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| Subspecies: | Unknown |
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| Est. World Population: | 4-50 |
| CITES Status: | NOT LISTED |
| IUCN Status: | Critically Endangered |
| U.S. ESA Status: | NOT LISTED |
| Body Length: | |
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| Jumping Ability: | (Horizontal) |
| Life Span: | in the Wild |
| Life Span: | in Captivity |
| Sexual Maturity: | (Females) |
| Sexual Maturity: | (Males) |
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Males call from late December through to mid-March, from small chambers (nests) in moss of other soft vegetation at the edges of breeding pools (Osborne 1990). The females lay their eggs in these nests, and the breeding males remain in them throughout the breeding season and can accumulate multiple clutches. Typically, the pools are dry when the eggs are laid, and the embryos remain in diapause until flooding of the nest site in autumn or winter stimulates them to hatch. When hatched, the tadpoles move from the nest in to the adjacent pool where they will complete their larval development. The tadpoles only grow slowly over winter and spring, until metamorphosis in early summer (Hunter et al. 1999). As they mature, juveniles disperse in to the adjacent non-breeding habitat, the forest, woodland and heath adjacent to breeding sites, where they stay until they reach sexual maturity.
The age to first reproduction was found to be four years from metamorphosis for the majority of individual males, with a small proportion of individuals attaining sexual maturity in three years (Hunter 2000). The oldest individuals identified using this technique were nine years old (Hunter 2000). It is likely that the majority of females take four or five years to reach sexual maturity (Hunter unpublished data 2011 cited in Hunter 2012). Based on the proportion of individuals in different age classes from one year to the next, annual survivorship for adult males was determined to be between 50–60% (Hunter 2000). The generation length of the species is estimated to be between 6–7 years based on this life history information.
Following rapid declines in the 1980s, this species has disappeared from much of its historical range, and the species now occurs in a small number of remnant subpopulations along the northwestern edge of its former range (Australian Department of Environment 2013). Its range has remained stable since 2012 due primarily to restocking of subpopulations with captive bred eggs (D. Hunter pers. comm. May 2022). Osborne (1989) estimated the species’ area of occupancy (AOO) to be approximately 400 km2, but by 2012 it was estimated to be only 1 km2, and the extent of occurrence in 2012 was estimated to be 60 km2 (Hunter unpublished data 2012 in Australian Department of Environment 2013). It is important to note that these estimates of AOO predate the requirement to use a 2x2 km grid cell to estimate AOO for the purposes of applying the IUCN categories and criteria (IUCN Standards and Petitions Committee 2019). The most recent estimate of the extent of occurrence (EOO) for the species is now less than 45 km2, and for the AOO is less than 36 km2 based on 2x2 km grid cells (NSW Threatened Species Scientific Committee 2019). When considering the ongoing threat of disease, droughts and wildfires, the species occurs in one threat-defined location.
Conservation Measures In-Place
The range of the species is entirely within Kosciusko National Park. The Southern Corroboree Frog is listed as an ‘Iconic’ species under the New South Wales ‘Saving our Species’ program, and has been the focus of a targeted conservation programme since 1997. It is listed as Critically Endangered under the Environmental Protection and Biodiversity Conservation Act 1999 (EPBC Act) (Australian Department of Environment 2013). A national recovery plan was published in 2012 (Hunter 2012). This species is one of 16 amphibians that were included on the Provisional List of Animals Requiring Urgent Management Intervention (Wildlife and Threatened Species Bushfire Recovery Expert Panel 2020) following the bushfires of 2019/2020. The species has recently been listed as one of three frog species on the Australian Government’s priority list of threatened species, and will receive funding through the Threatened Species Strategy over the next decade (Australian Government Department of Agriculture, Water and the Environment 2022).
This species has been kept successfully in captivity since 1997, with a number of eggs harvested from the wild each year between 2004 and 2012 to establish a large captive assurance colony (M. Mc Fadden pers. comm. May 2022). This species has been reliably bred in captivity since 2007 and since this time the captive assurance colony has been robust and self-sustaining (D. Hunter pers. comm. May 2022). Captive breeding of this species takes place at Melbourne Zoo, Taronga Zoo and Healesville Sanctuary and they also run education and awareness programmes highlighting the conservation of this species. The success of the captive breeding programs has led to approximately 2,000 Southern Corroboree Frog eggs being reintroduced annually to Kosciusko National Park (Corroboree Frog 2022).
Research and monitoring protocols are in place for this species. It has been, and continues to be, the subject of extensive monitoring to ensure its ongoing survival and assist in its long term recovery. Wild subpopulations are monitored as well as reintroduced subpopulations to determine their survivorship and learn lessons to improve techniques for further reintroductions. More recently, much of the conservation efforts for this species in the wild have focused on the establishment of disease free field enclosures (Hunter et. al. 2018).
Conservation Needed
This species, as well as Pseudophryne pengilleyi, are the focus of substantial conservation efforts. The species' habitat is entirely within a protected area, however the ongoing threat of drought and bushfires will require conservation management and action to avoid habitat degradation and any further decline in population. Captive breeding and reintroductions should be maintained to help with the recovery of this species. Ongoing management of invasive species, and in particular strategies to increase the resilience of subpopulations to Bd need to be continued. An updated Conservation Advice is currently being drafted for this species.
Research Needed
The Southern Corroboree Frog is currently the focus of a research programme investigating the potential to enhance the innate (genetic) resistance of this species to disease caused by infection with the amphibian chytrid fungus (D. Hunter pers. comm. May 2022). Further research is also needed to determine the ongoing impact of climate change on this species, and how it can be mitigated in the long term to ensure the continued survival of this species. Research is ongoing regards to better understand why some subpopulations are more successful in persisting with the presence of Bd than others, and how this can inform future reintroductions to improve their success. Considering the ongoing threat of disease, droughts and bushfires, continual monitoring of the population is essential.