Impacts of experimental dredged material disposal on a shallow, sublittoral macrofauna community in Mecklenburg Bay (western Baltic Sea)

An experimental disposal of dredged material was performed in June 2001 at two adjacent sites in Mecklenburg Bay (western Baltic Sea) to investigate the impacts on a sublittoral fauna community (macrozoobenthos). Temporal changes in community parameters were analysed: Total abundance and multidimensional scaling (MDS) ordination results showed that dredged material disposal causes significant changes in benthic assemblages in comparison to the original situation before the disposal activities. The bivalves Arctica islandica and Macoma balthica were almost not affected by the disposal. Abundances of the polychaete N. hombergii as well as the epibenthic cumacean D. rathkei decreased by a factor of 1.4-3.9 whereas most other invertebrates suffered even more. Two years after the experimental disposal a high level of benthic recovery was found, but also a change in dominance structure. These changes are rather due to inter-annual variability in regional benthic recruitment processes in the Mecklenburg Bay than due to the disposal.