Fauna Spotters logo

Wrinkled Toadlet (Uperoleia rugosa)

The Wrinkled Toadlet is a small terrestrial frog of dry woodlands, grasslands, flood-prone depressions and temporary wetlands in eastern Australia. It breeds after inundation, so clearing, soil disturbance, drainage changes and loss of tussocky ground cover can affect both adults sheltering on land and eggs or tadpoles in shallow water.

Conservation status

Victoria, Flora and Fauna Guarantee Act 1988: Endangered.

Breeding season

Wrinkled Toadlets emerge and breed after rain, mainly from spring to autumn. Clearing, draining and dewatering can affect calling adults, eggs, tadpoles and recently metamorphosed frogs, with timing varying with rainfall.

Reproductive mode: Egg laying. Eggs are fertilised as they emerge and are attached singly to submerged vegetation or other submerged objects.

Clutch size: Average 225 eggs, with 81 to 352 eggs reported.

Incubation: Not recorded.

Size at hatching or birth: Hatchling length is 2.51 mm.

Age at maturity: Not recorded. Growth rates and age at sexual maturity are largely unknown.

Nest or egg sites: Ponds, temporarily flooded ditches, flooded grassland, billabongs and slow flowing streams. Eggs are attached singly to submerged vegetation or other submerged objects.

Breeding frequency: One clutch per year is reported. About 2% of females may produce a second clutch later in the breeding season.

Confirm timing locally before works because breeding, emergence and recruitment are triggered by rainfall, with activity also influenced by warm temperatures.

  • Calling: Males call most strongly in January and February. Calling is also recorded from September to May, with occasional calling in April during a wet year. Calling follows warm, humid conditions and rain.
  • Egg laying: Egg laying occurs from spring to autumn, generally September to May, in response to rain. Eggs are attached singly to submerged vegetation or other submerged objects in ponds, flooded grassland, ditches and similar water bodies.
  • Tadpoles: Tadpoles may be present from September to July because development takes about 50 days, or around two months, after laying. They remain in temporary or permanent water and can reach about 3.5 to 3.6 cm total length.
  • Froglets: Metamorphosis occurs after about 50 days, so froglets may leave the water from November to July following spring to autumn egg laying. The exact emergence months are not recorded and will depend on when rain fills breeding sites.
  • Active period: Adults are most likely to be active and moving from September to May, when they emerge after rain, call and move to breeding sites. Activity is closely linked to rainfall, and local activity may occur outside this period after suitable rain.
  • Winter inactivity: June to August is the lower activity period in the temperate breeding records. The species is a burrowing taxon, and males may aestivate between breeding periods, although the duration and shelter depth are not recorded.
  • Highest clearing risk: The highest risk is from September to July, when calling and breeding adults, eggs, tadpoles and metamorphs may be present after rain. Ground disturbance can also affect burrowing or sheltering adults, so local rainfall and inundation should be checked before works.

Identification

The Wrinkled Toadlet is a small, stout frog with rough dorsal skin and distinctive orange to red markings on the groin and backs of the thighs. It is usually detected by its short call or by searching damp ground refuges after rain.

The upper surface is usually light brown or grey-brown, with darker blotches and patterns, cream patches and fine orange spots. A pale triangular patch is usually present on the top of the head. The back is granular or very rough, while the belly is smooth and grey to white with brown markings.

  • Check the groin and backs of the thighs for orange or red patches.
  • The toes have only a small amount of webbing or broad fringes, rather than fully webbed toes.
  • The head is small, which is a useful feature when the frog is examined closely.

Identification: Call and field detection

The call is a short, sharp click. It may also be heard as a short craak in South Australian descriptions. Calling males may be on land or in shallow water at the margins of temporary wetlands.

  • Listen after rain around dams, large ponds, claypans, swamps, floodplains, small ponds and puddles.
  • Search beneath ground-level refuges and within damp tussocky vegetation, taking care when lifting tiles or other cover.

Identification: Separation from similar toadlets

The combination of a pale triangular head patch, orange groin and thigh markings, granular back, grey or brown-marked belly and limited toe webbing helps separate the Wrinkled Toadlet from the Smooth Toadlet described in the same regional guide. The Smooth Toadlet has toes lacking webbing and a lighter belly with darker flecks and patterns.

  • Do not rely on colour alone. Confirm the call, skin texture, head marking, thigh and groin colour, and toe webbing together.

Distribution: States and regions

The species occurs in eastern Australia, from southern Queensland through New South Wales to Victoria, with additional records in north-east South Australia. The supplied documents provide habitat and regional range information, but do not provide a national population estimate or a quantified population trend.

In New South Wales, the species occurs along the western edge of the Slopes region and in north-western NSW channel country. It extends into southern Queensland and has a small, uncommon distribution in Victoria, including the Goulburn Broken Catchment.

Documented states: Queensland, New South Wales, Victoria and South Australia.

Victorian distribution: Very few records are reported in Victoria, where the species is uncommon in the Goulburn Broken Catchment.

  • Relevant regional settings include dry woodland and grassland country, flood-prone gullies, gilgais, river overflows and areas that flood after rain.
  • The Victorian records described in the supplied material are at the southern edge of the species' range.

Distribution: Population information

The supplied documents do not give a national abundance estimate, density, home range, number of subpopulations or quantified trend. The Goulburn Broken account describes the species as rare locally and uncommon in the catchment.

National population size: Not reported in the supplied documents.

Local abundance: Uncommon in the Goulburn Broken Catchment, with very few Victorian records reported.

Trend: No quantified population trend is reported.

Habitat: Habitat types

Wrinkled Toadlets use open and semi-open country where temporary water bodies form after rain, together with nearby terrestrial cover for shelter. Habitat is often associated with clay soils, flood-prone ground and vegetation that remains undisturbed between inundation events.

The species occurs in dry woodlands and grasslands, including grey box grassy woodlands, flood-prone gullies, gilgais, river overflows and other areas that become temporarily flooded after spring or summer rain.

  • Potential aquatic habitat includes dams, large ponds, ephemeral claypans, swamps, floodplains, small ponds and puddles.
  • Retain un-ploughed ground, tussocky vegetation, logs, branches and damp depressions near temporary or permanent water.

Habitat: Site features

Breeding sites are generally shallow or temporary water bodies formed by heavy rain or floodwater. Terrestrial habitat is used while frogs wait for inundation and between breeding events.

  • Map gilgais, claypans, flood runners, shallow depressions, wetland margins and drainage lines before clearing.
  • Record the connection between proposed work areas and nearby inundation areas, including areas that may hold water only briefly.

Habitat: Elevation and climate

No elevation limit is provided. The documented range includes dry inland and semi-arid settings in southern Queensland, north-western and south-western NSW, and the drier woodland country of northern Victoria.

Foraging habitat: Feeding areas

The Wrinkled Toadlet feeds on small invertebrates in terrestrial shelter and wetland-edge habitats. The supplied material does not identify particular prey taxa or plants.

Adults use damp ground beneath refuges and vegetation near flood-prone gullies, gilgais, grasslands, woodland and temporary wetlands. A ceramic roof tile placed on the ground was reported to provide a cool, damp refuge with abundant insects.

  • Inspect ground refuges, tussock bases, logs, branches and damp litter near likely breeding areas.
  • Avoid removing ground cover unless it has been checked for sheltering frogs and other fauna.

Foraging habitat: Diet and foraging range

Insects are identified as food in the supplied Victorian account. No species-specific foraging distance, prey list, feeding rate or key food plant is provided.

Documented prey: Insects.

Foraging range: Not reported in the supplied documents.

  • Treat adjacent un-cleared ground as part of the foraging habitat, not just the inundated breeding area.
  • Retain a continuous cover of tussocks, logs and branches around temporary wetlands where practicable.

Breeding habitat: Breeding sites and behaviour

Breeding follows inundation of temporary or permanent water bodies after rain. Males call from land or water, and eggs are attached singly to submerged vegetation or other submerged debris.

Breeding occurs along the margins of wetlands and in areas that become inundated after heavy rain. Suitable water bodies include dams, large ponds, ephemeral claypans, swamps, floodplains, small ponds and puddles.

  • Look for calling males at night around the edges of newly inundated grassland, gilgais, claypans and floodplain depressions.
  • Protect submerged vegetation and debris during works because eggs are attached individually to these structures.
  • Avoid clearing or earthworks during and after rain when temporary breeding habitat is inundated and calling or laying may be occurring.

Breeding habitat: Breeding facts

Females may assess calling males for several nights before selecting a mate. The Australian Museum reports that females of this species wandered around calling males for 3 to 4 nights before mating, with heavier males and deeper calls preferred.

Breeding season: Spring to autumn; males may call at any time except winter in South Australia.

Egg number: 81 to 352 eggs reported.

Egg placement: Single eggs attached to submerged vegetation, with each egg attached to a different piece of vegetation in the South Australian account.

Incubation period: Not reported in the supplied documents.

Tadpole development: About two months to develop into frogs in the Goulburn Broken account.

Age at maturity: Not reported in the supplied documents.

Lifespan: Not reported in the supplied documents.

Sheltering habitat: Natural refuges

Outside breeding periods, Wrinkled Toadlets shelter on the ground in cool, damp microhabitats close to suitable woodland, grassland and temporary wetland areas. Ground disturbance can remove shelter even where no permanent water body is present.

Reported sheltering settings include flood-prone gullies, gilgais, tussocky grassland, un-ploughed ground, logs and branches. These features provide cover while frogs wait for inundation and support invertebrate prey.

  • Retain tussock bases, coarse woody debris, fallen branches, damp litter and undisturbed soil around gilgais and wetland margins.
  • Search likely cover after rain and before clearing, particularly where shelter is close to temporary inundation areas.

Sheltering habitat: Artificial refuges

A ceramic roof tile placed on rocky ground sheltered a Wrinkled Toadlet. The account attributes its use to the cool, damp ground beneath the tile and associated insects.

Documented artificial refuge: A ceramic roof tile on the ground.

Refuge dimensions: Not reported in the supplied documents.

  • Lift tiles and similar flat ground cover by tilting them away from the person checking, allowing any animal underneath to move away safely.
  • Do not use artificial refuges as a substitute for retaining natural ground cover where natural habitat can be protected.

Sheltering habitat: Burrows and hollows

No use of burrows, tree hollows, dens or roosts is reported. The species is described as a terrestrial frog using ground-level cover.

Threats: Clearing and earthworks

The main project risks are loss of temporary wetland habitat, removal of terrestrial ground cover and changes to inundation. The supplied documents also identify habitat degradation and chytrid fungus as important frog conservation concerns, but do not quantify their effects on this species.

Clearing dry woodland, grassland, tussocky vegetation, logs and branches can remove shelter and feeding habitat. Filling, grading or compacting gilgais, claypans, puddles and floodplain depressions can remove breeding sites.

  • Survey both the proposed clearing footprint and nearby low points that may hold water after rain.
  • Avoid ploughing or disturbing un-cleared ground containing tussocky vegetation and coarse woody debris.
  • Check flat ground cover, rubble and tiles carefully before removal.

Threats: Hydrology and fragmentation

The species depends on areas that become inundated after heavy rain, spring or summer rain, or floodwater. Drainage, diversion, flood protection works, altered water levels and sediment or fill can prevent suitable inundation or shorten the period available for eggs and tadpoles.

  • Maintain natural overland flow to gilgais, claypans, floodplain depressions and wetland margins where practicable.
  • Avoid isolating temporary wetlands from surrounding tussocky and woodland habitat.

Threats: Disease and other risks

The NSW frog guide identifies chytrid fungus and habitat degradation as major causes of decline among threatened frogs in the region. The supplied documents do not state the disease status or species-specific impact for the Wrinkled Toadlet.

Documented disease concern: Chytrid fungus and chytridiomycosis are identified as major frog conservation concerns in south-west NSW.

Species-specific threat ranking in supplied documents: No quantified threat assessment is provided for Uperoleia rugosa.

  • Apply hygiene procedures for amphibian surveys and handling, including cleaning and disinfecting equipment between sites in accordance with current agency guidance.
  • Treat road construction, vehicle access, fire and introduced predators as site-specific risks requiring assessment where they alter wetland margins, ground cover or frog movement, because species-specific evidence for these pressures is not provided in the supplied documents.

Survey methodology: 1. Call and spotlight surveys

Survey this small, mostly terrestrial toadlet in dry woodland and grassland near temporary or seasonally inundated water. Detection is most likely during spring to autumn, after rain, when males call from land or shallow water.

Listen for the short, sharp click described for this species, then search the wetland margin and adjacent ground with a spotlight.

Survey during spring to autumn and target nights after rain or inundation, when breeding activity is most likely.

Search dams, large ponds, ephemeral claypans, swamps, floodplains, small ponds and puddles, as well as nearby flood-prone depressions and gilgais.

Inspect both the water margin and nearby terrestrial shelter, including tussocky grass, logs, branches, rocks and artificial ground refuges.

Adult size: 25 to 35 mm in the NSW field guide; 18 to 32 mm in the South Australian species account.

Breeding season: Spring to autumn.

Call: A short, sharp click; another account describes a short ‘craak’ sound.

  • Record the time, weather, recent rainfall, water condition, survey route, area searched, observers and all frog calls or animals detected.
  • Treat a short click as a detection that requires confirmation, because the species is small and may be concealed on land or in shallow water.

Survey methodology: 2. Wetland-margin and refuge searches

Undertake systematic daytime searches around inundated grassland, flood-prone gullies, gilgais, clay depressions and temporary water bodies.

Carefully inspect cool, damp ground refuges such as logs, branches, rocks and ceramic tiles where these are already present or have been lawfully installed for survey purposes.

Search unploughed ground with tussocky vegetation adjoining breeding areas, because adults may shelter away from the water between breeding events.

  • Lift artificial or natural cover by tilting it away from the searcher and replace it immediately after inspection.
  • Do not disturb submerged vegetation unnecessarily, because single eggs may be attached to separate pieces of submerged vegetation.

Survey methodology: 3. Breeding and tadpole checks

Inspect submerged vegetation and other debris for single eggs during spring to autumn breeding surveys.

Search the bottom of temporary water bodies for tadpoles, particularly where water remains after rain or flooding.

Repeat surveys across suitable wet and dry conditions where the project program allows, because breeding sites depend on inundation and may not contain water on every visit.

  • Record each water body separately, including whether it is inundated, the surrounding habitat, calling activity, eggs, tadpoles and adult observations.
  • Use the project’s approved amphibian survey design and any state survey guideline where one applies, because the supplied documents do not specify a standard number of nights, hours, trap nights, transect length or search area for this species.

Survey methodology: Minimum effort and reporting

  • Complete targeted searches in all suitable habitat that may be disturbed, including the wetland, its margin and adjoining dry woodland or grassland refuges.
  • Time at least part of the survey effort for spring to autumn and, where practicable, after rainfall or inundation.
  • Document zero detections as well as confirmed detections, with mapped tracks, survey dates, weather, recent rainfall, water condition, observers and methods.
  • Photograph animals or diagnostic features where this can be done without handling, and retain a sound recording of an uncertain call where possible.
  • Submit confirmed records and survey data to the relevant state wildlife database and comply with project, state and territory reporting requirements.
  • Obtain the required scientific, animal ethics, wildlife handling and access approvals before using traps, handling animals or installing artificial refuges.

Before habitat disturbance: Avoid and minimise habitat loss

Plan works around the species’ wetland dependence and its use of terrestrial shelter. The main controls are to retain temporary breeding sites, adjoining unploughed ground and connected refuge habitat, then stage disturbance after targeted surveys.

Retain flood-prone gullies, gilgais, ephemeral claypans, swamps, floodplains, ponds, puddles and other depressions that can hold water after rain.

Retain adjoining dry woodland and grassland, especially healthy unploughed ground with tussocky vegetation, logs and branches.

Keep retained breeding habitat connected to nearby terrestrial refuge areas and avoid creating isolated wetland fragments.

  • Set project exclusion zones around wetlands and their margins using the project ecologist’s mapped habitat boundaries and any applicable approval conditions.
  • Do not nominate a generic buffer distance where the project assessment has not established one; set the buffer from the hydrology, disturbance footprint and state or approval requirements.

Before habitat disturbance: Approvals and work planning

Confirm the species’ status in the relevant state or territory before works commence, because it is listed as endangered in Victoria and is not listed under the EPBC Act in the supplied information.

Obtain any state or territory wildlife permits, scientific licences and fauna handling approvals required for survey, capture, relocation or habitat disturbance.

Refer the project under the EPBC Act if the project assessment identifies another nationally listed matter or a change in status, even though this species is recorded as not listed in the supplied information.

Prepare a fauna management plan that identifies habitat, survey triggers, exclusion zones, authorised handlers, wetland protection measures and reporting requirements.

  • Stage clearing outside the spring to autumn breeding period where practicable, while recognising that animals may shelter on land at other times.
  • Use staged clearing so the fauna spotter catcher can inspect each work area before machinery enters it and respond to changing conditions after rain.

Before habitat disturbance: Pre-clearance controls

Complete a pre-clearance survey of all suitable wetland, wetland-margin, woodland and grassland habitat within and immediately adjoining the disturbance footprint.

Mark retained wetlands, inundation pathways, tussocky ground, logs, branches, rocks and other mapped refuges before plant arrives.

Install exclusion fencing where it can protect retained habitat and will not block necessary movement between breeding water and terrestrial refuge.

Brief all operators on the species’ appearance, call, habitat, stop-work procedure and the location of no-go areas.

  • Inspect the site again immediately before clearing if rain has created new puddles, inundated depressions or calling activity.
  • Do not place spoil, sediment, fuel, wash water or access tracks in depressions or wetland margins that may be used for breeding.

During habitat disturbance: Daily controls and machinery interface

Use active ecological supervision during clearing and earthworks in or near suitable habitat. Protect wetland hydrology, keep machinery within approved limits and stop work when an animal or previously unrecorded habitat is found.

The fauna spotter catcher must inspect the day’s work area before machinery starts and after rain, inundation or a change in the approved footprint.

Maintain exclusion fencing, wetland buffers and marked no-go areas throughout the shift.

Keep machinery, spoil, refuelling and vehicle movements out of retained wetlands, wetland margins and mapped terrestrial refuges.

Use a slow, staged clearing sequence that allows the spotter catcher to inspect the exposed ground and direct machinery away from animals and shelter features.

  • Stop the relevant plant immediately when the spotter catcher calls stop, when an animal is seen, or when a new wetland, puddle, egg cluster or tadpole concentration is exposed.
  • Allow only an authorised and appropriately licensed person to capture, handle or relocate a frog.

During habitat disturbance: Habitat feature handling

Retain logs, branches, rocks, tussocky vegetation and other ground cover wherever they are inside retained habitat or can remain safely within the approved footprint.

Inspect ground refuges before removal and move them only under the direction of the fauna spotter catcher and project ecologist.

Protect submerged vegetation and wetland debris from unnecessary removal because eggs may be attached singly to different submerged items.

Do not drain, fill or alter a temporary water body until the project ecologist has confirmed that the approved method and fauna controls allow it.

  • Place salvaged natural cover in nearby retained habitat with similar shade and moisture, where the approved fauna management plan permits salvage.
  • Do not create artificial wetland habitat or move water between sites without the required environmental and disease-control approvals.

During habitat disturbance: Animal encounters and stop-work response

On finding a Wrinkled Toadlet, stop work in the immediate area and keep people, plant and vehicles clear until the authorised handler assesses it.

Minimise handling and keep the animal cool, shaded and damp using an approved amphibian container and clean equipment.

Release the animal into nearby retained habitat with suitable cover and access to wetland habitat, at a location approved by the project ecologist and consistent with permit conditions.

Transfer an injured animal to an approved wildlife carer or veterinarian as soon as practicable, and record the transfer.

Stop work and seek ecological advice if eggs, tadpoles, multiple adults, active calling, a previously unmapped wetland or unexpected breeding habitat is found.

  • Do not relocate an animal across a road, into a different catchment or to an unassessed site.
  • Clean and disinfect footwear, nets, containers and other amphibian equipment between sites under the project’s disease-control procedure.
  • Record the location, time, condition, photograph, handler, action taken, release location and any injury or mortality for every encounter.

After habitat disturbance: Post-clearance checks

Close out the fauna controls only after the disturbed area and retained habitat have been checked. Confirm that wetland function, terrestrial refuge and movement connections have not been unintentionally reduced.

Complete a post-clearance inspection of the footprint, wetland margins, access routes, spoil areas and exclusion fencing for stranded, injured or dead frogs.

Recheck newly inundated depressions and retained wetland margins after rain, including for calling adults, eggs and tadpoles.

Confirm that logs, branches, rocks, tussocky ground and other retained refuges remain in place and have not been buried, compacted or isolated.

  • Maintain a fauna spotter catcher or ecological inspection regime until the approved plan confirms that the immediate risk has ended.
  • Report any mortality, habitat damage, sediment entry, changed drainage or failed exclusion fencing to the project manager and regulator where required.

After habitat disturbance: Monitoring and reporting

Monitor retained breeding habitat through the next suitable spring to autumn period where the project risk assessment or approval requires it.

Use repeat call, spotlight and wetland-margin searches to compare post-work detections with the pre-work record, noting rainfall and inundation on each visit.

Map all confirmed records, breeding evidence, habitat damage, relocations and restoration actions in the project fauna register.

  • Submit required records to the relevant state wildlife database and provide statutory or approval reports by the required due dates.
  • Review the fauna management plan if monitoring finds changed wetland hydrology, reduced refuge cover, disease concerns or unexpected mortality.

After habitat disturbance: Ongoing controls and offsets

Keep wetland exclusion fencing, sediment controls and habitat protection measures in place for as long as required by the construction method and approval conditions.

Maintain connectivity between retained wetland habitat and adjoining dry woodland or grassland refuge.

Provide offsets or other compensatory measures only where required by the relevant approval, state policy or residual-impact assessment.

  • Do not treat an offset as a substitute for avoiding and minimising direct damage to breeding water bodies and adjoining refuge habitat.
  • Record the area, location, tenure, management actions and monitoring period for any approved offset or conservation measure.

Rehabilitation actions: Wetland and ground restoration

Rehabilitation should restore temporary wetland function and the adjoining terrestrial shelter used by this species. Prioritise natural inundation patterns, unploughed tussocky ground and connected refuge cover over cosmetic revegetation.

Reinstate shallow depressions, floodplain flow paths, claypan function and wetland margins where construction has altered their shape or drainage.

Design temporary pond and puddle habitat to retain water after suitable rainfall without creating permanent water where that is inconsistent with the pre-work system.

Re-establish tussocky grassland and dry woodland ground cover beside breeding areas, using locally appropriate native plant species selected by the project ecologist and land manager.

Keep restored ground free of ploughing, excessive compaction, dumped material and barriers that prevent movement between wetland and refuge habitat.

  • Do not specify a planting list without local vegetation and seed availability information; use species from the pre-clearing community or approved restoration reference site.
  • Prevent sediment, herbicide, fertiliser and other pollutants from entering restored or retained water bodies.

Rehabilitation actions: Refuge, weeds and predators

Retain or reinstate logs, branches, rocks and other natural ground cover in shaded, damp positions near suitable wetland habitat.

Use artificial refuges only where approved, and inspect them safely as part of the monitoring program rather than treating them as a replacement for natural cover.

Control weeds that reduce native tussock cover or alter wetland function, using methods that protect frogs, eggs and tadpoles.

Manage introduced predators and other site-specific threats where identified by the ecological risk assessment and approved management plan.

  • Avoid moving soil, water, vegetation or amphibians between catchments unless the movement is approved and disease controls are in place.
  • Time weed and predator control to avoid disturbing active breeding sites and occupied refuges.

Rehabilitation actions: Monitoring and success measures

Monitor restored wetlands and adjoining ground through spring to autumn, including after rainfall or inundation.

Use repeat call listening, spotlighting, wetland-margin searches and egg or tadpole checks to test whether the restored area is being used.

Measure success by restored inundation, functioning wetland margins, persistent native tussock and ground cover, retained connectivity, absence of uncontrolled weeds and confirmed use by Wrinkled Toadlets or breeding evidence.

  • Record rainfall, water persistence, vegetation condition, refuge condition, predator or disease observations and all frog detections at each monitoring visit.
  • Continue corrective works where restored depressions dry too quickly, drainage is diverted, ground cover fails, weeds dominate or monitoring identifies mortality.
  • Submit confirmed records and required rehabilitation results to the relevant state wildlife database and approval authority.

Sources