Nearshore Dispersal and Reproductive Viability of Intertidal Fucoid Algae : how effective is drift in local to regional dispersal?

dc.contributor.authorHawes, Nicola Annen
dc.date.accessioned2009-02-22T22:46:21Z
dc.date.available2009-02-22T22:46:21Z
dc.date.issued2008en
dc.description.abstractThe ecological importance of drifting will depend on the abundance of drifting algae and whether it is reproductively viable. However, the ability of adult plants to successfully disperse long-distances by drifting is largely unknown, particularly for fucoids. The abundance, species composition, and reproductive status of drifting algae was examined by transect surveys around Kaikoura and Banks Peninsula. Abundance and species composition varied between sites, but all drifting algae that were in reproductive season, and had reproductive structures intact, were reproductively active. The reproductive longevity and viability of drifting and beach-cast Hormosira banksii, Durvillaea antarctica and Cytophora torulosa was compared with attached populations. Drifting algae remained reproductively viable, and fecundity did not differ from that of attached algae. Viable propagules were released from drifting algae for the duration of the experiments (H. banksii 57 days, D. antarctica 62 days, and C. torulosa 43 days). In contrast, beach-cast algae ceased to release propagules after 14 days. Dispersal by drifting relies on offshore transport after detachment. To determine the influence of wind and tidal currents on the nearshore transport of drifting algae, tagged H. banksii, D. antarctica, C. torulosa and GPS-tracked drifters were released from shore. Drifters generally moved in the direction of the prevailing wind, but some influence of tidal direction and bathymetry was detected. Offshore winds and outgoing tides were favourable for the offshore transport of surface drifting algae. Following dispersal and arrival at new locations, the distance between gametes may be important in determining the fertilisation success of dioecious species. Experiments testing the fertilisation success of H. banksii and D. antarctica, over increasing distances, showed that fertilisation success decreased with increasing distance between male and female gametes. Despite this, eggs were fertilised when male and female gametes were up to 2m apart, and sperm remained viable for 2 hours.en
dc.identifier.urihttp://hdl.handle.net/10092/2103
dc.identifier.urihttp://dx.doi.org/10.26021/8260
dc.language.isoen
dc.publisherUniversity of Canterbury. School of Biological Sciencesen
dc.relation.isreferencedbyNZCUen
dc.rightsCopyright Nicola Ann Hawesen
dc.rights.urihttps://canterbury.libguides.com/rights/thesesen
dc.subjectNearshore dispersalen
dc.subjectFucoid algaeen
dc.subjectIntertidalen
dc.subjectDriften
dc.subjectReproductive viabilityen
dc.subjectDurvillaeaen
dc.subjectHormosiraen
dc.subjectCystophoraen
dc.titleNearshore Dispersal and Reproductive Viability of Intertidal Fucoid Algae : how effective is drift in local to regional dispersal?en
dc.typeTheses / Dissertations
thesis.degree.disciplineZoologyen
thesis.degree.grantorUniversity of Canterburyen
thesis.degree.levelMastersen
thesis.degree.nameMaster of Scienceen
uc.bibnumber1122703en
uc.collegeFaculty of Scienceen
uc.embargo24en
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