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Australian Journal of Zoology Australian Journal of Zoology Society
Evolutionary, molecular and comparative zoology
RESEARCH ARTICLE

Structure and dynamics of a rainforest frog (Litoria genimaculata) population in northern Queensland

Stephen J. Richards A B C and Ross A. Alford A
+ Author Affiliations
- Author Affiliations

A School of Tropical Biology and Rainforest Cooperative Research Centre, James Cook University, Townsville, Qld 4811, Australia.

B Present address: Vertebrates Department, South Australian Museum, North Terrace, Adelaide, SA 5000, Australia.

C Corresponding author. Email: richards.steve@saugov.sa.gov.au

Australian Journal of Zoology 53(4) 229-236 https://doi.org/10.1071/ZO03036
Submitted: 25 June 2003  Accepted: 24 May 2005   Published: 6 September 2005

Abstract

We studied a population of the rainforest frog Litoria genimaculata over a 7-year period at Birthday Creek, an upland rainforest stream in northern Queensland. Estimated population size on a 60-m transect fluctuated seasonally, decreasing to zero during most winters and reaching a maximum of over 130 during most warmer spring and summer months with an influx of young adult males. Summer population estimates were much smaller during 1990–93, coinciding with the disappearance of two sympatric species. However the L. genimaculata population subsequently recovered to pre-‘decline’ levels. Females were rarely captured along the stream so the operational sex ratio of adult frogs was strongly biased in favour of males (overall sex ratio 1 : 0.04). Sexual dimorphism in this species is extreme. The mean weight of gravid females (23.35 g) was nearly five times that of males (4.68 g) and the ratio of female SVL to male SVL was 1.65. Reproductive and fat-body condition changed seasonally, with males reaching peak reproductive condition in late spring and summer when population densities were greatest. Our data suggest that Litoria genimaculata uses Birthday Creek largely or exclusively as a reproductive habitat. The extent to which this species uses habitats away from stream environments remains to be determined.


Acknowledgments

This research was funded by grants from the Australian Research Council and the CRC for Tropical Rainforest Ecology and Management. Manuscript preparation was funded by a grant from the WWF – Australia Frogs Program to SJR. Research was conducted under permits from Queensland DPI – Forestry and Queensland Parks and Wildlife Service.


References

Aichinger, M. (1987). Annual activity patterns of anurans in a seasonal Neotropical environment. Oecologia 71, 583–592.
Crossref | GoogleScholarGoogle Scholar | Fukuyama K., and Kusano T. (1989). Sexual size dimorphism in a Japanese stream-breeding frog, Buergeria buergeria (Rhacophoridae, Amphibia). In ‘Current Herpetology in East Asia’. (Eds M. Matsui, T. Hikida and R. C. Goris.) pp. 306–313. (Herpetological Society of Japan: Kyoto.)

Galatti, U. (1992). Population biology of the frog Leptodactylus pentadactylus in a central Amazonian rainforest. Journal of Herpetology 26, 23–31.
Hodgkinson S., and Hero J.-M. (2002). Seasonal behaviour of Litoria nannotis, Litoria rheocola and Nyctimystes dayi in Tully Gorge, north Queensland, Australia. In ‘Frogs in the Community’. (Ed. A. E. O. Natrass.) pp 29–39. (Queensland Frog Society: Brisbane.)

Inger, R. F. , and Bacon, J. P. (1968). Annual reproduction and clutch size in rain forest frogs from Sarawak. Copeia 1968, 602–606.
McDonald K. R., and Alford R. A. (1999). A review of declining frogs in northern Queensland. In ‘Declines and Disappearances of Australian Frogs’. (Ed. A. Campbell.) pp. 14–22. (Environment Australia: Canberra.)

Monnet, J.-M. , and Cherry, M. I. (2002). Sexual size dimorphism in anurans. Proceedings of the Royal Society of London. Series B. Biological Sciences 269, 2301–2307.
Crossref | GoogleScholarGoogle Scholar | Toft C. A., Rand A. S., and Clark M. (1982). Population dynamics and seasonal recruitment in Bufo typhonius and Colostethus nubicola (Anura). In ‘The Ecology of a Tropical Forest: Seasonal Rhythms and Long-term Changes’. (Eds E. G. Leigh, A. S. Rand and D. M. Windsor.) pp. 397–403. (Smithsonian Institution Press: Washington, DC.)

Tracey J. G. (1982). ‘The Vegetation of the Humid Tropical Region of North Queensland.’ (CSIRO: Melbourne.)

Tyler M. J. (1997). ‘The Action Plan for Australian Frogs.’ (Wildlife Australia: Canberra.)

Woolbright, L. L. (1983). Sexual selection and size dimorphism in anuran amphibia. American Naturalist 121, 110–119.
Crossref | GoogleScholarGoogle Scholar |

Woolbright, L. L. (1991). The impact of hurricane Hugo on forest frogs in Puerto Rico. Biotropica 23, 462–467.