Fleay’s Barred Frog is a large burrowing frog endemic to mid-eastern Australia. Females are larger than males, having a snout-to-vent length (SVL) of over 90 mm and weighing over 100 g. Males reach 80 mm (SVL) and weigh up to 59 g. The skin is finely granular above and smooth below. The dorsal surface is light to dark brown with indistinct darker marbling. Typical of barred frogs, an irregular, dark, vertebral stripe is present. The Y-shaped stripe commences between the eyes and extends to the vent, sometimes breaking up into a series of blotches along the midline. The flanks are grey-brown, fading to yellow posteriorly, and overlaid by a series of black spots. The ventral surface is typically yellow. The snout is steeply sloped and blunt with an irregular dark band running from the nostril, through the eye, to a point behind the large, oval tympanum. The eyes are prominent with a dark purple patch visible beneath. The upper part of the iris may be straw-brown through light blue to silvery-white. The pupil is vertical. The upper lip Mixophyes fleayi (Fleay’s Frog) Conservation Advice Page 2 of 23 is usually mottled brown with one or more purplish-brown blotches. A vocal sac is present in adult males. The thighs are grey-brown with seven or eight narrow, black cross-bands. The hands are not webbed, while the feet are about one-third webbed. The tips of the fingers and toes do not have disc-like pads. The soles and palms are black. Males develop dark brown nuptial pads on the prepollex, first finger, and sometimes the second finger.
Fleay's Frog |
Status: Endangered on the EPBC Act list
Government evidence of impact of climate change:
Australian Government, Conservation Advice, Mixophyes fleayi
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 (Hagger et al. 2013 Pearson et al. and change to 2014).
Climate projections for eastern Australia precipitation patterns include reduced rainfall; increased average temperatures; and more frequent droughts.
Impacts from climate change are compounded by Fleay s Barred Frog s restricted area of occupancy; low population density at sites; prevalence at higher altitudes (above 400 m); short generation length (four five years); and large body size.
These variables are identified as increasing the risk of local extirpation (Oza et al. 2012 Hagger et al. 2013 Pearson et al. 2014) and are amongst the strongest predictors of species vulnerability to climate change (Pearson et al. 2014).
Tanner McAllister et al. (2018) developed conceptual models for four World Heritage National Parks to predict the likely impact to stream dwelling frogs from climate change.
An increase in wildfire events was found to be the most detrimental impact; giving a higher probability of a decreasing population under both moderate and substantial climate change models; with the most severe scenario resulting in over a 50 probability that there would be a population decrease.
This sort of event is increasingly likely to reoccur as a result of climate change.
However; the resulting absence of the species from some historical locations; very low abundance at others; and isolation of remaining subpopulations (Hines the South east Queensland Threatened Frogs Recovery Team 2002 Newell et al. 2013 Newell 2018); together with the low dispersal ability (and associated poor recolonisation potential) of the species (Doak 2005); has reduced the likelihood of species recovery from extreme events associated with climate change or disease (Drielsma Ferrier 2009 Hagger et al. 2013 Newell et al. 2013).
Fleay s Barred Frog is highly vulnerable to climate change; having physiological and ecological traits that confer both low resistance and low resilience to climate change.
In particular; the small population size of Fleay s Barred Frog; already high degree of isolation of subpopulations (Hines the South east Queensland Threatened Frogs Recovery Team 2002 Newell et al. 2013 Newell 2018); and the low dispersal ability (and associated poor recolonisation potential) of the species (Doak 2005); reduces the likelihood of recovery from extreme events; such as climate change or disease (Drielsma Ferrier 2009 Hagger et al. 2013 Newell et al. 2013) (as identified in Criterion 1).
Further; Fleay s Barred Frog is highly vulnerable to climate change; having the physiological and ecological traits that confer both low resistance and low resilience to climate change (Hagger et al. 2013 Tanner McAllister 2018).
The direct and indirect impacts of the bushfires are the primary factors in this decline; with the surviving population further fragmented and less likely to recover from extreme events; such as climate change and disease (Drielsma Ferrier 2009 Hagger et al. 2013 Newell et al. 2013).
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.
Increased Known current Localised extirpation of frogs has been observed intensity frequency of through wildfire events.
An analysis by a team from the National Environmental Science Program (NESP) Threatened Species Recovery (TSR) Hub showed that 18 of the distribution of Fleay s Barred Frog was affected by these fires (with 3 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 7 from pre fire levels; but that the decline could be as large as 35 (bound of confidence limits) (Legge et al. 2021).
The fires 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 Fleay s Barred Frog after the fire was estimated to be two percent lower than it would have been had the 2019 20 fire not occurred (Legge et al. 2021).
Post fire sediment slugs have been observed within occupied subcatchments; impacting oviposition site availability.