New Zealand Journal of Marine and Freshwater Research abstracts
M00013Received 30 March 2000; accepted 22 June 2000
Distributional expansion of Carpophyllum flexuosum onto wave-exposed
reefs in north-eastern New Zealand
RUSSELL G. COLE*
RUSS C. BABCOCK
VICTORIA TRAVERS
ROBERT G. CREESE
Leigh Marine Laboratory
University of Auckland
P. O. Box 349, Warkworth
New Zealand
*Present address: National Institute of Water &
Atmospheric Research Ltd, P. O. Box 893, Nelson, New Zealand.
email: r.cole@niwa.cri.nz
Abstract The native fucalean macroalga Carpophyllum
flexuosum (Esper) Grev. has recently occupied many reefs on wave-exposed
coasts in north-eastern New Zealand. At recently colonised sites, C.
flexuosum occurs mainly on coralline-dominated areas with moderate
densities of sea urchins (Evechinus chloroticus). At these sites, stipes
of C. flexuosum are shorter, with more branching, reduced laminae, and
increased stipe weights compared to those at sheltered sites. Survivorship of
tagged individuals was less on wave-exposed than on sheltered reefs. On
sheltered shores, small C. flexuosum suffered moderate mortality, but
large individuals suffered little mortality from any source. All individuals
transplanted from sheltered to wave-exposed shores died or became moribund as
stipes, whereas those which survived transplanting from wave-exposed to
sheltered shores assumed a morphology more characteristic of sheltered sites.
Population modelling suggested that the existence of stands of C.
flexuosum on wave-exposed shores is dependent on regular recruitment,
though it is not clear whether populations are maintained by recruitment from
within or without. The establishment of C. flexuosum on wave-exposed
shores is correlated with decadal scale decreases in wave energy. We predict
that the patchiness of recruitment of C. flexuosum in space and time
(and the ubiquity and reproductive characteristics of the dominant laminarian
Ecklonia radiata) and its susceptibility to wave action will prevent the
fucalean from inducing long-term changes of assemblage organisation.
Keywords fucalean; seaweed; morphology; range expansion;
survivorship; wave climate
New Zealand Journal of Marine and Freshwater Research, 2001, Vol. 35: 17-32
0028-8330/01/3501-0017 $7.00 (c) The Royal Society of New Zealand 2001
PDF file of entire paper: medium quality (1608K); (scanned from paper original: notes about this process)
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