Central Hunter Ironbark-Spotted Gum-Grey Box Forest 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 Ironbark - Spotted Gum - Grey Box Forest 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:

2. Central Hunter Ironbark-Spotted Gum-Grey Box Forest 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 Ironbark - Spotted Gum - Grey Box Forest typically forms an open forest to woodland dominated by Eucalyptus crebra (Narrow-leaved Ironbark),  Corymbia maculata (Spotted Gum) and  Eucalyptus  moluccana (Grey Box). Other tree species may be present and occasionally dominate or co-dominate, and include  Eucalyptus fibrosa (Broad-leaved Ironbark) and  Eucalyptus tereticornis (Forest Red Gum). A sparse layer of small trees may be present in some areas, typically including  Allocasuarina luehmannii (Bulloak) or  Acacia  parvipinnula (Silver Streamed Wattle). The shrub layer is typically sparse or absent in some cases, through to moderately dense. Common shrub species include  Daviesia ulicifolia subsp.  ulicifolia (Gorse Bitter Pea),  Pultenaea spinosa (Grey Bush Pea),  Breynia oblongifolia (Coffee Bush),  Hakea sericea (Bushy Needlebush), and  Bursaria spinosa subsp.  spinosa (Native Blackthorn) (Peake 2006). Ground cover can be sparse to moderately dense, and consists of numerous forbs, a few grass species, and a limited number of ferns, sedges or other herbs. Common species include  Cheilanthes sieberi subsp.  sieberi (Poison Rock Fern),  Cymbopogon refractus (Barbed Wire Grass),  Pratia purpurascens (Whiteroot),  Lomandra multiflora subsp.  multiflora (Many-flowered Mat-rush),  Pomax umbellata (Pomax),  Glycine tabacina (Variable Glycine),  Dianella revoluta (Blue Flax Lily),  Laxmannia gracilis (Slender Wire Lily),  Microlaena stipoides var.  stipoides (Weeping Rice Grass),  Vernonia cinerea var.  cinerea,  Lissanthe strigosa (Peach Heath),  Brunoniella australis (Blue Trumpet),  Desmodium varians (Variable Tick-trefoil),  Dichondra repens (Kidney Weed),  Eremophila debilis (Winter Apple),  Calotis cuneifolia (Purple burr-daisy),  Hypercium gramineum (Small St. John's Wort),  Chrysocephalum apiculatum (Common Everlasting),  Opercularia diphylla (Stinkweed),  Paspalidium distans (Tufted Hedgehog Grass)  Themeda australis (Kangaroo Grass),  Stackhousia viminea (Slender Stackhousia) and  Wahlenbergia communis (Tufted Bluebell) (Peake 2006).

5. Central Hunter Ironbark - Spotted Gum - Grey Box Forest has been described by Peake (2006) as Central Hunter Ironbark - Spotted Gum - Grey Box Forest (Map Unit 27) and as Map Unit 18 (NSW NPWS 2000; DECC 2008). It includes a part of a unit described by Thomas (1998) as Eucalyptus crebra – Eucalyptus moluccana – Eucalyptus glaucina/tereticornis woodland. It shares some characteristics with, but is not part of a community described by Bell (2005) as Narrabeen Residual Spotted Gum Forest from a small area near Bulga. It shares some characteristics with, but is not part of a community described by Peake (2006) as Central Hunter Grey Box – Ironbark Woodland, and also shares some characteristics with but is not part of the Endangered Ecological Community ‘Central Hunter Grey Box – Ironbark Woodland in the NSW North Coast and Sydney Basin Bioregions (Scientific Committee 2010).

6. Central Hunter Ironbark - Spotted Gum - Grey Box Forest has been recorded from the local government areas of Cessnock, Singleton and Muswellbrook but may occur elsewhere within the NSW North Coast and Sydney Basin Bioregions (sensu Thackway and Creswell 1995).

7. Central Hunter Ironbark-Spotted Gum-Grey Box Forest is known to contain an Endangered Population of Cymbidium canaliculatum, the Vulnerable species  Diuris tricolor and  Eucalyptus glaucina, the Endangered species  Lepidium hyssopifolium and the Critically Endangered species  Persoonia pauciflora listed under the  Threatened Species Conservation Act 1995.

8. Central Hunter Ironbark - Spotted Gum - Grey Box Forest 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). It has been mapped as being recorded in Bellfield National Park and in the Singleton Military Area.

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 18,300 ha which is estimated to be 29% of the pre-European distribution (Peake 2006). Mapped occurrences of the community include 34 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 Ironbark-Spotted Gum-Grey Box Forest 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),  Lantana camara (Lantana),  Hyparrhenia hirta (Coolatai Grass), and  Sporobolus africanus (Giant Parramatta Grass) (Peake 2006). Lantana ( Lantana camara) has been demonstrated to increase following disturbances associated with fire or grazing (Gentle and Duggin 1997a). Lantana ( Lantana camara) poses a threat through structural alteration, invasion and allelopathic suppression of tree seedlings (Gentle and Duggin 1997b).

11. Threats to Central Hunter Ironbark - Spotted Gum - Grey Box Forest include clearing and weed invasion. 'Clearing of native vegetation', 'Invasion, establishment and spread of Lantana (Lantana camara L.  sens. lat.)', 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 pose threats to this community.

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

13. Central Hunter Ironbark - Spotted Gum - Grey Box Forest 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 the 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.

DECC (2008) Vegetation of the Cessnock-Kurri Region, Survey, Classification and Mapping, Cessnock LGA, New South Wales, Department of Environment and Climate change (NSW), Sydney.

Gentle CB, Duggin JA (1997a) Lantana camara L. invasions in dry rainforest-open forest ecotones: the role of disturbances associated with fire and grazing.  Australian Journal of Ecology 22, 298-306.

Gentle CB, Duggin JA (1997b) Allelopathy as a competitive strategy in persistent thickets of Lantana camara L. in three Australian forest communities.  Plant Ecology 132, 85-85.

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).

New South Wales National Parks and Wildlife Service (2000) Vegetation Survey, Classification and Mapping: Lower Hunter and Central Coast Region. Version 1.2. New South Wales National Parks and Wildlife Service, Hurstville.

NSW Scientific Committee (2010) Central Hunter Grey Box – Ironbark Woodland 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