Surveys of reef-building coral communities, benthic cover and environmental factors on nearshore reefs of the Great Barrier Reef

Species richness, cover and community structure of reef-building corals were assessed at 599 sites on 135 reefs along the Great Barrier Reef (GBR) between 1994 and 2001, with a focus on the nearshore area. Reefs were surveyed using a standard method of Rapid Ecological Assessment.On each reef, from 1 to 31 habitats were surveyed in up to 3 depth zones (sites), comprising (a) the shallow reef flat and crest; (b) the shallow reef slope (between 3 and 7m depth); and (c) the deeper reef slope (maximum depth of 16m) respectively. At each site, an inventory of reef-building corals was compiled.Approximately 600 of the ~2,400 reefs of the GBR are located nearshore. The biological structure and ecological status of many nearshore reefs remain relatively poorly understood. This gap in knowledge was addressed by undertaking the first broad-scale assessment of nearshore reefs along >75% of the length of the GBR focusing on patterns in the species composition, richness and community structure of reef-building corals.Haphazardly-chosen starting positions were recorded with a portable Global Positioning System. The swims took an average of 45 min and covered varying distances along the slope; generally areas were surveyed until no new taxa had been encountered for some time. Corals were identified to species level wherever possible, otherwise to genus and growth form (e.g. massive Porites). At the end of each site survey, the abundance of each taxon was recorded in six broad abundance categories - absent, rare, uncommon, common, abundant, or dominant. A visual estimate of average cover of live hard coral was also made, recorded in 6 categories: 0=0%, 1=1-10%, 2=11-30%, 3=31-50%, 4=51-75%, 5=76-100%.Data have been used for the e-Atlas:http://e-atlas.org.au/content/hard-coral-biodiversity-surveys-gbrA subset of the data has been provided to the Ocean Biogeographic Information System: Australian Institute of Marine Science - Great Barrier Reef nearshore coral diversity (https://obis.org/dataset/eee81b0b-6b72-4963-9f43-ff1631bbfea3)