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    This dataset consists of polygons delineating the broad-scale regional marine habitats of selected areas in Western Australia, mostly in existing and proposed marine conservation reserve areas. Habitat mapping was carried out by various organisations, including DPAW, using a range of methodologies over many years. Diverse classifications and habitat descriptions were standardised to the DPaW broad-scale Shallow-water Marine Habitat Classification scheme (SMHC) (Bancroft, 2003) after initial habitat mapping and classification work had been done. Habitat polygons are classified to the broad-scale ecological Community level and where more detailed data exist, local-scale Functional Group level (Bancroft, 2003). Polygons were attributed with habitat class names only, textual descriptions of these classes are provided in this metadata statement and further in Bancroft (2003).

  • Diel partitioning of animals within ecological communities is widely acknowledged, yet rarely quantified. Investigation of most ecological patterns and processes involves convenient daylight sampling, with little consideration of the contributions of nocturnal taxa, particularly in marine environments. Here we assess diel partitioning of reef faunal assemblages at a continental scale utilizing paired day and night visual census across 54 shallow tropical and temperate reefs around Australia. Day/night differences were most pronounced in the tropics, with fishes and invertebrates displaying distinct and opposing diel occupancy on coral reefs. Tropical reefs in daytime were occupied primarily by fishes not observed at night (64% of all species sighted across day and night, and 71% of all individuals). By night, substantial emergence of invertebrates not otherwise detected during sunlit hours occurred (56% of all species, and 45% of individuals). Nocturnal emergence of tropical invertebrates corresponded with significant declines in the richness and biomass of predatory and herbivorous diurnal fishes. In contrast, relatively small diel changes in fishes active on temperate reefs corresponded to limited nocturnal emergence of temperate invertebrates. This reduced partitioning may, at least in part, be a result of strong top-down pressures from fishes on invertebrate communities, either by predation or competitive interference. For shallow reefs, the diel cycle triggers distinct emergence and retreat of faunal assemblages and associated trophic patterns and processes, which otherwise go unnoticed during hours of regular scientific monitoring. Improved understanding of reef ecology, and management of reef ecosystems, requires greater consideration of nocturnal interactions. Without explicit sampling of nocturnal patterns and processes, we may be missing up to half of the story when assessing ecological interactions.