Wallum sedgefrog Photo: Scott Eipper
Common name: wallum sedgefrog
Scientific name: Litoria olongburensis
Conservation status: The wallum sedgefrog is listed as Vulnerable in Queensland (Nature Conservation Act 1992) and nationally (Environment Protection and Biodiversity Conservation Act 1999). It is ranked as a medium priority under the Department of Environment and Heritage Protection Back on Track species prioritisation framework.
The wallum sedgefrog is a small, slender tree-frog with a prominent pointed snout that protrudes over the lower jaw. Females (to 34 mm) tend to be slightly larger than males (to 26 mm). The skin on the top side is smooth and coloured grey-brown, beige or bright green, with occasional dark flecking. The granular underside is white except for the throat which is peppered brown. Distinguishing features include a dark brown stripe that runs from the snout through the eye and ear and an obvious white streak that starts below the eye and runs back to the flanks (side of animal between thigh and ribs). The dorsal (back) parts of the hind limbs are green to fawn, bordered by a blue/purple streak, while the ventral (front hidden) parts are orange. The toes are partly webbed and the finger discs and toe pads are prominent.
Habitat and distribution
Restricted to densely vegetated areas in the coastal lowlands of south-east Queensland, the wallum sedgefrog prefers acidic freshwater swamps (pH <5.5) with emergent reeds, ferns and sedges. It is less commonly found around creeks and reed beds around freshwater lakes.
The species geographic distribution encompasses coastal lowland areas of south-east Queensland and north-east New South Wales, from Lake Wongeel, Fraser Island, south to Woolgoolga. It is also known from several other offshore sand islands including Bribie, Moreton and North Stradbroke Islands. Large populations have persisted in protected reserves in both Queensland (Great Sandy, Noosa, Poona, Bribie Island, Blue Lake and Moreton Island National Parks) and New South Wales (Broadwater, Billinugel, Bundjalung, and Yuraygir National Parks and Tyagarah and Broken Head Nature Reserves).
Life history and behaviour
The wallum sedgefrog is a nocturnal species. Males make mating calls from sedges near water after rain. The male call sounds like a high-pitched buzzing lasting one second at irregular intervals. Calling may be heard from September through to April.
Juveniles have been found in February, suggesting the wallum sedgefrog breeds after rain in spring to summer. Eggs are laid singly in water at the base of sedges. Water at breeding sites is usually clear, heavily tannin-stained and acidic. Tadpoles may take 8 weeks or more to complete their development.
The diet of this species consists of arthropods including mosquitoes. Tadpoles feed on detritus and algae around sedges.
Similar to other wallum frog species, the wallum sedgefrog is largely threatened by habitat loss and fragmentation from urban and agricultural development (particularly on the mainland), pine plantation establishment and sandmining.
The wallum sedgefrog may also be adversely affected by habitat degradation due to trampling in tourist areas such as around the freshwater lakes of Fraser Island, weed invasion, inappropriate fire regimes, feral pigs, and the spread of mosquitofish Gambusia holbrooki. Other potential threats include altered hydrological regimes and deterioration of water quality, particularly where habitat adjoins urban or urban-fringe areas where biocides are used.
The National recovery plan for the wallum sedgefrog and other wallum-dependent frog species makes the following management recommendations for the conservation of wallum frogs:
- Protect wallum sedgefrog populations from further development and manage habitat to reduce the impact of identified threats.
- Conduct field surveys to clarify the impact and severity of threats, to inform management and ensure appropriate allocation of limited resources.
- Encourage stakeholder and community involvement in recovery activities.
- Rehabilitate degraded wallum sedgefrog habitat.
- Monitor frog numbers and distribution to determine if the species is recovering or in decline and to assess the efficacy of management activities.
What can you do to help this species?
- Contribute to recovery activities for the wallum sedge frog and other wallum frogs by ensuring that activities on, adjacent to or uphill from sites where wallum frogs occur do not alter water tables, hydrological patterns or affect water quality.
- Never release exotic fish into natural waterways, wetlands or dams (e.g. through disposal of aquarium collections, using exotic species as bait, or flushing fish down the toilet).
- Handling of frogs should be avoided to prevent introducing disease.
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Cogger HG. 1996. Reptiles and Amphibians of Australia. Reed Books, Port Melbourne, Victoria.
Department of Sustainability, Environment, Water, Population and Communities (SEWPaC). 2012. Litoria olongburensis Wallum Sedge Frog in the Species Profile and Threats Database. SEWPaC, Canberra.
Hines HB, Mahony M and McDonald K. 1999. An assessment of frog declines in wet subtropical Australia. Pp 44-63 in Campbell, A. (ed.) Declines and Disappearances of Australian Frogs. Environment Australia, Canberra.
Liem DS and Ingram G J 1977. Two new species of frogs (Anura: Myobatrachidae, Pelodryadidae) from Queensland and New South Wales. Victorian Naturalist 94, 255-262.
Meyer E Hero, J-M Shoo L and Lewis B. 2006. National recovery plan for the wallum sedgefrog and other wallum-dependent frog species. Report to Department of the Environment and Water Resources, Canberra. Queensland Parks and Wildlife Service, Brisbane.