Southern Highlands shale woodlands in the Sydney Basin Bioregion - endangered ecological community listing

The Scientific Committee, established by the Threatened Species Conservation Act, has made a Final Determination to list the Southern Highlands Shale Woodlands in the Sydney Basin Bioregion, as an ENDANGERED ECOLOGICAL COMMUNITY on Part 3 of Schedule 1 of the Act. Listing of Endangered Ecological Communities is provided for by Part 2 of the Act.

NSW Scientific Committee - final determination

The Scientific Committee has found that:

1. Southern Highlands Shale Woodlands in the Sydney Basin Bioregion is the name given to the ecological community characterised by the species assemblage listed in 2 below. It occurs on clay soils on Wianamatta Shale in the Southern Highlands. All sites are within the Sydney Basin Bioregion.

2. Southern Highlands Shale Woodlands includes vegetation ranging from open-forest to woodland and scrub though it was predominantly woodland. Remnants may now be of variable structure due to clearing and disturbance. Typical trees include Eucalyptus radiata,  Eucalyptus macarthurii,  Eucalyptus pauciflora,  Eucalyptus globoidea,  Eucalyptus cypellocarpa,  Eucalyptus quadrangulata,  Eucalyptus amplifolia,  Eucalyptus ovata. Other trees include  Eucalyptus smithii,  Eucalyptus obliqua,  Eucalyptus fastigata,  Eucalyptus viminalis,  Eucalyptus elata,  Eucalyptus punctata,  Eucalyptus tereticornis,  Eucalyptus mannifera and  Eucalyptus cinerea.

The understorey is variable with small trees including Acacia melanoxylon,  Acacia binervata and  Pittosporum undulatum, shrubs such as  Indigofera australis,  Leucopogon juniperinus,  Olearia microphylla and  Bursaria spinosa. Ground species may include  Hardenbergia violacea,  Lomandra longifolia,  Pteridium esculentum,  Themeda australis,  Dichelachne crinita and  Microlaena stipoides.

Southern Highlands Shale Woodlands is characterised by the following assemblage:

3. The total species list of the flora and fauna of the community is considerably larger than that given in 2 (above), with many species present in only one or two sites or in very small quantity. The community includes invertebrates, many of which are poorly known, as well as vertebrates. In any particular site not all of the assemblage listed above may be present. At any one time, seeds of some species may only be present in the soil seed bank with no above-ground individuals present. Invertebrate species may be restricted to soils or canopy trees and shrubs. The species composition of the site will be influenced by the size of the site and by its recent disturbance history. The number of species and the above-ground composition of species will change with time since fire, and may also change in response to changes in fire frequency.

4. Southern Highlands Shale Woodlands is found on clay soils derived from Wianamatta Shale on the Southern Highlands, south of Colo Vale, extending from west of Mittagong, eastwards to the Illawarra Escarpment, south to Bundanoon and south-west to Canyonleigh. Elevation ranges from about 600 m to about 800 m. Rainfall ranges from 1400 mm in the east to 900 mm per annum in the west. Southern Highlands Shale Woodlands for parts of this area are described in Fisher, Ryan & Lembit (1995) and Benson & Howell (1994)

5. Southern Highlands Shale Woodlands is or has been known to occur in the Wingecarribee Local Government Area, but may occur elsewhere in the Sydney Basin Bioregion.

6. Disturbed Southern Highlands Shale Woodlands remnants are considered to form part of the community including areas where the vegetation would respond to assisted natural regeneration, such as where the natural soil and associated seedbank is still at least partially intact.

7. Southern Highlands Shale Woodlands has been extensively cleared for agriculture and rural development. Remnants are mostly small isolated pockets. About 2000 ha, or less than 5% of the original extent now remains (Benson & Howell, 1994).

8. Southern Highlands Shale Woodlands has been reported from the Cecil Hoskins Nature Reserve, and the Hammock Hill and Old Bowral Airfield council reserves. There are small areas on the edges of the Metropolitan Catchment Area.

9. Animal species of conservation significance possibly occurring in Southern Highlands Shale Woodlands include Giant Burrowing Frog, Heleioporus australiacus; Rosenberg's Goanna,  Varanus rosenbergi; Glossy Black Cockatoo,  Calyptorhynchus lathami; Powerful Owl,  Ninox strenua; Regent Honeyeater,  Xanthomyza phrygia; and Yellow-bellied Glider,  Petaurus australis.

10. Much of the remaining area of Southern Highlands Shale Woodlands is highly fragmented with much of it occurring on private land. Many remnants are in poor condition, including in some reserves, with aging trees, lack of regeneration and weed invasion. Ongoing threats include clearing for agriculture, hobby farming and replacement with european landscape e.g. pines, grazing that kills saplings and understorey species, ringbarking by stock, firewood cutting and invasion by exotic species.

11. In view of the restricted and fragmented distribution of this community, its inadequate representation within conservation reserves, the extensive disturbance and weed invasion that has occurred, and the threats from ongoing development, the Scientific Committee is of the opinion that Southern Highlands Shale Woodlands in the Sydney Basin Bioregion is likely to become extinct in nature in New South Wales unless the circumstances and factors threatening its survival or evolutionary development cease to operate and that the community is eligible for listing as an endangered ecological community.

Proposed Gazettal date: 15/06/01
Exhibition period: 15/06/01 - 20/07/01

References

Benson, D. & Howell, J. (1994) Hawkesbury-Nepean Catchment Vegetation Mapping - Moss Vale - Kiama draft 1:100 000 vegetation map sheets. (Royal Botanic Gardens Sydney).

Fisher, M., Ryan, K. & Lembit, R. (1995) The natural vegetation of the Burragorang 1:100 000 map sheet. Cunninghamia 4(2): 143-215.