Macrofauna diversity in Posidonia oceanica detritus: distribution and diversity of mobile macrofauna in shallow sublittoral accumulations of Posidonia oceanica detritus

The mobile macrofauna in submerged detritus accumulations (SDAs) of the seagrass Posidonia oceanica was investigated in the Bay of Calvi, Corsica, Mediterranean Sea. The distribution of the macrofauna was related to the exposure of the habitat and to the degree of packing and decomposition of the SDAs. In the less decomposed, younger SDAs, the number of individuals per species, but also species richness, was relatively low. In the more decomposed, older SDAs, the abundance and number of species increased, showing predominance of a few crustacean taxa such as gammaridean amphipods, shrimps and the leptostracan Nebalia bipes. Many of the macrofaunal species in the SDAs are members of the animal communities of surrounding seagrass meadows or adjacent hard or soft bottoms, while others, like N. bipes, apparently live in closer association with the SDAs.