Biodiversity publications archive

Refugia for biological diversity in arid and semi-arid Australia

Biodiversity Series, Paper No. 4
S.R. Morton, J. Short and R.D. Barker, with an Appendix by G.F. Griffin and G. Pearce
Biodiversity Unit
Department of the Environment, Sport and Territories, 1995

8. Foci of biological diversity in New South Wales

8.1. Darling Riverine Plains

Area

13,838 km².

Primary land-use

Sheep grazing, cotton growing, tourism.

National Parks and Nature Reserves

Kinchega National Park, Macquarie Marshes National Park, Nearie Lake Nature Reserve, Narran Lake Nature Reserve.

Management problems

Land degradation through over-grazing (Benson 1991; Pickard 1991; Pickard and Norris 1994; Wilcox and Cunningham 1994). Water quality in the rivers of the Region is declining rapidly, mainly as a result of removal of water for irrigation and from increased salinity caused chiefly by irrigation runoff (e.g. Helman and Estella 1983; Pressey and Harris 1988; Dendy and Coombe 1991; Richardson 1994; Sharley and Huggan 1994). Clearing for agriculture in marginal lands continues to be a problem (Benson 1991; Cambell 1994). Finally, control of vertebrate pests (Freudenberger 1993; Newsome 1994).

ANZECC-listed species

The plants Senecio behrianus (E) and Swainsona pyrophila (V) are reported from the lower Darling River (Bowen and Pressey 1993).

Species that are regionally endemic

Reptiles: : The worm-skink Anomalopus mackayi is largely confined to the Region, although it extends a little to the north-east (Cogger 1992). It is at risk because its habitat has been cleared for cropping or degraded by grazing (Cogger et al. 1993, pp. 76-77; Sadlier and Pressey 1994).

Fishes: Two-spined blackfish Gadopsis bispinosus, Murray jollytail Galaxias rostratus, Australian rainbowfish Melanotaenia fluviatilis, Macquarie perch Macquaria australasica, Murray cod Maccullochella peeli, and silver perch Bidyanus bidyanus are endemic to the Murray-Darling system (Lloyd et al. 1991).

Relict populations

Many populations of the 29 species of fishes within the Murray-Darling system have contracted markedly due to dramatic changes in the rivers (Lloyd et al. 1991; Richardson 1994).

Other significant populations

Mammals: Dickman et al. (1993) considered the greater long-eared bat Nyctophilus timoriensis and the yellow-bellied sheath-tail bat Saccolaimus flaviventris to be sparse and at risk because their tree-roosting behaviour exposed them to loss of habitat and predation by cats.

Birds: Freckled ducks Stictonetta naevosa breed in the Region (Blakers et al. 1984). Smith et al. (1994) considered many waterbirds to be of conservation concern because of alterations to their habitats, and considered that the plum-headed finch Neochmia modesta was of conservation concern in the Region.

Reptiles: Populations of the elapid snake Notechis scutatus and the python Morelia spilota variegata are declining in riverine habitats along the Murray-Darling system (Sadlier and Pressey 1994). Eastern populations of the elapid snake Echiopsis curta are confined to mallee areas of the Region, and may be at risk from clearing and grazing (Cogger et al. 1993, pp. 147-149; Sadlier and Pressey 1994).

Plants: Bowen and Pressey (1993) recorded the rare plants Echinochloa lacunaria, Acanthocladium dockeri, Leptorhynchos waitzia, Ipomoea diamantinensis, Ptychosperma anomalum, Swainsona adenophylla, S. laxa, and Solanum karsensis.

Wetlands

Information is primarily extracted from Wettin et al. (1993).

Darling Anabranch Lakes: A complex of wetlands comprising Mindona Lake, Little Lake, Travellers Lake, Popio Lake, Popilta Lake, Yeltow Lake, Nialia Lake, Nearie Lake, Milkengay Lake and associated lagoons located along the Great Anabranch of the lower Darling River. The dominant features of the Anabranch are the large overflow lakes which occur along its middle reaches. The lakes are shallow and none is permanent, although the largest retain water for up to five years. When not flooded many of the lakes are cropped. Water regulation in the Anabranch has had a significant effect on flows to Nearie Lake Nature Reserve, modifying the original flooding regime, which may have a significant impact on vegetation and fauna species.

Macquarie Marshes: Located on the lower Macquarie River near Warren, NSW. The wetland comprises a complex of braided swamps, channels and gilgai floodplain, inundated by flooding from the lower Macquarie River and its effluents and anabranches (Paijmans, 1981). Some flooding occurs in most years, but the Macquarie River is a regulated system, and the magnitude and frequency of flooding have been reduced. The vegetation consists of extensive areas of reeds and woodlands of river red gum Eucalyptus camaldulensis, with limited areas of lignum. Marginal areas have woodlands of coolibah E. microtheca and black box E. largiflorens. Following flooding, there is widespread breeding of many species of waterbirds involving 42 species (Brooker 1992). The Macquarie Marshes provide drought refuge when wetlands in other parts of the state, especially more inland areas, are dry; over 60 species have been recorded (Brooker 1992). They also provide habitat for a substantial fauna of reptiles that are either aquatic or strongly associated with water (Brooker and Wombey 1986). The nature reserve area is already listed as a Ramsar wetland, and the remainder of the marshes are proposed for listing.

Narran Lakes: Comprises lakes and wetlands associated with the Narran River west of Walgett, NSW. The wetland is the terminal drainage basin of the Narran River, and consists of overflow swamps through which flows the River to terminate in the large Lake. Flooding probably occurs in about one in two to five years, after which water may persist for up to two years. The overflow swamp is vegetated with dense lignum, together with river cooba Acacia stenophylla and coolibah along the river banks. Following flooding, there is a large influx of waterbirds to the area, and many species breed. Very large nesting colonies of straw-necked ibis Threskiornis spinicollis occupy the overflow swamp, and large concentrations of ducks occur the lake as water recedes (Lawler and Briggs 1991). As with other wetlands of this Region, the Narran Lakes provide potential waterbird drought refuge when wetlands in other areas of the inland are dry (Kingsford et al. 1990). Narran Lake has been proposed for nomination to the Ramsar Convention.

Talyawalka Anabranch and Teryawynia Creek: Comprises wetlands of the Talyawalka Anabranch of the Darling River, and its distributary Teryawynia Creek, located between Wilcannia and Menindee. It consists of a series of braided channels across the floodplain, interspersed by a series of intermittent wet and dry lakebeds. Most of the lakes are inundated by overflow from Teryawynia Creek, but several (Sayers, Gum, Boolaboolka, North and Ratcatchers Lakes) are inundated by overflow from the other lakes. The system supports large areas of black box. When inundated, these lakes provide habitat for large numbers of waterbirds.

Refugia

The Darling and Talyawalka Anabranch lakes (see section 14.4), the Macquarie Marshes (14.5), and the Narran Lakes (14.6) appear to constitute refugia.