The Action Plan for Australian Frogs
Michael J. Tyler
with the assistance of the Editorial Advisory Committee
Wildlife Australia, April 1997
ISBN 0 642 21400 X
Recovery Outline No. 8: Southern Bell Frog
2. Scientific Name
3. English Name
Southern Bell Frog, Warty Swamp Frog
4. Intraspecific taxa:
5. Species survival status
Vulnerable. There is evidence of a dramatic decline in this species throughout portions of its range in south eastern Australia. In some areas where it was abundant it has disappeared. For example, searches have failed to locate a single individual at any of the localities from which it was known in the ACT and nearby areas of the southern tablelands of NSW, although these reports are probably based on both L. raniformis and L. castanea (Osborne et al. 1996). In the south east of SA numbers have declined substantially over the past decade. The condition of populations on the River Murray is unknown.
6. Former distribution
Known from south east SA and the Murray Valley, most of Victoria and the ACT, south western NSW and northern and eastern Tasmania.
7. Current distribution
Unclear. From Tasmania there is a report that at Launceston the number of individuals has shifted from abundant to scarce, and there have been contractions of range in north-west, central and southern Tasmania within the last 15 years. As indicated, the species has disappeared in the ACT and the southern tablelands of NSW. In south and central Victoria there are reports of serious declines and local extinctions. However, large populations still persist at several localities in parts of metropolitan Melbourne and in regional Victoria. In the south east of SA the species has become scarce, although it remains abundant in parts of the Murray Valley.
Commonly associated with swamps, irrigated areas, reservoirs, farm dams and the periphery of rivers.
9. Reasons for decline
Unknown. It may be significant that the closely related species L. aurea and L. castanea have also disappeared from the ACT. One feature that these species share is the habit of basking, and so may be exposed to high levels of ultra-violet radiation.
The decline of L. raniformis in Victoria was coincident with drought, and there is some evidence of recovery in subsequent wet years (G. Backhouse pers. comm.).
It has been suggested that a herbicide containing a dispersant is directly responsible for some declines where it has been used around dams. In WA the tadpoles of a closely related species, L. moorei, have been found to be very sensitive to glyphosate (Bidwell and Gorrie 1995).
The introduced mosquito fish Gambusia holbrooki may have also contributed to the decline, as they have been shown to affect the larval survival of L. aurea.
In Tasmania declines and disappearances have been attributed to wetland drainage, lowering of the watertable and associated removal of native vegetation. The destruction of wetlands by cattle grazing, particularly in north west Tasmania, can lead to ponds becoming slurry pools. It is unknown whether these factors operate elsewhere.
10. Conservation reserves on which species occurs
NSW: Cocoparra National Park, Willandra National Park (not recently recorded); Vic: Sale Common State Game Refuge, Grampians and Wilson's Promontory National Parks, Ewings Marsh Flora Reserve, Westgate Park, Nooramanga Coastal Park; Tas: Asbestos Range, Mt William, Maria Island, and Freycinet National Parks, Waterhouse Protected Area, Tamar River Wildlife Sanctuary; SA: Bool Lagoon, Messent Nature Reserve.
11. Other public lands on which species occurs
Tas: St Helen's Point State Recreation Area. NSW: Woomargarna and Bondi State Forests (not recently recorded).
12. Other lands on which species occurs
Farm areas throughout its range. Vic: Disused council land-fill sites in Melbourne. Tas: Woodstock Lagoon Conservation Area.
13. Is knowledge about species adequate for objectives and actions to be defined accurately?
No. Very little is known about the ecology and population biology of the species.
14. Recovery Plan objectives
14.1. To establish the extent and causes of the decline throughout the geographic range.
14.2. To identify strategies for alleviating threatening processes and conserving remaining populations.
15. Management actions completed or under way
15.1. Atlassed in Tasmania in 1993 and 1994.
15.2. A study of the status of populations and habitat at selected sites in Tasmania has been undertaken by the University of Tasmania (John Ashworth, Dept of Geography and Environmental Studies).
15.3. A population study has been initiated by the University of Melbourne at one locality in metropolitan Melbourne.
15.4. Species profiles and draft species management prescriptions have been jointly prepared by State Forests of NSW and NSW National Parks and Wildlife Service for protection of this species within production forest.
16. Management actions required
16.1. Survey historic range and identify characteristics of the habitat of remaining populations. On this basis estimate current distribution and clarify status.
16.2. Close monitoring of selected populations throughout its range, and identification and protection of wetlands important for its conservation.
16.3. Undertake experimental research aimed at identifying causes of population declines. For example, the susceptibility of eggs and tadpoles to Gambusia sp. and the effect of ultra-violet radiation on eggs and tadpoles.
16.4. Investigate differences between populations in Australia and New Zealand, where the species has been introduced.
17. Organisations responsible for conservation of species
NSW National Parks and Wildlife Service, SA Department of Environment and Natural Resources, Vic. Department of Natural Resources and Environment, Tasmanian Department of Environment and Land Management, ACT Parks and Conservation Service.
18. Other organisations involved
University of Tasmania, University of Melbourne Zoology Department, Vic. Frog Group, Frog and Tadpole Study Group NSW Inc., State Forests of NSW.
19. Can recovery be carried out with existing resources?
Desk-top study to establish historic range, survey to establish current status, research into causes of decline and monitoring of selected sites and identification of important wetlands.
Bidwell, J.R. and Gorrie, J.R. 1995. Acute toxicity of herbicides to selected frog species. Unpublished report to the Western Australian Department of Environmental Protection.
Osborne, W.S., Littlejohn. M.J. and Thomson, S.A., 1996. Former distribution and apparent disappearance of the Litoria aurea complex from the Southern Tablelands of NSW and the Australian Capital Territory. Australian Zoologist 30: 190-198.
Herpetological authorities consulted
G. Backhouse, H.G. Cogger, P. Brown, H. Ehmann, G.R. Gillespie, M.J Littlejohn, W.S. Osborne, D. Rounsevell.