Mollusc communities and epiphyte cover associated with seagrass habitats in Tayaritja Sea Country (Furneaux Group of Islands), Lutruwita (Tasmania) (NESP MaC 3.6)
Updated: 2026-10-26
Seagrass beds are a dominant marine ecosystem of Tayaritja (the Furneaux Group of Islands) in the north-eastern waters off Tasmania. Historical coarse mapping has indicated extensive beds of Posidonia, Amphibolis, Heterozostera, and Zostera species, potentially comprising some of the largest and deepest seagrass extents found in temperate Australian waters. However, limited data on the distribution and ecological value of these seagrass habitats represents a significant knowledge gap in understanding Australia's wetland natural assets. This project mapped the extent, ecological composition, population structure, and blue carbon value of seagrass beds around Tayaritja, in partnership with the Tasmanian Aboriginal Centre. This record specifically describes the collection and analysis of epiphyte and mollusc communities associated with seagrass beds. Quadrat-level sampling of seagrass, epiphyte and mollusc community data was undertaken across five subtidal sites in Tayaritja Sea Country in February 2024. At each site, seagrass species, morphology, biomass and cover; epiphyte cover; and mollusc taxon counts, richness, abundance, and diversity metrics were assessed. The dataset provides a baseline for understanding biodiversity values associated with different seagrass species and epiphyte loads in Tayaritja Sea Country. See the "Lineage" section of this record for full methodology. ***EMBARGO NOTE*** Data is currently embargoed until 31/12/2026. Please contact the NESP Data Wrangler (Southern node) to discuss access options: Emma.Flukes@utas.edu.au
Data
- MaC_3-6_Furneaux_seagrass_mollusc_abundance
- MaC_3-6_Furneaux_seagrass_mollusc_biomass
- MaC_3-6_Furneaux_seagrass_mollusc_richness
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- {"title":"NESP MaC Project 3.6 - Exploring the distribution and ecological value of seagrass at the Furneaux Islands, Tasmania, 2023-2025 (IMAS, Deakin Uni)","recordAbstract":"This record provides an overview of the NESP Marine and Coastal Hub Research Plan 2023 project \"Exploring the distribution and ecological value of seagrass at the Furneaux Islands, Tasmania\". For specific data outputs from this project, please see child records associated with this metadata.\n--------------------\n\nSeagrass meadows are a dominant marine ecosystem of Tayaritja (the Furneaux Group of Islands) in north-eastern Tasmania. Historical coarse-scale mapping indicated extensive beds of Posidonia, Amphibolis, Heterozostera and Zostera, with the Posidonia and Amphibiolis beds being potentially some of the largest and deepest extents in temperate Australian waters. These habitats provide ecological, social, cultural and economic values, including habitat for fish and for maireener shells used by Pakana people for traditional necklace making.\n\nThis project worked in partnership with the Tasmanian Aboriginal Centre (TAC) to improve knowledge of seagrass extent, composition, population structure, ecological condition and blue carbon value around Tayaritja. Existing data were collated to guide survey design for mapping, and high-resolution satellite remote sensing was used to map seagrass beds down to a depth of approximately 30 metres, including intertidal lagoon systems associated with the Logan Lagoon Ramsar site. Field surveys, including video observations and rhizome coring, were used to validate satellite-derived maps and collect ecological samples.\n\nOutputs from this project include spatial layers of seagrass extent, variability and species composition, classified using the Seamap Australia National Benthic Habitat Classification Scheme. Rhizome samples were used to assess blue carbon storage, genetic connectivity and diversity, population structure, reproductive strategies, and relationships between seagrass, animal and microbial communities in shallow waters.\n\nThe project developed new standards-based approaches for collecting, analysing, managing and reporting seagrass data, alongside training and guidance for the TAC land and sea management team and Pakana Rangers. The resulting methods and datasets will support Indigenous-led monitoring and management of the proposed Tayaritja Sea Country Indigenous Protected Area (IPA), and improve understanding of wetland values relevant to Ramsar reporting and future blue carbon opportunities.\n\nOutputs\n• Seagrass extent and composition map for Furneaux group [dataset]\n• Seagrass imagery and associated seafloor annotations [dataset]\n• Final project report [written]"}
- {"title":"Imagery from BOSS and uBRUVs deployed for mapping temperate subtidal seagrass of Tayaritja Sea Country (Furneaux Group of Islands), Lutruwita (Tasmania) (NESP MaC 3.6)","recordAbstract":"Seagrass beds are a dominant marine ecosystem of Tayaritja (the Furneaux Group of Islands) in the north-eastern waters off Tasmania. Historical coarse mapping has indicated extensive beds of Posidonia, Amphibolis, Heterozostera, and Zostera species, potentially comprising some of the largest and deepest seagrass extents found in temperate Australian waters. However, limited data on the distribution and ecological value of these seagrass habitats represents a significant knowledge gap in understanding Australia's wetland natural assets.\n\nThis project mapped the extent, ecological composition, population structure, and blue carbon value of seagrass beds around Tayaritja. The study area focused on the coastal waters surrounding Flinders Island in the western Furneaux Group, with mapping extending from the high tide line to the depth limit of reliable optical detection (approximately 30 m), based on analysis of field data and satellite imagery capabilities in the region.\n\nThe field validation component of this study involved deployment of benthic video platforms to capture imagery of seagrass beds and associated ecosystems. A field campaign deployed a Benthic Observation Survey System (BOSS) and unBaited Remote Underwater stereo-Video system (stereo-uBRUV) at approximately 400 locations to collect photoquadrats and validate remote sensing outputs. Imagery annotation was conducted in the SQUIDLE+ platform.\n\nThe approach developed through this study contributed to the creation of the NESP Standard Operating Procedure (SOP) for Seagrass Mapping using Optical Remote Sensing (https://sustainabledevelopmentreform.github.io/nesp-sop-seagrass-mapping)..\n\nSee the \"Lineage\" section of this record for full methodology of field collection techniques.\nSee associated dataset https://doi.org/10.25959/e4s6-ge74 for habitat maps derived from field validation and remote sensing inputs."}
- {"title":"Blue carbon stocks of temperate subtidal seagrass beds in Tayaritja Sea Country (Furneaux Group of Islands), Lutruwita (Tasmania) (NESP MaC 3.6)","recordAbstract":"Seagrass beds are a dominant marine ecosystem of Tayaritja (the Furneaux Group of Islands) in the north-eastern waters off Tasmania. Historical coarse mapping has indicated extensive beds of Posidonia, Amphibolis, Heterozostera, and Zostera species, potentially comprising some of the largest and deepest seagrass extents found in temperate Australian waters. However, limited data on the distribution and ecological value of these seagrass habitats represents a significant knowledge gap in understanding Australia's wetland natural assets.\n\nThis project mapped the extent, ecological composition, population structure, and blue carbon value of seagrass beds around Tayaritja, in partnership with the Tasmanian Aboriginal Centre. This record specifically describes the seagrass-associated blue carbon component of the project, supporting improved understanding of sedimentary carbon storage in the region.\n\nSediment cores were collected from ten seagrass habitat sites around Flinders Island to assess spatial variability in carbon stocks and differences among seagrass species. Cores were collected to a maximum depth of 50 cm, or to the boundary between sediment and underlying rock, and were processed to estimate organic carbon stocks in below-ground sediment and plant material. The dataset includes sampling site locations, carbon stock estimates for the upper 50 cm of sediment, and measurements reported by depth interval within the core. At selected sites, samples were sieved to separate roots/rhizomes from the soil fraction, allowing carbon components to be reported separately where available.\n\nSee the \"Lineage\" section of this record for full methodology.\n\n***EMBARGO NOTE*** Data is currently embargoed until 31/12/2026. Please contact the NESP Data Wrangler (Southern node) to discuss access options: Emma.Flukes@utas.edu.au"}
- {"title":"Mapping of temperate subtidal seagrass beds in Tayaritja Sea Country (Furneaux Group of Islands), Lutruwita (Tasmania) (NESP MaC 3.6)","recordAbstract":"Seagrass beds are a dominant marine ecosystem of Tayaritja (the Furneaux Group of Islands) in the north-eastern waters off Tasmania. Historical coarse mapping has indicated extensive beds of Posidonia, Amphibolis, Heterozostera, and Zostera species, potentially comprising some of the largest and deepest seagrass extents found in temperate Australian waters. However, limited data on the distribution and ecological value of these seagrass habitats represents a significant knowledge gap in understanding Australia's wetland natural assets.\n\nThis project mapped the extent, ecological composition, population structure, and blue carbon value of seagrass beds around Tayaritja, in partnership with the Tasmanian Aboriginal Centre. The study area focused on the coastal waters surrounding Flinders Island in the western Furneaux Group, with mapping extending from the high tide line to the depth limit of reliable optical detection (approximately 30 m), based on analysis of field data and satellite imagery capabilities in the region.\n\nThis record specifically describes the benthic mapping component of the study. See https://doi.org/10.25959/WRXK-KV06 for imagery annotation data from the field validation campaigns.\n\nA combination of close-range remote sensing methods was used to map the extent and ecological values of seagrass beds. The approach developed through this study contributed to the creation of the NESP Standard Operating Procedure (SOP) for Seagrass Mapping using Optical Remote Sensing (https://sustainabledevelopmentreform.github.io/nesp-sop-seagrass-mapping)..\n\nHigh-resolution satellite imagery from Sentinel-2 (10 m) sensors, combined with bathymetric LiDAR data and oceanographic variables, was used to map baseline seagrass extent and composition. A field campaign deployed a Benthic Observation Survey System (BOSS) and unBaited Remote Underwater stereo-Video system (stereo-uBRUV) at approximately 400 locations to validate remote sensing outputs. From these data, maps were produced showing the extent and coverage of seagrass, sand, and macroalgae, and where possible, seagrass species composition, subject to water depth and clarity constraints.\n\nSee the \"Lineage\" section of this record for full methodology.\n\nThree key types of mapping products were developed:\n\n---Occurrence probability maps---\nContinuous probability surfaces (0-100%), modelled from presence/absence data, indicating the likelihood of habitat presence at each pixel for:\n• Seagrass (all morphologies; > 5% cover observed in underwater field imagery)\n• Macroalgae species/assemblages\n• Sand\n\n---Habitat percentage cover maps---\nQuantitative estimates of percent cover for each habitat category:\n• Seagrass (all morphologies)\n• Macroalgae species/assemblages\n• Sand\n\n---Derived products---\n• Baseline binary presence/extent maps derived from optimised probability thresholds:\n ○ Seagrass: sgprob > 0.5 & sgprob > macroprob & sandcover < 0.9\n ○ Macroalgae: macroprob > 0.5 & macroprob > sgprob & sandcover < 0.9\n ○ Sand: sandprob > 0.5 & sandcover < 0.2\n• Predicted seagrass species composition of binary extent map.\n• Fractional cover visualisation: combining cover percentages of multiple habitats into a single composite product\n• Composite habitat maps: combining binary habitat extents and delineating mixed habitat classes\n\nThese complementary products serve different purposes: probability maps provide confidence measures, extent maps delineate habitat boundaries, percent cover maps support quantitative analysis of habitat density patterns, and composite habitat maps represent the diversity of mixed habitat classes. Together, they provide a comprehensive understanding of seagrass and associated habitat distribution across the study area."}
- {"title":"Population genetics of temperate subtidal seagrass beds in Tayaritja Sea Country (Furneaux Group of Islands), Lutruwita (Tasmania) (NESP MaC 3.6)","recordAbstract":"Seagrass beds are a dominant marine ecosystem of Tayaritja (the Furneaux Group of Islands) in the north-eastern waters off Tasmania. Historical coarse mapping has indicated extensive beds of Posidonia, Amphibolis, Heterozostera, and Zostera species, potentially comprising some of the largest and deepest seagrass extents found in temperate Australian waters. However, limited data on the distribution and ecological value of these seagrass habitats represents a significant knowledge gap in understanding Australia's wetland natural assets.\n\nThis project mapped the extent, ecological composition, population structure, and blue carbon value of seagrass beds around Tayaritja, in partnership with the Tasmanian Aboriginal Centre. This record specifically describes the seagrass population genetics component of the project.\n\nLeaf tissue samples were collected from four seagrass species: Amphibolis antarctica, Heterozostera nigricaulis, Posidonia australis and Zostera muelleri. Samples were collected from multiple sites around Tayaritja Sea Country and processed for genome-wide SNP genotyping using the DArTseq platform. The dataset includes population-level genetic summary statistics, associated DArT metadata and reports, and raw sequence data used to support assessment of genetic diversity, clonality, population structure and connectivity among sampled seagrass populations.\n\nSee the \"Lineage\" section of this record for full methodology.\n\n***EMBARGO NOTE*** Data is currently embargoed until 31/12/2026. Please contact the NESP Data Wrangler (Southern node) to discuss access options: Emma.Flukes@utas.edu.au"}
