MEPS 372:135-145 (2008)  -  DOI: https://doi.org/10.3354/meps07731

Coastline topography affects the distribution of indigenous and invasive mussels

Charles E. O. von der Meden1,*, Francesca Porri1, Johan Erlandsson2, Christopher D. McQuaid1

1Coastal Research Group, Department of Zoology and Entomology, Rhodes University, PO Box 94, Grahamstown 6140, South Africa
2Aronia Research Centre, Åbo Akademi University/Sydväst Polytechnic, 10600 Ekenäs, Finland

ABSTRACT: Coastline topography has important effects on nearshore oceanography, larval transport, settlement and the adult distribution of benthic organisms. The resultant physical regime also influences interactions between invasive and indigenous species. Such interactions can alter intertidal communities dramatically, including the local extinction and replacement of native species. We examined the effect of bays and their associated headlands on the distribution of indigenous (Perna perna) and invasive (Mytilus galloprovincialis) mussels along 500 km of the south coast of South Africa. Within this single biogeographic region, mussel cover was estimated at 22 sites across 4 bays and the intervening open coast. Given that mussel biomass is greater at intermediate levels of wave exposure and that wave exposure is strongly dependent upon coastline topography, we hypothesised that mussel cover would be greater in bays, and that bays would specifically favour M. galloprovincialis which is more easily disturbed by strong waves. The 2 species show partial vertical separation into 3 zones within the lower eulittoral zone. Both species had significantly greater cover within bays. There was, however, an interaction between bay and zone for P. perna, and the effect of bays was strongest within the preferred zones of each species. Although the overall effect of bay was stronger for M. galloprovincialis than for P. perna, this resulted from the strong spatial structure identified for the M. galloprovincialis distribution using semivariogram analysis. Overall findings illustrate how coastline topography and local processes operate in synchrony to affect the dynamics of invasive and indigenous intertidal species.


KEY WORDS: Perna perna · Mytilus galloprovincialis · Bay effect · Coastal morphology · Topography · Intertidal zone · Retention · Invasive species


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Cite this article as: von der Meden CEO, Porri F, Erlandsson J, McQuaid CD (2008) Coastline topography affects the distribution of indigenous and invasive mussels. Mar Ecol Prog Ser 372:135-145. https://doi.org/10.3354/meps07731

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