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Rattling Nursery Frog (Cophixalus hosmeri)

The Rattling Nursery Frog is a very small, critically endangered microhylid frog restricted to cool, wet upland rainforest in Queensland. It is relevant on development sites because it uses moist forest-floor shelters and breeds in shallow burrows beneath logs or fallen epiphyte clumps, with no free-swimming tadpole stage.

Conservation status

Commonwealth, EPBC Act 1999: Critically endangered.

Queensland, Nature Conservation Act 1992: Critically endangered.

Breeding season

Rattling Nursery Frogs call and breed after rain during the warmer part of the year. Eggs are laid on land and develop directly into froglets, so clearing in moist spring to summer conditions can damage nests even where there is no open water.

Reproductive mode: Terrestrial egg laying with direct development. Tadpoles remain inside the egg and hatch as fully developed tiny frogs.

Clutch size: Seven to 11 eggs, described elsewhere as a small cluster connected by a thin jelly string.

Incubation or gestation: Not recorded.

Size at hatching or birth: Fully developed tiny froglets. No hatchling measurement is recorded.

Age at maturity: Not recorded.

Nest or egg sites: Shallow burrows beneath logs or fallen epiphyte clumps, and sites under leaf litter and vegetation.

Breeding frequency: Not recorded. Breeding is reported after rain during spring to summer.

Confirm timing locally before works by checking recent rainfall, night temperatures and moist shelter sites, because the available records do not provide a confirmed laying or froglet emergence schedule.

  • Calling: Males call from October to March, with peak calling in October and November. Calling is associated with rain or moist summer nights.
  • Egg laying: Egg laying is expected during the reported spring to summer breeding period after rain, from October to March for planning. Eggs are laid on land in shallow concealed sites beneath logs, fallen epiphyte clumps, leaf litter or vegetation, but exact laying months are not recorded.
  • Eggs in nest: There are no free-swimming tadpoles. Embryos develop inside eggs held in terrestrial nests, so eggs may be present during the October to March breeding window; development time is unknown.
  • Froglets: Froglets hatch from the eggs rather than leaving water. The emergence month is unknown, so October to March is a general planning window based on the breeding season, not a confirmed emergence schedule.
  • Active period: Activity is best expected on moist nights after rain during the warmer, wetter period from October to March. The documents specifically report calling activity, not a complete seasonal movement schedule.
  • Highest clearing risk: Risk is highest during the October to March wet-season breeding window, when calling males, eggs and newly hatched froglets may occur in shallow ground shelters. Habitat remains relevant year round because clearing can remove logs, epiphyte clumps, leaf litter and vegetation used for shelter and nesting.

Identification

The Rattling Nursery Frog is Australia’s smallest frog in the source material. It is usually located by listening for its call and then searching moist forest-floor cover, rather than by relying on eyeshine or tracks.

Adult males are about 11 to 14 mm long. The species is described as a tiny rainforest frog with a short, fast rattling call. Calling occurs on moist summer nights.

Adult male length: 11 to 14 mm

Field call: Short, fast rattle

Identification: Field detection

Search moist undergrowth, leaf litter and sheltered ground cover near suitable upland rainforest habitat. Listening surveys are particularly useful during moist summer nights, when calling males may reveal otherwise difficult-to-see frogs.

  • Approach quietly and search beneath logs and fallen epiphyte clumps only where authorised.
  • Replace any natural shelter immediately after inspection.
  • Do not handle frogs unless this is necessary for approved identification or fauna management.

Identification: Similar species and field signs

The supplied material does not provide a reliable visual comparison between Cophixalus hosmeri and other Cophixalus species. It also does not report tracks, scats, sloughs, eyeshine or other distinctive field signs for this species.

Treat a suspected record as requiring confirmation by an appropriately qualified amphibian ecologist, using the call, location and photographs or other approved evidence.

Distribution: Range

The Rattling Nursery Frog is known from a very restricted area of north Queensland. The supplied records identify the Carbine Tablelands and Queensland, but do not provide a mapped population boundary or a complete list of occupied subpopulations.

The species is reported from the Carbine Tablelands in the Wet Tropics of Queensland, above 940 m. The available material describes it as occurring in a small area of cool, wet rainforest.

State: Queensland

Bioregional setting: Wet Tropics, including the Carbine Tablelands

Known elevation: Above 940 m

Distribution: Strongholds and population status

The Carbine Tablelands are the only specific stronghold identified in the supplied material. No population estimate, density, number of occupied sites or confirmed subpopulation count is provided.

A structured assessment estimated a 20 per cent probability of extinction in the wild by 2040 under the assumptions used in that study. This is an extinction-risk estimate, not a population count.

Estimated extinction probability by 2040: 20 per cent, assuming no improvements beyond the management occurring at the time of assessment

Population size: Not reported in the supplied documents

Population trend: Not quantified in the supplied documents

Habitat: Rainforest setting

The species is associated with cool, wet upland rainforest on the Carbine Tablelands. Its breeding and sheltering sites are close to the forest floor, where moisture and intact ground cover are retained.

Habitat is described as cool, wet rainforest on the Carbine Tablelands above 940 m. Retention of intact rainforest structure and a moist microclimate is important because the species uses ground-level shelters for breeding and refuge.

Habitat type: Cool, wet upland rainforest

Elevation: Above 940 m

Key ground features: Logs and fallen epiphyte clumps

  • Protect intact upland rainforest within and adjoining proposed works areas.
  • Avoid removing logs, fallen epiphyte clumps and other moist ground cover unless an approved ecological procedure requires it.
  • Maintain shade and limit activities that dry or heat the forest floor.

Habitat: Site conditions

The supplied documents do not identify a particular vegetation association, canopy height, stream distance, soil type or minimum patch size. They do identify moist rainforest conditions and sheltered ground sites as relevant features.

Foraging habitat: Feeding habitat

Species-specific information on diet, prey, feeding height and foraging range is not provided in the supplied documents. The available material supports careful protection of the moist forest-floor environment used by rainforest frogs generally.

Rainforest frogs provide insect-control services, but the documents do not state which prey are taken by Cophixalus hosmeri or how far individuals forage. Do not assign a species-specific prey list or foraging distance without additional survey information.

  • Retain moist leaf litter, low undergrowth and natural shelter around potential records.
  • Avoid pesticide, herbicide and other chemical use near occupied or potential frog habitat because frog skin is permeable and some product additives can harm frogs and tadpoles.
  • Prevent sediment, contaminants and drying effects from entering retained rainforest habitat.

Foraging habitat: Survey implications

Search should focus on moist undergrowth and forest-floor cover, particularly during suitable wet summer conditions when males may be calling. The supplied material gives no feeding-activity period or foraging-range measurement.

Breeding habitat: Breeding biology

The Rattling Nursery Frog uses terrestrial reproduction rather than open water. Eggs are laid in shallow, concealed sites and the embryo completes development within the egg.

The female lays eggs in a shallow burrow beneath a log or fallen epiphyte clump. Parents remain close to the eggs and may apply an antibacterial and antifungal substance. The embryo develops through a tadpole stage inside the egg, but there is no free-swimming tadpole.

Breeding period: Moist summer nights are associated with calling; the documents do not give a confirmed laying window.

Clutch size: Seven to 11 eggs

Egg development: Direct development within the egg

Free-swimming tadpole: Absent

Incubation duration: Not reported

Age at maturity: Not reported

Lifespan: Not reported

Breeding habitat: Breeding habitat features

Breeding sites require shallow, concealed ground cavities beneath logs or fallen epiphyte clumps. These features should be treated as potential breeding habitat even when no open water is present.

  • Inspect suitable logs and fallen epiphyte clumps before disturbance, using an approved fauna survey and handling procedure.
  • Retain occupied and potential egg-laying shelters wherever practicable.
  • Avoid clearing or soil disturbance during moist summer conditions until breeding-habitat checks and required approvals are complete.

Sheltering habitat: Known refuges

Known sheltering habitat is on or near the rainforest floor. The species is very small, so apparently minor changes to cover and moisture can remove usable refuge or breeding sites.

The documented refuge and egg-laying sites are shallow burrows beneath logs or fallen epiphyte clumps. The documents do not provide refuge dimensions, burrow depth or daily movement distances.

Shelter type: Shallow burrows beneath logs or fallen epiphyte clumps

Shelter dimensions: Not reported

  • Retain fallen logs, epiphyte clumps, leaf litter and shaded undergrowth in retained habitat.
  • Do not stockpile cleared vegetation, spoil or machinery over potential shelters.
  • Keep exclusion zones around suspected occupied shelters until they have been assessed by a qualified person.

Sheltering habitat: Handling and hygiene

Chytrid fungus is a major threat to Australian upland frogs and can cause adult mortality. Site personnel should use approved amphibian hygiene procedures when moving between habitat areas or handling frogs, equipment or shelter materials.

  • Use project hygiene protocols designed to prevent transfer of chytrid fungus between sites and habitat patches.
  • Keep collected animals, equipment and footwear separate from clean areas until decontaminated under the approved procedure.

Threats: Disease and climate

The species has a small upland range and is exposed to threats that affect cool, moist mountain rainforest frogs. Chytrid disease and climate change are the main documented concerns, while clearing and construction can directly remove breeding shelters and alter the local microclimate.

Chytridiomycosis, caused by Batrachochytrium dendrobatidis, is a major threat to Australian upland frogs. Climate change is also a major threat to range-restricted montane frogs that depend on cool, damp conditions.

  • Apply strict amphibian hygiene controls across survey and construction activities.
  • Retain shaded, moist rainforest conditions around occupied and potential habitat.
  • Plan works to avoid unnecessary drying, heating or exposure of the forest floor.

Threats: Clearing and construction

Clearing can remove the logs, fallen epiphyte clumps, leaf litter and shallow ground cavities used for shelter and egg laying. Fragmentation or construction near retained forest can also reduce the cool, wet microclimate on which this upland species depends.

  • Map and avoid occupied records and potential breeding shelters before clearing.
  • Use staged clearing and fauna spotter catcher procedures where required by the approval or management plan.
  • Prevent spoil, sediment, fuels, chemicals and machinery from entering retained rainforest habitat.
  • Keep access tracks, laydown areas and drainage works out of moist ground-cover habitat wherever practicable.

Threats: Other threats

The national assessment identified habitat loss, invasive species and changed fire regimes among the threats affecting highly imperilled Australian frogs. The supplied documents do not identify a species-specific predator, road mortality rate or hydrology threshold for Cophixalus hosmeri.

  • Control project weeds and avoid chemical applications near potential frog habitat.
  • Prevent altered drainage, ponding or concentration of runoff from changing moisture conditions in retained rainforest.
  • Manage fire in accordance with site-specific ecological advice, avoiding impacts on cool, wet upland rainforest.

Survey methodology: 1. Call-based night searches

Survey this frog as a very small, range-restricted rainforest species. The supplied material identifies habitat above 940 m on the Carbine Tablelands, a short rattling male call on moist summer nights, and terrestrial breeding beneath logs or fallen epiphyte clumps.

Conduct searches on moist summer nights, when males are reported to call. Listen for the short, fast, rattling call and search the vegetation and ground surface around the calling location.

Use experienced amphibian surveyors who can distinguish the call from other nursery frogs. Record the position of each calling frog or calling cluster as accurately as practicable.

Adult male length: 11 to 14 mm

Known habitat in the supplied material: Cool, wet rainforest on the Carbine Tablelands above 940 m

Call timing: Moist summer nights

  • Search retained cool, wet rainforest above 940 m within and adjoining the proposed disturbance area.
  • Repeat searches under suitable moist conditions because the species is very small and may be missed during a single visit.

Survey methodology: 2. Visual and microhabitat searches

Search the undergrowth and forest floor carefully, particularly beneath logs and fallen epiphyte clumps. These are reported egg-laying sites for this species.

The species does not lay eggs in water and does not produce free-swimming tadpoles, so searches must not be limited to streams, pools or other open water.

Breeding site: Shallow burrows beneath logs or fallen epiphyte clumps

Development: The embryo develops inside the egg and hatches as a fully developed, tiny frog

Clutch size: Seven to 11 eggs

  • Inspect retained logs, fallen epiphyte clumps, moist litter and shallow ground shelter without damaging the feature.
  • Replace every log, epiphyte clump or other shelter exactly as found after inspection.
  • Use a torch and move slowly because an adult male may be only 11 to 14 mm long and newly hatched froglets are smaller.

Survey methodology: 3. Habitat and disease-aware survey practice

Map all suitable cool, wet upland rainforest and all breeding features within the work area, access routes, spoil areas and proposed clearing limits.

Treat disease hygiene as a survey requirement. Chytrid fungus has caused major mortality in Wet Tropics stream-dwelling frogs and is widespread across Australia, while the species occurs in a cool, wet upland environment.

  • Use clean, disinfected footwear, equipment and handling materials between sites in accordance with the project biosecurity procedure.
  • Do not move water, soil, leaf litter, logs or frogs between catchments or work areas unless this is authorised by the project fauna management plan.
  • Record survey date, start and finish time, weather, recent rainfall, observer names, search area, search conditions, call detections, visual detections and habitat features inspected.

Survey methodology: Minimum effort and reporting

The supplied documents do not provide a species-specific statutory survey effort, number of nights, transect length, trapping effort or area-based search requirement for Cophixalus hosmeri. Set the final effort through the applicable Queensland survey guideline, approval conditions and advice from the relevant wildlife authority.

  • Obtain and follow the current Queensland threatened-frog survey and handling requirements before fieldwork starts.
  • Use more than one suitable moist summer night where access, weather and approvals allow, and document any failure to achieve planned conditions or effort.
  • Submit all confirmed records, negative survey results where required, locations and associated evidence to the relevant Queensland wildlife database.
  • Report the record to the project ecologist and environmental officer immediately if it is inside the disturbance footprint or close enough to be affected by the works.
  • Retain call recordings, photographs, coordinates, habitat descriptions, effort logs and specimen or tissue records in the project file.

Before habitat disturbance: Avoid and minimise

The frog is listed as Critically Endangered under the EPBC Act and in Queensland. Treat suitable upland rainforest as potential habitat until a competent ecologist and the relevant authority determine otherwise.

Redesign the work to retain cool, wet rainforest above 940 m on the Carbine Tablelands, especially intact ground cover and the moist shelter features used for egg laying.

Retain logs, fallen epiphyte clumps, moist litter, shallow burrows and connected rainforest wherever practicable. Avoid fragmenting retained habitat with access tracks, compounds, drainage or spoil placement.

  • Keep machinery, vehicle parking, stockpiles, sediment controls and worker access outside retained habitat and identified breeding features.
  • Maintain connection between retained rainforest patches rather than creating isolated vegetation remnants.
  • Prevent sediment, chemicals, dust and altered drainage from entering retained moist rainforest or any adjoining wet areas.
  • Do not apply herbicides near frog habitat unless the method, product and weather conditions have been assessed and approved, because frog skin readily absorbs substances and some herbicide wetting agents can kill frogs and tadpoles.

Before habitat disturbance: Approvals and planning

Confirm the EPBC Act requirements before finalising the work footprint because the species is nationally listed as Critically Endangered. Confirm Queensland threatened-species permits, survey approvals and animal-handling requirements before any capture, disturbance or relocation.

National status: Critically Endangered under the EPBC Act

Queensland status: Critically Endangered

  • Obtain written advice on whether the project requires an EPBC referral or approval and retain the decision in the environmental records.
  • Include the species in the project fauna management plan, clearing plan, unexpected-find procedure and incident escalation process.
  • Nominate the authorised fauna spotter catcher, ecologist, wildlife carer and veterinary contact before clearing begins.
  • Stage clearing so that the pre-clearance survey, habitat-feature inspection, fauna management and progressive restoration can be completed before the next work area is opened.

Before habitat disturbance: Site preparation

Complete a targeted pre-clearance survey in suitable weather before disturbance, with particular attention to moist summer nights, calling males and breeding shelter beneath logs or fallen epiphyte clumps.

  • Mark the approved clearing boundary and all retained rainforest, logs, epiphyte clumps, shallow burrows and other potential breeding features before machinery enters.
  • Install and inspect exclusion fencing where it can keep people, machinery and sediment out of retained habitat without trapping frogs.
  • Brief all operators that a frog may be only 11 to 14 mm long and may be concealed beneath a retained habitat feature.
  • Keep a clean equipment and footwear washdown point available to reduce chytrid transfer between work areas.

During habitat disturbance: Daily controls and supervision

Use a stop, inspect and release process for all clearing and ground disturbance in potential habitat. A fauna spotter catcher must work within the approved management plan and only handle wildlife under the relevant authority and permit requirements.

Inspect exclusion fencing, clearing limits, sediment controls and retained habitat before work starts each day.

Maintain a fauna spotter catcher at the active clearing edge and ahead of machinery where the approval or fauna management plan requires it.

Use staged clearing and low-speed, controlled machinery movements so the spotter catcher can inspect ground shelter and direct the operator safely.

  • Stop machinery when the spotter catcher calls stop, when visibility is inadequate, or when clearing moves outside the marked boundary.
  • Do not allow workers to search independently, chase frogs, dismantle habitat features unnecessarily or enter retained habitat without authorisation.
  • Keep fuels, chemicals, wash water, spoil and waste away from retained rainforest and wet habitat.
  • Apply the project hygiene procedure before moving personnel, vehicles or equipment between frog habitat areas.

During habitat disturbance: Habitat feature handling

Inspect logs, fallen epiphyte clumps, moist litter and shallow burrows before they are moved or crushed. These features may contain eggs, froglets or adults.

Handle each feature as a habitat unit where practicable and place it in nearby retained, suitable rainforest approved by the ecologist.

  • Do not fill, drain, burn or compact shallow burrows or moist ground shelter until they have been inspected.
  • Do not move water, soil, litter or habitat features between catchments or unrelated work areas without approval and disease controls.
  • Treat any frog, eggs or occupied shelter as a stop-work matter until the authorised person has assessed the situation.
  • Record the original and release locations of any moved habitat feature or animal.

During habitat disturbance: If a frog is found

Stop work immediately within the animal's risk area and notify the fauna spotter catcher and project ecologist. Confirm the identification from the call, photograph or other evidence before recording it as this species.

Limit handling to an authorised and trained person. Use clean, disinfected equipment and handling materials, keep handling brief, and avoid unnecessary contact with the skin.

  • Release an uninjured frog into nearby retained, suitable cool and wet rainforest, at a location approved by the ecologist and outside the immediate work area.
  • Do not relocate the frog to a different catchment or distant site unless this is specifically authorised by the relevant wildlife authority.
  • Place an injured frog in a clean, suitable container and transfer it promptly to the nominated wildlife carer or veterinarian under the project procedure.
  • Keep people and machinery away from the release or treatment area until the authorised person confirms that work can resume.
  • Stop work and escalate if the species is found repeatedly, if eggs or a breeding site are found, if the approved habitat boundary is wrong, or if a threatened-frog permit, approval condition or hygiene control cannot be met.
  • Record date, time, coordinates, person who found it, identification evidence, condition, handling, release or treatment location, and the machinery and work area involved.

After habitat disturbance: Post-clearance checks

Close out each work area only after checking that no fauna management issue remains and that retained habitat controls are functioning. The species' small size and concealed terrestrial breeding sites make post-clearance inspection important.

Inspect the cleared edge, retained logs, fallen epiphyte clumps and adjoining moist rainforest after clearing and after major ground disturbance.

Check that no frog, egg clutch, froglet or occupied shelter has been buried, crushed, stranded or isolated by access tracks, drainage or fencing.

  • Remove temporary fencing only after the ecologist confirms that it will not direct frogs into the work area or prevent access to retained habitat.
  • Repair damaged exclusion fencing, sediment controls, drainage controls and retained habitat immediately.
  • Keep machinery and stockpiles out of retained habitat during construction and maintenance.

After habitat disturbance: Monitoring and reporting

Continue targeted monitoring where the approval, fauna management plan or project risk assessment requires it. Give priority to moist summer nights and retained habitat containing logs or fallen epiphyte clumps.

Compare post-work observations with the pre-clearance habitat map and survey records, while recognising that the supplied documents do not specify a standard post-construction monitoring duration or effort.

  • Submit confirmed records and required survey outcomes to the relevant Queensland wildlife database.
  • Provide the regulator, approval holder and project environmental officer with records of detections, injuries, deaths, relocations, stop-work events, hygiene incidents and corrective actions.
  • Report any unexpected population concentration, breeding site or repeated mortality promptly to the relevant wildlife authority.
  • Maintain an auditable register of clearing dates, areas disturbed, habitat retained, habitat moved, fauna interactions and rehabilitation progress.

After habitat disturbance: Offsets and ongoing controls

Check whether the approved action requires an offset, habitat protection measure or other compensatory action. Do not treat rehabilitation or relocation as a substitute for avoiding impacts to this Critically Endangered species.

Maintain weed, sediment, drainage, chemical and access controls for the life of the project where they protect retained habitat.

  • Keep retained rainforest and identified breeding features protected during later maintenance, inspections and utility access.
  • Review controls after heavy rain, fire, earthworks or changes to drainage that could dry or disturb the moist rainforest floor.
  • Escalate any failure to meet an approval condition or management-plan commitment as an environmental incident.

Rehabilitation actions: Restore rainforest structure and shelter

Rehabilitation should recreate cool, wet upland rainforest structure and protect the terrestrial breeding places used by this frog. The supplied documents do not identify particular plant species, so planting should use locally appropriate rainforest species specified by the rehabilitation ecologist.

Re-establish locally appropriate native rainforest vegetation from the relevant Carbine Tablelands community, using a design that restores shaded, moist ground conditions rather than an open grassed surface.

Retain and reinstate sound logs, fallen epiphyte clumps, moist litter and other natural ground shelter in positions that provide shallow, undisturbed breeding sites.

Do not create open ponds as the primary rehabilitation measure for this species because it lays eggs on land and the developing frog remains inside the egg rather than becoming a free-swimming tadpole.

Breeding habitat to reinstate: Shallow burrows beneath logs or fallen epiphyte clumps

Development type: Direct development inside the egg, without free-swimming tadpoles

  • Use clean soil, mulch and plant material that will not transfer chytrid, weeds or other pathogens between sites.
  • Stabilise disturbed soil and drainage without covering or compacting retained breeding shelter.
  • Maintain shade, ground moisture and continuous rainforest cover as vegetation establishes.

Rehabilitation actions: Control threats during recovery

Control weeds and prevent chemical use near retained or rehabilitated frog habitat. Frog skin is permeable, and the supplied material reports that wetting agents in some glyphosate products can kill frogs and tadpoles.

Manage feral animals, invasive species, fire and altered drainage where they threaten retained upland rainforest. Climate change and chytridiomycosis are recognised major threats to highly imperilled Australian frogs, including range-restricted montane species.

  • Keep rehabilitation areas free from machinery, stockpiles, sediment and uncontrolled vehicle access.
  • Use the approved fire regime for the rainforest community and do not burn retained or rehabilitated frog shelter without ecological and regulatory approval.
  • Prevent introduced fish from entering any constructed or natural water feature connected to the site, even though open water is not the breeding habitat described for this species.
  • Apply disease hygiene to all rehabilitation monitoring, maintenance and fauna handling.

Rehabilitation actions: Monitoring and success measures

Monitor survival and recruitment of planted rainforest vegetation, ground moisture, shelter features, weed cover, erosion, drainage and evidence of frog use.

Use repeat call searches on suitable moist summer nights and careful searches beneath logs and fallen epiphyte clumps, with effort and conditions recorded consistently.

  • Set success measures for retained and restored rainforest cover, functioning drainage, stable moist ground, intact breeding shelter and absence of project-related fauna deaths.
  • Record any rattling calls, adults, froglets, eggs or breeding shelters with coordinates, photographs or recordings and submit required records to the relevant Queensland wildlife database.
  • Continue corrective works until the rehabilitation area no longer exposes frogs to avoidable project threats and the approval holder accepts the monitoring results.
  • Review the rehabilitation plan if monitoring shows drying, loss of shelter, weed invasion, fire damage, chytrid concerns or a decline in detections.

Sources