Artesian springs ecological community - endangered ecological community listing

NSW Scientific Committee - final determination



The Scientific Committee, established by the Threatened Species Conservation Act, has made a Final Determination to list theArtesian Springs Ecological Community as an ENDANGERED ECOLOGICAL COMMUNITY on Part 3 of Schedule 1 of the Act. The listing of Endangered Ecological Communities is provided for by Part 2 of the Act.

The Scientific Committee has found that:

1. TheArtesian Springs Ecological Community is the name given to the ecological community that is naturally restricted to artesian springs at the southern and western margins of the Great Artesian Basin in north western NSW.

2. The vegetation within the community frequently consists of sedges or similar vegetation (Pickard 1992). Trees and shrubs may be adjacent to, or nearby, the springs. Plant assemblages differ between springs. As the springs have been a focus for domestic and feral animals for nearly 150 years, the flora has become less specifically related to the permanent water and more typical of a heavily disturbed area (Pickard 1992). A number of exotic species also occur in the community. The Artesian Springs Ecological Community is variable as each individual spring varies in shape, water flow, topographic and geographic location. In general, the Artesian Springs are characterised by a suite of plant species generally associated with water (Pickard 1992):

  • Abutilon otocarpum
  • Acacia victoriae
  • Alternanthera denticulata
  • Alternanthera angustifolia
  • Atriplex spp.
  • Boerhavia coccinea
  • Calandrinia ptychosperma
  • Centipeda minima
  • Centipeda thespidioides
  • Chamaesyce drummondii
  • Chenopodium cristatum
  • Chenopodium melanocarpum
  • Chloris pectinata
  • Cyperus bulbosus
  • Cyperus difformis
  • Cyperus gymnocaulos
  • Cyperus iria
  • Cyperus laevigatus
  • Cyperus squarrosus
  • Dactyloctenium radulans
  • Diplachne fusca
  • Dodonaea viscosa subsp. angustissima
  • Einadia nutans subsp. nutans
  • Eragrostis spp.
  • Eremophila deserti
  • Eremophila sturtii
  • Eucalyptus largiflorens
  • Eucalyptus populnea
  • Geijera parviflora
  • Glinus lotoides
  • Marsilea spp.
  • Myoporum montanum
  • Oxalis sp.
  • Pimelea microcephala subsp. microcephala
  • Portulaca oleracea
  • Sclerolaena spp.
  • Sclerostegia sp.
  • Solanum esuriale
  • Sporobolus caroli
  • Sporobolus mitchellii
  • Stemodia florulenta
  • Swainsona spp.
  • Trianthema triquetra
3. The total species list of the community is considerably larger than that given in 2 (above), with many species present in only one or two sites or in very small quantity. In any particular site only a small component of the assemblage listed in 2 may be present. At any one time, seeds of some species may only be present in the soil seed bank with no above-ground individuals present. The species composition of the site will be influenced by the size of the site, its disturbance history and the water status of each spring.

4. The ecological community is naturally rare. The springs are characterised by mounds of sediment and salts deposited as water evaporates (Ponder 1986, 1999) or may be depressions. Unique aquatic invertebrate, vertebrate and plant communities occupy the springs. Where artesian water emerges at the surface through fault lines in the overlying rock, mounds form from salts and sediments as the water evaporates. These occur at the edges of the Great Artesian Basin. Most occur in Queensland and South Australia and a few occur in the Mulga Lands, Darling Riverine Plains and Cobar Peneplain Bioregions of New South Wales.

5. The "community of native species dependent on natural discharge of groundwater from the Great Artesian Basin" is listed as an Endangered Ecological Community under the Commonwealth's Environment Protection and Biodiversity Act, 1999.

6. TheArtesian Springs Ecological Community is described by Pickard (1992) and by Sattler and Williams (1999) for Queensland. Approximately 45 sets of springs occur in north western NSW. Some 30 still have permanent seeps or slight flows of artesian water (Pickard 1992).

7. Systematic surveys ofArtesian Springs fauna are limited in NSW. In Queensland and South Australia, the springs are described as supporting unique aquatic invertebrates and vertebrates. Many unique freshwater snails and fishes (desert gobies) have been collected from mound springs and have been recorded nowhere else. Many species occur in one spring only (Ponder 1986, 1999).

8. Flora studies at Peery Lake have found that the only known population of Schoenoplectus pungens in far western NSW occurs at Peery Lakes Springs (Bowen and Pressey 1993). The endangered species of perennial forb, Eriocaulon carsonii (Salt Pipewort) has been recorded at several springs at Peery Lake.

9. Major threats toArtesian Springs Ecological Community are trampling and grazing by stock and feral animals such as pigs, goats and rabbits, alteration of flow or unsustainable extraction of water from artesian bores reducing flows to the mound springs. A number of springs have dried in the past 100 years due to falling water pressure caused by over-extraction. This has probably caused the extinction of undescribed species of aquatic invertebrates (Ponder 1986, 1999).

10. The onlyArtesian Springs that are within a reserve are at Peery Lake in Peery National Park. However, presence in the conservation reserve will not protect the ecological community from the threat of alteration of flows as the unsustainable extraction of artesian water occurs outside the reserve, yet may influence all mound springs within the region.

11. In view of the above, the Scientific Committee is of the opinion that theArtesian Springs Ecological Community in New South Wales is likely to become extinct in nature unless factors threatening its survival or evolutionary development cease to operate.

Proposed Gazettal date: 15/06/01

Exhibition period: 15/06/01 - 20/07/01


References

Bowen, R. and Pressey, B.(1993) Localities and habitats of plants with restricted distributions in the Western District of New South Wales. NSW National Parks and Wildlife Service Occasional Paper No. 175.

Pickard, J. (1992) Artesian Springs in the Western Division of New South Wales. Graduate School of the Environment Working Paper Series No. 9202, pp. 1-120.

Ponder, W.F. (1986) Mound Springs of the Great Artesian Basin. pp 403-420 In de Deckker, P. and Williams W.D. ( Eds), Limnology in Australia. CSIRO, Melbourne and W. Junk, The Hague.

Ponder, W.F. (1999) Box 4.5, Mound Springs. p 50 In Boulton, A.J. and Brock, M.A. Australian Freshwater Ecology: processes and management . Glen Eagles Publishing, Adelaide.

Sattler, P.S. and Williams, R.D. (1999) The Conservation Status of Queensland's Bioregional Ecosystems. Queensland Environmental Protection Agency, Brisbane.

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Page last updated: 27 February 2011