The invasion and subsequent die-off of Mytilus galloprovincialis in Langebaan Lagoon, South Africa: effects on natural communities

Abstract

The alien mussel Mytilus galloprovincialis invaded sand banks in Langebaan Lagoon on the west coast of South Africa in the mid-1990s. However, by 2001 these beds had completely died off, with only empty shells and anoxic sand remaining. In an effort to prevent the re-settlement of this aggressive invader, all dead mussel shells were then cleared. This study considered the impacts of the invasion and subsequent die-off on natural benthic communities. Community composition differed significantly between non-invaded and invaded areas (ANOSIM, R = 0.685 and P 0.05). Invasion thus dramatically altered natural communities and although the subsequent removal of the dead mussel shells appears to have aided recovery, community composition remained different from the pre-invasion state after 5 months.