The Mountain Frog is a small, squat, pear-shaped frog with a snout-to-vent length (SVL) to 28 mm. The skin is smooth with the occasional low ridge or tubercle present in some specimens, with the frequency of individuals with tubercles increasing to the south of the distribution range. Like other Philoria species, individuals are variable in colour and pattern. The dorsal surface can be a base colour of yellow, orange, bright red, or black with patches of alternative colours. Two black V-shaped markings may be present on the back above the groin. In about half of the specimens, a pair of raised ridges is present, starting behind the eye and continuing posteriorly about a third of the way along the dorsum. The ventral surface is usually yellow or red with smaller patches of either colour, including a red patch on the throat and/or sides of the belly. Brown patches and white dots are also sometimes present. The under surfaces of the limbs range from yellow to yellow with a red or brown wash. Small,
irregular-shaped, white marks are visible when the limbs are a darker colour. A black patch is present covering the cloaca and sometimes the adjacent upper thighs or entire upper thighs. The head is wider than it is long, and the snout is bluntly rounded. The tympanum is indistinct. A dark facial stripe is present in about half the specimens, running from near the tip of snout, crossing the eye, and through to the base of the shoulder. The eyes are brown and prominent. The hind-limbs are short and stocky, and the arms are more robust in males than females. The fingers and toes are unwebbed. Breeding males have a poorly developed nuptial pad on the first finger, and females have spatula-shaped first and second fingers. The description of the adult is drawn from Knowles et al. 2004; Cogger 2014; Anstis 2017; and OEH 2019. Tadpoles are small, growing to 22 mm in total length. The body is very small (5.5 mm) and oval, with the abdomen wider than it is deep. At later stages, the body turns darker with increased grey pigmentation, but the intestinal mass remains visible. The snout is rounded. The eyes are lateral in earlier stages, dorso-lateral later. The oral disc edges are slightly keratinised. The fins are clear with numerous blood vessels. The dorsal fin begins from just onto the body. Both the dorsal and ventral fins are shallow along the length of the tail with the tail-tip broadly rounded.
Mountain Frog |
Philoria kundagungan
Status: Endangered on the EPBC Act list
Government evidence of impact of climate change:
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Australian Government, Conservation Advice, Philoria kundagungan
This effectively limits the available habitat the Mountain Frog can shift to in response to increased temperatures associated with climate change.
Threat factor Threat type Evidence base and status Climate Change Increased Known current Climate change is expected to cause a pronounced temperature increase in extinction risk for frog species over the intensity frequency coming century; with terrestrial breeding and change to frogs identified as some of the most vulnerable taxa precipitation patterns (Hero et al. 2005 Lemckert Penman 2012 Hagger et al. 2013 Pearson et al. 2014 Lopez 2016).
Climate projections for eastern Australia include reduced rainfall; increased average temperatures; and more frequent droughts.
Despite this buffering; impacts from climate change have been observed.
Increased Known current Climate projections for eastern Australia of higher intensity frequency of temperatures and change to rainfall patterns will bushfire increase the scale; frequency; and intensity of wildfires in the region (CSIRO 2007 CSIRO Bureau of Meteorology 2015).
This sort of event is increasingly likely to reoccur as a result of climate change.
Compounding habitat loss through disturbance; an anticipated decline in the amount of montane rainforest habitat is predicted under moderate (RCP6.0) and extreme (RCP8.5) climate change scenarios (Lopez 2016).
However; there is no evidence of Bd related declines for the species and its disappearance from historical sites is thought to be related to climate change (drought) rather than disease.
Threats; in particular climate change; are likely to have resulted in a population decline in the Mountain Frog.
Climate change has the greatest impact at higher elevations; which are home to the largest concentration of threatened anuran species (41 percent); with terrestrial breeding frogs identified as some of the most vulnerable taxa (Hero Morrison 2004 Hero et al. 2005 Lemckert Penman 2012 Hagger et al. 2013 Pearson et al. 2014 Lopez 2016).
The species small and fragmented range; habitat specialisation of bogs and soaks; together with small clutch sizes and slow growth rates; increase its susceptible to perturbations under climate change.
Impacts from climate change have already been observed in the Mountain Frog population.
Given the extent of the habitat burnt by the 2019 20 bushfires and the sensitivity of Philoria species to drought and fire intensity under climate change (Newell 2018); the Committee considers that the Mountain Frog will undergo a substantial reduction in numbers over three generation lengths (with the time period including both the past and future); equivalent to at least 30 percent; and the reduction and cause have not ceased.
In particular; the small population size; already high degree of isolation of subpopulations (Knowles et al. 2004 OEH 2019); and the low dispersal ability (and associated poor recolonisation potential) of the species (Newell 2018) reduces the likelihood of recovery from extreme events associated with climate change and disease (Hagger et al. 2013) (as identified in Criterion 1).
Climate change has already impacted the population.
In addition; the surviving population is further fragmented and less likely to recover from extreme events; such as climate change and disease (Hagger et al. 2013).
Information and research priorities Understand the potential influence of climate change on the long term survival prospects of the species; due to altered temperatures; rainfall patterns; bushfires; environmental stressors and diseases.
An analysis by a team from the National Environmental Science Program (NESP) Threatened Species Recovery (TSR) Hub showed that 47 of the distribution of the Mountain Frog was affected by these fires (with 8 burnt in high to very high severity fire); and the estimated proportional population change for this species from pre fire levels to 1 year after the fire was an overall decline of 19 from pre fire levels; but that the decline could be as large as 34 (bound of 80 confidence limits) (Legge et al. 2021).
They compete with native species and can produce very high fuel loads; leading to higher intensity wildfires that can damage native vegetation and impact wildlife (DNPRSR 2013).
The 2019 20 bushfires may have accelerated any population decline; through direct mortality; and the unfavourable post fire conditions (loss of shelter; increased susceptibility to predators; and loss of prey); as well as a reduction in future recruitment (egg and tadpole death and breeding site degradation).
A structured expert elicitation process was used to estimate the proportional population change for this species from pre fire levels to immediately after the fire and then out to three generations after the fire; when exposed to fires of varying severity.
For comparison; experts also estimated the population change over time in the absence of fire by three generations; the overall population of the Mountain Frog after the fire was estimated to be 13 percent lower than it would have been had the 2019 20 fires not occurred (Legge et al. 2021).
Field studies during the 2020 21 breeding season found evidence of the impact of the 2019 20 bushfires; as well as drought conditions prevailing before the fires.
Prolonged drought is believed to be responsible for absence of frogs at formerly known lower elevation sites during the 2017 breeding seasons (D Newell 2020. pers comm 15 April) and the impact of the 2019 20 bushfires is significant; with 47 percent of the distribution range burnt (see Criterion 1).
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