Hunter Valley Vine Thicket 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 Hunter Valley Vine Thicket 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. Hunter Valley Vine Thicket in the NSW North Coast and Sydney Basin Bioregions is the name given to the ecological community mainly occurring on Carboniferous sediments on rocky slopes and characterised by the assemblage of species in paragraph 2. The community typically forms a low closed forest dominated by trees with shrubs and vines. All sites are within the NSW North Coast and Sydney Basin Bioregions. Those sites within the NSW North Coast Bioregion are in the southern part of the bioregion.

2. Hunter Valley Vine Thicket in the NSW North Coast and Sydney Basin Bioregions 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 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. Hunter Valley Vine Thicket typically forms a low forest, usually less than 10 m tall, with a closed canopy dominated by trees, with shrubs and vines. The canopy may include the two varieties of Elaeodendron  australe (Red Olive Plum),  Geijera parviflora (Wilga),  Notelaea microcarpa var.  microcarpa (Native Olive) and  Alectryon  oleifolius subsp.  elongatus (Western Rosewood). Emergent eucalypts are common and include  Eucalyptus  albens (White Box),  E. dawsonii (Slaty Box) and  E. crebra (Narrow-leaved Ironbark). A shrub stratum is usually present and includes  Olearia elliptica subsp.  elliptica (Sticky Daisy Bush) and  Rhagodia parabolica (Mealy Saltbush). Vines dominate the canopy and include  Cissus opaca (Small-leaved Water Vine),  Marsdenia  flavescens (Hairy Milk Vine),  Parsonsia eucalyptophylla (Gargaloo) and  Pandorea pandorana subsp.  pandorana (Wonga Vine). Ground cover is generally sparse and includes  Urtica incisa (Stinging Nettle) and  Austrostipa  verticillata (Slender Bamboo Grass).

5. Hunter Valley Vine Thicket mainly occurs on rocky slopes on Carboniferous strata often on limestone. Hunter Valley Vine Thicket has been described by Peake (2006) and Curran (2006) and Curran et al. (2008). It falls broadly within the rainforest classification  Alliance VIII, Sub-Alliance 32 Notelaea microcarpa-Ehretia membranifolia-Geijera parviflora of Floyd (1990). It shares some characteristics with, but is not part of two Endangered Ecological Communities listed under the  Threatened Species Conservation Act 1995:  Cadellia  pentastylis (Ooline) community in the Nandewar and Brigalow Belt South Bioregions, and Semi-evergreen Vine Thicket in the Brigalow Belt South and Nandewar Bioregions.

6. Hunter Valley Vine Thicket has been recorded from the local government areas of Muswellbrook, Singleton, and Upper Hunter but may occur elsewhere within the Sydney Basin Bioregion and NSW North Coast Bioregion (sensu Thackway and Creswell 1995).

7. Hunter Valley Vine Thicket has a highly restricted geographic distribution. Its area of occupancy is estimated to be approximately 52 km2 based on 2 x 2 km grids, the scale recommended for assessment of species distributions by IUCN (2008). Within these grids, the community occurs mostly as patches less than 10 ha in extent and a few somewhat larger patches exceeding 100 ha, which are estimated to represent approximately 85% of the pre-European distribution of the community (Peake 2006). The only stand known to occur in a conservation reserve is at Mt Dangar within the Goulburn River National Park.

8. Some stands of Hunter Valley Vine Thicket contain an endangered population of Cymbidium canaliculatum, and the endangered species  Senecio linearifolius var.  dangarensis, both listed under the  Threatened Species Conservation Act 1995.

9. Threats to Hunter Valley Vine Thicket include clearing and track building, frequent fire, trampling and grazing by cattle, and weed invasion. The community is threatened by stochastic events due to its fragmented distribution and the small size of remnant patches. These threats are escalating and are intensified by the absence of a buffer around forest margins (Turner and Vernon 1994). The largest area of Hunter Valley Vine Thicket at Brushy Hill has been fragmented by construction and maintenance of a track and a pipeline. This has also allowed the incursion of livestock and the invasion of exotic species. Invasion by the exotic thicket-forming shrub Lantana (Lantana camara) has been demonstrated to increase following disturbances associated with fire or grazing (Gentle and Duggin 1997a). Lantana ( Lantana camara) occurs in and around many stands and poses a threat through structural alteration, invasion and allelopathic suppression of rainforest seedlings (Gentle and Duggin 1997b). African Olive ( Olea europea subsp . cuspidata) also poses a significant threat through invasion (Peake 2006). 'Clearing of native vegetation', 'Invasion and establishment of exotic vines and scramblers', and 'Invasion, establishment and spread of Lantana ( Lantana camara L . sens.  lat.)' are listed as Key Threatening Processes under the  Threatened Species Conservation Act 1995.

10. Hunter Valley Vine Thicket in the NSW North Coast and Sydney Basin Bioregions is not eligible to be listed as a critically endangered ecological community.

11. Hunter Valley Vine Thicket 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 26

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

(b) highly 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.

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:

(d) change in community structure

(e) change in species composition

(f) disruption of ecological processes

(g) invasion and establishment of exotic species

(h) degradation of habitat

(i) fragmentation of habitat

Dr Richard Major
Chairperson
Scientific Committee

Proposed Gazettal date: 31/07/09

Exhibition period: 31/07/09 - 25/09/09

References:

Curran TJ (2006) Rainforest, drought and soil type: phytogeography and functional and evolutionary ecology of dry rainforest on the western slopes of New South Wales. PhD. Thesis, University of New England, Armidale, Australia.

Curran TJ, Clarke PJ, Bruhl JJ (2008) A broad typology of dry rainforests on the western slopes of New South Wales. Cunninghamia10 , 381-405

Floyd AG (1990) Australian rainforests in New South Wales Vol 2 Surrey Beatty & Sons, NSW.

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 Ecology22 , 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 Ecology132 , 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)

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 4.10. ANCA: Canberra.)

Turner JC, Vernon SL (1994) Rainforest stands between Barrington Tops and the Hunter River, New South Wales. Cunninghamia3 , 465-514.