Warkworth Sands Woodland in the Sydney Basin Bioregion - Determination to make a minor amendment to Part 3 of Schedule 1 of the Threatened Species Conservation Act

The Scientific Committee, established by the Threatened Species Conservation Act, has made a Determination to make a minor amendment to Part 3 of Schedule 1 (Endangered ecological communities) of the Act by inserting the Warkworth Sands Woodland in the Sydney Basin Bioregion (as described in the determination of the Scientific Committee under Division 5 Part 2) and as a consequence to omit reference to the Warkworth Sands Woodland of the Sydney Basin Bioregion (as described in the final determination to list the ecological community) which was published on pages 10614 to 10618 in the NSW Government Gazette No. 255 dated 13 December 2002. Minor amendments to the Schedules are provided for by Division 5 of Part 2 of the Act.

The Scientific Committee is of the opinion that the amendment is necessary or desirable to correct minor errors or omissions in the Determination in relation to the Thackway and Cresswell (1995) reference.

NSW Scientific Committee - final determination

The Scientific Committee has found that:

1. Warkworth Sands Woodland in the Sydney Basin Bioregion is the name given to the ecological community occurring on aeolian sand deposits south east of Singleton in the Hunter Valley. This ecological community is currently known to occur in the local government area of Singleton but may occur elsewhere in the Bioregion. Bioregions are defined in Thackway and Cresswell (1995).

2. Warkworth Sands Woodland is characterised by the following assemblage of species.

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 very small quantity. 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. Warkworth Sands Woodland is generally of woodland to low woodland structure with trees of Angophora floribunda and  Banksia integrifolia, and shrubs and ground species including  Acacia filicifolia, Pteridium esculentum, Imperata cylindrica, Brachyloma daphnoides and  Melaleuca thymifolia.

5. Small drainage lines within the community may support a higher abundance of certain species (such as Melaleuca thymifolia) and less of others (such as  Banksia integrifolia). Such areas are included as part of this community. In addition, adjacent areas, where woodland occurs on a shallow A horizon of sand, are included within this community.

6. The community supports a number of threatened species including squirrel glider (Petaurus norfolcensis), speckled warbler ( Pyrrholaemus saggitata), brown treecreeper ( Climacteris picumnis subsp.  victoriae) and grey-crowned babbler ( Pomatosomus temporalis subsp.  temporalis).

7. Warkworth Sands Woodland occupies sand dunes generally 1-6 m high, resting on a river terrace. The main dune deposit is aligned NW-SE. The sand deposit is thought to be of Pleistocene age (Story et al. 1963).

8. Woodlands occurring adjacent to the sand dunes on Permian clays share many species with Warkworth Sands Woodland but also have a higher abundance of Permian substrate species, such as Corymbia maculata, Eucalyptus moluccana, Allocasuarina luehmannii and  Eucalyptus crebra. These areas are not considered to be part of this community, except in ecotones where there is a dominant abundance of the species of the Warkworth Sands Woodland. This is generally where a thin sandy veneer overlies the Permian substrate.

9. Warkworth Sands Woodland is now mainly confined to a small area near Warkworth, about 15 km south east of Singleton in the Hunter Valley. This occurrence now comprises nearly 80% of the extant vegetation. Due to the extent of vegetation clearing and modification in other areas, the original extent is now difficult to estimate, though assuming the community occurred on most of the other occurrences of the Warkworth Land System (Story et al. 1963), except that at Kurri Kurri which is clearly different, the current Warkworth Sands Woodland extent may be as little as 13% of its pre-settlement extent.

10. Approximately 800 ha of Warkworth Sands Woodland (based on air photo interpretation, GIS mapping and field reconnaissance) remains. Ongoing threats include open-cut coalmining, sandmining and the construction of mining infrastructure as well as pressures from agricultural clearing, altered fire frequency, weed invasion and grazing.

11. No areas of Warkworth Sands Woodland occur within a conservation reserve.

12. In view of the above the Scientific Committee is of the opinion that the Warkworth Sands Woodland 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.

Dr Richard Major

Proposed Gazettal date: 14/10/11
Exhibition period: 14/10/11 - 9/12/11

Note this ecological community was originally listed in 2002 as indicated in the determination

Reference

Story, R., Galloway, R.W. & van de Graaff, R. H. M. (1963) Land Systems of the Hunter Valley. pp 12-61 in Story, R., Galloway, R.W., van de Graaff, R.H.M. & Tweedie, A. (eds) General Report on the Lands of the Hunter Valley. Land Research Series No. 8. CSIRO, Melbourne.

Thackway R, Cresswell ID (1995) An interim biogeographic regionalisation for Australia: a framework for setting priorities in the National Reserves System Cooperative Program. (Version 4.0. Australian Nature Conservation Agency: Canberra.)