Central Hunter Grey Box-Ironbark Woodland in the NSW North Coast and Sydney Basin Bioregions - endangered ecological community listing

The Scientific Committee, established by the Threatened Species Conservation Act, has made a Final Determination to list the Central Hunter Grey Box – Ironbark Woodland in the NSW North Coast and Sydney Basin Bioregions as an ENDANGERED ECOLOGICAL COMMUNITY in 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. Central Hunter Grey Box – Ironbark Woodland in the NSW North Coast and Sydney Basin Bioregions is the name given to the ecological community that generally occurs on Permian sediments in the Hunter Valley and is characterised by the assemblage of species in paragraph 2. The community typically forms a woodland to open forest on slopes and undulating hills.

2. Central Hunter Grey Box – Ironbark 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 low abundance. The species composition of a site will be influenced by the size of the site, recent rainfall, drought condition and by its disturbance (including fire and grazing) history. The number of species, and the above ground relative abundance of species will change with time since disturbance, and may also change in response to changes in disturbance 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. Central Hunter Grey Box – Ironbark Woodland typically forms a woodland dominated by Eucalyptus crebra (Narrow-leaved Ironbark),  Brachychiton populneus subsp.  populneus (Kurrajong) and  Eucalyptus moluccana (Grey Box). Other tree species may be present and occasionally dominate or co-dominate, and include  Angophora floribunda (Rough-barked Apple) and  Callitris endlicheri (Black Cypress Pine). A shrub layer may also be present and common shrub species include  Notelaea microcarpa var.  microcarpa (Native Olive),  Breynia  oblongifolia (Coffee Bush),  Bursaria spinosa subsp.  spinosa (Native Blackthorn),  Cassinia quinquefaria (Cough Bush) and  Dodonaea viscosa (Hop Bush). Subshrubs may also be common and include  Solanum cinereum (Narrawa Burr), and  Phyllanthus virgatus (Spurge) and  Maireana microphylla (Eastern Cotton Bush) (Peake 2006). Ground cover can be moderately dense to dense, and consist of numerous forbs and grass species, and a small number of ferns, sedges and twiners. The more common species include  Cymbopogon refractus (Barbed Wire Grass),  Aristida ramosa (Three-awned Wire Grass),  Dichondra repens (Kidney Weed),  Cheilanthes  sieberi subsp.  sieberi (Poison Rock Fern),  Chloris ventricosa (Tall Chloris),  Austrostipa scabra (Corkscrew Grass),  Desmodium varians (Variable Tick-trefoil),  Microlaena stipoides var.  stipoides (Weeping Rice Grass),  Eragrostis  leptostachya (Paddock Lovegrass),  Sporobolus creber (Slender Rat's Tail Grass),  Calotis lappulacea (Yellow Burr Daisy),  Lomandra multiflora subsp.  multiflora (Mat Rush),  Brunoniella australis (Blue Trumpet),  Eremophila debilis (Winter Apple),  Chrysocephalum apiculatum (Common Everlasting),  Cyperus gracilis, Einadia nutans (Climbing Saltbush),  Ajuga australis (Austral Bugal),  Vittadinia cuneata (Fuzzweed),  Bothriochloa decipiens (Red Grass), and  Glycine tabacina (Variable Glycine) (Peake 2006).

5. Central Hunter Grey Box – Ironbark Woodland has been described by Peake (2006) as Central Hunter Box – Ironbark Woodland (Map Unit 10). It has also been described by Thomas (1998) as part of Eucalyptus crebra – Eucalyptus moluccana – Eucalyptus glaucina/tereticornis woodland (Map Unit 4.4) and by Fallding  et al. (1999) as Ironbark Forest on Alluvium (Map Unit Q2). It shares some characteristics with, but is not part of a community described by Peake (2006) as Central Hunter Spotted Gum – Ironbark – Grey Box Forest and by Bell (2005) as Goulburn Valley Ironbark Woodland. This community also shares some characteristics with, but is not part of the Endangered Ecological Community 'Central Hunter Ironbark – Spotted Gum' – Grey Box Forest in the NSW North Coast and Sydney Basin Bioregions (Scientific Committee 2010).

6. Central Hunter Grey Box – Ironbark Woodland has been recorded from the local government areas of Cessnock, Singleton and Muswellbrook but may occur elsewhere within the Sydney Basin Bioregion (sensu Thackway and Creswell 1995).

7. Central Hunter Grey Box – Ironbark Woodland is known to contain an Endangered Population of Cymbidium  canaliculatum, the Vulnerable species  Diuris tricolor and  Eucalyptus glaucina, and the Endangered species  Pterostylis gibbosa listed under the  Threatened Species Conservation Act 1995.

8. Central Hunter Grey Box – Ironbark Woodland occupies an area of less than 2000 km2 based on 2 x 2 km grid cells, the scale of assessment recommended for species by IUCN (2008).

9. Land clearing, primarily for agriculture, has lead to a large reduction in geographic distribution of the community. The mapped area of the community is approximately 46,920 ha which is estimated to be 32% of the pre-European distribution (Peake 2006). Mapped occurrences of the community include 27 remnants greater than 100 ha and more than 1000 small remnants less than 10 ha indicating a high level of fragmentation (Peake 2006).

10. Central Hunter Grey Box – Ironbark Woodland has been subject to intensive livestock grazing and clearing which has made it vulnerable to weed invasions. The community has been invaded by a range of woody and herbaceous weed species including Olea europaea subsp.  cuspidata (African Olive),  Lycium ferocissimum (African Boxthorn), and  Hyparrhenia hirta (Coolatai Grass) (Peake 2006).

11. Threats to Central Hunter Grey Box – Ironbark Woodland include, clearing and weed invasion. 'Clearing of native vegetation' and 'Invasion of native plant communities by exotic perennial grasses', are listed as Key Threatening Processes under the Threatened Species Conservation Act 1995. Collectively, the effects of these threats indicate a large reduction of the ecological function of the community. Continual clearing related to open-cut coal mining and rural sub-division are potential threats to this community.

12. Central Hunter Grey Box – Ironbark Woodland in the NSW North Coast and Sydney Basin Bioregions is not eligible to be listed as a Critically Endangered Ecological Community

13. Central Hunter Grey Box – Ironbark Woodland in the NSW North Coast and Sydney Basin Bioregions is eligible to be listed as an Endangered Ecological Community as, in the opinion of the Scientific Committee, it is facing a very high risk of extinction in New South Wales in near future, as determined in accordance with the following criteria as prescribed by the Threatened Species Conservation Regulation 2002:

Clause 25

The ecological community has undergone, is observed, estimated, inferred or reasonably suspected to have undergone or is likely to undergo within a time span appropriate to the life cycle and habitat characteristics of its component species:

(b) a large reduction in geographic distribution.

Clause 27

The ecological community has undergone, is observed, estimated, inferred or reasonably suspected to have undergone or is likely to undergo within a time span appropriate to the life cycle and habitat characteristics of its component species:

(b) a large reduction in ecological function,

as indicated by any of the following:

(g) invasion and establishment of exotic species

(i) fragmentation of habitat.

Dr Richard Major
Chairperson
Scientific Committee

Proposed Gazettal date: 12/02/10
Exhibition period: 12/02/10 – 09/04/10

References:

Bell SAJ (2005) The vegetation and floristics of Wollemi National Park, central eastern New South Wales. Unpublished Report.

Fallding M, Bell S, Murray M, Klaphake V (1999) Myambat Vegetation and Fauna Management. Guidelines for Landscape management and the Myambat Logistics Company Site. Prepared for Land and Environment Planning for the Department of Defence.

IUCN (2008) 'Guidelines for using the IUCN Red List Categories and Criteria. Version 7.0.' (Standards and Petitions Working Group of the IUCN Species Survival Commission Biodiversity Assessments Sub-committee: Switzerland).

NSW Scientific Committee (2010) Central Hunter Ironbark - Spotted Gum - Grey Box Forest in the NSW North Coast and Sydney Basin Bioregions. Final Determination. NSW Scientific Committee, Sydney.

Peake TC (2006) The Vegetation of the Central Hunter Valley, New South Wales. A report on the findings of the Hunter Remnant Vegetation Project. Hunter- Central Rivers Catchment Authority, Paterson.

Thackway R, Creswell ID (1995) 'An interim biogeographic regionalisation for Australia: a framework for setting priorities in the National Reserve System Cooperative Program'. Version 4.0. ANCA, Canberra

Thomas D (1998) Vegetation Communities of the Singleton Military Area. Unpublished report to the Department of Defence.