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

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22 Natural values of the Solitary Islands Marine ParkFigure 29.Stingray buried in sand.Figure 30.Diggers Camp rockplatform.Figure 31.Boulder habitat ArrawarraHeadland.In general, the abundance and diversity of sessilemacrofauna decreases with depth, with deepunconsolidated habitats containing few octocorals(soft corals and sea fans) and ascidians (Bax andWilliams 2001, Beaman et al 2005). While there islittle information on the distribution and diversityof soft-sediment assemblages in the SIMP region, itis likely that the considerable structural complexityseen in the swath-mapping data will influence thepatterns of faunal assemblages in this habitat.The distribution and structure of invertebratesare also likely to influence fish assemblages, givenfindings in other regions. Areas of low structuralcomplexity on the inner-shelf region of southernNSW differ significantly in fish species from morestructurally complex unconsolidated habitatscontaining sponges, sea-whips and bryzoans(Williams and Bax 2001).A very diverse range of fish, sharks, rays andcrustaceans occur in soft-sediment habitats on thecontinental shelf (Figure 29). See NSW Departmentof Primary Industries 2004 for details of speciescomposition; distribution; and biology such as growth rate, longevity, diet andfecundity of many of these species.4.3 Rocky intertidal habitatIntertidal rocky shores occupy a zone of transition between marine and terrestrialenvironments, and include the intertidal zone and the adjacent wave surge zone.These habitats are often characterised by local variations in the distribution oforganisms determined by levels of exposure, wave action, biological interactions andthe history of disturbances at individual sites (Underwood and Chapman 1995, Otway1999).The geomorphic structure of rocky shores can vary greatly, depending on:• the dominant rock type and structure such as a platform, cobble or boulder (Figs. 30and 31);• exposure, for example, protected or exposed;• slope, for example, steep, inclined or flat (Banks and Skilleter 2002, Otway andMorrison in prep).Rock pools, crevices and shallow gulches are alsoimportant areas as they generally retain seawaterduring low tide. There is evidence that an increasein the structural complexity of the rocky shore canresult in an increase in the diversity of species withinan area (Smith and James 1999, Smith 2005, Otwayand Morrison in prep).
Ocean ecosystems 23There is generally a broad pattern of dominance ofa suite of abundant, conspicuous species at differentlevels across the shore, including:• a high-shore area dominated by littorinid snails(snails with spiral globular shells);• wave-exposed, mid-shore areas occupied bybarnacles and limpets;• sheltered mid-shore areas dominated by barnaclesand grazing snails such as Nerita atramentosa,Bembicium nanum and Austrocochlea constricta;• low-shore areas dominated by the encrusting tubeworm Galeolaria caespitosa;• a low shore algal assemblage with a rangeof animals including solitary ascidians (Pyurastolonifera) and macro-algal grazing chitons (molluscs living on rocks with shellsconsisting of eight overlapping calcareous plates) (Underwood and Chapman 1995,Smith and James 1999, Otway 1999 and references within).While some organisms occupy a range of habitats, many are restricted to certain areason the rocky shore, such as rock pools and crevices. Some of the most diverse andabundant animals are gastropods such as whelks, chitons, and bivalves such as oystersand mussels (Smith and Simpson 1991b, Smith and James 1999, Smith 2005). Somecrustacean species are also common, particularly barnacles and crabs, as are severalconspicuous echinoderms (marine invertebrates with an internal calcareous skeleton,often with spines) such as sea urchins and starfish, and anemones (Figure 32).A diverse and conspicuous range of plant species often grow on these rocky shores,which are generally defined as encrusting, foliose and canopy-forming. Some of themore obvious species are Neptune’s necklace (Hormosira banksii) (Figure 33), severalgreen algae (Ulva spp. and Enteromorpha spp.) and assemblages of red algae.Coastal rocky shores are also important roosting and feeding habitat for many birds,including the threatened sooty oyster catcher. Rocky shores on the islands mayprovide an important refuge from disturbance and predators.There are coastal rocky shores on numerous small headlands in the marine park, andalong longer stretches of rocky coastline at Corindi, between Station Creek and Wooli,and at Sandon River. These coastal rocky shores are often associated with adjoiningareas of subtidal rocky reef.A number of specific habitat types have been described and surveyed on rocky shoresin the marine park (Smith and James 1999). These are:• scree – an intertidal area dominated by bouldersor scree;• shallow pools – intertidal rock-pools less than1 metre deep and less than 100 square metres insurface area;• deep pools – intertidal rock-pools more than1 metre deep and less than 100 square metres insurface area;• lagoons – intertidal pools more than 100 squaremetres in surface area.Figure 32.Waratah anemones.Figure 33.Neptunes necklace algae.
Page 1 and 2: Naturalvalues of theSolitary Island
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 16 and 17: 3 Ecosystems and habitatsBiological
Page 18 and 19: 4 Ocean ecosystemsConsolidated area
Page 20 and 21: 14 Natural values of the Solitary I
Page 32 and 33: Figure 37.Station Creek.5 Estuarine
Page 38 and 39: 6 Pelagic ecosystemsOcean currents

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