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

Published source details Waye-Barker G.A., McIlwaine P., Lozach A. & Cooper K.M. (2015) The effects of marine sand and gravel extraction on the sediment composition and macrofaunal community of a commercial dredging site (15 years post-dredging).. Marine Pollution Bulletin, 99, 207-215.
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This study is summarised as evidence for the following.

	Action	Category
	Cease or prohibit aggregate extraction Action Link

Cease or prohibit aggregate extraction

A systematic review of 22 case studies reported between 1977 and 2007 of marine aggregate extraction sites across the world (Waye-Barker et al. 2015) found that, after extraction stopped, invertebrate communities took between nine months (Bristol Channel, UK) and several decades (Thames, UK) to ‘recover’ (terminology not explained) and become similar to communities occurring at non-impacted sites or prior to-extraction. Invertebrate community recovery time varied with seabed type and current strength (data not statistically tested). The shortest average ‘recovery’ time (4.5 years) was recorded for shallow mixed sediment plains with moderate currents (1.8–4 Nm²). The longest average ‘recovery’ time (10.8 years) was recorded for shallow coarse sediment plains with weak currents (0–1.8 Nm²). Case studies were identified by using set search terms, and included peer-reviewed publications (n=18), technical reports (n=2), unpublished data (n=1) and personal communication (n=1). Aggregate extraction sites were categorised by seabed type and current strength. Invertebrate ‘recovery’ times were extracted from community composition, abundance, biomass and diversity data for each site (data not presented).

(Summarised by: Anaëlle Lemasson)