NVIS Fact sheet MVG 8 – Casuarina forests and woodlands Australia’s native vegetation is a rich and fundamental Overview element of our natural heritage. It binds and nourishes our ancient soils; shelters and sustains wildlife, protects Typically, vegetation areas classified under MVG 8 – streams, wetlands, estuaries, and coastlines; and absorbs Casuarina forests and woodlands: carbon dioxide while emitting oxygen. The National • feature Casuarinas (she-oaks) that are a distinctive Vegetation Information System (NVIS) has been developed part of the Australian landscape. The name Casuarina and maintained by all Australian governments to provide is derived from the Malay Kasuari and alludes to the a national picture that captures and explains the broad similarity between the drooping foliage of some species diversity of our native vegetation. in the genus and that of the feathers of the cassowary This is part of a series of fact sheets which the Australian • feature casuarinas that have a unique leaf structure, Government developed based on NVIS Version 4.2 data to in which individual leaves are reduced to small teeth, provide detailed descriptions of the major vegetation groups the bases of which are fused and surround the stem. (MVGs) and other MVG types. The series is comprised of This gives the leaf-bearing branchlets the appearance of a fact sheet for each of the 25 MVGs to inform their use by needles and the plant canopies a fine structure allowing planners and policy makers. An additional eight MVGs are permeability of more light than broad-leaf tree canopies available outlining other MVG types. • while several contrasting vegetation types are dominated by Casuarinas, most species of Allocasuarina are For more information on these fact sheets, including subordinate or subdominant members of mixed its limitations and caveats related to its use, please see: plant communities ‘Introduction to the Major Vegetation Group • include vegetation dominated by Casuarina or (MVG) fact sheets’. Allocasuarina in contrasting environments such as arid sandplains, coastal floodplains and riparian corridors in humid landscapes. (Banner Photo) Casuarina forest (floodplain), Western Sydney, NSW (Photo: B. Pellow) SSD18H.0117 environment.gov.au Facts and figures Structure and physiognomy • Dominated by Casuarina species, often in monospecific MVG 8 - Casuarina forests stands or otherwise with infrequent co-dominants. Major Vegetation Group and woodlands Dominant tree Casuarina species reproduce vegetatively by suckers to varying degrees. 26. Casuarina and Major Vegetation Subgroups Allocasuarina forests • In riparian and estuarine environments, tree canopies and woodlands may reach 20 - 30 m tall with 30 – 40 per cent canopy cover, sometimes producing a deep layer of Casuarina Closed forest (low, mid) ‘needles’ which can limit the growth of shrubs and Typical NVIS Open forest (low, mid) ground layer species. Some stands, however, have a structural formations conspicuous ground layer of moisture-tolerant forbs and Woodland (low, mid, tall) sedges or rushes. Number of IBRA regions 52 • In semi-arid regions ephemeral plant species are an Present: Great Victoria important component of this group. The canopy Most extensive in Desert (WA, SA) tends to be sparser in the semi-arid areas than in moist IBRA region environments, permitting the development of an open Est. pre-1750: Murray shrub layer and ground layer of perennial and ephemeral (Est. pre-1750 and present) Darling Depression (NSW, forbs and grasses. SA, Vic) • Trees are typically around 12 m tall with crown cover Estimated pre-1750 >20 per cent, foliage projective cover >10 per cent, and 31 278 extent (km2) the understorey includes an open layer chenopod or Present extent (km2) 16 579 other shrubs. Area protected (km2) 4 358 Casuarina forest along Kilaben Creek, near Kilaben Bay, Lake Macquarie NSW (Photo: J. Baker) environment.gov.au Indicative flora are often dominated by chenopod shrubs and forbs including species of Maireana, Chenopodium Enchylaena, • Although MVG 8 is dominated by species of Casuarina Rhagodia and Sclerolaena. The ground layer includes or Allocasuarina, species composition varies between ephemeral species of Asteraceae and Zygophyllum geographic locations. with tussocks of Austrostipa, Chloris, Enneapogon • Typical species in inland areas include belah (Casuarina and Sporobolus. cristata), drooping she-oak (Allocasuarina verticillata), desert oak (A. decaisneana) and river she-oak (C. cunninghamiana). Coast she-oak Environment (C. equisetifolia) can also occur in association with • Pure stands of Casuarina (the she-oaks) are often coastal banksias along the south-east and eastern restricted in area to specific sites. Coast she-oak seaboards in less exposed sites. (C. equisetifolia) is typically restricted to the coastal • Large areas of A. decaisneana (desert oak) open foredunes of eastern Australia; grey she-oak woodlands occur in arid Northern Territory, Western (C. glauca), Western Australian swamp she-oak (C. Australia and South Australia. obesa) and river oak (C. cunninghamiana) to fringes of • In floodplain/estuarine environments Casuarina glauca, flow lines in swamps, and A. huegeliana on granitic soils are found either in pure or mixed stands, with Melaleuca and near outcrops in Western Australia. styphelioides, M. quinquenervia or M. ericifolia. The • May occur as mosaics with other MVGs, such as with ground layer includes a varying mixture of forb genera other floodplain forests in their upper reaches (MVGs such as Alternanthera, Commelina, Persicaria, Solanum 3 and 9) or coastal saltmarshes (MVG 22) at their tidal and Viola, and graminoids including species of Baumea, extremity, and in semi-arid climates Carex, Cynodon, Gahnia, Juncus, Lomandra, Microlaena (220 to 350 mm mean annual rainfall) with mallee and Phragmites. woodlands (MVG 14 and 32) and bluebush • Casuarina cunninghamiana (river oak) typically shrublands (MVG 22). dominates riparian zones. Various eucalypts and • Found in association with acacia and eucalypts in other other genera may co-occur in low densities. Common inland areas. understoreys include riparian graminoids Lomandra • In South Australia and Tasmania Allocasuarina longifolia and Carex appressa, with forbs such as species verticillata forms monospecific stands on a range of of Alternanthera, Aneilema, Hydrocotyle and Persicaria. topographies from hill slopes and crests to coastal dunes • In semi-arid areas, Casuarina pauper in pure or mixed and plains. Coastal dune assemblages of A. verticillata stands, often with a subcanopy of Alectryon oleifolius, belong to MVG 15. are associated with calcareous sandplains. Understoreys Casuarina cristata subsp. pauper woodland, Carrawinya National Park, QLD (Photo: M. Fagg) environment.gov.au Geography Change • Occur on littoral and riverbank sites along the • Approximately 10 per cent (>14 500 km2) of the south-eastern, eastern and northern coast of Australia, estimated pre-1750 extent cleared accounting for 1.7 per semi-arid south-eastern Australia and rocky sites cent of total clearing in Australia. throughout the continent. • Clearing for intensive agriculture. • In floodplain/estuarine zones such as periodically • Changes to floodplain drainage have further modified inundated subsaline flats associated with lower the distribution of floodplain vegetation. Soil oxidation floodplains and estuarine fringes. related to ditching has resulted in dense regrowth of • Narrow riparian zones restricted to alluvial soils of largely Casuarina glauca in locations where it may not have permanent streams draining the Great Dividing Range previously occurred, but rarely with the range of other (up to 800 m). species characteristic of the native forests. • On calcareous sandplains of semi-arid climates (lower • Invasions by weeds associated with fertiliser use Murray Darling Basin to the Nullarbor Plain in the west) in catchments. on soils of solonized sandy loams with calcrete nodules • Casuarina woodlands have been cleared for cropping and in the subsoil. pasture improvement in the higher rainfall parts of their • The largest distribution is in South Australia (6 507km2). range, and more recently mining activities. • Grazing by sheep, cattle, feral goats and rabbits, limits The image below outlines the location of this MVG group recruitment of Casuarina and other woody species. in Australia. • Dieback related to salinisation affects coastal and inland woodlands where tidal flows have been altered or water tables are rising as a result of clearing and fragmentation of vegetation. • Threats to these restricted-site communities include grazing by feral animals, pollution, sedimentation, rising water tables and dryland salinity in temperate Australia, and coastal development affecting wetland and supratidal forests of Casuarina glauca. environment.gov.au Key values Harris S. and Kitchener A (2005) From Forest to Fjaeldmark. Descriptions of Tasmania’s Vegetation. pp. 398. Department of • Biodiversity including wetland biota and species of Primary Industry, Water and Environment Hobart. parrot that feed on Casuarina fruits. Keith D. (2004) Ocean Shores to Desert Dunes. The native • Hydrological functions of streams and floodplains. vegetation of New South Wales and the ACT. Department of • Health of coastal estuaries and wetlands. Environment and Conservation (NSW), Hurstville. • Fire management in semi-arid landscapes, as Casuarina woodlands are much less flammable than National Land and Water Resources