Western Sydney dry rainforest 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 Western Sydney Dry Rainforest (WSDR) in the Sydney Basin Bioregion as an ENDANGERED ECOLOGICAL COMMUNITY on Part 3 of Schedule 1 of the Act. The 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. The Western Sydney Dry Rainforest (WSDR) is the name given to the plant community from the local government areas of Camden, Wollondilly, Fairfield, Hawkesbury and Baulkham Hills (within the Sydney Basin Bioregion) that is characterised by the following assemblage of species:

2. The total species list of the community is considerably larger than that given in 1 (above), with many species present in only one or two sites or in very small quantity. In any particular site not all of the assemblage listed in 1 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. 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.

3. WSDR has been recorded from the local government areas of Camden, principally near Cobbitty, Fairfield (Fairfield City Farm) and Wollondilly (Razorback Range), Hawkesbury and Baulkham Hills (within the Sydney Basin Bioregion).

4. WSDR is typically associated with gullies and sheltered slopes of hilly, relatively steep sections of the generally elevated Cumberland Plain in the Razorback Range from Cobbitty to Picton, and sporadically elsewhere in Western Sydney including Fairfield City Farm, Grose Vale and Cattai. Soils are clay soils on Wianamatta Shale.

5. The structure of the community was originally a canopy of dry vine thicket rainforest as a similar understorey in eucalypt forest or woodland, but as a result of partial clearance it may now exist as woodland or shrubland.

6. WSDR includes vegetation described by National Parks and Wildlife Service (NPWS) - referred to as Dry Rainforest in UBBS (1997); referred to as Vine Thicket in Benson & Howell (1990); referred to as Dry Rainforest in Benson, Howell & McDougall (1996) and James, McDougall & Benson (1999). The vegetation was also referred to as Cobbitty Vine Thicket and is included in the Camden Significant Tree and Vegetated Landscape Study.

7. Significant species for WSDR listed by NPWS (1997) include: Cynanchum elegans,  Croton verreauxii,  Streblus brunonianus,  Legnephore moorei,  Deeringia amaranthoides,  Diospyros australis,  Celastrus australis,  Geijera latifolia,  Solanum stelligerum,  Maclura cochinchinensis,  Aphanopetalum resinosum and  Senna clavigera.

8. Sites where WSDR remnants are found are less than 2 ha. in area and are mostly located on private property. An occurrence of WSDR is known from Cattai National Park.

9. Occurrences of WSDR have been reduced to tiny remnants by clearing. The remnants are subject to disturbance and edge effects as a consequence of small size and threatened by woody weed invasion particularly by African Olive Olea europea subsp  africana.

10. In view of the small size of existing remnants, the threat of further clearing and disturbance, the Scientific Committee is of the opinion that Western Sydney Dry Rainforest in the Sydney Basin Bioregion is likely to become extinct in nature unless factors threatening its survival or evolutionary development cease to operate and that listing as an endangered ecological community is warranted.

References

Benson, D and Howell, J. (1990) Taken for Granted; The Bushland of Sydney and its Suburbs. (Kangaroo Press: Kenthurst).

Benson, D., Howell, J. and McDougall, L (1996) A Guide to Natural Vegetation in the Hawkesbury-Nepean Catchment. (Royal Botanic Gardens: Sydney).

National Parks & Wildlife Service (1997), Urban Bushland Biodiversity Survey of Western Sydney. (National Parks and Wildlife Service: Sydney).

James, T. McDougall, L & Benson, D. (1999) Rare Bushland Plants of Western Sydney (Royal Botanic Gardens: Sydney).

Landarc Landscape Architects (1993) Camden Significant Tree and Vegetated Landscape Study (Camden Municipal Council).