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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.
The Gulf of Carpentaria and Torres Strait in northern Australia support globally significant seagrass ecosystems which provide food for migratory species such as dugong and turtle, habitat for commercially important fisheries, and underpin the livelihoods and wellbeing of the region’s First Nations saltwater people. Having a source of reliable data on seagrass distribution and species composition is critical to understanding how this ecosystem may be changing while managing for resilience and mitigating risks, and when designing monitoring programs in this remote region. Spatial data on seagrass has been collected across these regions since the early 1980’s, but the data was often poorly curated and its location and storage disparate. In many cases the data has not been publicly available, and in some cases has already been lost. To address these issues, we compiled, validated, and synthesized historical seagrass spatial data to create a publicly available database accessible on eAtlas (https://doi.org/10.26274/2CR2-JK51) under a Creative Commons 4.0 Licence.
This spatial database includes compiled and standardised data from 40 years of field surveys. It includes (1) a site layer with 48,612 geolocated data points including features such as seagrass and seagrass species presence/absence, depth, dominant sediment type, collection date, and data custodian; and (2) a meadow layer that includes 641 individual seagrass meadows with features including meadow persistence, meadow depth (intertidal/subtidal), meadow density based on mean biomass and/or mean percent cover, meadow area, meadow area range (based on the composite of seagrass meadows across different survey dates at the same location), dominant seagrass species, seagrass species present, survey date range, and survey method. We include records collected under commercial contracts being made available here for the first time, and previously unpublished data collected during mangrove surveys in 2017 (Duke et al. 2020).
This data has resulted in the identification of thirteen seagrass species in the region. The deepest seagrass was found at -38 m mean sea level (MSL). Our database is a valuable resource that provides management agencies, rangers, Traditional Owners, ports, industry, and researchers with a long-term spatial resource describing seagrass populations from the early-1980s through to early 2022 against which to assess change.
This seagrass data compilation provides an important evidence base for marine spatial planning and management, to underpin or assist with:
- Assessments of benthic habitats and associated species (fish, turtle, dugong) in the Gulf of Carpentaria and Torres Strait.
- Understanding how risk, land use management and spatial protection intersect with the location of seagrass communities, e.g. Queensland, Northern Territory and Commonwealth Marine Parks, Indigenous Protected Areas, Fish Habitat Areas and Port Exclusion Zones.
- A transparent methodology to expand spatial analysis across northern Australia, including the remainder of the Northern Territory coast and tropical Western Australia coast.
- Regional assessments of seagrass resources used in combination with the previous synthesis of seagrass spatial data from the Great Barrier Reef.
- Designing a stratified seagrass monitoring program for northern Australia, and a reference spatial data set against which to identify future seagrass change.
- Identification of significant knowledge gaps that will guide future mapping and monitoring efforts, including consistent data collection and curation methods for seagrass communities in the Gulf of Carpentaria.
- Seagrass species identification and initial DNA assessment for “future proofing” ecological systems in any restoration endeavours.
Our work highlights the important role of historical data in understanding spatial complexity and for making informed management decisions on the current state of seagrass in northern Australia. Our approach can be adapted for monitoring, management, and assessment of pressures at a range of spatial scales and jurisdictions.