This dataset summarises 30 years of seagrass data collection (1984-2014) within the Great Barrier Reef World Heritage Area. The Meadow data describes seagrass at 1,169 individual or composite meadows. The data includes information on species, meadow type and age and reliability of the data. Data represented in this dataset has been collected by the TropWATER Seagrass Group and CSIRO in a GIS database.
In making this data publicly available for management, the authors from the TropWATER Seagrass Group request being contacted and involved in decision making processes that incorporate this data, to ensure its limitations are fully understood. The site and meadow GIS available on eAtlas should be considered a “living” document that will be updated and modified as new data become available.
Additional 'point' site data, and alternative download formats are available from eAtlas. https://eatlas.org.au/geonetwork/srv/eng/catalog.search#/metadata/77998615-bbab-4270-bcb1-96c46f56f85a
A later version (2020) of this dataset including 35 years of data has been published under "Seagrass mapping synthesis: A resource for coastal management in the Great Barrier Reef (NESP TWQ Project 3.2.1 and 5.4, TropWATER, James Cook University)." https://eatlas.org.au/data/uuid/5011393e-0db7-46ce-a8ee-f331fcf83a88
Data Dictionary:
Seagrass meadow data:
NRM_REGION: The NRM region in which the survey occurred.
SURVEY_DAT: Survey month and year, or a list of survey dates for meadows repeatedly sampled.
METHOD: Sampling and mapping methods – GPS/aerial photography, helicopter, walking, boat with camera, diver, grab and/or sled.
PERSISTENC: Meadows were classed according to four categories: Stable, Variable, Highly variable ephemeral, or Unknown.
MEADOW_LOC: Meadows were classed according to three categories, although some meadows cover a range of these locations: Intertidal, Shallow subtidal, or Deep subtidal.
DENSITY: Meadow density categories (light, dense, variable among years, unknown) were determined by the consistency of mean above-ground biomass of the dominant species among all years sampled.
DOMINANT_S: Dominant species and species present.
SPP_PRESEN: All species present.
MEAN_BIOMA: Mean meadow biomass in g DW m-2 (+ standard error if available), or the minimum and maximum biomass recorded for meadows sampled more than once.
AREA_HA: Meadow area in hectares (+ reliability estimate if available), or the minimum and maximum area recorded for meadows sampled more than once.
HECTARES: Total extent of meadow (HA)
PERCENT_CO: Meadow percent cover - this value represents mean seagrass percent cover, or the range of percent cover (if >1 number in the data cell). Meadow percent cover was most commonly calculated in pre-1990s surveys and recorded as “n/a” if not available.
CUSTODIAN: Data custodians
COMMENTS
Meadow Persistence:
- Stable: enduring meadow form; seagrass presence, biomass and area expected to be stable over time and seagrass meadow expected to be a permanent feature apart from extreme events or sustained long term impacts;
- Variable: meadow presence, biomass and area expected to fluctuate within and among years, but generally some seagrass expected to be present apart from extreme events or sustained long term impacts;
- Highly variable ephemeral: meadow not persistent over time; at some time periods seagrass will be present and at other times absent. Ephemeral meadows that have a naturally extreme level of variation in area and biomass within and among years;
- Unknown: undetermined persistence as meadow sampled only once.
Meadow Location:
- Intertidal - all sites surveyed by helicopter or walking within a meadow and/or comments in field books identified an intertidal meadow,
- Shallow subtidal - meadows where free divers SCUBA, sled collection, or cameras were used to sample and water depth was generally <10 m;
- Deep subtidal - for this project meadows >10 m deep were included as deep subtidal.
