Biodiversity Strategy - Gosford City Council - NSW Government

Lily) was once relatively widespread but has been historically cleared for horticulture and
agricultural purposes. Small areas of heath associated with large expanses of sandstone rock
pavements and hanging swamp are scattered across the Somersby Plateau.
To the west within Dharug National Park on the MacDonald Ranges landscape exposed
woodlands on Hawkesbury sandstone are dominated by Corymbia eximia (Yellow Bloodwood)
and A. costata. Drainage lines in the west and Somersby Plateau area contain Hawkesbury
Peppermint-Apple Forest, characterised by E. piperita (Sydney Peppermint), A. costata,
Allocasuarina torulosa (Forest Oak), Syncarpia gloumulifera susbsp. glomulifera (Turpentine),
C. gummifera, E. scias subsp. Scias (Large-fruited Red Mahogany) and E. umbra (Broad-leaved
White Mahogany).
On the coast, the Erina Hills region has relatively higher coastal rainfall and shale-enriched soils
supporting moist tall forest and coastal warm temperate rainforest in protected gullies,
particularly in the Holgate and Matcham valleys. These consist of a variety of rainforest species
including Acmena smithii (Lillypilly), Doryphora sassafras (Sassafras) and Ceratopetalum
apetalum (Coachwood). Coastal Narrabeen Moist Forest is relatively widespread in the north
eastern section of the LGA with a tall moist forest dominated by E. saligna (Bluegum), A.
torulosa, S. glomulifera and to a lesser extent E acmenioides (White Mahogany) and E. pilularis
(Blackbutt).
On higher ridges with deeper shales Coastal Narrabeen Ironbark Forest occurs dominated by E.
paniculata subsp. paniculata (Grey Ironbark), E. punctata (Grey Gum), S. glomulifera subsp.
glomulifera and E. acemenioides. Narrabeen Coastal Blackbutt Forest occurs on drier ridges
dominated by Blackbutt, Turpentine and Forest Oak with a shrubby understorey. On Kincumba
Mountain and Mount Elliot ridges the Hawkesbury Sandstone geology supports Katandra
Hawkesbury Woodland and further south on the Bouddi peninsular supports Killcare
Hawkesbury Woodland. Both are described by Bell as being variants of the more widespread
Exposed Hawkesbury Woodland that occurs across the Somersby Plateau.
Along the major creeks and estuaries in the eastern parts of the LGA as well as along the banks
of the Hawkesbury River around Spencer and along Mangrove Creek mangrove and saltmarsh
communities occur. These are generally fringed by Estuarine Swamp Forest dominated by C.
glauca (Swamp Oak) with an understorey of sedges and rushes. Furtherback on areas with
impeded drainage Swamp Mahogany-Paperbark forests occur characterised by E. robusta
(Swamp Mahogany) and a range of paperbark species such as Melaleuca biconvexa, M.
linariifolia (Snow in Summer), M. styphelioides (Prickly-leaved Paperbark) and M.quinquenervia
(Broad-leaved Paperbark).
A - 5.2.2
Vegetation Mapping
The extent and condition of native vegetation is considered to be a useful surrogate for
biodiversity conservation (NPWS 2000a) and vegetation mapping is therefore an important
resource for conservation planning. Vegetation mapping has been undertaken previously by
Benson (1986) for Gosford and Lake Macquarie, Benson and Fallding (1981) for Brisbane
Water and environs, and by Benson and Howell (1994) for the northern part of the LGA. These
provide broad vegetation community mapping; for example open and closed forest, scrub and
woodland.
Regional scale vegetation mapping was undertaken in 1999 on behalf of the LHCCREMS
(NPWS 2000a). This was modeled across the landscape based on environmental variables and
flora surveys and was at a scale of 1:25,000. The mapping was updated in 2002 by EcoLogical
on behalf of LHCCREMS when digitized aerial photography became available which enabled
more accurate linework. The mapping was however not at a scale that could be considered
accurate enough for local scale planning and assessment.
Biodiversity - Technical Report Page 98