Clayton et al.
1997
).
The general zonation pattern for the shores of Macquarie Island has been
described to comprise an upper littoral
Porphyra
zone, a “bare” zone (dominated
by siphonariid mollusc
Kerguelenella lateralis
), an upper red algal zone
(
Rhodymenia
sp.,
Chaetangium fastigiatum
,
Palmaria georgica
,
Acrosiphonia
pacifica
,
Porphyra columbina
), a kelp zone (
Durvillaea antarctica
), and lower red
algal zone below the infralittoral with understory species such as
Delesseria
spp.,
Iridaea
sp., and
Desmarestia
sp. (Kenny and Haysom
1962
; Smith and Simpson
2002
). Similarly, in Marion Island,
D. antarctica
is the dominant species at the
infralittoral fringe, while
Desmarestia rossii
and
Durvillaea
sp. occur in a zone of
3-6m. Encrusting coralline algae are particularly abundant in shallow areas (Beckley
and Branch
1992
). At subtidal locations, beds of the endemic
Macrocystis laevis
are
abundant (Perissinotto and McQuaid
1992
; Beckley and Branch
1992
). In general,
infralittoral
D. antarctica
, shallow-water encrusting coralline algae,
Desmarestia
spp., and subtidal
Macrocystis
beds seem to overall characterize the benthic seaweed
communities in many sub-Antarctic islands (Beckley and Branch
1992
).
For the sub-Antarctic islands near New Zealand, 14-148 seaweed species have
been reported, with the highest species richness being recorded for Chatham Islands
and the lowest for the Bounty Island (Parsons
1985
). Although notable differences
in species composition and dominance patterns can exist among islands (Freeman
et al.
2011
),
Durvillaea antarctica
and
Macrocystis pyrifera
occur in all these island
groups,
Lessonia flavicans
reported for Auckland, Campbell, the Antipodes, and
Bounty. The fucalean
Xiphophora chondrophylla
is present in all the island groups,
except for the Bounty (L
uning
1990
). Endemic
Durvillaea
species have been
proposed for the Antipodes (undescribed species) and Chatham Island (
D.
chathamensis
) (Cheshire et al.
1995
; Fraser et al.
2010b
; Fig.
14.3
). In the light of
a re-examination of the description of
Porphyra columbina
using molecular
techniques, this species is distributed in the Auckland, Campbell, Antipodes,
Chatham, and Falkland Islands, with a very restricted distribution in mainland
New Zealand (Nelson and Broom
2010
).
In the Chatham Island, the shallowest subtidal areas are dominated by
Durvillaea
.
Several fucalean species (e.g.,
Xiphophora chondrophylla
,
Carpophyllum
plumosum
and
C. maschalocarpum
) are abundant to a depth of around 10 m,
C.
flexuosum
occurring mostly in deeper waters (9-20 m). The endemic
Lessonia
tholiformis
and
L. variegata
are abundant at 2.5-15 m depth. In some sites,
Macrocystis pyrifera
forms dense beds at 15-20 m depth. In the Auckland Islands,
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