Assessment of ecosystem function following marine aggregate dredging

A number of indices designed to assess ecosystem function were applied to an existing benthic macrofaunal dataset collected following recent marine aggregate extraction activity at the Hastings Shingle Bank (UK). The objective of the study was to assess the use of these different functional metrics, some incorporating biological traits analysis, to investigate the rate of recovery in ecosystem function after dredging impact. All of the indices tested behaved in a broadly similar fashion following the aggregate extraction event, although some suggested faster rates of functional recovery than others. All indicated that the disturbed area of seabed was capable of full recovery given enough time. It is considered that this outcome may be because the physical nature of the seabed was unlikely to have been permanently altered by dredging for aggregate by the method used. This is not always the case following aggregate extraction and depends on the dredging protocol used (e.g., sediment screening). The indices tested (some applied for the first time to benthic macrofaunal data) were considered to be complementary to traditional environmental assessment metrics and each might be used under different circumstances.