Impacts of dredged material disposal on macrobenthic invertebrate communities: A comparison of structural and functional (secondary production) changes at disposal sites around England and Wales.

Although the impacts of dredged material disposal in the marine environment have been well studied, there is currently a limited understanding of the associated impacts on benthic function. This study compares macrofaunal structural and functional (based on secondary production estimates) responses to dredged material disposal at 14 sites across the coast of England and Wales. Disposal resulted in significant reductions of total secondary production at seven sites; no sites exhibited significant increases in production estimates. These seven sites were generally those which displayed significant structural impacts. There was no clear relationship between multivariate structural changes and taxonomic contribution to total production, indicating that a lack of change in the former (regarded as a sensitive indicator of change) does not always signify a lack of a significant functional impact. The need to evaluate functional changes, in addition to structural impacts, with respect to dredged material disposal site monitoring is discussed.