This report provides a preliminary assessment of the utility of a satellite remote sensing approach for the identification and characterisation of coastal habitats that are critical for threatened and migratory species in northern Australia. This work is part of the Habitats research theme in the A12 Northern Seascapes Scoping Project. The Australian Landsat archive in the Digital Earth Australia (DEA) analysis platform for satellite imagery was utilised to demonstrate its potential for mapping intertidal areas and mangrove extent, and changes over time in the extent of coastal landforms and habitats. Seven estuaries were examined, Darwin Harbour and the Keep, Daly, Roper, Macarthur, Flinders and Gilbert River estuaries. The estuaries were selected by the A12 Project team because they are known to provide important areas for the species of interest. Features of importance to shorebird populations were a focus. The focus of this scoping work was to utilise the DEA Landsat archive to build understanding of the effects of tidal dynamics on intertidal habitats across this region of large and complex tides, examine approaches to mapping the extent of key coastal habitats, and test the potential of the archive to detect coastal habitat change, in particular mangrove. In northern Australia, cloud interference can make it difficult to obtain clear satellite imagery. To avoid this issue, the geometric median of surface reflectance values was used to produce crisp, cloud-free composite images that depict the maximum observed tidal extent in the seven estuaries. Tide-tagging of satellite imagery was also successfully employed to allow any tide induced change to be removed from change-detection analyses and clearly depict the intertidal extent. Application of the Intertidal Extent Model in the DEA enabled the extent and morphology of estuarine intertidal environments to be mapped. The DEA also enabled habitat change change detection using the fully processed, high density, three decade long Landsat time series. The results clearly depict the dynamic nature of some areas, including large-scale rapid island growth and mangrove expansion (e.g. Keep River and Gilbert River estuaries), gradual long-term expansion of mangrove (Flinders River and McArthur River estuaries), and estuaries with areas of rapid recent die back of mangrove (Roper River and Flinders estuaries). This information is important for the management of key species as well decisions around coastal developments. With Landsat and new satellite data streams (e.g. Sentinal 2) continually being added to the DEA, this time-series analysis approach could be developed into an effective habitat extent and condition monitoring tool for northern Australia. The image products and analysis tools employed in this study demonstrate the potential utility of DEA for mapping the extent and dynamics of key coastal and estuarine habitats utilised by threatened and migratory species. To better inform the management of these species, a key next step in this approach is to utilise ground-validation data to enable these habitats to be robustly classified and quantified using the Landsat archive. This analysis should provide important baseline information and enable the extent and condition of key habitats to be monitored. Preferred Citation: Phillips, C., Lymburner, L. & Brooke, B. (2018). Characterising northern estuaries using Digital Earth Australia. Report to the National Environmental Science Programme, Marine Biodiversity Hub. Geoscience Australia.

This report provides a preliminary assessment of the utility of a satellite remote sensing approach for the identification and characterisation of coastal habitats that are critical for threatened and migratory species in northern Australia. This work is part of the Habitats research theme in the A12 Northern Seascapes Scoping Project. The Australian Landsat archive in the Digital Earth Australia (DEA) analysis platform for satellite imagery was utilised to demonstrate its potential for mapping intertidal areas and mangrove extent, and changes over time in the extent of coastal landforms and habitats. Seven estuaries were examined, Darwin Harbour and the Keep, Daly, Roper, Macarthur, Flinders and Gilbert River estuaries. The estuaries were selected by the A12 Project team because they are known to provide important areas for the species of interest. Features of importance to shorebird populations were a focus. The focus of this scoping work was to utilise the DEA Landsat archive to build understanding of the effects of tidal dynamics on intertidal habitats across this region of large and complex tides, examine approaches to mapping the extent of key coastal habitats, and test the potential of the archive to detect coastal habitat change, in particular mangrove. In northern Australia, cloud interference can make it difficult to obtain clear satellite imagery. To avoid this issue, the geometric median of surface reflectance values was used to produce crisp, cloud-free composite images that depict the maximum observed tidal extent in the seven estuaries. Tide-tagging of satellite imagery was also successfully employed to allow any tide induced change to be removed from change-detection analyses and clearly depict the intertidal extent. Application of the Intertidal Extent Model in the DEA enabled the extent and morphology of estuarine intertidal environments to be mapped. The DEA also enabled habitat change change detection using the fully processed, high density, three decade long Landsat time series. The results clearly depict the dynamic nature of some areas, including large-scale rapid island growth and mangrove expansion (e.g. Keep River and Gilbert River estuaries), gradual long-term expansion of mangrove (Flinders River and McArthur River estuaries), and estuaries with areas of rapid recent die back of mangrove (Roper River and Flinders estuaries). This information is important for the management of key species as well decisions around coastal developments. With Landsat and new satellite data streams (e.g. Sentinal 2) continually being added to the DEA, this time-series analysis approach could be developed into an effective habitat extent and condition monitoring tool for northern Australia. The image products and analysis tools employed in this study demonstrate the potential utility of DEA for mapping the extent and dynamics of key coastal and estuarine habitats utilised by threatened and migratory species. To better inform the management of these species, a key next step in this approach is to utilise ground-validation data to enable these habitats to be robustly classified and quantified using the Landsat archive. This analysis should provide important baseline information and enable the extent and condition of key habitats to be monitored. Preferred Citation: Phillips, C., Lymburner, L. & Brooke, B. (2018). Characterising northern estuaries using Digital Earth Australia. Report to the National Environmental Science Programme, Marine Biodiversity Hub. Geoscience Australia.

This report provides a preliminary assessment of the utility of a satellite remote sensing approach for the identification and characterisation of coastal habitats that are critical for threatened and migratory species in northern Australia. This work is part of the Habitats research theme in the A12 Northern Seascapes Scoping Project. The Australian Landsat archive in the Digital Earth Australia (DEA) analysis platform for satellite imagery was utilised to demonstrate its potential for mapping intertidal areas and mangrove extent, and changes over time in the extent of coastal landforms and habitats. Seven estuaries were examined, Darwin Harbour and the Keep, Daly, Roper, Macarthur, Flinders and Gilbert River estuaries. The estuaries were selected by the A12 Project team because they are known to provide important areas for the species of interest. Features of importance to shorebird populations were a focus. The focus of this scoping work was to utilise the DEA Landsat archive to build understanding of the effects of tidal dynamics on intertidal habitats across this region of large and complex tides, examine approaches to mapping the extent of key coastal habitats, and test the potential of the archive to detect coastal habitat change, in particular mangrove. In northern Australia, cloud interference can make it difficult to obtain clear satellite imagery. To avoid this issue, the geometric median of surface reflectance values was used to produce crisp, cloud-free composite images that depict the maximum observed tidal extent in the seven estuaries. Tide-tagging of satellite imagery was also successfully employed to allow any tide induced change to be removed from change-detection analyses and clearly depict the intertidal extent. Application of the Intertidal Extent Model in the DEA enabled the extent and morphology of estuarine intertidal environments to be mapped. The DEA also enabled habitat change change detection using the fully processed, high density, three decade long Landsat time series. The results clearly depict the dynamic nature of some areas, including large-scale rapid island growth and mangrove expansion (e.g. Keep River and Gilbert River estuaries), gradual long-term expansion of mangrove (Flinders River and McArthur River estuaries), and estuaries with areas of rapid recent die back of mangrove (Roper River and Flinders estuaries). This information is important for the management of key species as well decisions around coastal developments. With Landsat and new satellite data streams (e.g. Sentinal 2) continually being added to the DEA, this time-series analysis approach could be developed into an effective habitat extent and condition monitoring tool for northern Australia. The image products and analysis tools employed in this study demonstrate the potential utility of DEA for mapping the extent and dynamics of key coastal and estuarine habitats utilised by threatened and migratory species. To better inform the management of these species, a key next step in this approach is to utilise ground-validation data to enable these habitats to be robustly classified and quantified using the Landsat archive. This analysis should provide important baseline information and enable the extent and condition of key habitats to be monitored. Preferred Citation: Phillips, C., Lymburner, L. & Brooke, B. (2018). Characterising northern estuaries using Digital Earth Australia. Report to the National Environmental Science Programme, Marine Biodiversity Hub. Geoscience Australia.

Seven case study locations (Keep, Daly, Roper, McArthur, Flinders, and Gilbert River estuaries, and Darwin Harbour) were used to test the utility of the Australian Landsat data archive in the Digital Earth Australia analysis platform for characterising and monitoring the condition and change in coastal habitats. A suite of analyses was undertaken including: assessing the extent of different coastal habitats, detecting coastal change including change in mangrove communities, and the distribution of intertidal areas. The work was successful in: (a) generating baseline information for the case study areas; and, (b) developing valuable monitoring tools for future use.

Data associated with outputs from the final report of the NESP MBH A12 report "Distribution and habitat suitability of Threatened and Migratory Marine Species in Northern Australia". The North Marine Bioregion is home to a diversity of threatened and data-poor marine species. In the absence of critical data on species’ distributions, population connectivity, and essential habitat, decision-making to progress the current ‘Developing the North’ agenda has the potential to negatively impact Matters of National Environmental Significance. Data compiled across multiple sources were used to model and map the distribution of 16 priority Threatened and Migratory marine species. The objective of the project was to improve the current data-poor species distribution maps held by DAWE to assist with policy decisions for these species. We used a spatial distribution modelling approach based on presence data for these species from 121 spatial datasets and associated, remotely sensed environmental variables. The output is a series of distribution maps to enhance decision-makers’ ability to assess potential impacts of development proposals in Northern Australia under the EPBC Act.

This record provides an overview of the scope and research output of NESP Marine Biodiversity Hub Project A12 - "Scoping a seascape approach to managing and recovering Northern Australian threatened and migratory marine species". For specific data outputs from this project, please see child records associated with this metadata. Northern Australia is the current focus of substantial economic development, which has the potential to impact biodiversity and cultural values. The Northern Seascape scoping project will assess the status of knowledge of EPBC-listed Threatened and Migratory Marine species, and pressures, Indigenous priorities, habitats, fisheries bycatch, and EPBC referrals in relation to them across the North Marine Bioregion (coast to EEZ edge). The focus will be at the multiple taxa level, including elasmobranchs, shorebirds, turtles and cetaceans. The project will scope research needs and directions for a broad Northern Seascape project (2018–2020), by identifying future research hotspots. Planned Outputs • Maps of Threatened and Migratory Marine species occurrence and habitats, and a gap analysis of research and data needs • Maps of state and trends in pressures and Threatened and Migratory Marine species, and the intersection between them • A report on Indigenous marine research and management priorities for Threatened and Migratory Marine species • Maps and time-series graphs that depict the extent and timing of past changes in coastal habitats that are important for TMM species • Identification of Threatened and Migratory Marine species bycatch and bycatch mitigation research priorities • Identification of EPBC referral spatial and species trends • Data, data visualisation and summaries available online through an appropriate web-based portal and/or existing internal DoEE information products • Project report synthesizing northern Australian Threatened and Migratory Marine species, pressures, Indigenous priorities, coastal habitat change, fisheries bycatch mitigation research priorities, and EPBC referral trends, and the identification of future research hotspots

This dataset corresponds to land area polygons of Australian coastline and surrounding islands. It was generated from 10 m Sentinel 2 imagery from 2022 - 2024 using the Normalized Difference Water Index (NDWI) to distinguish land from water. It was estimated from composite imagery made up from images where the tide is above the mean sea level. The coastline approximately corresponds to the mean high water level. This dataset was created as part of the NESP MaC 3.17 northern Australian Reef mapping project. It was developed to allow the inshore edge of digitised fringing reef features to be neatly clipped to the land areas without requiring manual digitisation of the neighbouring coastline. This required a coastline polygon with an edge positional error of below 50 m so as to not distort the shape of small fringing reefs. We found that existing coastline datasets such as the Geodata Coast 100K 2004 and the Australian Hydrographic Office (AHO) Australian land and coastline dataset did not meet our needs. The scale of the Geodata Coast 100K 2004 was too coarse to represent small islands and the the positional error of the Australian Hydrographic Office (AHO) Australian land and coastline dataset was too high (typically 80 m) for our application as the errors would have introduced significant errors in the shape of small fringing reefs. The Digital Earth Australia Coastline (GA) dataset was sufficiently accurate and detailed however the format of the data was unsuitable for our application as the coast was expressed as disconnected line features between rivers, rather than a closed polygon of the land areas. We did however base our approach on the process developed for the DEA coastline described in Bishop-Taylor et al., 2021 (https://doi.org/10.1016/j.rse.2021.112734). Adapting it to our existing Sentinel 2 Google Earth processing pipeline. The difference between the approach used for the DEA coastline and this dataset was the DEA coastline performed the tidal calculations and filtering at the pixel level, where as in this dataset we only estimated a single tidal level for each whole Sentinel image scene. This was done for computational simplicity and to align with our existing Google Earth Engine image processing code. The images in the stack were sorted by this tidal estimate and those with a tidal high greater than the mean seal level were combined into the composite. The Sentinel 2 satellite follows a sun synchronous orbit and so does not observe the full range of tidal levels. This observed tidal range varies spatially due to the relative timing of peak tides with satellite image timing. We made no accommodation for variation in the tidal levels of the images used to calculate the coastline, other than selecting images that were above the mean tide level. This means tidal height that the dataset coastline corresponds to will vary spatially. While this approach is less precise than that used in the DEA Coastline the resulting errors were sufficiently low to meet the project goals. This simplified approach was chosen because it integrated well with our existing Sentinel 2 processing pipeline for generating composite imagery. To verify the accuracy of this dataset we manually checked the generated coastline with high resolution imagery (ArcGIS World Imagery). We found that 90% of the coastline polygons in this dataset have a horizontal position error of less than 20 m when compared to high-resolution imagery, except for isolated failure cases. During our manual checks we identified some areas where our algorithm can lead to falsely identifying land or not identifying land. We identified specific scenarios, or 'failure modes,' where our algorithm struggled to distinguish between land and water. These are shown in the image "Potential failure modes": a) The coastline is pushed out due to breaking waves (example: western coast, S2 tile ID 49KPG). b) False land polygons are created because of very turbid water due to suspended

This record provides an overview of an NESP Marine and Coastal Hub Research Project 3.17 - Locating Unidentified Reef and Habitat Features in the Northern Australian Seascape. For specific data outputs from this project, please see child records associated with this metadata. This project will map the reefs of the northern Australian seascape, from central Western Australia, through to western Cape York in Queensland. Reefs are hotspots of conservation as they provide habitat for numerous marine species but are poorly mapped for much of northern Australia. This project will deliver datasets of reef boundaries, satellite imagery optimised for the marine environment, and geomorphic and benthic habitat maps for shallow clear reefs based on improvements to the Allen Coral Atlas. These products are targeted at assisting in the planning and evaluation of coastal development in northern Australia, helping to ensure that sensitive high value habitats are identified and considered in development proposals. This project will use satellite imaging techniques to map this region based on methods consistent with existing reef mapping of the Great Barrier Reef, Torres Strait, and the Coral Sea. Planned Outputs • Marine optimised satellite imagery for northern Australian seascape dataset (AIMS) [spatial dataset] • Reef boundary mapping for northern Australia seascape dataset (AIMS) [spatial dataset] • Improved shallow water habitat dataset (UQ) [spatial dataset] • Updated Benthic and Geomorphic Reference Data for Global Coral Reef Mapping (Western Australia, Timor Sea and Arafura Sea regions) dataset (UQ) [spatial dataset] • Technical report on Standard Operating Procedures for mapping reef boundaries (AIMS, UQ) • Final technical report with analysed data and a short summary of recommendations for policy makers of key findings [written]

This record provides an overview of the NESP Marine and Coastal Hub small-scale study - "A national framework for improving seagrass restoration". For specific data outputs from this project, please see child records associated with this metadata. Seagrasses provide resources and ecosystem services critical to the health of coastal ecosystems and human populations. They increase water clarity, stabilise sediments and reduce coastal erosion, sequester carbon, and provide habitat and food to marine animals, including commercially important fish and invertebrates. Across Australia, the loss of >275,000 ha of seagrass meadows and associated ecosystem services—valued at AU$ 5.3 billion—has contributed to the long-term degradation of estuarine and coastal marine ecosystems. Restoration of seagrass is critical for improving the health and function of these ecosystems and sustaining coastal communities and industries that depend on them, yet restoration projects to date typically occur at small scales, driven by local priorities and with variable success. This project addressed this problem by bringing together scientists and key stakeholders to collate knowledge on seagrass ecology and restoration, and generated a framework to scaling-up restoration nationally. A national workshop with experts identified a shortlist of drivers key to restoration success, including sediment dynamics, microbial communities, hydrodynamics, and species interactions. It highlighted the importance of incorporating seagrass genetics and life histories into site and donor material selection to improve long-term resilience. New technologies such as eDNA, automation, and AI were also assessed for their potential to improve monitoring and reduce costs, while standardised methodologies and molecular tools were recommended to track microbial indicators and site suitability. A key insight from the workshop was the central role of sediment processes in feedback loops that determine seagrass health—providing a foundation for more effective, scalable restoration strategies. On-ground case studies were conducted in Western Australia and New South Wales to test the proposed restoration framework in collaboration with Indigenous and community partners: sediment quality assessment and manipulation (Gamay Rangers, UNSW); seed and seedling capture using sediment-filled hessian tubes (Malgana Rangers, UWA); and large-scale seed collection for seed-based restoration through the 'Seeds for Snapper' initiative (OzFish and UWA). These trials demonstrated the effectiveness of community-led restoration and reinforced the potential of seed-based methods for scaling up seagrass recovery. Outputs • Effect of sediment quality and manipulation on seagrass transplant success [field data] • Locations and health of beachcast fragments of Posidonia in Botany Bay [field data] • Effect of engineering hydrodynamics (by use of hessian socks) on seagrass transplant success [field data] • Final project report [written]

This record provides an overview of the NESP Marine and Coastal Hub scoping study - "National Areas of Interest for Seabed Mapping, Characterisation and Biodiversity Assessment". For specific data outputs from this project, please see child records associated with this metadata. Seabed and marine biodiversity data are time-consuming and costly to collect, so it is imperative that acquisition is focused on areas that align with end user priorities. The value that different stakeholders place on seabed and biodiversity data can be difficult to determine. Therefore, a shared process for identifying survey priorities is required to ensure the maximum shared benefit of future survey investment across research users, funding agencies, infrastructure providers, as well as the wider marine research community. The project aimed to assist with the planning and prioritisation of marine surveys (both physical and biological) by scoping a prioritisation framework for marine surveys undertaking physical and biological seabed data collection in Australia. Focused workshops and targeted engagements with seabed mapping organisations were used to develop a standard set of metadata for agencies to define spatial Areas of Interest (AOI). The standard metadata were used in a prototype prioritisation framework that allows users to transparently and consistently rank and prioritise survey work or data delivery processes. The prioritisation is then based on rankings established by defined sets of criteria. A web-based AOI submission tool and mapping publication service was then developed for these defined areas as part of the AusSeabed Survey Coordination Tool. Adoption of this tool facilitates the development of an interim national areas of interest product to inform future survey planning. This product supports both the needs of Parks Australia's network Science Plans, and consideration of information needs for Indigenous Protected Areas within Sea Country. Outputs • National Areas of Interest polygon & interactive map [dataset] • Code for Survey Coordination Tool [Github Repo] • Final Report with Value Prioritisation Framework [written]