Hunter Valley Footslopes Slaty Gum Woodland in the Sydney Basin Bioregion - vulnerable ecological community listing

The Scientific Committee, established by the Threatened Species Conservation Act, has made a Final Determination to list the Hunter Valley Footslopes Slaty Gum Woodland in the Sydney Basin Bioregion, as a VULNERABLE ECOLOGICAL COMMUNITY in Part 2 of Schedule 2 of the Act. Listing of Vulnerable Ecological Communities is provided for by Part 2 of the Act.

NSW Scientific Committee - final determination

The Scientific Committee has found that:

1. Hunter Valley Footslopes Slaty Gum Woodland in the Sydney Basin Bioregion is the name given to the ecological community that generally occurs at the interface of Narrabeen Sandstone and Permian sediments in the Hunter Valley and is characterised by the assemblage of species in paragraph 2. The community typically forms a low to mid-high woodland. All sites are within the Sydney Basin Bioregion.

2. Hunter Valley Footslopes Slaty Gum Woodland in the Sydney Basin Bioregion 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. Hunter Valley Footslopes Slaty Gum Woodland typically forms a woodland, or occasionally forest, comprising a sparse to moderately dense tree stratum, occasional low tree stratum, and moderately dense to dense shrub stratum. The tree canopy is typically dominated by Eucalyptus dawsonii (Slaty Gum) and/or  Eucalyptus  moluccana (Grey Box).  Acacia salicina (Cooba) and  Allocasuarina luehmannii (Buloke) may form a low tree stratum, or may be part of the upper-most canopy. Other trees which may be present include  Brachychiton  populneus subsp.  populneus (Kurrajong),  Callitris endlicheri (Black Cypress Pine),  Eucalyptus crebra (Narrow-Leaved Ironbark) and  Eucalyptus punctata (Grey Gum). The shrub layer may include  Olearia elliptica (Sticky Daisy Bush),  Acacia cultriformis (Knife-leaved Wattle),  Canthium odoratum (Shiny-leaved Canthium),  Notelaea  microcarpa var.  microcarpra (Native Olive),  Dodonaea viscosa subsp.  cuneata (Wedge-leaf Hopbush),  Acacia  decora (Western Golden Wattle),  Bursaria spinosa subsp.  spinosa (Native Blackthorn),  Myoporum montanum (Water Bush) and  Solanum brownii (Violet Nightshade). The groundcover is typically sparse to very sparse and is relatively species poor. It may include  Dichondra repens (Kidney Weed),  Lomandra multiflora subsp.  multiflora (Many-Flowered Mat-rush),  Aristida ramosa (Wire Grass),  Brunoniella australis (Blue Trumpet),  Cymbopogon refractus (Barbed Wire Grass),  Desmodium brachypodum (Large Tick-trefoil),  Eremophila debillis (Winter Apple),  Fimbristylis dichotoma (Common Fringe-rush) and  Sida corrugata (Corrugated Sida) (Peake 2006).

5. Hunter Valley Footslopes Slaty Gum Woodland typically occurs in colluvial soils on exposed footslopes associated with the interface of Triassic Narrabeen sandstone and Permian sediments. Hunter Valley Footslopes Slaty Gum Woodland has been described by Peake (2006) as Narrabeen Footslopes Slaty Box Woodland (Map Unit 7). It is also included in vegetation types described by Fallding et al. (1999) as Dawson's Box Woodland on Permian Sediments (Map Unit P1), by Bell (1998) as Permian Widden Talus Woodland (Map Unit W23), by Hill (1999) as Slaty Gum Open Forest (Map Unit OF8), and by McRae and Cooper (1985) as Woodland in Sandstone Gullies (Map Unit 4). It shares some characteristics with, but is not part of a community in the Western Blue Mountains called Capertee Slopes Slaty Gum - Grey Gum - Mugga - Callitris Open Forest (DECC 2006), nor is it part of the Narrabeen Grey Box Forests of Wollemi National Park (Bell 2005).

6. Hunter Valley Footslopes Slaty Gum Woodland has been recorded from the local government areas of Singleton and Muswellbrook but may occur elsewhere within the Sydney Basin Bioregion (sensu Thackway and Creswell 1995).

7. Hunter Valley Footslopes Slaty Gum Woodland in the upper Hunter Valley 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). Mapped occurrences of the community include a few remnants greater than 100 ha and many small remnants less than 10 ha indicating a high level of fragmentation (Peake 2006).

8. Hunter Valley Footslopes Slaty Gum Woodland is known to contain an Endangered Population of Acacia  pendula in the Hunter Catchment listed under the  Threatened Species Conservation Act 1995.

9. Threats to Hunter Valley Footslopes Slaty Gum Woodland include clearing, inappropriate fire regimes, and weed invasion. Clearing for agriculture, expanding hobby farms, and mining has reduced the extent of this community (Peake 2006). Fire frequency has also increased with increased hazard reduction to reduce risk to farms and other community infrastructure in parts of the Hunter Valley (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 rainforest seedlings (Gentle and Duggin 1997b). African Olive ( Olea europaea subsp.  cuspidata) also poses a significant threat through invasion (Peake 2006) as well as exotic perennial grasses (Peake 2006). 'Clearing of native vegetation', 'Invasion, establishment and spread of Lantana ( Lantana  camara L.  sens. lat.)', 'High frequency fire resulting in the disruption of life cycle processes in plant and animals and loss of vegetation structure and composition', and 'Invasion of native plant communities by exotic perennial grasses', are listed as Key Threatening Processes under the  Threatened Species Conservation Act 1995. Collectively, these threats indicate a moderate reduction of the ecological function of the community.

10. Hunter Valley Footslopes Slaty Gum Woodland in the Sydney Basin Bioregion is not eligible to be listed as an Endangered or Critically Endangered Ecological Community.

11. Hunter Valley Footslopes Slaty Gum Woodland in the Sydney Basin Bioregion is eligible to be listed as an Vulnerable Ecological Community as, in the opinion of the Scientific Committee, it is facing a high risk of extinction in New South Wales in the medium-term future, as determined in accordance with the following criteria as prescribed by the Threatened Species Conservation Regulation 2002:

Clause 26

The ecological community’s geographic distribution is estimated or inferred to be:

(c) moderately restricted,

and the nature of its distribution makes it likely that the action of a threatening process could cause it to decline or degrade in extent or ecological function over a time span appropriate to the life cycle and habitat characteristics of the ecological community’s component species.

Dr Richard Major
Chairperson
Scientific Committee

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

References:

Bell SAJ (1998) 'Wollemi National Park Vegetation Survey: A Fire Management Document'. Unpublished Report to NSW National Parks and Wildlife.

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

DECC (2006) ‘The Vegetation of the Western Blue Mountains’. Unpublished report funded by the Hawkesbury – Nepean Catchment Management Authority. Department of Environment and Conservation, Hurstville.

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.

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.

Hill LM (1999) Goulburn River National Park and Munghorn Gap Nature Reserve: Vegetation Survey for Fire Management Purposes. Unpublished report prepared for NSW National Parks and Wildlife Service, Upper Hunter District, Muswellbrook.

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). 

McRae RHD, Cooper MG (1985) Vegetation of the Merrriwa Area, New South Wales. Cunninghamia 1, 351–368.

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.