Moreton Bay broadscale habitats 2008

Brief description

Broadscale habitat types identified within the Moreton Bay Marine Park as part of the 2007 zoning review (see lineage for full details of study).

Lineage

Maintenance and Update Frequency: notPlanned

Statement: The habitat model was designed to capture broadscale ecological marine habitats that exist within the Moreton Bay Marine Park. The starting point for the model was a study conducted by Stevens (2004) that investigated macrobenthic habitat types in Moreton Bay using underwater video techniques. The study surveyed 111 sites, spaced five kilometres apart, extending from shallow subtidal waters to offshore waters to the 50m isobath. Nine habitat types were recognized in the study, including: bioturbated mud, sparse sand and rubble, seagrass dominated, inshore algae and sponge, diverse sandy, depauperate sandy, offshore sparse diverse, bioturbated sparse, and reefal. Although the Stevens (2004) study was the most comprehensive of its type ever undertaken in Moreton Bay it was generally limited to depths greater than five metres and waters where the turbidity did not prevent the use of underwater video. Hence, many of the nearshore and estuarine areas of the bay were not mapped as part of the study. A habitat model working group, consisting of EPA staff and several members of the EAP, was established to review existing data and determine what habitats would be required for inclusion to the model. It was determined that a hierarchical approach was required where the bay was divided into five broadscale biomes consisting of: riverine/estuarine, coastal hard/rocky, coastal sedimentary, deep sedimentary, and hard/rocky deep. Within two of the biomes only one habitat type was identified, however there were 14 habitat types identified within the other three biomes. Habitat types within each biome: 1. Riverine/estuarine biome: Riverine/estuarine 2. Coastal hard/rocky biome: Inshore reef, Rocky shores, Rocky headland, Inshore algae/sponge habitat 3. Coastal sedimentary biome: Seagrass, Mangrove/intertidal habitat (mangroves, saltmarsh, mudflats), Sandy channels (sandy tidal banks, shallow channels), High energy coastal, Bioturbated mud 4. Sedimentary deep biome: Diverse sandy, Bioturbated sand, Offshore sandy, Sand/rubble, Offshore deep 5. Hard/rocky deep biome: Offshore reef The spatial extents of the habitats not identified in the Stevens (2004) study were derived using existing datasets or by using bathymetry as a proxy for the habitat boundary. For example, the high energy the coastal habitats were defined using the six metre depth contour. Other habitats such as mangrove habitat and the sandy channels were defined by amalgamating the classifications in the Geoscience Australia Coastal Waterways Geomorphic Habitats model. Once amalgamated these habitats were checked against orthorectified aerial photography for accuracy. The least studied regions of the park were the offshore reefs and habitats in greater than 50m of waters. To fill this void in knowledge the EPA commissioned WBM to undertake a habitat mapping investigation throughout a large portion of the Marine Park's oceanic area. The habitat mapping performed by WMB was done using a combination of georeferenced sonar and video. The acoustic sonar readings were processed using special seabed habitat mapping software known as QTC view. This software clusters the raw acoustic data by calculating statistics for the acoustic echoes. This data was then interpolated to fill in the voids between the acoustic survey lines. The modelled habitat classifications were then validated by the georeferenced video that had been collected for 90 different locations in the offshore region. The resulting habitat Moreton Bay habitat model represents 16 broadscale habitats extending from the highest astronomical tide line on the mainland to the waters of the marine park that extend to the edge of the Coastal Waters of Queensland. The model represents the most comprehensive habitat model currently available for the Moreton Bay region and will form the basis for many of the decisions relating to the size and placement of zones during the rezoning of Moreton Bay. Short description of identified habitats: Bioturbated Mud - Generally shallow muddy inshore environment that is heavily worked by infauna. The waters are usually very turbid allowing little light penetration to the seabed. Regular nutrient enrichment to this area from the adjacent river systems provides habitat for a diverse community of fish and benthic species. Bioturbated Sand - Sandy areas with heavily worked sediment and littered with small burrows from infauna such as worms and yabbies. Diverse Sandy - Dynamic sandy area that generally consists of a complex series of channels and sand banks. Unlike many of the sparse sandy areas of Moreton Bay this habitat is dominated by very high density patches of anemones. High Energy Coastal - Sandy strip of coastline extending from the hightide mark to six metre depth contour. The area is generally very dynamic due to the high energy wave action that it experiences during most of the year. Inshore, Algae Sponge Habitat - Macrobenthos dominated by algae and sponges, with significant contributions from solitary sea squirts, anemones and seagrass. Inshore reef - Generally fringing reefs and reef flats that are patchy, and interspersed with seagrass or soft substrate communities. Support particularly rich and diverse fish and invertebrate communities. Mangrove/Intertidal Habitat - Distributed throughout the bay this habitat incorporate stands of seven different species of mangroves and also includes adjacent saltmarshes and mudflats. The mangroves generally occur in intertidal areas that are protected from strong wave action by extensive mud flats. Offshore Deep - Characterised by fine silty sand at depths greater than 50m. The bedform is usually flat and featureless. There is little conspicuous fauna in this habitat although there is evidence of bioturbation. Offshore Reef - covers a range of reef habitats from emergent reefs, such as Flinders Reef, through to deep algae dominated reefs such as Deep Tempest. These areas host a unique assemblage of tropical and subtropical species, with many of the tropical species at their southernmost limit. Offshore Sandy - Habitat between depths of six to 50m dominated by fine to medium sand. Bioturbation in this habitat is highly variable and patchy with a diverse, yet sparse faunal community. Riverine/Estuarine - This habitat includes the rivers and creeks of Moreton Bay that are often lined with mangroves. These areas are often nursery grounds for juveniles of many fish and invertebrate species. Rocky Headland - Exposed to moderate to strong wave action from the South Pacific Ocean. Distinct communities of fish and invertebrates inhabit these areas that often are dotted with rock pools at low tide. Rocky Shores - Sheltered low energy rocky shores found that experience much less wave action than rocky headlands. These areas are typified by rocky outcrops that are exposed at low tide. They support a diverse mix of plants and animals that have adapted to survive this habitat's unique conditions. Sandy Channels - Area of sandy and muddy channels that flow through the mangrove habitats of Moreton Bay. These areas are typified with shifting sand banks and patches of seagrass. Sand/Rubble - Relatively sparse areas with low densities of mobile macroinvertebrates such as sea urchins, feather stars, bivalves, and occasional sponges and soft corals attached to patches of rubbly substrate. Seagrass - Generally sandy areas with medium to high seagrass cover. This habitat provides important feeding grounds for turtles and dugongs.

Statement: Creation of habitat polygons from Stevens (2004): Polygons were derived from the Voronoi tessellation constructed from the point data and habitat classifications found in Stevens (2004). The resulting dataset formed the basis for the following habitats within the model: bioturbated mud; bioturbated sand; diverse sandy; inshore algae/sponge; offshore sandy; sand rubble. Stevens T.F. (2004) Initial Classification of Subtidal Benthic Habitats of Moreton Bay. A report for the Queensland Environmental Protecton Agency and Queensland Parks and Wildlife Service, August 2004. Griffith University, Australia. Inshore reef: Inshore reef polygons were derived from the EPA data layer Moreton Bay Coral 2004. This dataset was checked against NRW orthophotography and was generally extended to include the reef flat area adjacent of the reef proper. Mangrove/intertidal habitat: Polygons digitised from NRW orthophotography Offshore deep: Polygon was generated from the 50m depth contour in MSQ bathymetry dataset. Offshore reef: Polygons were primarily derived from the data reported in the offshore mapping project undertaken by WBM (Morgan et al. 2007). In addition to the WBM data, which included acoustic and video surveys, reef habitat was derived from hydrography charts, offshore fishing guides and trawling data. Morgan C., Hastie B., Richardson D. (2007) SubTidal Benthic Habitat Mapping Study Priority Areas within the Moreton Bay Marine Park: Draft Report. BMT WBM Pty Ltd. Riverine/estuarine: Polygons were derived by determining cutoff lines for the mouths of rivers and creeks from NRW orthophotography. Rocky headland: Created by buffering the coastline for 200m around rocky headland areas identified using NRW orthophotography. Rocky shores: Created by buffering the coastline for 200m around rocky shore habitat identified using NRW orthophotography. Sandy channels: Polygons derived by clipping the mangrove/intertidal, riverine/estuarine, and inshore coral habitat polygons from the northern and southern ends of Moreton Bay. High energy coastal: Polygons built from 6m depth contours derived from MSQ bathymetric contour and spot depth data. Seagrass: Polygons derived from Moreton Bay Seagrass 2004 dataset and Stevens (2004) data.

Notes

Credit
State of Queensland (Department of National Parks, Sport and Racing) 2016.