Expansive seagrass meadows grow in the tropical waters of the Gulf of Carpentaria and Torres Strait. They provide food and habitat for a diverse range of species, including dugongs and green turtles, which are of special importance to Islander and coastal Indigenous peoples. Seagrasses also stabilise substrates, baffle waves and tidal energy, increase water clarity and quality, and capture carbon.
Over recent decades, seagrass meadows have contracted globally as a result of human impacts and changes in coastal processes. Climate change-induced water temperature increases and more frequent and intense tropical storms may exacerbate this decline.
Australian communities and land and sea managers are developing and implementing management frameworks to support healthy and resilient seagrass ecosystems, but have been hampered by access to scientific data on seagrass distributions.
Seagrass mapping and monitoring has occurred in the Gulf of Carpentaria since the 1980s, and in Torres Strait since the early 2000s. This work has increasingly used geographic information systems (GIS) for collecting, storing and analysing Torres Strait and Gulf spatial (location) records of seagrasses, and associated measurements. Despite the breadth and high-value of this information for developing a comprehensive understanding of seagrass ecosystem change over time, its usefulness has been very limited as it was held in many forms by numerous individuals and organisations, and has therefore been largely inaccessible.
This project addressed this problem by compiling, validating, and integrating historical seagrass data from multiple sources, and making it publicly accessible.
Approach and findings
The project utilised and built on the experience and techniques developed during earlier National Environmental Science Program projects that similarly collated Great Barrier Reef World Heritage Area seagrass studies.
Seagrass survey data was located and obtained from around 50 separate research and monitoring studies which had occurred between 1983 and 2022 within the Torres Strait and Gulf of Carpentaria, including records from commercial research and unpublished works.
The data was evaluated and standardised for inclusion in a comprehensive spatial database.
The 1983–2022 seagrass data had been collected using a variety of survey methods such as diving, walking, helicopters, video transects and quadrats, and from a range of studies with different objectives.
Thirteen seagrass species from three families were included in the data, which represented information on around 1,465,000 ha of seagrass. Most survey data came from shallow subtidal or intertidal areas, reflecting the logistical difficulties and costs of deeper water surveys.
The newly developed seagrass database is available on the public-access web platform, eAtlas. It comprises:
- a site ‘layer’ (a logical collection of related data) of 48,612 geolocated data-point records of: seagrass species, depth, dominant sediment type, presence or absence, collection date, and data custodian; and
- a meadow layer featuring 641 individual seagrass meadows with information on: persistence over time, depth, intertidal or subtidal, biomass density, percentage cover, meadow area, temporal changes in meadow range, species, date, and survey method.
- Regional management and planning supported.
- Refinement of an integrative approach to improve the accessibility of historical data sets.
- A resource for researchers, Traditional Owners, Indigenous rangers, government and industry managers, and decision-makers.
This work has provided a valuable, interactive long-term spatial data set, publicly accessible on the internet at eAtlas. Stakeholders and the public can now use this system to access relevant seagrass information and to better understand meadow ranges through time, and associated species characteristics; knowledge that will inform management decisions.
The project also revealed a number of information gaps. For example, the data for the Gulf of Carpentaria is limited to the inshore coastlines, leaving the vast majority of the Gulf seabed unsurveyed. These deficiencies need to be remedied for optimal understanding and management of seagrass and its associated species into the future.
Gulf of Carpentaria and Torres Strait
James Cook University
Torres Strait Regional Authority
li-Anthawirriyarra Sea Rangers
Northern Territory Government
North Queensland Bulk Ports
Torres Strait Regional Authority
Local Aboriginal Land Councils
Land and sea rangers
Department of Climate Change, Energy, the Environment and Water
Journal article – Project 1.13
Seagrass spatial data synthesis from north-east Australia, Torres Strait and Gulf of Carpentaria, 1983 to 2022
Carter A, McKenna S, Rasheed M, Taylor H, van de Wetering C, Chartrand K, Reason C, Collier C, Shepherd L, Mellors J, McKenzie L, Duke N, Roelofs A, Smit N, Groom R, Barrett D, Evans S, Pitcher R, Murphy N, Carlisle M, David M, Lui S, and Coles R. (2023), Seagrass spatial data synthesis from north-east Australia, Torres Strait and Gulf of Carpentaria, 1983 to 2022. Limnol. Oceanogr. Lett. https://doi.org/10.1002/lol2.10352
Technical report – Project 1.13
Four decades of seagrass spatial data from Torres Strait and Gulf of Carpentaria
Carter A, McKenna S, Rasheed M, Taylor H, van de Wetering C, Chartrand K, Reason C, Collier C, Shepherd L, Mellors J, McKenzie L, Roelofs A, Smit N, Groom R, Barrett D, Evans S, Pitcher R, Murphy N, Duke N, Carlisle M, David M, Lui S, Pearson L, Laza T, Bon A, and Coles R (2022). Four Decades of Seagrass Spatial Data from Torres Strait and Gulf of Carpentaria. Report to the Reef and Rainforest Research Centre. Cairns, Queensland.
Fact sheet – Project 1.13
Project 1.13 Information sheet
NESP Marine and Coastal Hub (2021). Synthesising three decades of seagrass spatial data from Torres Strait and Gulf of Carpentaria. Project 1.13 Information sheet. Reef and Rainforest Research Centre, Cairns, Queensland.