Acacia ausfeldii - vulnerable species listing

The Scientific Committee, established by the Threatened Species Conservation Act, has made a Final Determination to list the shrub Acacia ausfeldii Regel. as a VULNERABLE SPECIES in Part 1 of Schedule 2 of the Act. Listing of vulnerable species is provided for by Part 2 of the Act.

NSW Scientific Committee - final determination

The Scientific Committee has found that:

1. Acacia ausfeldii (family Fabaceae) is described in Harden (2002) as an: "erect or spreading shrub 2-4 m high; branchlets angled or flattened, resinous, glabrous. Phyllodes straight to slightly curved, oblanceolate to narrow-elliptic, 2-7 cm long, 2-5 mm wide, glabrous and dotted with resin glands, midvein prominent, lateral veins obscure, apex obtuse with a mucro; 1 gland near base; pulvinus + straight, + flat, 4-9 cm long, 2-4 mm wide, glabrous; seeds longitudinal; funicle filiform. Flowers Aug.-Oct. Grows in eucalypt woodland on sandy soil.

2. Acacia ausfeldii occurs in NSW and Victoria. In NSW it is found in the Mudgee -Ulan - Gulgong area, predominantly in the northern part of the NSW South Western Slopes bioregion, with some occurrences in the adjoining bioregions of Brigalow Belt South and the Sydney Basin (Thackway & Creswell 1995). In the Mudgee - Ulan area,  A. ausfeldii is mostly found on flat ground in remnant roadside patches of woodland with  Eucalyptus albens (White Box),  E. blakelyi (Blakely's Red Gum) and  Callitris spp. (Native Cypress Pines) , with an understorey dominated by  Cassinia spp. and grasses. The largest populations occur to the NW of Gulgong in Tuckland State Forest and the recently declared Yarrobil National Park and Goodiman State Conservation Area.  A. ausfeldii was also recorded in Munghorn Gap Nature Reserve in 1963.

3. The geographic distribution of A. ausfeldii was estimated to be at least moderately restricted, though could be highly restricted, based on an extent of occurrence of approximately 2300 - 2600 km2 (the area of a minimum convex polygon encompassing all known sites in the Mudgee - Ulan - Gulgong area of NSW).

4. There is thought to be in excess of 20 000 individuals of A. ausfeldii in NSW. The proportion of mature individuals in the total population is not known. The individuals are distributed between 11 and 14 locations. However, populations located in the Mudgee area contain small numbers of plants. Therefore, only a small number of locations (6-8) are estimated to contain 90% of the total population.

5. Established plants of Acacia ausfeldii are likely to be killed by fire, as mature and juvenile plants have a single-stemmed habit, with no evidence of fire-resistant organs. During recent field inspections, a range of size classes of  A. ausfeldii plants, including juveniles, were observed at most sites, particularly in disturbed areas. This may be interpreted as evidence of seedling recruitment during recent years.  A. ausfeldii is likely to have a dormant soil seedbank from which germination is stimulated by fire, as is the case in many other  Acacia species, but a fraction of seeds have been observed to germinate in the absence of fire. The population is therefore unlikely to undergo extreme fluctuations.

6. The landscape around Mudgee, Ulan and Gulgong has largely been cleared for agriculture, with some remnant patches of native vegetation remaining. This suggests that a substantial loss of habitat for A. ausfeldii has occurred since settlement of the region. Approximately half of the remaining populations are located within an agricultural landscape on road verges, while others occur on private pastoral land. Roadside disturbance, weed invasion, grazing and small-scale clearing are therefore likely to result in continuing decline in these populations, and hence the species overall in NSW. The largest populations of the species occur on conservation reserves, state forests and leasehold lands to the north-west of Gulgong, and are less likely to decline unless their viability is affected by adverse grazing regimes or adverse fire regimes.

7. Acacia ausfeldii Regel is not eligible to be listed as an endangered or critically endangered species.

8. Acacia ausfeldii Regel is eligible to be listed as a vulnerable species 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 15

The geographic distribution of the species is estimated or inferred to be:

(a) moderately restricted,

and:

(d) a projected or continuing decline is observed, estimated or inferred in:

• (i) an index of abundance appropriate to the taxon,
• (ii) geographic distribution, habitat quality or diversity, or genetic diversity;

(e) the following conditions apply:

• (i) the population or habitat is observed or inferred to be severely fragmented;
• (ii) all or nearly all mature individuals are observed or inferred to occur within a small number of populations or locations,

Professor Lesley Hughes
Chairperson
Scientific Committee

Proposed Gazettal date: 07/09/07
Exhibition period: 07/09/07 - 02/11/07

References:

Harden, G.J. (ed.) (2002) Flora of NSW Revised Edition Volume 2. UNSW, Sydney.

Thackway R, Creswell ID (1995) An interim biogeographic regionalisation for Australia: a framework for setting priorities in the National Reserves System Cooperative Program. Version 4.0. Australian Nature Conservation Agency, Canberra.