NSW Scientific Committee - final determination
The Scientific Committee has found that:
1. Southern Corroboree Frog Pseudophryne corroboree Moore, 1953 (family Myobatrachidae) is an endemic Australian frog, described by Cogger (2000) as follows: ‘Bright yellow above with shiny longitudinal irregular black stripes, the latter frequently broken and interconnected. This pattern extends over the limbs and flanks. Ventral surface broadly marbled with black and white or black and yellow. Skin slightly granular above with low warts which tend to coalesce to form longitudinal ridges. Smooth below. A large, flat femoral gland on each hindlimb. Inner metatarsal tubercle low, round, not shovel-shaped. Inner toe with a single phalanx 30 mm’.
2. Two species of Corroboree Frog are known; the northern, Pseudophryne pengilleyi and the southern. The two species are distinguished by differences in range, colour-pattern, morphology and call (Pengilley 1966; Osborne et al. 1996), skin biochemistry (Daly et al. 1990) and genetics (Roberts and Maxson 1989; Osborne and Norman 1991, Morgan et al. 2008).
3. Pseudophryne corroboree has a very highly restricted distribution, with all known and historical populations occurring entirely within Kosciuszko National Park (DECC 2007). In the past, small populations of P. corroboree occurred in the Perisher-Smiggins and the Guthega resort areas within the park (Osborne 1988). The species has experienced a contraction in range and now only occurs along the western edge of its former distribution, from the Dargals Range in the south, to the Maragle Range in the north (D. Hunter pers. comm. June 2008).
4. Pseudophryne corroboree utilises two distinct habitat types: a breeding season habitat associated with pools and seepages in Sphagnum bogs, wet tussock grasslands and wet heath, and a terrestrial non-breeding habitat in forest, sub-alpine woodland and tall heath adjacent to the breeding area.
5. The breeding season of Pseudophryne corroboree occurs from January to February (Pengilley 1966, 1973). Females deposit 16 to 38 eggs in terrestrial nests occupied by the breeding males. Tadpoles develop within the egg capsule and hatching occurs during autumn and winter in periods of high rainfall or snowmelt. Tadpoles then move out of the nest site and into the adjacent pool before undergoing metamorphosis in early summer (Hunter et al. 1999).
6. The overall geographic range of the species includes extensive areas where the Southern Corroboree Frog is now either extinct or in much reduced numbers. The extent of occurrence for the species is now less than 45 km2, and area of occupancy is less than 36 km2 based on 2 x 2 km grid cells, the scale recommended for assessing area of occupancy by IUCN (2008).
7. Based on the number of calling males recorded in surveys undertaken in 2008, the total number of mature individuals of Pseudophryne corroboree in the wild is estimated to be between 100 and 150 (D. Hunter pers. comm. June 2008).
8. The Southern Corroboree Frog has undergone a very large and sustained decline in abundance over a time frame appropriate to the life history of the species. Generation length is estimated to be five to seven years based on a minimum breeding age of four years, oldest known individual of 10 years and an average longevity of 6 years (DECC 2007; D. Hunter pers. comm. 2008). A total number of 13 calling males were recorded at monitoring sites in the 2007 survey, compared to 379 calling males estimated in 1999, a decline of more than 95% over 8-9 years (Hunter et al. 2007). Of the 40 monitored sites supporting P. corroboree in 1999 only eight had records for the species in 2007, all with critically low numbers (Hunter et al. 2007). Between 1986 and 1999 the species had been monitored at eighteen sites, populations at fourteen of these sites were extinct by 1999 and the remaining four sites supported extremely low densities of frogs (Osborne et al. 1999; Hunter et al. 2007).The species appears very likely to become extinct in the wild within the next few years.
9. The major cause of decline in Pseudophryne corroboree over the last three decades is believed to be the introduced Amphibian Chytrid Fungus (Batridiochytrum dendrobatoides) (Berger et al. 1999; Hunter et al. 2006). ‘Infection of frogs by amphibian chytrid causing the disease chytridiomycosis’ is listed as a Key Threatening Process under the Threatened Species Conservation Act 1995.
10. As the Southern Corroboree Frog occurs in a narrow climatic range (the sub-alpine and alpine regions of eastern Australia), any human induced or natural climate change is likely to have a serious impact on this species (Bennett et al. 1991). ‘Anthropogenic Climate Change’ is listed as a Key Threatening Process under the Threatened Species Conservation Act 1995.
11. Both Feral Pigs (Sus scrofa) and Horses (Equus equus) damage the over-wintering and breeding habitats of the Southern Corroboree Frog (DECC 2007). ‘Predation, habitat degradation, competition and disease transmission by Feral Pigs Sus scrofa Linnaeus 1758’ is listed as a Key Threatening Process under the Threatened Species Conservation Act 1995.
12. Fire is likely to affect this species through direct mortality of individuals and from longer-term impacts resulting from habitat alteration. Fire regimes may be modified by future climate change. ‘High frequency fire resulting in the disruption of life cycle processes in plants and animals and loss of vegetation structure and composition’ is listed as a Key Threatening Process under the Threatened Species Conservation Act 1995.
13. Since July 2000, the Southern Corroboree Frog has been listed as an Endangered species under the Environment Protection and Biodiversity Conservation Act 1999.
14. The Southern Corroboree Frog Pseudophryne corroboree Moore, 1953 is eligible to be listed as a Critically Endangered species as, in the opinion of the Scientific Committee, it is facing an extremely high risk of extinction in New South Wales in the immediate future as determined in accordance with the following criteria as prescribed by the Threatened Species Conservation Regulation 2002:
The species has undergone, is observed, estimated, inferred or reasonably suspected to have undergone or is likely to undergo within a time frame appropriate to the life cycle and habitat characteristics of the taxon:
(a) a very large reduction in population size
based on:
(d) an index of abundance appropriate to the taxon,
(e) geographic distribution, habitat quality or diversity, or genetic diversity.
Clause 15
The geographic distribution of the species is estimated or inferred to be:
(a) very highly restricted
and:
(d) a projected or continuing decline is observed, estimated or inferred in:
(i) an index of abundance appropriate to the taxon,
(ii) geographic distribution, habitat quality or diversity, or genetic diversity
(e) the following conditions apply:
(i) the population or habitat is observed or inferred to be severely fragmented,
(ii) all or nearly all mature individuals are observed or inferred to occur within a small number of populations or locations.
Clause 16
The estimated total number of mature individuals of the species is:
(a) very low
and:
(d) a projected or continuing decline is observed, estimated or inferred in:
(i) an index of abundance appropriate to the taxon, and
(ii) geographic distribution, habitat quality or diversity, or genetic diversity
(e) the following conditions apply:
(i) the population or habitat is observed or inferred to be severely fragmented
(ii) all or nearly all mature individuals are observed or inferred to occur within a small number of populations or locations.
Dr Richard Major
Chairperson
Scientific Committee
Proposed Gazettal date: 04/12/09
Exhibition period: 04/12/09 – 29/01/10
References:
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Cogger HG (2000) ‘Reptiles and Amphibians of Australia. 6th ed’. (Reed New Holland: Sydney).
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DECC (2007) ‘Draft NSW and National Recovery Plan for the Southern Corroboree Frog Pseudophryne corroboree’. DECC, Queanbeyan, NSW.
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Pengilley RK (1973) Breeding biology of some species of Pseudophryne (Anura: Leptodactylidae) of the Southern Highlands, New South Wales. Australian Zoologist 18, 15-30.
Roberts JD, Maxson LR (1989) A molecular perspective on the relationships of Australian Pseudophryne (Anura: Myobatrachidae). Systematic Zoology 38, 154-165.