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Providing evidence to improve practice

Individual study: Gravel seeding – A suitable technique for restoring the seabed following marine aggregate dredging?

Published source details

Cooper K., Ware S., Vanstaen K. & Barry J. (2011) Gravel seeding – A suitable technique for restoring the seabed following marine aggregate dredging? Estuarine, Coastal and Shelf Science, 91, 121-132


This study is summarised as evidence for the intervention(s) shown on the right. The icon shows which synopsis it is relevant to.

Landscape or artificially enhance the seabed (natural habitats) Subtidal Benthic Invertebrate Conservation

A controlled, before-and-after study in 2005–2007 in a sandy seabed area in the southern North Sea, UK (Cooper et al. 2011) found that depositing gravels to recreate natural habitat after ceasing aggregate extraction changed invertebrate community composition and increased species richness, abundance and biomass, after 12 months. Community composition became less similar to that of a site without gravel and more similar to that of a natural site (similarity with site without gravel presented as graphical analyses; similarity with natural site community increased from 14% to 28%). Invertebrate species richness increased from 46/m2 before gravel deposition to 118/m2 after 12 months. There were also increases in invertebrate abundance (before: 222; after: 3,081 individuals/m2) and biomass (before: 0.6; after: 7.5 g/m2). In May 2005, July 2005, July 2006 and May 2007, invertebrates were surveyed at three sites at 22–33 m depths. Two sites were historically subjected to aggregate extraction (1996–2000), of which one was added 4,444 m3 of gravels in July 2005 and the other left without gravel. The third site was natural (never subjected to aggregate extraction). Ten samples/site/survey were collected using sediment grabs (0.1 m2). Invertebrates (>0.5 mm) were dried, weighed, and counted.

(Summarised by Anaëlle Lemasson)