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Wallum Froglet (Crinia tinnula)

The wallum froglet is a very small, nocturnal terrestrial frog of acidic coastal wetlands, heathlands, sedgelands and paperbark swamps in south-east Queensland and New South Wales. It is Vulnerable in Queensland and New South Wales, and development can remove breeding pools, damp refuges and movement areas or alter the acidity and hydrology on which the species depends.

Conservation status

Queensland, Nature Conservation Act 1992: Vulnerable.

New South Wales, Biodiversity Conservation Act 2016: Vulnerable.

Breeding season

Wallum froglets can call and breed in any month after rain, with breeding and calling activity generally greatest from autumn through winter. For clearing, treat shallow acidic wetlands, sedgelands and nearby damp ground cover as occupied habitat throughout the year, with the highest risk from autumn to winter.

Reproductive mode: Egg laying in shallow, acidic water.

Clutch size: Usually 33 to 118 eggs.

Incubation: Not recorded.

Size at hatching or birth: Not recorded.

Age at maturity: Not recorded.

Nest or egg sites: Eggs are attached singly or in small groups to submerged vegetation, twigs, leaves or other underwater surfaces in still or shallow water.

Breeding frequency: Breeding can occur in all seasons after rain, particularly after significant rainfall and while water is available.

Confirm timing locally before works by checking recent rainfall, water levels and calling activity, because breeding and larval presence can occur in any month after rain.

  • Calling: Males may call in every month, especially after rain. Calling peaks in June to August, and usually occurs at night, although winter calling can also occur during daylight.
  • Egg laying: Egg laying can occur in any month following rain. Eggs are laid singly or in clumps and attached to submerged vegetation or other underwater surfaces in shallow acidic water, usually below pH 6.
  • Tadpoles: Tadpoles may be present in any month after breeding and rainfall. Development takes about 2 to 6 months and slows over winter, so larvae may remain in water across several seasons.
  • Froglets: Froglets may leave the water in any month because breeding and tadpole development can follow rain in all seasons. The timing of juvenile emergence is not separately recorded, but tadpole development may take 2 to 6 months.
  • Active period: No separate seasonal activity period is recorded. Adults are nocturnal and may call or move in any month when suitable water and damp habitat are available, particularly after rain.
  • Winter inactivity: A secondary account reports winter hibernation, but the main species accounts do not confirm a defined winter dormancy. Treat June to August as a precautionary period for sheltering frogs, while retaining damp cover throughout the year.
  • Highest clearing risk: Risk is highest from March to August, when autumn and winter breeding, calling, eggs and tadpoles may overlap. Risk remains in every month because breeding follows rain and frogs use damp ground cover away from breeding pools.

Identification

Wallum froglets are small, variable-coloured frogs that are often detected by their call rather than seen. They may be found well away from water outside the breeding period, so searches should include damp terrestrial cover around wetlands.

The wallum froglet is about 20 mm long, with some field material recording individuals to 22 mm. The upper surface ranges from light grey or brown to dark grey, brown or reddish brown, with variable stripes, irregular markings and texture. The underside is white or light brown, and may be sparsely flecked or heavily mottled with darker patches. A fine pale median line or line of white dots may run along the throat and belly.

  • The snout is relatively pointed and projects beyond the lower jaw.
  • The feet have no webbing and the toes have no pads.
  • The pupils are horizontal.

Identification: Call and field signs

The call is a short, high-pitched ringing sound described as ‘tching.tching.’ or a short ‘tcheh’ that may increase in speed before a pause. It is most likely to be heard at the water's edge, from sedge tussocks or among emergent vegetation, and often after rain.

  • Males call from secluded positions beside water or while afloat among vegetation.
  • During the day, frogs may be concealed under leaf litter, vegetation, other debris or in burrows made by other species.
  • Eggs are attached to submerged vegetation. Tadpoles occur in shallow acidic pools, swamps, dams or drainage ditches.
  • No species-specific tracks, scats, sloughs, nests or eyeshine signs are documented. Identification should rely on the frog's morphology, call, habitat and, where required, expert confirmation.

Identification: Similar frogs

The wallum froglet resembles other small Crinia in south-east Queensland because its colour and pattern vary widely. The pale median belly line, lack of toe pads and webbing, distinctive ringing call, and association with acidic coastal wetlands are useful features when separating it from similar froglets.

  • Do not identify the species from colour alone.
  • Confirm records from disturbed sites or outside typical wallum vegetation using the call, detailed morphology and an experienced amphibian identifier.

Distribution: National range

The wallum froglet has a discontinuous coastal distribution in eastern Australia. It is restricted mainly to lowland coastal sand plains, dunes and associated wetlands, with records extending from south-east Queensland to the Sydney region.

The documented range extends from Littabella National Park in south-east Queensland south to Kurnell in central New South Wales. It includes coastal lowlands and offshore sand islands including Fraser Island, Bribie Island, Moreton Island and North Stradbroke Island.

Estimated extent of occurrence: Approximately 30,300 km².

Altitude: Usually in coastal lowlands below 100 m above sea level.

  • In Queensland, the species is recorded from coastal and near-coastal lowlands, including the South Eastern Queensland subregions of Burringbar-Conondale Ranges, Clarence Lowlands, Scenic Rim and Sunshine Coast-Gold Coast Lowlands.
  • In New South Wales, documented IBRA subregions include Coffs Coast and Escarpment, Karuah Manning, Macleay Hastings, Yuraygir, Hunter, Pittwater and Wyong. Some records are restricted to within 10 km or 30 km of the coast, while others have no stated geographic restriction.
  • The species occurs in both states listed in the supplied material, Queensland and New South Wales.

Distribution: Strongholds and population information

Known strongholds include coastal sand plains, wallum wetlands and sand islands in south-east Queensland, together with coastal wetland systems in northern and central New South Wales. Moreton Bay supports an important population and is identified as providing habitat for more than 1% of the species' population.

Moreton Bay Ramsar site estimate: The total population was estimated in the supplied assessment to be in the tens of thousands to hundreds of thousands, with more than 1% occurring at the site.

Population trend: Relatively stable within protected habitats; localised extinctions have occurred where habitat was lost or fragmented.

  • The species is associated with suitable habitat rather than a continuous coastal belt, so apparently connected coastal areas may contain separate local populations.
  • Local population extinctions have occurred following habitat loss or fragmentation.
  • National populations appear relatively stable within protected habitats, but the range is discontinuous and has been reduced or fragmented by coastal development.

Habitat: Wetland and vegetation types

Wallum froglets use a mosaic of acidic aquatic habitat and damp terrestrial habitat. The physical and chemical conditions of breeding water, particularly acidity, appear to be more important than any single broad vegetation type.

Typical habitat includes acidic swamps on coastal sand plains, wet heathlands, sedgelands, wallum woodland, Melaleuca swamps and swamp sclerophyll forest. Frogs may also occur along drainage lines, in eucalypt woodland with a heathy understorey, near creeks and soaks, and in disturbed wallum habitat such as roadsides, quarry sites, partly cleared areas and exotic pine plantations.

  • Breeding habitat includes permanent swamps, shallow ephemeral pools, flooded ditches, dams and drainage lines.
  • Relevant vegetation communities include heathland, sedgeland, Melaleuca quinquenervia woodland and swamp, paperbark swamp, Banksia-associated wetland vegetation and wet or dry wallum heath.
  • At the Colton project site, large numbers were associated with low-lying Melaleuca quinquenervia mixed woodland on tertiary plains, and the species was also recorded in heathland and sedgeland.

Habitat: Site features and limits

Suitable sites are generally low-lying, sandy coastal habitats with low-nutrient soils and periodic or permanent water. Breeding pools are shallow and acidic, and may dry between rainfall events. The species can persist in disturbed areas, but disturbance may still reduce habitat quality through changes to water chemistry, nutrients, hydrology or cover.

Typical breeding-water pH: Below 6, commonly pH 4.3 to 5.2.

Hydroperiod: Breeding occurs in permanent water and shallow ephemeral water; available water must persist long enough for tadpoles to develop.

  • Retain both the aquatic breeding area and damp terrestrial habitat around it.
  • Avoid treating an isolated pool as the whole habitat unit. Frogs may shelter and move through heath, sedgeland, woodland and forest away from water.
  • The documented elevation limit is generally below 100 m above sea level in coastal lowlands.

Foraging habitat: Adult foraging

Adult wallum froglets feed on small moving invertebrates in damp terrestrial habitat. Tadpoles use the bottom and water column of shallow breeding pools, where they feed on sediment and algae.

WildNet records adults eating several species of arthropods. Other supplied guidance indicates that likely prey includes insects such as ants, termites, spiders, beetles, bugs, grasshoppers and cockroaches, although species-specific dietary research is limited.

  • Search for foraging frogs in damp leaf litter, sedge bases, wet heath, swamp margins and other ground cover near wetlands.
  • Adults are terrestrial and may forage well away from water, particularly when damp conditions follow rain.
  • No quantified adult foraging range has been documented in the supplied material.

Foraging habitat: Tadpole feeding

Tadpoles feed on sediment and algae in shallow acidic water. Maintaining natural water quality and avoiding nutrient enrichment helps retain the food conditions used during larval development.

  • Prevent sediment, fertiliser, chemical and nutrient runoff from entering breeding pools.
  • Do not create permanent standing water where predatory fish can establish.

Breeding habitat: Breeding biology

Breeding is linked to rainfall and shallow acidic water. Males call from cover at the water's edge or among emergent vegetation, and eggs are attached to submerged stems.

Breeding usually occurs in autumn and early winter, with activity peaking in the colder months. Breeding can occur throughout the year after rain, and supplied project survey material also records breeding in late winter, spring and late summer.

Breeding season: Usually autumn to early winter, with a peak in colder months; possible in all seasons after rain.

Egg number: Usually 33 to 118 eggs.

Egg size: Approximately 1.1 to 1.2 mm in diameter.

Egg placement: Attached singly or in clumps to submerged vegetation.

Tadpole period: Approximately 2 to 6 months.

Age at maturity: Not stated in the supplied documents.

Lifespan: Not stated in the supplied documents.

  • Males call from the base of sedges, beside water or while afloat among emergent vegetation.
  • Eggs are attached to fine stems of grass or reeds, singly or in clumps, below the water surface.
  • Tadpoles may take 2 to 6 months to become frogs, with development slowing over winter.

Breeding habitat: Breeding-site requirements

Breeding sites include acidic swamps, permanent and ephemeral pools, shallow lakes, dams, flooded ditches and drainage lines. Water is generally nutrient poor and has a pH below 6, commonly between 4.3 and 5.2.

  • Retain emergent sedges, grasses and other submerged vegetation for calling and egg attachment.
  • Protect the pool and its surrounding damp terrestrial habitat from clearing, trampling, drainage, sediment, nutrient enrichment, chemicals and pH change.
  • Maintain a natural hydroperiod. Water that disappears too quickly may not support tadpole development, while permanent water may allow predatory fish to establish.
  • Avoid mosquito-control treatments during the main breeding period of March to September unless the method is known to be safe for frogs and approved for the site.

Sheltering habitat: Daytime refuges

The wallum froglet is cryptic and uses small, damp refuges on the ground. Shelter is not restricted to the immediate edge of a breeding pool.

During the day, wallum froglets shelter under leaf litter, vegetation and other debris, in the base of reeds or sedges, and in burrows made by other species. They need wet or very damp shelter, especially when shallow pools dry or during prolonged dry periods.

  • Retain dense ground cover, sedge tussocks, leaf litter and damp debris around wetlands.
  • Inspect ground cover and likely refuges before clearing, slashing, machinery access or removal of vegetation.
  • Include nearby heath, woodland and forest with suitable damp cover in the search area, because individuals may be found well away from water.

Sheltering habitat: Movement and refuge context

Detailed dispersal distances are not available. Individuals have been trapped a considerable distance from breeding sites, and movement into terrestrial habitat may be extensive when shallow water bodies dry.

  • Maintain habitat connectivity between wetland patches and adjacent terrestrial cover.
  • Avoid isolating breeding pools with roads, drains, cleared strips or hard surfaces.
  • Treat burrows, leaf litter, sedge bases and damp ground as potential fauna habitat even when no frogs are visible.

Threats: Clearing, fragmentation and roads

The main project risks are loss or fragmentation of coastal wetlands and associated terrestrial cover, followed by changes to water chemistry, nutrient status and hydrology. Because the species uses both aquatic and terrestrial habitat, impacts outside the pool can also affect local populations.

Clearing for coastal development, roads, drainage works, agriculture, pine plantations, quarries and infrastructure removes breeding sites and terrestrial refuges. Fragmentation can prevent movement between wetlands and isolate local populations.

  • Avoid clearing acidic wetlands, sedgelands, wet heath and Melaleuca swamps wherever practicable.
  • Retain a minimum 50 m of intact terrestrial habitat or buffer around aquatic habitat as a preliminary management guideline, while recognising that site-specific advice may require more.
  • Keep construction access, stockpiles, compounds and laydown areas out of wetland margins and movement corridors.
  • Plan road crossings to reduce mortality, runoff impacts and loss of connectivity.

Threats: Hydrology and water quality

Drainage, water extraction, altered groundwater or surface-water flow, changed hydroperiod, sediment, fertilisers, urban runoff and chemical use can make breeding water unsuitable. Liming disturbed acid sulfate soils can raise pH and reduce habitat suitability.

  • Prevent stormwater, sediment, nutrients, concrete washout, fuels, herbicides and insecticides from entering breeding wetlands.
  • Do not drain or permanently inundate ephemeral pools without assessing the effect on breeding and predator establishment.
  • Maintain the natural acidity and hydroperiod of breeding water.
  • Avoid creating permanent shallow water that can support mosquitofish or other predators.

Threats: Fire and invasive species

Inappropriate fire can remove refuge cover or damage wetland vegetation. Fire management guidance varies between sources, but both identify the need for an appropriate, patchy regime and protection of swamps during burning.

  • Use a fire regime suited to the local wallum vegetation and avoid burning swamps during periods when standing water or breeding habitat would be damaged.
  • Control weeds without contaminating breeding water or removing all ground cover.
  • Manage feral pigs, which can trample, wallow in and disturb breeding habitat.
  • Prevent the introduction of mosquitofish, Gambusia holbrooki, to breeding pools. Mosquitofish can prey on eggs and larvae and compete for food.
  • Consider cane toads and competing frog species in disturbed wetlands, particularly where altered water quality or hydrology allows them to increase.

Threats: Disease and other pressures

Chytrid fungus is a potential threat to the species and can be spread between wetlands on contaminated equipment, footwear, vehicles or handling materials. Amphibians are also sensitive to chemical contamination because of their permeable skin.

  • Apply the current approved hygiene protocol for amphibian fieldwork and move from clean sites to potentially contaminated sites where practicable.
  • Use dedicated or disinfected footwear, nets, traps, containers and other equipment between wetlands.
  • Limit handling and obtain specialist advice where a frog is found during clearing or construction.
  • Record the location and condition of any wallum froglets, eggs or tadpoles and notify the fauna spotter catcher and project environmental officer.

Survey methodology: 1. Habitat assessment and desktop review

Survey for Wallum Froglets in and around acidic coastal wetlands, including sedgeland, wet heathland, Melaleuca swamps, drainage lines and shallow ephemeral pools. Surveys should account for the species’ small size, cryptic behaviour, nocturnal activity and calling response after rain.

Map acidic wetlands and potential refuge habitat before fieldwork. Include wet and dry heathland, sedgeland, Melaleuca woodland, swamp margins, drainage lines, shallow pools, flooded ditches and adjoining damp terrestrial habitat.

Check the project area and nearby retained habitat for known records, essential habitat mapping, protected areas, proposed clearing and likely movement routes between breeding and refuge areas.

Treat habitat as potentially occupied where suitable wetland and terrestrial features are present, even if frogs are not detected during a single visit.

Survey methodology: 2. Call playback and nocturnal listening

Conduct nocturnal listening surveys after rain, when males are most likely to call. Males may call throughout the year, with breeding generally peaking in autumn and the colder months.

Stand quietly at the edge of water, among sedge tussocks and along drainage lines, then listen for the short, high pitched ringing call described as ‘tching’ or ‘tcheh’.

Search the water margin and emergent vegetation with a torch after listening. Record calling locations, water condition, vegetation structure, pH where measured, weather and the duration of active searching.

Do not rely on call detection alone because the species is cryptic and adults may shelter under leaf litter, vegetation, debris or in burrows away from water.

Preferred survey conditions: At night, particularly following rain, when shallow water and damp refuge sites are present

Breeding period: Throughout the year following rain, generally peaking in autumn and colder months

Survey methodology: 3. Targeted searches and trapping

Undertake systematic searches around wetland margins, sedge tussocks, leaf litter, damp debris, crayfish burrows and nearby terrestrial refuge habitat.

Use appropriate amphibian trapping methods only where authorised and where they can be operated without drying, overheating or injuring frogs. Inspect traps frequently and release non-target animals promptly.

If pitfall or funnel trapping is used, document the number and type of traps, trap nights, spacing, wetland area covered, inspection frequency and weather conditions. The supplied documents do not specify a standard number of trap nights or transect length for this species.

Use strict amphibian hygiene procedures between sites and equipment to reduce the risk of spreading chytrid fungus.

Adult size: About 20 millimetres, with some material recording up to 22 millimetres

Breeding water: Shallow acidic water, commonly pH below 5.5 and reported as pH 4.3 to 5.2

Tadpole period: Two to six months, with development slowing over winter

Survey methodology: Minimum effort and reporting

  • Use more than one survey visit where practicable, including at least one nocturnal survey after suitable rain and one survey during the main autumn to winter breeding period.
  • Record survey dates, start and finish times, rainfall, temperature, wind, cloud, water depth and persistence, water pH where measured, habitat condition, survey area, personnel, method and effort.
  • Record positive and negative results separately for each wetland, drainage line and adjoining terrestrial search area.
  • Photograph habitat and any captured or observed frog only where this can be done without handling stress or habitat damage.
  • Submit confirmed records and suitable negative survey records to the relevant state wildlife database, including Queensland WildNet or the NSW BioNet Atlas, and retain the project data in the environmental management system.
  • Report survey limitations, including dry conditions, inaccessible habitat, poor calling conditions, incomplete trap coverage or disturbed wetlands.

Before habitat disturbance: Avoid and minimise

Plan clearing around the species’ dependence on acidic wetlands and nearby damp terrestrial refuge habitat. Avoid changes to water chemistry, water levels, drainage and connectivity, not only direct removal of breeding pools.

  • Retain acidic swamps, sedgelands, wet heathlands, Melaleuca swamps, shallow ephemeral pools, drainage lines and damp refuge habitat.
  • Retain a minimum 50 metre intact terrestrial habitat or buffer around aquatic habitat where the local approval framework allows, noting that the published figure is a preliminary Brisbane guideline.
  • Keep works, stockpiles, access tracks, drainage, sediment controls and machinery out of retained wetland buffers wherever practicable.
  • Maintain movement routes between breeding water and nearby terrestrial refuge areas because individuals may move well away from water during dry conditions.
  • Prevent changes that raise pH, add nutrients or sediment, lower the water table, create permanent water or alter the duration of ponding.
  • Stage clearing so that retained habitat remains connected and available while other areas are being cleared.

Before habitat disturbance: Approvals and project planning

  • Confirm the current Commonwealth and state conservation status before works begin. The Wallum Froglet is not listed under the EPBC Act in the supplied sources, and is Vulnerable in Queensland and New South Wales.
  • Obtain any required state clearing, wildlife, animal ethics, scientific, rehabilitation or translocation approvals before survey, capture, handling or relocation.
  • Assess whether the project affects other EPBC Act listed species, ecological communities or Ramsar values, because the frog itself is not nationally listed in the supplied material.
  • Prepare a fauna management plan that defines survey triggers, exclusion zones, spotter catcher authority, hygiene, wetland protection, relocation, injury response, stop-work rules and reporting.
  • Schedule ground disturbance outside active breeding conditions where practicable, particularly the main March to September period identified in the Brisbane guidance, while recognising that breeding can occur in any season after rain.

Before habitat disturbance: Pre-clearance preparation

  • Complete a pre-clearance survey of all wetland and adjoining terrestrial habitat within and beside the disturbance footprint.
  • Mark wetland boundaries, shallow pools, sedge tussocks, damp refuge areas, burrows, drainage lines and the retained buffer before machinery arrives.
  • Install exclusion fencing or clearly visible flagging around retained wetlands and buffers where it can be maintained without blocking frog movement between retained habitat patches.
  • Brief all workers on the frog’s appearance, call, habitat, handling restrictions, hygiene requirements and stop-work triggers.
  • Inspect machinery, footwear, nets, buckets and other equipment and apply the approved amphibian hygiene protocol before entering occupied or potential habitat.

During habitat disturbance: Daily controls

Use a trained fauna spotter catcher during clearing and earthworks in potential habitat. The spotter catcher should control the work area, not simply collect animals after machinery has disturbed the habitat.

  • Inspect exclusion fencing, wetland markers, sediment controls and drainage controls before work starts each day.
  • Keep machinery, personnel, spoil, fuels, concrete washout, fertilisers, herbicides and wastewater outside retained wetlands and buffers.
  • Avoid works during heavy rain or when water is flowing into retained wetlands unless the fauna management plan specifically addresses the risk.
  • Use clean equipment between wetlands and do not move water, sediment, aquatic plants or soil from one wetland to another.
  • Maintain a clear communication channel between the spotter catcher, machine operator, supervisor and environmental officer.

During habitat disturbance: Spotter catcher and machinery protocol

  • The spotter catcher should inspect the next work area immediately before disturbance, remain in a position with a clear view of the active edge and direct the operator to stop when fauna or habitat risk is identified.
  • Clear vegetation progressively towards retained habitat, leaving a safe route for animals to move away from machinery where this does not increase the risk of entering the work zone.
  • Search leaf litter, sedge bases, damp debris, wetland margins and suitable burrows before and after each clearing stage.
  • Do not chase frogs through dense vegetation or repeatedly disturb wetland margins to obtain a detection.
  • Only an appropriately authorised and experienced person should capture, handle or relocate a frog.

During habitat disturbance: Animal finds, habitat features and stop work

  • Stop the relevant activity if a Wallum Froglet is found in the active work area, if the animal cannot be safely avoided, or if clearing exposes a previously unrecorded wetland or damp refuge area.
  • Keep the animal cool, shaded, moist and in a clean container suitable for amphibians while an authorised person determines the next action.
  • Relocate a healthy frog only to nearby suitable retained habitat identified in the fauna management plan, preferably within the same local wetland system and away from machinery, roads and active works.
  • Do not move frogs across unsuitable habitat or to a different catchment without specific approval and ecological justification.
  • Send an injured or distressed frog to an appropriately qualified wildlife carer or veterinarian as soon as practicable, and record the chain of custody.
  • Treat logs, rocks, dense litter, sedge clumps, burrows and wetland edge debris as potential refuge features and inspect or retain them before removal.
  • Stop work and obtain ecological advice if clearing changes wetland drainage, causes sediment or chemical entry, exposes acid sulfate soils, or creates permanent standing water.
  • Resume work only after the spotter catcher or environmental officer has documented the find, confirmed the control measure and released the work area.

During habitat disturbance: Records and incident reporting

  • Record every observation, capture, relocation, injury, mortality, stop-work event and habitat feature retained or removed.
  • For each frog record the date, time, location, GPS accuracy, habitat, weather, condition, action taken, release location and the names and authorisations of people involved.
  • Report any mortality, repeated disturbance, wetland damage, chemical spill, fish introduction or failure of exclusion controls under the project incident procedure and any relevant government approval.
  • Update the site map each day to show cleared areas, retained habitat, relocation sites, wetland buffers and unresolved risks.

After habitat disturbance: Post-clearance checks

Check that clearing has not left frogs, isolated wetland habitat or altered drainage within the work area. Continue controls until disturbed areas are stable and retained habitat is functioning.

  • Complete a final fauna search of the cleared footprint, wetland margins, spoil areas, access tracks and exclusion fence line before demobilisation.
  • Inspect retained wetlands after the first substantial rainfall and after major earthworks to check for sediment, altered flow, changed pond duration, pH change or new permanent water.
  • Remove temporary fencing only after the environmental officer confirms that machinery, stockpiles and personnel no longer threaten retained habitat.
  • Repair damaged buffers, wetland markers, sediment controls and drainage controls immediately.
  • Check that no frogs, tadpoles, eggs or aquatic refuge features have been stranded by drainage or staged works.

After habitat disturbance: Monitoring and reporting

  • Monitor retained and rehabilitated wetlands through at least the first wet season and include nocturnal listening after rain where the project risk assessment requires it.
  • Compare calling activity, occupied wetland locations, water persistence, pH where measured, vegetation cover and invasive species presence with the pre-clearance baseline.
  • Report all confirmed records and mortality records to the relevant state wildlife database and provide approval reporting within the required timeframe.
  • Document whether buffers, connectivity, drainage controls, hygiene controls and rehabilitation measures were maintained.
  • Escalate declining detections, repeated mortality, chytrid concerns, mosquitofish presence, cane toad increase or wetland drying to the project environmental manager and relevant authority.

After habitat disturbance: Offsets and residual impacts

  • Apply the relevant state and Commonwealth offset or environmental compensation requirements if authorised impacts remain after avoidance and mitigation.
  • Do not treat relocation as an offset or as evidence that habitat loss has been avoided.
  • Use retained or protected habitat that matches the species’ acidic wetland, wet heath, sedgeland and terrestrial refuge requirements when designing any approved residual impact measure.

Rehabilitation actions: Wetland and habitat restoration

Rehabilitation should restore the wetland processes and acidic, low nutrient habitat used for breeding, shelter and movement. The target is functioning habitat, not only replacement vegetation.

  • Reinstate shallow ephemeral pools, damp depressions and drainage patterns that provide breeding water without creating permanent water bodies.
  • Use local native wetland, sedge, heath, Melaleuca and wallum woodland species suited to the site and its acidic, low nutrient soils.
  • Avoid liming, fertiliser enrichment and other treatments that raise pH or nutrient levels in soil or water.
  • Retain or reinstate at least the approved terrestrial buffer around aquatic habitat, with 50 metres used as a preliminary reference where applicable.
  • Replace suitable logs, leaf litter, coarse woody debris and other damp ground cover that provide daytime refuge, while avoiding the movement of potentially contaminated material between sites.
  • Maintain connected habitat between breeding pools, wetland margins and adjoining heath, sedgeland or woodland refuge areas.

Rehabilitation actions: Weeds, predators and disease

  • Control weeds using methods that prevent herbicide or sediment entering breeding water and that retain dense native ground cover.
  • Prevent the introduction of Gambusia holbrooki and remove it from occupied breeding water where authorised and practicable.
  • Manage cane toads and feral pigs in accordance with approved control plans, particularly where they damage wetland edges or compete with native frogs.
  • Apply amphibian hygiene procedures to rehabilitation equipment, footwear, vehicles and water handling.
  • Inspect rehabilitated wetlands for mosquito fish, cane toads, feral pig damage, nutrient enrichment, altered pH and invasive plants.

Rehabilitation actions: Fire and monitoring targets

  • Prepare a fire regime suited to the local wallum vegetation and protect swamps from inappropriate burning.
  • Use patchy burning only where supported by the fire management plan, retain unburnt refuge areas and maintain standing water if prescribed burning is undertaken.
  • Use the local approved fire interval because the supplied sources give different guidance, including 6 to 35 years in the NSW profile and a minimum fire-free interval of 8 to 10 years in the Brisbane action statement.
  • Monitor rehabilitation after rain and during the colder months for Wallum Froglet calls, adults, eggs or tadpoles, water persistence, pH, sedge and wet heath cover, refuge cover and connectivity.
  • Set success measures before works start, including stable wetland hydrology, no damaging sediment or nutrient inputs, suitable acidic water where naturally present, recruitment evidence and no new pest fish.
  • Continue monitoring until the environmental officer and relevant approval authority accept that wetland function, native cover and frog use are comparable with the agreed reference habitat.

Sources