Habitat value of Sydney rock oyster (Saccostrea glomerata) reefs on soft sediments

Estimates of the ecological and economic value of ecosystems can provide important information for the prioritisation of conservation and restoration actions. Oyster reefs that were once common in temperate coastal waters have now been largely degraded or lost. Oyster reefs provide a suite of ecological services, including habitat and a food supply for a range of other species. In Australia, there is growing interest in oyster reef restoration, but there are knowledge gaps with regard to their structure and habitat value. Here, we describe the structure of eight remnant Sydney rock oyster (Saccostrea glomerata) reefs and estimate the density, biomass, productivity and composition of mobile macroinvertebrate and infaunal communities associated with them. The oyster reefs had a distinct assemblage of macroinvertebrates, with fivefold higher density of larger ($2 mm) macroinvertebrates, fivefold higher biomass and almost fivefold higher productivity, than that of adjacent bare sediments. The productivity of infaunal communities was twice as high under oyster reefs than in adjacent bare sediments. Therefore, S. glomerata reef restoration is likely to provide important habitat for macroinvertebrate communities and boost local secondary production