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. 10: Spotted Tree Frog
2. Scientific Name
3. English Name
Spotted Tree Frog
4. Intraspecific taxa:
5. Species survival status
Endangered. The review of Watson et al. (1991) revealed a marked contraction of geographic range, and argued that the species should be considered endangered.
6. Former distribution
Known prior to 1991 from 12 river systems, of which 11 are in north eastern Victoria and one in adjacent southern NSW (Watson et al. 1991).
7. Current distribution
Extensive searches have extended the known range in Victoria (Gillespie 1993, Gillespie and Hollis 1996), and a large population was located on Bogong Creek, NSW, in 1993 (Ehmann et al. 1993). During a 1996 survey for riverine frogs in Kosciusko National Park an additional population was located in the Murray River (Hunter pers. comm.). Gillespie and Hollis (1996) summarise the distribution as confined to 16 rivers in the Central Highlands and north east of Victoria, and Bogong Creek and the Murray River in NSW. They confirm L. spenceri has disappeared entirely from four streams and from six sites on another four streams at which it previously occurred. During annual monitoring in 1996/97, the important Bogong Creek population declined dramatically, by about 97% (Gillespie pers. comm.).
All records of L. spenceri are from naturally vegetated, rocky, fast-flowing upland streams and rivers, in dissected mountainous country, at altitudes of 280-1110m.
9. Reasons for decline
Watson et al. (1991), Gillespie (1993), and Gillespie and Hollis (1996) review a number of possible causes of decline. Trout are considered a major threat (Gillespie pers. comm.). Other key threats include streambed eductor dredging (now illegal) (Hall 1988), impoundments, roads, fire, timber harvesting activities, recreational activities, cattle, and weed invasion of riparian vegetation.
10. Conservation reserves on which species occurs
Vic: Alpine and Eildon National Parks; NSW: Kosciusko National Park.
11. Other public lands on which species occurs
Vic: State Forest (several, unnamed).
12. Other lands on which species occurs
13. Is knowledge about species adequate for objectives and actions to be defined accurately?
No. The biology and habitat requirements are being studied. Knowledge of key threats, habitat use, population demography and ecology is limited.
14. Recovery Plan objectives
14.1. To determine biology and habitat requirements.
14.2. To identify causes of decline.
14.3. To implement habitat management and minimise impacts of factors responsible for decline.
15. Management actions completed or under way
15.1. A National Estate grant funded the investigation of Watson et al. (1991) and provided a basis for future studies.
15.2. A draft Action Statement has been prepared and summarises previous management actions.
15.3. A survey for L. spenceri and other riverine frogs has been conducted in Kosciusko National Park (Hunter 1996).
15.4. A Research Plan, funded by the Endangered Species Program of Environment Australia over three years, has focussed on:
- the use of mark-recapture techniques for monitoring recruitment, growth, reproductive behaviour, habitat use, activity and movement of L. spenceri and associated species;
- monitoring tadpoles to establish habitat use, activity patterns and development;
- developing and implementing radio tracking techniques to obtain information on sheltering sites, movement patterns and dispersal;
- examining the palatability of tadpoles of L. spenceri and other riverine frog species to native fish and introduced trout;
- examining interactions between L. spenceri and
L. lesueuri tadpoles to determine whether this sympatric species limits abundance and distribution;
- researching the ecology of all life stages and breeding biology; and
- examining the effects of sedimentation and food availability on the growth and survival of tadpoles.
16. Management actions required
16.1. Research on biology, ecology, population dynamics and potential threats, in particular: factors which limit growth and survival of the tadpoles of this and other riverine frog species; genetic analyses of the variability within, and isolation between, populations; the effects of disturbances, climatic variation and other factors on distribution and abundance; and the age classes of populations, growth, longevity and age at sexual maturity from skeletal chronology, for use in Population Viability Analyses.
16.2. Survey known and potential sites, and regular monitoring of populations and habitat.
16.3. Implement stream and off-stream habitat protection prescriptions.
16.4. Monitoring and management of introduced fish.
16.5. Increase water management authorities' awareness of the potential impacts of stream works and the need to maintain natural flows.
16.6. Weed control in riparian vegetation at key sites.
16.7. Control recreational use, relocate camping areas where possible, restrict road use particularly in wet weather and increase public awareness of minimising impacts on water quality and river ecology.
16.8. Strategic planning of fuel reduction burning and control of wildfires in L. spenceri catchments.
16.9. Strictly enforce ban on eductor dredging in stream systems that support known habitat.
16.10. If further populations are discovered, implement protection from disturbance.
16.11. Develop captive husbandry techniques to increase embryonic, larval and adult survivorship.
16.12. Increase public awareness of the sensitivities and significance of mountain streams and riparian habitats for threatened species such as L. spenceri, and monitor impacts of recreational activities.
17. Organisations responsible for conservation of species
Vic. Department of Natural Resources and Environment and NSW National Parks and Wildlife Service.
18. Other organisations involved
University of Melbourne Department of Zoology staff have undertaken research on the species. The Snowy Mountains Authority is involved in water management aspects of Bogong Creek.
19. Can recovery be carried out with existing resources?
The Vic. Department of Natural Resources and Environment has received funding from the Biodiversity Group, Environment Australia, to undertake research and monitoring over three years. The NSW National Parks and Wildlife Service is providing resources for habitat management in Kosciusko National Park. A Recovery Plan, identifying specific actions and funding requirements, is being prepared by the Recovery Team..
Ehmann, H., Ehmann, J., and Ehmann, N. 1993. The rediscovery of the endangered spotted tree frog (Litoria spenceri) in New South Wales and some subsequent findings. Herpetofauna 22: 21-4.
Gillespie, G.R. 1993. Research plan for the Spotted Tree Frog Litoria spenceri (Spencer 1901). Unpublished report to ANPWS, Canberra.
Gillespie, G.R. and Hollis, G.J. 1996. Distribution and habitat of the Spotted Tree Frog, Litoria spenceri Dubois (Anura: Hylidae), and an assessment of potential causes of population declines. Wildlife Research 23: 49-75.
Hall, D.N. 1988. Effects of eductor dredging of gold tailings on aquatic environments in Victoria. Proceedings of the Royal Society of Victoria 100: 53-59.
Hunter, D. 1996. Riverine frogs of Kosciusko National Park: The results of a survey conducted during January and February 1996. Unpublished report to NSW NPWS.
Watson, G.F., Littlejohn, M.J., Hero, J-M. and Robertson, P. 1991. Conservation status, ecology and management of the Spotted Tree Frog (Litoria spenceri). Arthur Rylah Institute of Environmental Research Tech. Report Ser. No. 116, Department of Conservation and Environment, Melbourne.
Herpetological authorities consulted:
H. Ehmann, G.R. Gillespie, K. Green, D. Hunter, A. Jelinek, P. Robertson, G.F. Watson.