The effects of marine sand and gravel extraction on the sediment composition and macrofaunal community of a commercial dredging site (15 years post-dredging)

• Seabed subject to high intensity dredging remained disturbed after 11 years.
• Based on the available data, we predicted a recovery after 15-20 years.
• Results from year 15 showed that seabed macrofauna recovery had occurred.
• Knowledge of recovery times is important for sustainable seabed development.

A prediction that faunal recovery of a marine aggregate extraction site subjected to high dredging intensity was likely to take 15–20 years was investigated. Samples were collected at the high dredging intensity site and two reference sites in 2011 (15 years post-dredging). Results indicated that the high site had similar sediment characteristics to the reference sites by 2011. Macrofaunal data analyses showed no difference between the values of all calculated univariate measures (abundance, number of taxa, biomass and evenness) between the high and reference sites. Multivariate analyses found that the macrofaunal community at the high site was comparable to those of the reference sites by 2011. Overall, the results supported the predicted recovery time. The findings of the study suggest that persistent physical impacts prolonged the biological recovery of the high site.