Acacia dangarensis (a small tree) - endangered species listing

The Scientific Committee, established by the Threatened Species Conservation Act, has made a Final Determination to list the small tree Acacia dangarensis Tindale & Kodela as an ENDANGERED SPECIES in Part 1 of Schedule 1 of the Act. Listing of endangered species is provided for by Part 2 of the Act.

NSW Scientific Committee - final determination

The Scientific Committee has found that:

1. Acacia dangarensis Tindale & Kodela (family Fabaceae) is described by Kodela and Harden (2002) in Harden, G.J. (ed).  Flora of New South Wales Volume 2, Revised Edit. p 467, UNSW Press, Sydney, as a "small tree to 10m high; bark at first smooth and grey, later fissured and blackish at base; branchlets more or less terete with low ridges, glabrous. Leaves with rachis 1.5-6cm long, more or less glabrous or with very sparse hairs, jugary glands present, interjugary glands absent; pinnae 2-6 pairs, 3-8cm long; pinnules 14-30 pairs, linear, mostly 4-9mm long, 0.25-0.4mm wide, glabrous; petiole 0.4-4.5cm long, with 1 prominent gland. Heads globose, 12-26-flowered, bright yellow, in terminal or axillary panicles; peduncles 1-3mm long, glabrous. Pods more or less straight, more or less flat, 3-8cm long, 5-7mm wide, glabrous; seeds longitudinal; funicle filiform and expanded towards seed. Flowers August to September."  A. dangarensis is distinguished from its closest relative  A. decurrens by its branchlets being terete with several low longitudinal ridges to c. 0.2 mm high (the branchlets of  A. decurrens are prominently winged with narrow ridges to 2 mm high), leaves with rachis (1.6-)3-6 cm long, 2-6 pairs of pinnae and a gland often present above each secondary pulvinus, and flower heads 2-4 mm in diameter (Tindale and Kodela 1991).

2. Acacia dangarensis is endemic to NSW and confined to the summit and surrounding slopes of Mount Dangar south of Merriwa, within Goulburn River National Park (Tindale and Kodela 1991). It occurs in pure stands or as a co-dominant tree in sclerophyll woodland on the edge of dry rainforest on basalt and basalt colluvium.

3. The total population size of Acacia dangarensis is estimated to be of the order of 1750 plants extending over an area of about 70 hectares. It is not known to occur in any other location despite considerable survey around the Hunter district in recent years (Bell  et al. 1993, Bell 1998, Thomas 1998, Hill 2000).

4. The low total number of plants and the highly restricted distribution of Acacia dangarensis make it susceptible to demographic and environmental stochasticity, such as frequent or very severe fires, or storms. Weed infestation, particularly from prickly pear,  Opuntia stricta, may reduce seedling recruitment and threaten the future persistence of  Acacia dangarensis.

5. In view of the above the Scientific Committee is of the opinion that Acacia dangarensis Tindale & Kodela 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 Lesley Hughes
Chairperson
Scientific Committee

Proposed Gazettal date: 25/11/05
Exhibition period: 25/11/05 - 20/01/06

References 

Bell SAJ (1998) 'Wollemi National Park vegetation survey.' Volumes 1 & 2. NSW National Parks and Wildlife Service, Hurstville.

Bell SAJ, Vollmer J, Gellie N (1993) 'Yengo National Park and Parr State Recreation Area. Vegetation survey for use in fire management.' NSW National Parks and Wildlife Service, Hurstville.

Hill L (2000) 'Goulburn River National Park and Munghorn Gap Nature Reserve: vegetation survey for fire management purposes.' NSW National Parks and Wildlife Service, Muswellbrook.

Thomas D (1998) 'Vegetation communities of the Singleton Military Area.' Department of Defence, Singleton.

Tindale MD, Kodela PG (1991) Acacia tessellata, A. cangaiensis and  A. dangarensis (Fabaceae: Mimosoideae), three new species from northern New South Wales, Australia.  Australian Systematic Botany 4, 579-589.