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Mesoscale dispersal of the introduced kelp Undaria pinnatifida attached to unstable substrata


Sliwa, C and Johnson, CR and Hewitt, CL, Mesoscale dispersal of the introduced kelp Undaria pinnatifida attached to unstable substrata, Botanica Marina, 49, (5-6) pp. 396-405. ISSN 0006-8055 (2006) [Refereed Article]

DOI: doi:10.1515/BOT.2006.051


In areas of Tasmania and New Zealand, the introduced Japanese alga, Undaria pinnatifida, grows attached to unstable substrata such as small cobbles and shells. Observations suggest these algae may disperse by saltation (i.e., a series of jumps) while attached to their substratum. A predictive model was developed to estimate the dispersal rate of U. pinnatifida by this mechanism, depending on drag force (as a function of lamina surface area and water velocity), the buoyant weight of the attached substratum and the depth at which the alga was located. The model was parameterised based on empirical measurements of 89 tagged thalli in the field, and estimates of drag on different sized laminae determined from experiments in a large flume tank. Empirical observations and model predictions suggest that under typical conditions at moderately exposed sites, dispersal via this mechanism is likely to be of the order of at least 101-102 m per year. When compared to the likely dispersal of spores from the parent (≈101 m per year), and the likely dispersal of fertile drift thalli (≈10 3-104 m per year), we suggest that algae on unstable substrata may provide a mechanism for intermediate dispersal over moderate distances, providing sufficient spore density to ensure high fertilisation success. This is likely to enhance the rate of spread of U. pinnatifida in circumstances where habitat suitable for establishment is available. © 2006 by Walter de Gruyter.

Item Details

Item Type:Refereed Article
Research Division:Biological Sciences
Research Group:Ecology
Research Field:Marine and estuarine ecology (incl. marine ichthyology)
Objective Division:Environmental Management
Objective Group:Marine systems and management
Objective Field:Control of pests, diseases and exotic species in marine environments
UTAS Author:Sliwa, C (Miss Cathryn Sliwa)
UTAS Author:Johnson, CR (Professor Craig Johnson)
UTAS Author:Hewitt, CL (Professor Chad Hewitt)
ID Code:42743
Year Published:2006
Web of Science® Times Cited:21
Deposited By:TAFI - Zoology
Deposited On:2006-08-01
Last Modified:2007-08-31

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