Cascade treefrog
Litoria pearsoniana (Copland, 1961)
Queensland Legislative Status: Vulnerable
Endemicity: Australian endemic
Description: A small frog, males 24-29mm SVL and females 31-37mm SVL. Dorsal colouration highly variable, and can change seasonally. Ranges from green, through various combinations of green and brown to dark brown, with or without black spots or reticulations. A thin pale stripe runs from the nostril, through the eye, passes above the tympanum and continues along the flank to the midbody. This stripe is bordered below by a brown band, broadening as it extends along the flank to the midbody. There may be a pale stripe along the upper lip. The tympanum is distinct and brown in colour.
The ventral surface is white or cream. The hidden parts of the groin and thighs are yellowish tan to brick red. The skin is smooth or shagreened above, granular below. The limbs have well developed disks, but only the toes have extensive webbing. (Copeland 1960; McDonald & Davies 1990; Barker et al. 1995).
Call: The mating call is a diphasic three note call lasting for 0.8 to 1.8 seconds; "Weeeak kuk kuk". Variations include; a very slow version of the 1st part of the call heard early in the evening, or the first part of the call is made by one male and answered by a second by completing the sequence, or individuals may merely repeat the last two notes several times. (McDonald & Davies 1990).
Tadpoles: Tadpoles are ~ 30mm long at stage 37. Dorsal surface is a light golden colour during early stages, darkening to brown, and some specimens develop dark spots in the later stages. The ventral surface is unpigmented. The body is broader than deep with the greatest breadth behind the eyes. The mouth is ventral with two upper and three lower rows of labial teeth, with a median gap in the inner-most rows. Labial papillae surround the lateral and posterior margins of the mouth. The tail is moderately thick and has a rounded tip. The fins are transparent with dark spots. (McDonald & Davies 1990).
Reproduction: Reproductive activity occurs from August to April, peaking from October to early February. Females may possess the ability to breed more than once a season.
Amplexus is axillary, taking place near oviposition sites. Eggs are deposited as a clump of 363-732 eggs attached to rocks, debris or aquatic plants in still, shallow pools adjacent to, or connected with the main stream. The eggs are dark, 1.1-1.3mm in diameter and are covered in a clear jelly capsule 3.0-3.5mm in diameter, generally obscured by grey or brown silt.
Eggs hatch 3-5 days after spawning, with metamorphosis typically occurring 2-2.5 months later depending on temperatures (McDonald & Davies 1990).
Habitat: Inhabits streams in rainforest and adjacent wet sclerophyll forest at elevations of 200 - 1000m in southeastern Queensland and north-eastern New South Wales. During spring and summer adult males are located under logs, rocks, rotting leaf litter and moist soil cavities adjacent to the water edge during the day, emerging to call from rocks, low vegetation, and debris in or near streams at night. Activity is predominantly nocturnal, peaking on warm nights during and after rain but may also be active on warm overcast days. Males call from low perches <= 1m above water, retreating to humid crevices during the day. During winter may form large mixed sex aggregations in humid crevices with relatively stable temperatures. Within these, hibernaculum form closely packed groups, adopting a compact pose with dorsal and ventral surfaces pressed against the crevice surfaces to reduce surface area and individuals are lethargic with eyes closed (McDonald & Davies 1990).
Distribution: Restricted to areas of wet forest between Lismore, NE NSW (28° 50'S, 153° 01'E) & Kenilworth, SE Queensland (26° 35'S, 152° 43'E) with an disjunct population further north at Kroombit Tops (24° 24'S, 151° 01'E) (Covacevich & McDonald 1993).
MtDNA sequencing indicates there are two distinct populations in south-eastern Queensland separated by the Brisbane River valley, a southern population occupying the Gibraltar, Main and Border Ranges, and a northern population in the D'Aguilar and Conondale Ranges (McGuigan et al 1998). There is some evidence that the Kroombit Tops population may represent a distinct taxon (Parris & Norton 1997, Donnellen et. al. 1999, Hines et. al. 1999).
Latitude: Between 24&186; 24' and 28&186; 50';
Longitude: Between 151&186; 01' and 153&186; 20'.
National Parks (Queensland):
Conondale, D'Aguilar, Girraween, Kondalilla, Lamington, Main Range, Mapleton, Mount Barney, Springbrook, Tambourine.
Threatening Processes: Possible - destruction of winter aggregation sites, habitat loss and reduced water quality due to clearing, forestry practices, cattle grazing, pig damage, weed invasion, chryrtid fungal infection (McDonald & Davies 1990; Paris & Norton 1997). A chytrid fungus has been isolated from moribund individuals (Berger et. al. 1998, Berger et. al.1999). Information on disease investigations and management can be located at http://www.jcu.edu.au/school/phtm/PHTM/frogs/ampdis.htm.
Status: Experienced significant population declines in the late 1970s and 1980s, with some populations disappearing (Czechura 1991; Ingram & McDonald 1993; McDonald & Davies 1990). Recent monitoring indicates populations have recovered at some sites (McGuigan et al 1998, Hines et al 1999).
The causes of this and similar declines in the upland rainforest frog fauna of south-east Queensland remain unknown although chytrid fungus has been found in sick and dying animals (Berger et. al. 1999).
Management Recommendations:
- The Southeast Queensland Threatened Frogs Recovery Team is developing a Recovery Plan for this species and other declining species.
- Monitor historical localities to detect recovery.
- Investigate disease in preserved animals and species occupying similar habitat.
- Develop and refine husbandry techniques for rainforest stream dwelling frogs.
- Continue studies on the autecology on this species.
- Train park staff and community volunteers in identification of this species.
- Implement monitoring by park staff at select locations within the national park estate where L. pearsoniana occurs.
References:
Barker, J., Grigg, G.C. & Tyler, M.J. (1995). A Field Guide to Australian Frogs. Surrey Beatty & Sons, Chipping Norton, NSW.
Berger, L., Speare, R, and Hyatt, A. (1999). Chytrid fungi and Amphibian declines: Overview, Implications and Future Directions. Pp23-33. In Campbell, A (ed), 'Declines and Disappearances of Australian frogs'.(Environment Australia, Department of the Environment and Heritage: Canberra). 234 pp.
Berger, L., Speare, R., Daszak, P., Green, D. E., Cunningham, A. A., Goggin, C. L., Slocombe, R., Ragan, M. A., Hyatt, A. D., McDonald, K. R., Hines, H. B., Lips, K. R., Marantelli, G., and Parkes, H. (1998). Chytridiomycosis causes amphibian mortality associated with population declines in the rain forests of Australia and Central America. Proceedings of the National Academy of Science USA 95, 9031-9036.
Copland, S.J. (1960) A new tree frog (genus Hyla) from Queensland. Proceedings of the Linnaean Society of New South Wales 85(1): 154-156.
Copland, S.J. (1961) A new name for Hyla pearsoni, preoccupied (Amphibia). Ibid 86(1): 168.
Covacevich, J.A. & McDonald, K.R. (1993) Distribution & conservation of frogs & reptiles of Queensland rainforests. Memoirs of the Queensland Museum 34(1):189-199.
Czechura, G.V. (1991) The Twighlight Zone. Wildlife Australia 28(4): 20-22.
Donnellan, S., McGuigan, K., Knowles, R., Mahony, M. and Moritz, C. 1999. Genetic evidence for species boundaries in frogs of the Litoria citropa species-group (Anura:Hylidae). Australian J. Zool. 47, 275-293.
Hines, H., Mahony, M and McDonald K.R. 1999. An Assessment of Frog Declines in Wet Subtropical Australia. In Campbell, A (ed), 'Declines and Disappearances of Australian frogs'.(Environment Australia, Department of the Environment and Heritage: Canberra). 234 pp.
Ingram, G.J. & McDonald, K.R. (1993) An update on the decline of Queensland's frogs. Pp 297-303 In Lunney, D. & Ayers, D. (eds), 'Herpetology in Australia. A diverse discipline'. (Royal Zoological Society of New South Wales: Mosman, NSW). 414pp.
McDonald, K.R. & Davies, M. (1990) Morphology & biology of the Australian tree frog Litoria pearsoniana (Copland) (Anura: Hylidae). Transactions of the Royal Society of South Australia 114(3): 145-156.
McGuigan, K., McDonald, K., Parris, K. & Moritz, C. (1998) Mitochondrial DNA diversity & historical biogeography of a wet forest-restricted frog (Litoria pearsoniana) from mid-east Australia. Molecular Ecology 7: 175-186.
Parris, K. & Norton, T. (1997) The significance of State Forests for conservation of Litoria pearsoniana (Copland) & associated amphibians. In: Conservation Outside Nature Reserves (eds Hale, P. & Lamb, D), pp. 521-526. Centre for Conservation Biology, University of Queensland, Brisbane.
Last updated: 30 August 2005