Benthic habitats of the Kurtijar Indigenous Protected Area 2023 (NESP MaC 3.5, JCU, CDU, ECU)

Full description

This dataset summarises intertidal and subtidal benthic surveys of the Kurtijar IPA, Gulf of Carpentaria, in 2023 into 3 GIS layers. (1) The point (site) shapefile describes features for 431 survey intertidal and subtidal sites. (2) The meadow shapefile describes seagrass features for the individual meadows. (3) The interpolation raster describes variation in seagrass biomass across sites within each meadow. Data access: Public access to this dataset is restricted. Please refer to the Data Access Control Plan (https://nextcloud.eatlas.org.au/apps/sharealias/a/GoC_NESP-MaC-3-5_JCU_Benthic-habitats-Kurtijar-IPA-2023) for more information. Methods: The sampling methods used to survey and monitor benthic habitats were developed by TropWATER 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) using ArcGIS Pro 3.4. Rectified colour satellite imagery of the southern Gulf of Carpentaria (Source: Planet, ESRI, 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. The seagrass meadow layer consists of polygons that were manually digitised and smoothed based on the visual interpretation of the in-situ data aligning with low tide satellite imagery collected within 3 months of the field survey (from PlanetScope Super Dove 3 m pixel resolution). Three GIS layers were created to describe spatial features of the region: a site layer, seagrass meadow layer, and seagrass biomass interpolation layer. Survey 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 name and location; 4. Seagrass information including presence/absence of seagrass, above-ground biomass (total and for each species), percent cover of seagrass at each 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. Depth below mean sea level; 10. Survey method and vessel; 11. Relevant comments and presence/absence of megafauna (dugong, turtle, dolphin, evidence of dugong feeding trails); 12. 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 Pro. 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 survey site groupings; 3. Survey method and vessel; 4. Meadow depth – Intertidal: meadow was mapped on an exposed bank during low tide; Subtidal: meadow does not expose to air. 5. Species presence – a list of the seagrass species in the meadow; 6. Density – Seagrass meadows were classified as light, moderate, dense based on the mean biomass of the dominant species within the meadow. For example, a Halodule uninervis dominated meadow would be classed as “light” if the mean meadow biomass was <1 grams dry weight m^-2 (g DW m^-2), and “dense” if mean meadow biomass was >4 g DW m^-2. 7. Community – 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. 8. Mean meadow biomass measured in g DW m^-2 (+ standard error if available); 9. Meadow area (hectares; ha) (+ mapping precision) of each intertidal meadow was calculated in the GDA2020 MGA Zone 54 projection using the ‘calculate geometry’ function in ArcGIS Pro. Mapping precision estimates (R; in ha) were based on the mapping method used for that meadow. 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 ArcGIS Pro 3.4. Base map: The base map used is courtesy Planet 2024. Limitations of the data: Recordings of dugong, turtle, sea cucumber and dolphin were opportunistic sightings and recorded if nearby a survey site. This presence/absence data was not collected as part of a formal structured survey of these animals and should therefore be used with caution. Three subtidal meadows in the meadow layer are indicative of seagrass presence only and do not represent the true extent of the meadows. Format of the data: This dataset consists of 3 layers with a spatial reference of GDA2020 MGA Zone 54: 1. Kurtijar IPA seagrass meadows 2023 Includes seagrass meadows mapped in 2023 with information including meadow ID, meadow mean seagrass biomass (g DW m^-2) + SE, number of sites surveyed, meadow area + R, seagrass community, seagrass species present, survey dates, survey method, and data author. Planet satellite low tide imagery was used to delineate the meadow boundaries with the help of the site data. 2. Kurtijar IPA biomass interpolation 2023 An inverse distance weighted (IDW) interpolation was applied to seagrass site data to describe spatial variation in biomass within seagrass meadows. 3. Kurtijar IPA survey sites 2023 Site information including latitude/longitude, seagrass presence/absence, algae and benthic macro-invertebrate percent cover, percent cover of algae functional groups, individual seagrass species biomass, survey date, survey method, and data author. Data Dictionary: Kurtijar IPA survey sites 2023 (point data): - SITE (numeric) - Unique identifier representing a single sample site. - SURVEY_DAT (numeric) - Survey date/s - TIME (numeric) - Sample time (24 hours; AEST GMT +10); subtidal surveys only. - SURVEY_NAM (text) - Name of the survey. - LATITUDE (numeric) - Site location in decimal degrees south. - LONGITUDE (numeric) - Site location in decimal degrees east. - SUBSTRATE (text) - Tags identifying the types of substrates at the sample site. Possible tags are Sand, Shell, Rock, Reef, Rubble and various combinations. - VESSEL (text) - Name of vessel used in the survey. If no name then leave blank - COMMENTS (text) - Any comments for that site. - SEAGRASS_P (numeric) - Absence (0) or Presence (1) of seagrass. - DFTS_PRESE (numeric) - Absence (0) or Presence (1) of dugong feeding trails at site. - EXCLU_BIO (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). - DOLPHIN (numeric) - Absence (0) or Presence (1) of dolphin at site. - TURTLE (numeric) - Absence (0) or Presence (1) of turtle at site. - DUGONG (numeric) - Absence (0) or Presence (1) of dugong at site. - SEA_CU (numeric) - Absence (0) or Presence (1) of sea cucumber/s at site. - SEAGRASS_C (numeric) - Estimated % of seagrass cover at sample site. - TURF_MAT (numeric) - Turf mat algae % cover - forms a dense mat on the substrate. - ERECT_MACR (numeric) - Erect macrophyte algae % cover - erect growth form and high level of cellular differentiation, e.g. Sargassum, Caulerpa and Galaxaura species. - ENCRUSTING (numeric) - Encrusting algae % cover - grows in sheet-like form attached to the substrate or benthos, e.g. coralline algae. - ERECT_CALC (numeric) - Erect calcareous algae % cover - erect growth form and high level of cellular differentiation containing calcified segments, e.g. Halimeda species. - FILAMENTOU (numeric) - Filamentous algae % cover - thin, thread-like algae with little cellular differentiation. - HARD_CORAL (numeric) - Hard coral % cover - all scleractinian corals including massive, branching, tabular, digitate and mushroom. - SOFT_CORAL (numeric) - Soft coral % cover - all alcyonarian corals, i.e. corals lacking a hard limestone skeleton. - OPEN_SUBST (numeric) - Open substrate, no seagrass, algae or benthic macro-invertebrates at site. - SPONGE (numeric) - Sponge % cover. - OTHER_BMI (numeric) - Other benthic macro-invertebrates (BMI) % cover - e.g. ascidians, clams. Other benthic macro-invertebrates are listed in the “comments” attribute. - DEPTH_MSL (numeric) - Depth of site below mean sea level (dbmsl) unit is in metres. 0 if intertidal. - MEADOW (numeric) - Unique identifier representing what meadow the sample site is located in. Blank if sample site is not located within a meadow. - CUSTODIAN (text) - Custodian/owner of the data set. - UPDATED (date) - The date the shapefile was last updated. - TIDAL (text) - Sample site is intertidal or subtidal. - SG_BIOMASS (numeric) - Estimated total biomass per square metre for sample site calculated from the mean of three replicate quadrats. Unit is gdw m^-2. - BIO_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. - EA_BIO (numeric) - Estimated biomass of Enhalus acoroides at the sample site. Unit is gdw m^-2. - TC_BIO (numeric) - Estimated biomass of Thalassodendron ciliatum at the sample site. Unit is gdw m^-2. - TH_BIO (numeric) - Estimated biomass of Thalassia hemprichii at the sample site. Unit is gdw m^-2. - CR_BIO (numeric) - Estimated biomass of Cymodocea rotundata at the sample site. Unit is gdw m^-2. - ZC_BIO (numeric) - Estimated biomass of Zostera muelleri subsp. capricorni at the sample site. Unit is gdw m^-2. - HU_BIO (numeric) - Estimated biomass of Halodule uninervis at the sample site. Unit is gdw m^-2. - SI_BIO (numeric) - Estimated biomass of Syringodium isoetifolium at the sample site. Unit is gdw m^-2. - HS_BIO (numeric) - Estimated biomass of Halophila spinulosa at the sample site. Unit is gdw m^-2. - HT_BIO (numeric) - Estimated biomass of Halophila tricostata at the sample site. Unit is gdw m^-2. - HO_BIO (numeric) - Estimated biomass of Halophila ovalis at the sample site. Unit is gdw m^-2. - HD_BIO (numeric) - Estimated biomass of Halophila decipiens at the sample site. Unit is gdw m^-2. - MONTH (text) - Survey month. - YEAR (numeric) - Survey year. - LOCATION (text) - Name of survey location. - METHOD (text) - Survey method, e.g. helicopter, boat, camera, sled, van Veen grab. Note: SEAGRASS_C + TURF_MAT + ERECT_MACR + ENCRUSTING + ERECT_CALC + FILAMENTOU + OPEN_SUBST + HARD_CORAL + SOFT_CORAL + SPONGE + OTHER_BMI = 100% Kurtijar IPA seagrass meadows 2023 (polygon data): - MEADOWID (text) - Unique identifier representing a single meadow. - SURVEY_DAT (text) - Sample date (day/month/year). - TIDAL (text) - Classified into three categories (intertidal, subtidal, intertidal-subtidal). - LOCATION (text) - Survey location. - COMMUNITY (text) - Meadow community type determined according to seagrass species composition within the meadow. - SPECIES (text) - List of seagrass species found within the meadow. Species are recorded as abbreviated species names such as “E. acoroides”. - 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 area of the error buffer around each meadow as calculated from the mapping precision estimate. Intertidal meadows only. - TOT_SITES (numeric) - Number of survey sites. The number of sample sites within the meadow. - BIO_SITES (numeric) - Number of survey sites within each meadow that mean biomass was calculated from. May differ from TOT_SITES due to site exclusions where biomass estimates were not made because of low visibility, or seagrass detected using a van Veen grab only. - 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. - METHOD (text) - Survey method, e.g. helicopter, boat, camera, sled, van Veen grab. - CUSTODIAN (text) - Custodian/owner of the data set. - COMMENTS (text) - Any relevant comments for that meadow. - UPDATED (date) - The date the shapefile was last updated. - VESSEL (text) - Vessel name. - SURVEY_NAM (text) - Survey name. - MONTH (text) - Survey month. - YEAR (numeric) - Survey year. - PERSISTENC (text) - Meadow form on three categories: enduring, transitory, unknown: enduring meadows are persistent over time (seagrass is present in the meadow ≥90% of the surveys), transitory meadows are not persistent over time (seagrass is present in the meadow <90% of the surveys), unknown (the meadow was surveyed less than five times). - AUTHOR (text) - Creator of the GIS dataset. Kurtijar IPA biomass interpolation 2023 (interpolation layer): - Band 1: Interpolated biomass in gdw m^-2. References: Proctor M, Carter A, Savo K, Bee R, George X, Toby M, Webster C, Wilkinson J, Collier C, Groom R, McMahon K (2025). Marine Habitats of Kurtijar Indigenous Protected Area. Report to the Reef and Rainforest Research Centre, Cairns, Queensland eAtlas Processing: In "GoC_NESP-MaC-3-5_JCU_Kurtijar-IPA_2023_Surveys-Sites.shp" the attribute "BIO_SE1" was renamed to "BIO_SE" as defined in the data dictionary. No modifications were made to the data as part of publication. Location of the data: This dataset is filed in the eAtlas enduring data repository at: data\custodian\2023-2026-NESP-MaC-3\3.5_Northern-Australia-seagrass-distribution\data\GoC_NESP-MaC-3-5_JCU_Benthic-habitats-Kurtijar-IPA-2023

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Maintenance and Update Frequency: asNeeded

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Purpose
Northern Australian seagrass meadows support dugongs, green turtles, fish, prawns and other important species. Understanding their distribution and health now, and over time, is essential so regional planners have information to make the right decisions about community activities and economic development. Unfortunately, for large areas of the coast, data on these important habitats is lacking. Few large-scale surveys have been done, and only a handful of ongoing seagrass monitoring programs exist. Presently, regional planning often proceeds without accurate seagrass information, and therefore, with very minimal understanding of potential effects on these critically important ecosystems. NESP Project 3.5 addresses gaps in seagrass knowledge by consolidating existing data, identifying the gaps, producing new data sets, and making data more widely available. Project 3.5 will work collaboratively with Traditional Owners, Indigenous rangers, managers, and others to prioritise regions where there is no data, or minimal information, then undertake field surveys by helicopter, drone or boat. The Kurtijar Indigenous Protected Area survey aimed to address key knowledge gaps in Queensland’s southern Gulf of Carpentaria.