, Volume 117, Issue 4, pp 517–526

Dispersal and recruitment of a canopy-forming intertidal alga: the relative roles of propagule availability and post-settlement processes

  • Ladd E. Johnson
  • Susan H. Brawley


The daily settlement of eggs and zygotes of the monoecious brown alga Pelvetia compressa (J. Agardh) De Toni was measured on artificial substrata in areas inside and outside patches of adults in the high intertidal zone of central California. Settlement was generally 1–2 orders of magnitude higher under the adult canopy. This pattern seems to be due to the synchronous release of gametes during the daytime low tide. The release of gametes also appears periodic over longer time scales (e.g., 3- and 14-day cycles). In spite of the high availability of propagules under the adult canopy, juveniles were most abundant outside patches, where propagule availability was lower. In both areas, juveniles were disproportionately associated with patches of a red algal turf [primarily Endocladia muricata (Postels & Ruprecht) J. Agardh and Masticarpus papillata (C. Agardh) Kützing]. The turf, which is less common under the P. compressa canopy, may offer protection from dislodgment, grazing, and/or desiccation and thus facilitate recruitment at this site. Overall, post-settlement processes appear more important in determining population structure than does the availability of propagules in areas in and around patches of adults. However, the apparent small range of dispersal of P. compressa may make propagule availability an important limitation to the establishment of new populations and may restrict gene flow between populations.

Key words Algal turf Fucoid Periodicity Settlement Succession 


Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

Copyright information

© Springer-Verlag Berlin Heidelberg 1998

Authors and Affiliations

  • Ladd E. Johnson
    • 1
  • Susan H. Brawley
    • 3
  1. 1.Hopkins Marine Station, Stanford University, Pacific Grove, CA 93950, USAUS
  2. 2.Département de biologie and GIROQ, Université Laval, Québec, QC, G1K 7P4, Canada e-mail: ladd.johnson@bio.ulaval.ca, Fax: +1-418-6562339CA
  3. 3.School of Marine Science, University of Maine, Orono, ME 04469-5722, USAUS

Personalised recommendations