African Journal of Marine Science 2011, 33(2): 327–332 Copyright © NISC (Pty) Ltd Printed in South Africa — All rights reserved AFRICAN JOURNAL OF MARINE SCIENCE ISSN 1814–232X EISSN 1814–2338 doi: 10.2989/1814232X.2011.600433 Short Communication Tube-forming polychaetes enhance invertebrate diversity and abundance in sandy sediments of Mozambique, Africa MS Thomsen1,2*, MF Muth3 and KJ McGlathery3 1 Marine Department, National Environmental Research Institute, University of Aarhus, PO Box 4000, Roskilde, Denmark 2 School of Plant Biology, University of Western Australia, Crawley 6009 WA, Australia 3 Department of Environmental Sciences, University of Virginia, 291 McCormick Rd, Clark Hall, Charlottesville, VA 22904, USA * Corresponding author, e-mail:
[email protected] Manuscript received March 2011; accepted May 2011 In marine soft-bottom systems, polychaetes can increase habitat complexity by constructing rigid tubes (e.g. several onuphid species) that contrast with surrounding topographically flat sediments. These structures can provide predation refuges and increase larval settlement and thereby increase the richness and abundance of fauna. We collected invertebrate samples from an intertidal flat with low onuphid tube density (2.7 m–2) in Mozambique and document that more organisms (70 times higher mollusc abundances) and more species (15 times more mollusc species) were found associated with solitary tubes of an onuphid polychaete compared with surrounding sand habitats. These results are in agreement with tube versus sand comparisons from soft-bottom systems in the North Atlantic where polychaete tube densities are often much higher. Keywords: habitat formation, onuphid polychaete, species richness, western Indian Ocean Introduction Species that form or modify habitat, often referred to as (Thomsen et al.