Oecologia

, Volume 109, Issue 3, pp 442–453 | Cite as

Effects of gastropod grazers on recruitment and succession of an estuarine assemblage: a multivariate and univariate approach

  • M. J. Anderson
  • A. J. Underwood

Abstract

Grazers have been shown to affect assemblages of species in many habitats. Here we studied the effects of the gastropod grazers, Austrocochlea porcata and Bembicium auratum, on intertidal estuarine assemblages in a sheltered bay in New South Wales, Australia. We examined the effects of gastropods on individual species and on the assemblage as a whole. The multivariate response was compared with data on succession in these assemblages to estimate potential effects of grazers on succession. The experiment was repeated several times to determine the generality of grazer effects in the light of possible variation in the timing or intensity of recruitment. There were different responses of individual species to the presence of grazers. Grazers reduced the abundance of ephemeral algal species, bryozoans, copepods, insect larvae and Balanus spp. barnacles. They had a positive effect on oysters and spirorbids and no effect on the barnacles Elminius covertus and Hexaminius spp. These effects were consistent through time. Multivariate analyses confirmed that grazers caused significant changes to whole assemblages and that these effects were far-reaching and not only caused by changes to algal species. The removal of grazers appeared to neither speed up nor slow down succession, but rather caused a completely different assemblage to develop. Apparent important mechanisms affecting the composition of animal species when grazers were removed included accumulation of sediments and detritus and pre-emption of space by algae.

Key words Assemblage structure Gastropods Grazing Oysters Multivariate effects 

Preview

Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

Copyright information

© Springer-Verlag Berlin Heidelberg 1997

Authors and Affiliations

  • M. J. Anderson
    • 1
  • A. J. Underwood
    • 1
  1. 1.Marine Ecology Laboratories, A11 University of Sydney Sydney, NSW 2006 Australia Tel: 61-2–351–4282 fax: 61-2–351–6713 email: mjanders@bio.usyd.edu.auAU

Personalised recommendations