Australia has 240 known native amphibian species, all of which are frogs. Unfortunately, frogs are one of the most threatened animal groups on Earth, with an estimated 40 per cent of species worldwide threatened with extinction. In Australia alone we have officially listed four species as extinct and a further 40 species are currently threatened with extinction.
One such Australian frog under threat is the Magnificent Broodfrog (Pseudophryne covacevichae), a species endemic to the Wet Tropics of north Queensland. Earlier this year, Ecohealth surveys conducted by AWC ecologists at Mount Zero-Taravale in 2021 successfully recorded calls of this cryptic species at a number of new locations on the sanctuary.
These new records provide hope of a larger, more secure population and offers ecologists a greater understanding of the behaviour and habitat preference for this vulnerable species in the southern extent of its range.
A magnificent mystery
‘Magnificent’ is a great descriptor for this little frog, which grows to only 3cm – about the length of the end of your thumb.
They are distinguished from other members of the genus by their bluish-grey body, with upper arms of vibrant yellow. A vivid red triangular patch extends from the upper snout to the forehead and continues in a line along the back, ending in a bright yellow stripe and their belly is marbled with black and white.
These amazing amphibians inhabit seepage areas along small streams in open eucalypt woodlands, and during the wet season, use grassy tussocks and leaf litter in these areas to call for a mate and lay their eggs. The short ‘ark’ of the males may be heard on warm, wet nights from October to May.
Eggs are laid as a small cluster on land under moist leaf litter and in muddy holes in the ground along drainage lines, seeps and shallow creeks. The nest is built and guarded by the male, as it is with other Pseudophryne species, with the tadpoles released into bodies of water after rains flood the nest.
The Magnificent Broodfrog was known to inhabit only a few scattered sites above 800m elevation, in the vicinity of Ravenshoe and Herberton, on the Atherton Tablelands in north Queensland. In 2013 the species was discovered in the Paluma Range, extending the known distribution by 160 km southeast.
Following this discovery, in 2014, AWC ecologists confirmed the species’ presence on Mount Zero-Taravale for the first time.
Threats to the species include habitat loss and degradation through grazing, logging, roads and infrastructure development. Mount Zero-Taravale is potentially a reliable refuge for the species given that the sanctuary has no cattle and is not at risk of land clearing and development.
Calls in the night
This year’s initial survey efforts aimed to obtain baseline information on the distribution of the Magnificent Broodfrog across the sanctuary. The species was previously known only from eight locations in Paluma, seven of which are on the sanctuary.
“This was the first targeted survey for this species at Mount Zero-Taravale and the first extensive research into the population since they were discovered in Paluma in 2013,” explains ecologist Emily Rush.
“We deployed 32 song meters at 16 sites across the north of the sanctuary. The species were detected on eight of the song meters at six sites (2 song meters per site) which increased the known locations of the frogs in Paluma from seven to eleven.”
The survey took place in two stages, conducted four weeks apart. Each stage deployed “song meters” – specially engineered audio recorders used in the field to detect birds, frogs and other vocal wildlife – at eight sites, which were left in the field on a four-week rotation.
There is still much to learn about the Magnificent Broodfrog’s basic ecology, including their full distribution, habitat preference and threats. This targeted survey is one of the first, intensive surveys for the species in the south of its range and knowledge gained through continuing these surveys will greatly improve our understanding of this enigmatic species.