Marine Biology

, Volume 143, Issue 1, pp 47–55 | Cite as

Morphology of Ecklonia radiata (Phaeophyta: Laminarales) along its geographic distribution in south-western Australia and Australasia

  • T. WernbergEmail author
  • M. Coleman
  • A. Fairhead
  • S. Miller
  • M. Thomsen


Ecklonia radiata (C. Ag.) J. Agardh is a common macroalga on reefs in the warm-temperate parts of the southern hemisphere. It is a dominant habitat-former and as such has a strong structuring effect on associated algal assemblages. Morphological variation in E. radiata potentially affects its interactions with the surroundings and contributes to confusion about its taxonomy. We quantified the magnitude of morphological variation in fully developed E. radiata sporophytes across Australasia and tested the hypotheses that E. radiata has different morphology at different locations and that the degree of morphological difference depends on spatial distances among locations. A total of 11 morphological characters were sampled from 11 locations along the Australian coastline from Kalbarri in Western Australia to Sydney in New South Wales as well as from Doubtful Sound, New Zealand. Most morphological characters varied considerably from one location to another. For example, the average (±SE) thallus length was 135.2±12.5 cm in Kalbarri and only 69.7±5.5 cm in Sydney. There were no consistent spatial patterns of variation among individual morphological characters, and, generally, variations among individual characters were poorly correlated (−0.5<R<0.5). This suggests that individual morphological characters develop independently of each other in response to processes operating at different spatial scales. Multivariate measures of morphology were found to be different among some locations and similar among others (−0.37≤Clarke's R≤1), but there was no correlation (Spearman's R=0.08) between morphological similarity and distance between locations. Consequently, our results do not support clinal variation in E. radiata morphology. Rather, they suggest the presence of discrete morphologically different populations, in which the morphology at any one location reflects multiple forcing factors operating on different morphological characters at different spatial scales.


Macroalgae Morphological Character Grazing Pressure Lateral Spinousity Wave Exposure 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.



Thanks to S.D. Connell for sharing information on unpublished data. G.A. Kendrick and M.A. Vanderklift provided useful critique and comments on various stages of this work. Also thanks to the many respondents from the ALGAL-L email list who showed interest in the subject and offered comments and suggestions. This work was supported by grants from the Danish Natural Science Research Council and the Danish Research Academy to T. Wernberg.


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Copyright information

© Springer-Verlag 2003

Authors and Affiliations

  • T. Wernberg
    • 1
    Email author
  • M. Coleman
    • 2
  • A. Fairhead
    • 3
  • S. Miller
    • 4
  • M. Thomsen
    • 5
  1. 1.School of Plant BiologyUniversity of Western AustraliaCrawleyAustralia
  2. 2.Centre for Research on Ecological Impacts of Coastal CitiesUniversity of SydneySydneyAustralia
  3. 3.Department of Environmental BiologyUniversity of AdelaideAdelaideAustralia
  4. 4.Department of BotanyUniversity of OtagoDunedinNew Zealand
  5. 5.Department of Environmental ScienceUniversity of VirginiaCharlottesvilleUSA

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