Kincumber Scribbly Gum Forest in the Sydney Basin Bioregion - critically endangered ecological community listing

The Scientific Committee, established by the Threatened Species Conservation Act, has made a Final Determination to list the Kincumber Scribbly Gum Forest in the Sydney Basin Bioregion, as a critically endangered ecological community in Part 2 of Schedule 1A of the Act. Listing of critically endangered ecological communities is provided for by Part 2 of the Act.

NSW Scientific Committee - final determination

The Scientific Committee has found that:

1. Kincumber Scribbly Gum Forest in the Sydney Basin Bioregion is the name given to the ecological community characterised by the species assemblage listed in paragraph 2. The community is restricted to New South Wales and all sites are within the Sydney Basin Bioregion.

2. Kincumber Scribbly Gum Forest in the Sydney Basin Bioregion is characterised by the following assemblage of species:

A large number of infrequently recorded species also characterise the community. These include:

3. The total species list of the community is considerably larger than that given above, with many species present in only one or two sites or in low abundance. The species composition of a site will be influenced by the size of the site, recent rainfall or drought condition and by its disturbance (including fire) history. The number of species, and the above ground relative abundance of species will change with time since fire, and may also change in response to changes in fire regime (including changes in fire frequency). At any one time, above ground individuals of some species may be absent, but the species may be represented below ground in the soil seed banks or as dormant structures such as bulbs, corms, rhizomes, rootstocks or lignotubers. The list of species given above is of vascular plant species; the community also includes micro-organisms, fungi, cryptogamic plants and a diverse fauna, both vertebrate and invertebrate. These components of the community are poorly documented.

4. Kincumber Scribbly Gum Forest has an open tree canopy with Eucalyptus racemosa (Scribbly Gum),  Angophora costata (Smooth-barked Apple),  Corymbia  gummifera (Red Bloodwood),  Syncarpia glomulifera (Turpentine) and  Eucalyptus  piperita (Sydney Peppermint).  Allocasuarina littoralis (Black Sheoak) and  Glochidion  ferdinandi (Cheese Tree) may be present in the subcanopy. There is a prominent stratum of shrubs, which typically include  Dodonaea triquetra (Hopbush),  Platylobium formosum,  Persoonia levis (Broad-leaved Geebung),  Polyscias  sambucifolia (Elderberry Panax),  Breynia oblongifolia (Coffee Bush),  Leptospermum  polygalifolium (Lemon-scented Tea-tree),  Banksia spinulosa var.  collina (Hill Banksia),  Epacris pulchella,  Grevillea linearifolia and  Lomatia silaifolia (Crinkle Bush). The groundcover comprises herbs, scramblers, grasses, sedges and ferns, including  Billardiera scandens (Appleberry),  Cassytha glabella,  Dianella caerulea (Blue Flax Lily),  Entolasia stricta (Wiry Panic),  Lepidosperma laterale,  Pratia  purpurascens (Whiteroot),  Pteridium esculentum (Bracken),  Smilax glyciphylla (Sweet Sarsaparilla) and  Tetrarrhena juncea (Wire Grass).

5. A number of fauna species listed as threatened in NSW occur, or are likely to occur in Kincumber Scribbly Gum Forest. These include the Yellow-bellied Glider (Petaurus australis, Vulnerable), the Regent Honeyeater ( Xanthomyza phrygia, Endangered), the Little Bent-wing Bat ( Miniopterus australis, Vulnerable), the Common Bent-wing Bat ( Miniopterus schreibersii, Vulnerable) and the Yellow-bellied Sheath-tail Bat ( Saccolaimus flaviventris, Vulnerable).

6. Kincumber Scribbly Gum Forest was originally described by Bell (2004; Unit E102). In a survey of the Lower Hunter-Central Coast Region, vegetation referable to Kincumber Scribbly Gum Forest was classified as part of a broader map unit, ‘Coastal Narrabeen Shrub Forest” (Unit E22), defined by (NPWS 2000). An analysis of all available plot data shows that Kincumber Scribbly Gum Forest is distinct from other vegetation types in the region (Mackenzie and Keith 2007). The relationship of Kincumber Scribbly Gum Forest to broader map units defined in McCauley’s (2006) regional study is uncertain. Kincumber Scribbly Gum Forest belongs to the Sydney Coastal Dry Sclerophyll Forests vegetation class of Keith (2004), although it includes some mesophyllous shrubs, as well as grasses and herbs, which typically are not common components of that class.

7. Kincumber Scribbly Gum Forest has been recorded from the local government area of Gosford within the Sydney Basin Bioregion, (sensu Thackway and Creswell 1995) and may occur elsewhere in the Bioregion. Bell (2004) estimated the total remaining area of Kincumber Scribbly Gum Forest to be c. 80 ha. The entire known distribution is within an area of 4 km2. The geographic distribution of the community is therefore very highly restricted.

8. Kincumber Scribbly Gum Forest is not known from any conservation reserves managed under the National Parks and Wildlife Act 1974 or the Forestry Act 1916 (Bell 2004). The presence of cleared areas within the community’s very highly restricted distribution suggests that Kincumber Scribbly Gum Forest is likely to have been fragmented by clearing activity in the past. Further clearing and fragmentation of Kincumber Scribbly Gum Forest is highly likely, given the rapidly growing population and demand for land on the Central Coast of NSW. ‘Clearing of native vegetation’ is listed as a Key Threatening Process under the Threatened Species Conservation Act 1995.

9. The intensifying urban and industrial land uses in the area surrounding Kincumber Scribbly Gum Forest exposes the community to increased risks of degradation. Processes associated with degradation of urban bushland include weed invasion (Bell 2004), altered fire regimes, rubbish dumping and heavy recreational use. The introduced shrub species, Lantana camara, has been recorded in the quadrat data for Kincumber Scribbly Gum Forest. ‘Invasion, establishment and spread of Lantana camara’ is listed as a Key Threatening Process under the  Threatened Species Conservation Act 1995.

10. Kincumber Scribbly Gum Forest in the Sydney Basin Bioregion is eligible to be listed as a critically endangered ecological community as, in the opinion of the Scientific Committee, it is facing an extremely high risk of extinction in New South Wales in the immediate future, as determined in accordance with the following criteria as prescribed by the Threatened Species Conservation Regulation 2002:

Clause 26

The ecological community’s geographic distribution is estimated or inferred to be:

(a) very highly restricted,

and the nature of its distribution makes it likely that the action of a threatening process could cause it to decline or degrade in extent or ecological function over a time span appropriate to the life cycle and habitat characteristics of the ecological community’s component species.

Professor Lesley Hughes
Chairperson
Scientific Committee

Gazetted 4 July 2008

References:

Bell SAJ (2004) ‘The natural vegetation of Gosford Local Government Area, Central Coast,

New South Wales: Part 1 - Technical Report.’ Report to Gosford City Council.

Keith DA (2004) ‘Ocean shores to desert dunes: the native vegetation of New South Wales and the ACT.’ NSW Department of Environment and Conservation, Sydney.

Mackenzie BDE, Keith DA (2007) ‘Assessment of Kincumber Scribbly Gum Forest for listing as a threatened ecological community under the Threatened Species Conservation Act.’ Report to the NSW Scientific Committee, Sydney.

McCauley A (2006) ‘Vegetation Survey and Mapping of the Hunter, Central and Lower North Coast Region of NSW.’ A report prepared for the Hunter-Central Rivers Catchment Management Authority by the HCCREMS team at the Environment Division of Hunter Councils Inc., NSW.

NPWS (2000) ‘Vegetation Survey, Classification and Mapping: Lower Hunter and Central Coast Region.’ A project undertaken for the Lower Hunter and Central Coast Regional Environmental Management Strategy. Rivers Catchment Management Authority undertaken by the CRA Unit, Sydney Zone.

Thackway R, Creswell ID (1995). An Interim Biogeographic Regionalisation for Australia: a framework for establishing the national system of reserves, Version 4.0. (Australian Nature Conservation Agency: Canberra).