Impacts of physical disturbance on the recovery of a macrofaunal community: A comparative analysis using traditional and novel approaches

The recovery of macrofaunal communities after marine aggregate dredging was assessed using both traditional indices (abundance, biomass and species diversity), and functional analysis techniques (Somatic Production, Taxonomic Distinctness, Infaunal Trophic Index, Biological Traits Analysis and Rao's Quadratic Entropy). A previously dredged area (Area 222), located off the southeast coast of England was selected for this investigation. Area 222 was split into sites that had been subjected to relatively high dredging intensity, relatively low dredging intensity, and undisturbed reference areas. Both traditional and functional analyses indicated that macrofauna at the low dredging intensity site had fully recovered at least 7 years after the dredging ceased. Recovery times at the high intensity site had a greater variability and most of the techniques recorded the recovery had yet to take place even 11 years after the dredging had ceased. Since Area 222 was dredged for a long period of time (approx. 25 years), it is suggested that a longer time series of study be carried out so that the definitive recovery period in this high intensity site can be determined. While a longer time series study is not always a realistic or cost effective, the present study could be useful to facilitate the selection of metrics to support in the assessment of macrofaunal recovery.