Halosarcia lylei low open-shrubland in the Murray Darling Depression Bioregion - endangered ecological community listing

The Scientific Committee, established by the Threatened Species Conservation Act, has made a Final Determination to list the Halosarcia lylei low open-shrubland in the Murray Darling Depression Bioregion, 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. Halosarcia  lylei low open-shrubland in the Murray Darling Depression Bioregion is the name given to the ecological community described by Westbrooke  et al. (1998) in their report on the vegetation of the area covered by the Scotia 1:100 000 map sheet in south-western New South Wales (NSW). The community is dominated by the chenopod shrub  H. lylei and occurs on saline clay soils on the beds of small salt lakes and around the perimeter of larger salt lakes. Before the Westbrooke  et al. (1998) study, both  Halosarcia  lylei low open-shrubland and its dominant species had not previously been recorded from NSW (Harden 1993).

2. Halosarcia  lylei low open-shrubland in the Murray Darling Depression Bioregion was observed at most sites to be almost entirely monospecific (Westbrook  et al. 1998), Species found in the community include:

• Atriplex vesicaria
• Disphyma crassifolium subsp . clavellatum
• Halosarcia lylei
• Halosarcia pergranulata
• Osteocarpum acropterum var . deminuta

3. The total species list of the community varies between sites, with some 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 history. 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. Although 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. The Halosarcia lylei low open-shrubland was recorded from 14 locations within the Scotia map sheet (Westbrooke  et al. 1998), and all locations occurred within the Wentworth and Unincorporated local government areas (within the Murray Darling Depression Bioregion). Most locations (11) occurred to the immediate north-east and south-east of Nanya Station. This community belongs to the Inland Saline Wetlands vegetation class of Keith (2004).

5. Westbrook et al. (1998) estimated that the  Halosarcia lylei low open-shrubland covered less than one percent of the area of the Scotia map sheet. Further, the community is not protected within any formal reserves in south-western NSW, including Tarawi Nature Reserve, which falls entirely within the Scotia map sheet.

6. Halosarcia lylei low open-shrubland is potentially threatened by over-grazing and trampling by domestic livestock. This may become prevalent in areas where the availability of water for stock is increased through more efficient reticulation of water in previously unstocked or moderately stocked areas. Clearing of vegetation for agricultural purposes and during mineral exploration may also threaten this community. In particular, the targeting of salt lakes for sand mining is a significant threat to this community. Together with direct adverse effects on plants of trampling and mechanical destruction, disturbance may facilitate the invasion of weeds, cause erosion, disrupt cryptogamic flora and soil-dwelling invertebrates, and affect associated vertebrate fauna e.g. Orange Chats,  Epthianura aurifrons, and White-fronted Chats,  E. albifrons. Moreover, as a consequence of its apparent limited range and isolation, the community is vulnerable to local extinction via stochastic events.

7. In view of the above the Scientific Committee is of the opinion that the Halosarcia lylei low open-shrubland in the Murray Darling Depression Bioregion is likely to become extinct in nature in New South Wales unless the circumstances and factors threatening its survival cease to operate.

Associate Professor Paul Adam
Chairperson
Scientific Committee

Proposed Gazettal date: 17/12/04

Exhibition period: 17/12/04 - 28/01/05

References 

Keith DA (2004) 'Ocean shores to desert dunes: the native vegetation of New South Wales and the ACT.' (NSW Department of Environment and Conservation, Sydney.)

Harden GJ (1993) (Ed.) 'Flora of New South Wales, Vol. 4.' (New South Wales University Press: Sydney)

Westbrooke ME, Miller JD, Kerr MKC (1998) The vegetation of the Scotia 1: 100 000 map sheet, western New South Wales. Cunninghamia5 , 665-684.