Eastern Torres Strait intertidal benthic survey: Ugar, Campbell and Nepean Islands (TropWATER, James Cook University)

This dataset summarises intertidal benthic surveys of Ugar, Campbell, Nepean Islands, Torres Strait, in March 2022 into 3 GIS shapefiles.

(1) The point (site) shapefile describes (a) seagrass presence/absence, (b) species composition, (c) algae cover and (d) benthic macro-invertebrate cover at 404 sites.
(2) The meadow shapefile describes seagrass communities for the intertidal meadows.
(3) The interpolation shapefile describes variation in seagrass biomass across sites for the intertidal meadows.

The full report is: Reason CL, Wilkinson J, and Carter AB, (2022), “Eastern Torres Strait intertidal benthic survey: Ugar, Campbell and Nepean Islands”, Centre for Tropical Water &amp; Aquatic Ecosystem Research (TropWATER) report no. 22/22, James Cook University, Cairns, 33 pp.

Methods:

The sampling methods used to study, describe and monitor seagrass meadows were developed by the TropWATER Seagrass Group and tailored to the location and habitat surveyed; these are described in detail in the relevant publications (https://research.jcu.edu.au/tropwater).

Geographic Information System (GIS):
All survey data were entered into a Geographic Information System (GIS) developed for Torres Strait using ArcGIS 10.8. Rectified colour satellite imagery of Eastern Torres (Source: ESRI, Planet, Maxar, GeoEye, Earthstar Geographics, CNES/Airbus DS, USDA, USGS, AeroGRID, IGN, and the GIS User Community), field notes and aerial photographs taken from the helicopter during surveys were used to identify geographical features, such as reef tops, channels and deep-water drop-offs, to assist in determining seagrass meadow boundaries. Three GIS layers were created to describe spatial features of the region: a site layer, seagrass meadow layer, and seagrass biomass interpolation layer.

Seagrass site layer:
This layer contains information on data collected at assessment sites, and includes:
1. Temporal survey details – Survey date;
2. Spatial position - Latitude/longitude;
3. Survey location;
4. Seagrass information including presence/absence of seagrass, above-ground biomass (total and for each species), percent cover of seagrass at each site and whether individual species were present/absent at a site;
5. Benthic macro-invertebrate information including the percent cover of hard coral, soft coral, sponges and other benthic macro invertebrates (e.g. ascidian, clam) at a site;
6. Algae information including percent cover of algae at a site and percent contribution of algae functional groups to algae cover at a site;
7. Open substrate – the percent cover of the site that had no flora or habitat forming benthic invertebrates present;
8. Dominant sediment type - Sediment type based on grain size visual analysis or deck descriptions.
9. Survey method
10. Relevant comments and presence/absence of megafauna (dugong, turtle, dolphin, evidence of dugong feeding trails);
11. Data custodians.

Seagrass meadow layer:
Seagrass presence/absence site data, mapping sites, field notes, and satellite imagery were used to construct meadow boundaries in ArcGIS®. The meadow (polygon) layer provides summary information for all sites within the meadow, including:
1. Temporal survey details – Survey month and year as individual columns and the survey date (the date range the survey took place);
2. Spatial survey details – Survey location, meadow identification number that identifies the reef name and the meadow number. This allows individual meadows to be compared among years;
3. Survey method;
4. Meadow depth – Intertidal: meadow was mapped on an exposed bank during low tide;
5. Species presence – a list of the seagrass species in the meadow;
6. Meadow density – Seagrass meadows were classified as light, moderate, dense based on the mean biomass of the dominant species within the meadow (see Table 3 in Reason et al. 2022). For example, a Thalassia hemprichii dominated meadow would be classed as “light” if the mean meadow biomass was &lt;5 grams dry weight m^-2 (g DW m^-2), and “dense” if mean meadow biomass was &gt;25 g DW m^-2.
7. Meadow community type – Seagrass meadows were classified into community types according to seagrass species composition within each meadow. Species composition was based on the percent each species’ biomass contributed to mean meadow biomass. A standard nomenclature system was used to categorize each meadow (see Table 2 in Reason et al. 2022).
8. Mean meadow biomass measured in g DW m^-2 (+ standard error if available);
9. Meadow area (hectares; ha) (+ mapping precision) of each meadow was calculated in the GDA 1994 Geoscience Australia MGA Zone 54 projection using the ‘calculate geometry’ function in ArcMap. Mapping precision estimates (R; in ha) were based on the mapping method used for that meadow (see Table 1 in Reason et al. 2022). Mapping precision estimate was used to calculate an error buffer around each meadow; the area of this buffer is expressed as a meadow reliability estimate (R) in hectares;
10. Any relevant comments;
11. Data custodians.

Seagrass biomass interpolation layer:
An inverse distance weighted (IDW) interpolation was applied to seagrass site data to describe spatial variation in seagrass biomass within seagrass meadows. The interpolation was conducted in ArcMap 10.8.

Base map:
The base map used is courtesy ESRI 2022.

Format of the data:

This dataset consists of a two point shapefiles, a polygon shapefile and a raster file with a projected coordinate system of GDA 1994 Geoscience Australia. The files have been saved as layer packages:
1. Ugar Campbell Nepean Islands seagrass present absent 2022.lpk
    - Symbology representing seagrass presence/absence at each survey site
2. Ugar Campbell Nepean Islands species composition 2022.lpk
    - Symbology representing the species composition at each survey site 
3. Ugar Campbell Nepean Islands community type 2022.lpk
    - Symbology representing the community type of each meadow
4. Ugar Campbell Nepean Islands biomass interpolation 2022.lpk
    - Symbology representing the spatial variation in seagrass biomass within seagrass meadows

Data Dictionary:

Ugar Campbell Nepean Islands seagrass survey sites 2022 (point data):
- SITE (numeric) - Unique identifier representing a single sample site
- MEADOW (text) - Unique identifier representing what meadow the sample site is located in. Blank if sample site is not located within a meadow
- DATE (numeric) - sample date (day/month/year)
- LOCATION (text) - Name of survey location
- LATITUDE (numeric) - Site location in decimal degrees south
- LONGITUDE (numeric) - Site location in decimal degrees east
- TIME (numeric) - sample time (24 hours; GMT +10)
- SUBSTRATE (text) - Tags identifying the types of substrates at the sample site. Possible tags are Sand, Shell, Rock, Reef, Rubble and various combinations
- SEAGRASS_P (numeric) - Absence (0) or Presence (1) of seagrass
- SEAGRASS_C (numeric) - Estimated % of seagrass cover at sample site
- SEAGRASS_B (numeric) - Estimated total biomass per square metre for sample site calculated from the mean of three replicate quadrats. Unit is gdw m^-2
- SE (numeric) - standard error of biomass at sample site calculated from the three replicate quadrats used to estimate biomass at a sample site. Unit is gdw m^-2
- EXCLUDE_FR (numeric) - Any site identified that needs to be excluded from contributing to the calculation of mean meadow biomass, e.g. where a visual estimate of biomass could not be optioned (i.e. no visibility at the site, only a van Veen sediment grab was used at the site)
- EA (numeric) - Estimated biomass of Enhalus acoroides at the sample site. Unit is gdw m^-2
- TC (numeric) - Estimated biomass of Thalassodendron ciliatum at the sample site. Unit is gdw m^-2
- TH (numeric) - Estimated biomass of Thalassia hemprichii at the sample site. Unit is gdw m^-2
- CR (numeric) - Estimated biomass of Cymodocea rotundata at the sample site. Unit is gdw m^-2
- HUT (numeric) - Estimated biomass of Halodule uninervis at the sample site. Unit is gdw m^-2
- HO (numeric) - Estimated biomass of Halophila ovalis at the sample site. Unit is gdw m^-2
- HD (numeric) - Estimated biomass of Halophila decipiens at the sample site. Unit is gdw m^-2
- ALGAE_COVE (numeric) - Estimated % of macro-algae cover at sample site
- TURF_MAT_A (numeric) - (Turf mat %) Algae that forms a dense mat on the substrate
- ERECT_MACR (numeric) - (Erect macrophyte %) Macrophytic algae with an erect growth form and high level of cellular differentiation, e.g. Sargassum, Caulerpa and Galaxaura species
- ENCRUSTING (numeric) - (Encrusting algae %) Algae that grows in sheet-like form attached to the substrate or benthos, e.g. coralline algae
- ERECT_CALC (numeric) - (Erect calcareous %) Algae with erect growth form and high level of cellular differentiation containing calcified segments, e.g. Halimeda species
- FILAMENTOU (numeric) - (Filamentous %) Thin, thread-like algae with little cellular differentiation
- HARD_CORAL (numeric) - (Hard coral %) All scleractinian corals including massive, branching, tabular, digitate and mushroom
- SOFT_CORAL (numeric) - (Soft coral %) All alcyonarian corals, i.e. corals lacking a hard limestone skeleton
- SPONGES (numeric) - (Sponge %)
- OTHER_BMI (numeric) - Any other benthic macro-invertebrates identified, e.g. ascidians, clams. Other benthic macro-invertebrates are listed in the “comments” attribute
- OPEN_SUBST (numeric) - Open substrate, no benthic macro-invertebrates at site
- DFTS_PRESE (numeric) - Absence (0) or Presence (1) of dugong feeding trails at site
- HELICOPTER (numeric) - Helicopter utilised (1) or not (0) at sample site
- CAMERA (numeric) - Drop camera utilised (1) or not (0) at sample site
- WALKING (numeric) - Walking access utilised (1) or not (0) at sample site
- COMMENTS (text) - Any comments for that site
- UPDATED (date) - The date the shapefile was last updated
- AUTHOR (text) - Custodian/owner of the data set

Ugar Campbell Nepean Islands seagrass meadows 2022 (polygon data):
- ID (numeric) - Unique identifier representing a single meadow
- LOCATION (text) - Name of survey location
- MONTH (numeric) - Sample month
- YEAR (numeric) - Sample year
- Survey_dat (numeric) - Sample date (day/month/year)
- MEAD_DEPTH (text) - Classified into three categories (intertidal, subtidal, intertidal-subtidal)
- DENSITY (text) - Meadow density categories (light, moderate, dense)
- TYPE (text) - Meadow community type determined according to seagrass species composition within the meadow
- Species (text) - (Seagrass species): seagrass species found within the meadow. Species are recorded as abbreviated species names such as “E. acoroides”
- TOT_SITES (numeric) - (Number of survey sites): the number of sample sites within the meadow
- BIO_SITES (numeric) - (Number of survey sites): the number of sample sites within the meadow that contributed to calculating the mean meadow biomass
- BIOMASS_P (numeric) - Presence (1) or absence (0) of a mean meadow biomass calculated
- Biomass (numeric) - (Seagrass biomass (gdw m^-2)): Mean biomass calculated from all sites (BIO_SITES) within an individual meadow
- SE (numeric) - (Standard Error (gdw m^-2)): The error is a calculation of standard error of biomass from all (BIO_SITES) sites within an individual meadow
- AREA_HA (numeric) - (Meadow area (Ha)): Estimated meadow size (unit: hectares)
- R_m (numeric) - (Meadow mapping precision (m)): Estimated mapping precision based on mapping method
- R_ha (numeric) - (Meadow reliability estimate (Ha)): Meadow reliability estimate (unit: hectares). Expressing the error buffer around each meadow as calculated from the mapping precision estimate
- Methods (text) - e.g. helicopter, walking, hovercraft, boat-based including camera, free diving, scuba diving, van Veen grab, sled net
- Comments (text) - Any relevant comments for that meadow
- Updated (date) - The date the shapefile was last updated
- CUSTODIAN (text) - Custodian/owner of the data set

Ugar Campbell Nepean Islands biomass interpolation 2022 (interpolation layer):
- Band 1: Interpolated biomass in gdw m^-2

References:
Reason CL, Wilkinson J, and Carter AB, (2022), “Eastern Torres Strait intertidal benthic survey:
Ugar, Campbell and Nepean Islands”, Centre for Tropical Water &amp; Aquatic Ecosystem Research (TropWATER) report no. 22/22, James Cook University, Cairns, 33 pp.

eAtlas Processing:
The original data were provided as Layer Packages. The lpkg files were imported to ArcGIS Pro 3.7 and exported as shapefiles and GeoTiff. The attribute "Landscape" was removed from "TS_JCU_Ugar-Campbell-Nepean-Islands_2022_Seagrass-Community-Type.shp" as it was not in the data dictionary and did not contain data. No modifications modifications to the underlying data were performed and the data package are provided as submitted.

Location of the data:
This dataset is filed in the eAtlas enduring data repository at: custodian\2018-2022-TSRA\TS_JCU_Ugar-Campbell-Nepean-Islands_2022

Tags: World
Organization: Australian Ocean Data Network