Distribution and Habitat

Country distribution from AmphibiaWeb's database: Australia

View distribution map in BerkeleyMapper.

Population and Distribution
Geocrinia vitellina is confined to a 6.3 km2 area east of the Leeuwin-Naturaliste Ridge in the extreme s.w. of WA (Tyler 1997). Only six populations of G. vitellina are known (Roberts et al. 1999). Population estimates are available for Spearwood North and South from 1992 to 1998 (Driscoll 1998, 1999; Roberts et al. 1999) and Geo Ck from 1993 to 1994 (Driscoll 1998, 1999). Estimates of calling males for the three locations varied between approximately 30 and 160 individuals (Driscoll 1998, 1999; Roberts et al. 1999). Populations at Spearwood varied in size over the survey period with no obvious cause of decline or increase at either site (Roberts et al. 1999). In 1994 the maximum total number of adults of the species was estimated at 2,230 frogs (Wardell-Johnson et al. 1995 in Roberts et al. 1999).

Habitat
Geocrinia vitellina is wholly distributed within SF (Tyler 1997). However, most of the species range has been recommended for gazettal as a Nature Reserve as part of the Regional Forest Agreement.
Wardell-Johnson and Roberts (1993) described the biogeographic barriers separating the distributions of four allopatric species from the Geocrinia rosea complex. Both G. alba and G. vitellina occur in permanently moist sites in relatively dry and seasonal climatic zones and their distributions are separated by 9 km of lateritic uplands and narrow valleys (Wardell-Johnson & Roberts 1993). Geocrinia vitellina occupies six unconnected and undisturbed areas of riparian vegetation at an elevation of 120 m in broad u-shaped valleys where there is marked topographic relief (Tyler 1997). The species is abundant at seepages but rare on the valley floor (Tyler et al. 1994).

Life History, Abundance, Activity, and Special Behaviors
Reproduction
Males call from small depressions in clay under dense vegetation cover. Egg are deposited in small depressions and are often associated with calling males. Eggs hatch and the tadpoles develop in a jelly mass with no free swimming of feeding stage. [Roberts et al. 1990]

Invasive species
Feral pigs have been identified as a potential threat to the species, however, pig control has been conducted in the area and there has been no evidence of pig damage at any known population of this species (Roberts et al. 1999).

Movements
Genetic structuring of populations indicate that movement is extremely limited with little or no migration among populations for any life stage or sex, even at very local scales (Driscoll 1997, 1998). The genetic differences throughout the range of the species are very large, especially given the small distances between populations (maxima 4 km) (Driscoll 1998). While a precise value for the rate of dispersal cannot be calculated, the conclusion that individuals do not disperse far from their natal swamp is consistent with a mark-recapture study of G. alba and G. vitellina (Driscoll 1997). Driscoll (1997) found that 97% of adult male frogs were displaced less than 20 m over one year, while the maximum displacement was 50 m. Migration rates between populations are so low that any local extinctions are unlikely to be countered in the short term by recolonisation (Driscoll 1998).

Trends and Threats
No populations are known to have gone extinct, however, populations burnt in 1997 are currently the subject of monitoring to assess their status (Roberts et al. 1999). All six known populations occur in State Forest or areas proposed as conservation reserves and are under no immediate threat from clearing or logging activity (Roberts et al. 1999). Potential threats to G. vitellina include inappropriate fire management and feral pigs, however, there has been no evidence of pig damage at any known population of this species (Roberts et al. 1999).
A fire exclusion zone has been established for part of the range of this species (covering about half of the geographic range and containing approximately 80% of the adult frog population). The remainder of the range is subject to fuel reduction burning which is restricted to spring on an eight year cycle (Roberts et al. 1999). Importantly, however, since establishment 85% of the fire exclusion zone was burnt at varying intensities in a 1997 wild fire (an escape from a fuel reduction burn in an adjacent block) (Roberts et al. 1999).
As there are large genetic differences between populations, many populations will need to be conserved in order to maintain genetic variation in the long term (Driscoll 1998). Maintaining many small populations is an effective way of preventing allelic loss from the species as a whole and is likely to be more effective than conserving a smaller number of large populations provided that small populations do not become extinct, which would result in loss of unique genetic variants (Driscoll 1998). The likely biogeographic history of G. vitellina suggests that contractions and expansions of geographic range may be a natural phenomenon, and that they play an important role in the evolution of the species (Driscoll 1998). Therefore, if evolutionary processes are to be maintained, range changes need to be accommodated in the long term. For range expansion to take effect, unoccupied swamps need to be available, and there needs to be suitable habitat between sites through which frogs can migrate (Driscoll 1998).
Conservation concern is primarily a result of the restricted range of this species (Roberts et al. 1999).

References

Driscoll, D.A. (1997). ''Mobility and metapopulation structure of Geocrinia alba and Geocrinia vitellina, two endangered frog species from southwestern Australia.'' Australian Journal of Ecology, 22, 185-195.

Driscoll, D.A. (1998). ''Genetic structure, metapopulation processes and evolution influence the conservation strategies for two endangered frog species.'' Biological Conservation, 83, 43-54.

Driscoll, D.A. (1999). ''Genetic neighbourhood and effective population size for two endangered frogs.'' Biological Conservation, 88, 221-229.

Roberts, D., Conroy, S., and Williams, K. (1999). ''Conservation status of frogs in Western Australia.'' Declines and Disappearances of Australian Frogs. A. Campbell, eds., Environment Australia, Canberra, 177-184.

Roberts, J.D., Wardell-Johnson, G., and Barendse, W. (1990). ''Extended descriptions of Geocrinia vitellina and Geocrinia alba (Anura: Myobatrachidae) from south-western Australia, with comments on the status of G. lutea.'' Records of the Western Australian Museum, 14, 427-437.

Tyler, M.J. (1997). The Action Plan for Australian Frogs. Wildlife Australia, Canberra, ACT.

Tyler, M.J., Smith, L.A., and Johnstone, R.E. (1994). Frogs of Western Australia. Western Australian Museum, Perth.

Wardell-Johnson, G. and Roberts, J.D. (1993). ''Biogeographic barriers in a subdued landscape: the distribution of Geocrinia rosea (Anura: Myobatrachidae) complex in south-western Australia.'' Journal of Biogeography, 20, 95-108.

Wardell-Johnson, G., Roberts, J.D., Driscoll, D., and Williams, K. (1995). Orange-bellied and White-bellied Frogs Recovery Plan. Wildlife Management Program No. 10, Department of Conservation and Land Management, Perth.

Species Account Citation: AmphibiaWeb 2008 Anstisia vitellina: Orange-bellied Frog <https://amphibiaweb.org/species/3574> University of California, Berkeley, CA, USA. Accessed Nov 22, 2024.

Citation: AmphibiaWeb. 2024. <https://amphibiaweb.org> University of California, Berkeley, CA, USA. Accessed 22 Nov 2024.

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