MEPS 380:59-71 (2009)  -  DOI: https://doi.org/10.3354/meps07926

Differences in soft-sediment macrobenthic assemblages invaded by Caulerpa taxifolia compared to uninvaded habitats

Justin G. McKinnon1, Paul E. Gribben2,4, Andrew R. Davis1, Dianne F. Jolley3, Jeffrey T. Wright1,5,*

1Institute for Conservation Biology and School of Biological Sciences, University of Wollongong, Wollongong 2522, Australia
2Centre for Marine Biofouling and Bio-Innovation and School of Biological, Earth and Environmental Sciences, University of New South Wales, Sydney 2052, Australia
3GeoQuest, School of Chemistry, University of Wollongong, Wollongong 2522, Australia
4Present address: Institute of Water and Environmental Management, and Department of Environmental Sciences, University of Technology, Sydney 2007, Australia
5Present address: National Centre for Marine Conservation and Resource Sustainability, Australian Maritime College, The University of Tasmania, PO Box 986, Launceston 7250, Australia
*Corresponding author. Email:

ABSTRACT: Caulerpa taxifolia is a habitat-forming green alga that has invaded several temperate regions worldwide. Although C. taxifolia covers large areas of soft-sediment habitat, little is known about its effects on soft-sediment invertebrate assemblages. We compared soft-sediment macroinvertebrate assemblages in 2 estuaries in southeastern Australia invaded by C. taxifolia to examine 2 main predictions: (1) areas covered with C. taxifolia will have different assemblages compared to unvegetated sediment because infauna are inhibited but epifauna are facilitated, and (2) areas with C. taxifolia will have different assemblages compared to those with native seagrasses (Halophila ovalis and Zostera capricorni) because infauna are inhibited but epifauna are not. Multidimensional scaling and ANOSIM showed differences in invertebrate assemblages between all habitats. In C. taxifolia, infauna were less abundant and epifauna were more abundant compared to unvegetated sediment. However, when compared to native seagrasses, epifauna in C. taxifolia were more abundant than in H. ovalis in one estuary but less abundant than in Z. capricorni in another estuary, while infauna in C. taxifolia were less abundant than in both seagrass species. The consistently low infaunal abundance in C. taxifolia, irrespective of infaunal feeding mode, suggests C. taxifolia impacts infauna generally. Examination of environmental factors potentially responsible for the low abundance of infauna indicated that differences in redox potential (and associated chemical changes) may explain patterns in abundance of infauna among habitats. Our findings indicate that invasion by C. taxifolia causes important changes to soft-sediment macroinvertebrate assemblages and suggest that infauna may be particularly vulnerable to invasion because of changes to sediment chemistry.


KEY WORDS: Caulerpa taxifolia · Community composition · Ecosystem engineers · Facilitation · Habitat-forming species · Inhibition · Invasion biology · Seagrass


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Cite this article as: McKinnon JG, Gribben PE, Davis AR, Jolley DF, Wright JT (2009) Differences in soft-sediment macrobenthic assemblages invaded by Caulerpa taxifolia compared to uninvaded habitats. Mar Ecol Prog Ser 380:59-71. https://doi.org/10.3354/meps07926

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