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

6. Foci of biological diversity in the Northern Territory (continued)

6.3. Gulf Fall and Uplands

Area

116,389 km².

Primary land-use

Cattle grazing, Aboriginal lands.

National Parks and Nature Reserves

Lawn Hill National Park (part), Queensland. The "Gulf Region Land Use and Development Study" recommended the creation of several conservation reserves in this Region (Northern Territory Department of Lands and Housing 1991).

Management problems

Better cattle management required (Northern Territory Department of Lands and Housing 1991), as well as improved fire management.

ANZECC-listed species

Mammals: Black-footed rock-wallabies Petrogale lateralis (V) occur at Lawn Hill, Queensland (Eldridge et al. 1993). The ghost bat Macroderma gigas (V) occurs in the Northern Territory (Northern Territory Department of Lands and Housing 1991, p. 31).

Birds: The Carpentarian grasswren Amytornis dorotheae (V) occurs in scattered pockets (Garnett 1992, pp. 122-3). McKean and Martin (1989) reported on the species in the Gulf region, noting that it occurs just across the border in Queensland. The species is confined to spinifex on dissected sandstone plateaus and slopes (see also Northern Territory Department of Lands and Housing 1991, p. 37). Gouldian finches Erythrura gouldiae occur in the McArthur River area (Northern Territory Department of Lands and Housing 1991, p. 37).

Plants: Solanum carduiforme (V) occurs in Queensland (Thomas and McDonald 1989).

Species that are regionally endemic

Mammals: The Carpentarian rock-rat Zyzomys palatalis, and an undescribed species of pebble-mound mouse Pseudomys sp. from Bauhinia (Northern Territory Department of Lands and Housing 1991, pp. 31 and 37; Kitchener 1989; Menkhorst and Woinarski 1992).

Reptiles: A gecko Gehyra borroloola (Cogger 1992).

Plants: Astartea intratropica, Calytrix mimiana, Melaleuca aff. symphyocarpa and Trachymene glandulosa (Thomas and McDonald 1989; Northern Territory Department of Lands and Housing 1991, pp. 30 and 35).

Relict populations

The vine thickets scattered along the rivers through the sandstone country probably contain relict species, including undescribed species of ferns (Northern Territory Department of Lands and Housing 1991, p. 35).

Other significant populations

In the Northern Territory, the plants Fimbristylis clavata, F. dolera, Tiliacora australiana, Brachychiton collinus, Livistona rigida, Arenga australasica and Heterodendrum tropica occur among sandstone (Northern Territory Department of Lands and Housing 1991, pp. 31 and 35). Thomas and McDonald (1989) listed as rare or threatened in Queensland the plants Dodonaea oxyptera, and Brachychiton collinus.

Wetland sites

The following information is summarised from Blackman et al. (1993).

Lawn Hill Gorge: The Gorge is characterised by deep permanent open fresh water, by narrow levees at the base of vertical cliffs/bluffs dominated by Pandanus aquaticus, Livistona sp., Nauclea orientalis, and Melaleuca sp., an aquatic bed in the lower Gorge dominated by Nymphaea violoacea, and emergent and fringing wetlands dominated by sedges, rushes, grasses and ferns. The permanent deep water and fringing habitats in a semiarid environment provide refugia for a diverse and locally distinct biota. The 'oasis' species which utilise the permanent moisture associated with the Gorge comprise ferns, mosses, algae, palms and a diverse riverine flora. Notable fauna includes the rock ringtail possum Pseudocheirus dahli, and a range of freshwater fish, crustaceans and molluscs. Freshwater crocodiles Crocodylus johnstoni occur in the creek.

Thorntonia Aggregation: Streamlines on dissected country of the Gulf fall on the Thorntonia Limestone of the extensive limestone surface and upper catchments of Lawn Hill Creek, the Gregory, O'Shannessy Rivers and Thornton Creek. The main streams are permanent, and there are variable communities of forested wetland on well developed levees where seasonally flooded areas support Livistona sp., Melaleuca sp., Nauclea orientalis, Eucalyptus camaldulensis, Eucalyptus papuana, and Lophostemon grandiflorus. Pandanus aquaticus, Ficus racemosa occur with the above species on levees of the main channels an semi-permanently flooded channels. Emergent wetlands occur on the levees with Typha sp., Phragmites australis, Imperata cylindrica, Vetiveria elongata, Cyperus sp., Eleocharis sp., Fimbristylis sp., Polygonum sp. with the fern Lygodium microphyllum on moist ground. Aquatic beds are dominated by Nymphaea violaceae. The system possibly represents the only perennial stream in arid Queensland. The perennial streams are considered to provide a refugial environment during the dry season.

Refugia

Areas of the Carpentarian sandstone in the Northern Territory (see section 12.6) and Lawn Hill Gorge (13.5) seem to constitute refugia.