Habitat modelling of 'functional reef' and broad-scale ecosystem components for temperate Australian waters (NESP MaC 2.1)

This record describes the outputs of two different modelling exercises that were used to characterise the seafloor habitats for temperate Australian waters. The modelled area includes all shelf waters (<250m depth) in southern Australia south of the Tropic of Capricorn. Bioregional benthic habitat maps were constructed using (1) the Geoscience Australia 250m 2023 grid (ref); (2) ground-truthing observations derived from horizontally facing imagery from stereo-BRUV and BOSS camera systems; and (3) several physical datasets as covariates in model development (all oceanographic variables smoothed to 250m resolution). Source data is available from Geoscience Australia's eCat: https://doi.org/10.26186/148758 (bathymetry), Squidle+: (benthic imagery annotations), and (3) AODN Portal: https://portal.aodn.org.au/search (IMOS oceanographic datasets). The specific subset of GA observations used in this modelling exercise is available from https://github.com/UWA-Marine-Ecology-Group-projects/nesp-2.1/blob/main/data/tidy/NESP-2.1_broad-habitat.csv. See the NESP Mac Project 2.1 final report for a description of the sampling design for ground-truthing observations and annotation technique. -----Functional Reef model (binomial)----- This model discriminates ‘functional reef’ from sediment (non-reef) ecosystem types. Functional reef is defined by this project as “any seabed area functioning as a reef, which may include dense beds of sessile invertebrates or molluscs”. This term was chosen because much of the continental shelf is dominated by sediment yet is stable enough to support emergent sessile biota that provide structure and resources for “reef-affiliated” species. The modelling approach uses a Bayesian representation of a Binomial generalised linear model. For ground-truthing benthic annotations, the following benthic categories were collapsed into the ‘functional reef’ classification: sessile invertebrates, bare rocky reef (consolidated), macroalgae, Amphibolis spp. and Thalassodendron spp. All other benthic classifications were assigned to the ‘non-reef’ category. -----Ecosystem Component model (multinomial)----- This model discriminates between five broad habitat types (hereafter ‘ecosystem components’): seagrass, macroalgae, sessile invertebrates, bare consolidated substrata, bare unconsolidated substrata. The modelling approach uses a Bayesian implementation of a Multinomial generalised linear model. For ground-truthing benthic annotations, benthic annotations for mobile species (e.g. echinodermata) were discarded. All remaining annotations were collapsed into the five broad ecosystem components. A selection of mapping (WMS) services are listed in the 'Downloads & Links' section of this record. See the 'Lineage' section for a full description of the data packages available for download, and for more visualisation options.