Natural values of the Solitary Islands Marine Park - Marine Parks ...

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3 Ecosystems and habitatsBiological diversity can be described and classified at a number of levels, andinformation about the spatial distribution of biodiversity at most levels is very limited.The Integrated Marine and Coastal Regionalisation of Australia (IMCRA v4.0) is a spatialframework for classifying Australia’s marine environment into bioregions that areecologically based and are at a scale useful for regional planning (Commonwealthof Australia 2006). They are based on collated data and inferred patterns across avariety of spatial scales and assist in the description of ecosystem boundaries andprovide a framework for subsequent finer levels of planning and management. Thisbuilds on the inshore regionalisation (IMCRA v3.3) which defined bioregions using arange of biological and physical information (ANZECC TFMPA 1998a). This hierarchicalclassification has been used by all governments in Australia to develop a NationalRepresentative System of Marine Protected Areas (ANZECC TFMPA 1998b).Further classification of estuarine and ocean environments can be applied at thefollowing levels:• ecosystem: a dynamic combination of plant and animal communities and theirenvironment interacting as a functional unit;• habitat: a specific type of environment inhabited permanently or temporarily byorganisms, and based on factors such as substrate type and tidal exposure;• community: a number of species occupying a particular habitat or area;• estimated distributions and abundances of species and populations.Physical parameters such as ocean currents, climate, bathymetry and coastalgeomorphology result in the formation of many types of marine ecosystems, whichsupport a variety of habitats, communities and populations of animals and plants.These ecosystems are interconnected as species move between them and currentspass in and out of the marine park, transporting larvae, sediments and nutrients. Theecosystems can be broadly split into oceanic and estuarine ecosystems, which arefurther divided into smaller units based primarily on the dominant geomorphology,aquatic vegetation, benthos or depth, and distance offshore.The most distinct separation of assemblages occurs between habitats which are:• consolidated: that is, made up of rocky reef;• unconsolidated: soft-sediment that generally consists of mostly sand, silt or mud.Unconsolidated habitats can be further divided based on the presence or absenceof vegetation cover (e.g. seagrass), sediment size and composition, the dominantseagrass species and the spatial structure. Such separation recognises that differentspecies of seagrass, or those of varying density, often contain different assemblages offish (Rotherham and West 2002) and invertebrates (Webster et al 1998).The distribution and structure of consolidated habitats can vary widely, primarilydue to differences in rock type and size (e.g. boulders), complexity (e.g. gutters, walls,pinnacles) and patchiness.As detailed spatial information on the distribution of many individual species islimited in the marine park, ecosystems and habitats are used as ‘surrogates’ for speciesdiversity in the planning process. Surrogates are components shown or assumed to berelated to biological diversity that are more easily measured or more capable of beingmapped than species diversity itself. The distribution and measures of biodiversity areinferred from the distribution and measures of surrogates.
Ecosystems and habitats 11There is evidence that the use of habitats as surrogates for species diversity iseffective, provided they are validated (Ward et al 1999) and all representative habitatsare included (Roff et al 2003). However, the effectiveness of habitat classification asa surrogate for biodiversity will depend, to some extent, on how well it representspatterns of biodiversity (Gladstone 2007). To improve the likelihood that habitats arerepresented in appropriate marine park zones, and to facilitate discussion of possiblelocations based on the inclusion of other planning criteria, seabed habitat maps havebeen developed from several sources.Firstly, unconsolidated vegetated habitats in the estuaries of the marine park weremapped using ground-truthed aerial photographs as part of the NSW ComprehensiveCoastal Assessment (West et al 2006).Island boundaries were based on the Australian Maritime Boundaries InformationSystem provided by Geoscience Australia. Shallow inshore reefs were digitised fromaerial photographs provided by the then NSW Department of Land and WaterConservation (now Department of Environment and Climate Change NSW) (seeBreen et al 2004). Many offshore reefs were digitised from contours on AustralianHydrographic Office 1:150,000 charts and from reefs identified along transects inMau et al (1998).To expand the available information on the distribution of subtidal marine habitatsin the marine waters of the SIMP, a seabed swath-mapping program was instigatedin late 2004. A bathymetric sidescan sonar that collected geo-referenced depth andsidescan backscatter data generated high resolution bathymetric and backscattermosaics of the seafloor. The swath width of the instrument was mostly around 160–200 metres depending on water depth and sea conditions. The information on depthand sediment roughness and texture was used to develop habitat maps of rocky reefand unconsolidated areas in the marine park.As at June 2007, around 115 km 2 of seabed in the marine park had been swathmapped. The areas targeted were a combination of reefs of particular interest (e.g.40 Acres Reef), continuous reefs around selected islands, sanctuary zone areas withunknown seabed habitats types, and areas where there was some evidence ofdeeper reefs.
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Page 3: ContentsGlossary1 Introduction . .
Page 6 and 7: littorinid snails: species of mollu
Page 8 and 9: 2 Natural values of the Solitary Is
Page 10 and 11: 2 Physical environment2.1 ClimateTh
Page 18 and 19: 4 Ocean ecosystemsConsolidated area
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Page 32 and 33: Figure 37.Station Creek.5 Estuarine
Page 38 and 39: 6 Pelagic ecosystemsOcean currents

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