Arcadia Velvet Gecko (Oedura lineata)

Conservation status

Commonwealth, EPBC Act 1999: Critically endangered.

Queensland, Nature Conservation Act 1992: Critically endangered.

Breeding season

The Arcadia velvet gecko is expected to lay one or two clutches of two eggs each year, but no breeding months, incubation period or young-of-year records are available. Plan clearing as a year-round risk, with particular care around mature brigalow stems, loose bark, cracks, holes and fallen timber.

Reproductive mode: Egg laying is expected, based on the reported similarity to other Oedura species.

Clutch size: Probably two eggs.

Incubation: Not recorded.

Size at hatching: Not recorded.

Age at maturity: About 1 to 2 years, with the expert assessment stating about two years.

Nest or egg sites: Not recorded. Mature brigalow stems, loose bark, holes, cracks and fallen timber may provide breeding sites and should be retained.

Breeding frequency: Assumed to be one or two clutches per year.

Confirm timing locally through targeted night surveys and local observations, and reassess after rainfall or temperature changes that may alter gecko activity.

• Mating: No mating months are recorded. All months are shown as possible for planning because breeding timing is unknown.
• Gravid females: No records identify when females carry eggs. Treat gravid females as possible in any month until local surveys provide better timing information.
• Egg laying: The species is expected to lay clutches of two eggs, with one or two clutches per year, but laying months are not recorded. All months are shown as possible rather than as a documented seasonal peak.
• Incubation: The incubation period and timing of eggs in nest sites are not recorded. Protect potential egg sites throughout the year because egg-laying timing is unknown.
• Hatchlings: Hatching and juvenile emergence have not been recorded. All months are treated as possible for planning, with no supported peak period.
• Active period: Individuals have been found at night on brigalow stems, branches and fallen timber, but no active season is recorded. Night activity is documented, while the monthly pattern is unknown.
• Highest clearing risk: Clearing risk is year-round because breeding timing is unknown and the species shelters behind bark and in holes and cracks in standing or fallen brigalow timber. Retain and inspect these features before disturbance in every month.

Identification

This is a medium-sized, slender velvet gecko with a distinctive pale striped pattern. It is most likely to be encountered at night on brigalow trunks, branches or fallen timber.

The Arcadia velvet gecko has a moderately depressed head and body, short limbs, a moderately long cylindrical tail and small granular scales. Its back has a yellowish background, a thin pale midline, white lines or spots along each side, and dark smudging or flecking forming a messy dorsolateral line.

Snout to vent length: Average 71 mm; recorded range 62 to 79 mm

Total length: Up to 130 mm

Body mass: Up to 9.93 g as a calculated estimate, not a weighed field measurement

Identification: Distinguishing pattern

The usual diagnostic feature is a V-shaped broken bar or Y-shaped pale marking on the nape. The marking may continue as two continuous or broken stripes down the front half of the back.

• Oedura elegans and Oedura monilis usually have an unbroken nape bar rather than a V or Y-shaped marking.
• Oedura tryoni usually has many spots or blotches rather than the linearly arranged streaks and spots of Oedura lineata.
• Oedura monilis has a lower interorbital scale count, usually 16 to 20 compared with 21 to 23 in Oedura lineata.

Identification: Field signs and handling

The species has been found at night perched on brigalow stems, branches and fallen timber. When disturbed, it retreats behind bark or into holes and cracks in timber.

• Do not rely on tracks, scats, calls, nests, sloughs or eyeshine for detection. The supplied sources do not report reliable field signs for this species.
• Record the exact tree or fallen timber feature where a gecko is found, and photograph the dorsal pattern before relocation or release.
• Treat a gecko found on a tree, branch or fallen log in brigalow as a potential Arcadia velvet gecko until it has been checked against the similar Oedura species.

Distribution: National range

The species is endemic to central Queensland and is known from only two isolated brigalow remnants in the Arcadia Valley. No confirmed populations are reported from elsewhere in Australia.

All known records are from Queensland, in the Arcadia Valley of central Queensland. The species is associated with the Brigalow Belt region, although the supplied documents do not provide a formal bioregion name for each record.

• The known range is restricted to Queensland.
• Surveys in surrounding brigalow regrowth, non-brigalow woodland and nearby areas have not located the species.
• Further targeted survey is warranted in small brigalow fragments in the central and southern Arcadia Valley, brigalow north of the valley, brigalow remnants east of the valley, and small remnants between the two known sites.

Distribution: Known strongholds

One subpopulation occurs in the Lonesome section of Expedition National Park, where targeted surveys in November 2022 found the species at moderate density. The other is in Nuga Nuga National Park, where targeted surveys in November 2022 did not detect it.

• The Expedition National Park, Lonesome section remnant is about 7 km2.
• The Nuga Nuga National Park remnant is about 2 km2.
• The two known habitat patches are about 54 km apart and separated by cleared grazing land.
• The species may now be extinct at Nuga Nuga National Park, but further surveys are required before drawing that conclusion.

Distribution: Population information

There is no reliable measured population size or trend. A rough estimate based on 20 mature individuals per hectare suggested about 18,000 mature individuals across 9 km2 of remaining habitat, but recent surveys indicate that this estimate may be inaccurate because density at Nuga Nuga National Park appears very low or the species may be absent.

Estimated extent of occurrence: 61 km2

Estimated area of occupancy using 2 km grids: 16 km2

Estimated remaining potential habitat at the two known sites: About 9 km2

Known subpopulations: Two, although one may no longer persist

Population trend: Unknown; future declines are inferred if severe wildfire removes habitat

Habitat: Vegetation and structure

The Arcadia velvet gecko appears to be restricted to mature, thick brigalow forest. Its habitat is defined by standing woody structure and fallen timber, not simply by the presence of young brigalow regrowth.

Known habitat consists of tall, fairly closed-canopy brigalow forest and mixed brigalow forest communities. The species has not been found in adjacent young brigalow regrowth, surrounding non-brigalow woodlands or rock outcrops.

• Retain mature brigalow stems, branches, standing dead timber, fallen timber and loose bark during site planning and clearing.
• Inspect mature brigalow forest edges as well as the interior, because both known remnants are surrounded by cleared grazing land and are exposed to edge-related fire entry.
• Do not treat young brigalow regrowth as equivalent to occupied mature habitat without targeted survey evidence.

Habitat: Climate and elevation

The known sites are in central Queensland at about 400 m elevation. The supplied sources do not define upper or lower climatic limits, preferred temperature or a broader elevation range.

Known elevation: About 400 m above sea level

Habitat context: Small, isolated brigalow forest remnants within a largely cleared grazing district

Foraging habitat: Diet and feeding

The species is a nocturnal arboreal gecko. Detailed feeding observations are not available, but it is expected to feed on insects and other arthropods in and around brigalow vegetation.

There are no species-specific data on feeding ecology. The conservation assessment states that it is probably similar to other Oedura species, feeding largely on insects and other arthropods.

Diet: Probably insects and other arthropods; species-specific feeding data are unavailable

Feeding period: Likely at night, consistent with the species' nocturnal activity

Foraging range: Unknown

• Inspect brigalow trunks, branches and fallen timber at night when searching for active geckos.
• Avoid assuming that a gecko on a tree is feeding. The available evidence confirms nocturnal perching but does not describe prey capture or feeding rates.
• Retain woody structure and bark refuges that may support both the gecko and its arthropod prey.

Breeding habitat: Breeding biology

The breeding biology of the Arcadia velvet gecko is poorly known. The available assessment provides only an expected clutch size and an estimated number of clutches per year.

There are no confirmed data on breeding season, sexual maturity, incubation, lifespan or natural mortality. The species is assumed to be similar to other Oedura species in laying clutches of two eggs, with females possibly producing one or two clutches per year.

Breeding season: Unknown

Clutch size: Probably two eggs, based on comparison with other Oedura species

Clutches per year: Assumed to be one or two

Incubation period: Unknown

Age at maturity: Unknown

Lifespan: Unknown

Breeding habitat: Breeding habitat features

The habitat features needed for nesting have not been documented. Mature brigalow stems, fallen timber, bark, holes and cracks are important refuge features and should be retained because they may also provide breeding sites.

• Avoid removing mature woody debris or stripping loose bark from retained brigalow trees.
• If clearing is unavoidable, have a qualified fauna spotter catcher inspect bark, cracks, hollows and fallen timber before disturbance.
• Do not assume that the absence of visible eggs indicates that a feature is unused, because breeding sites and egg-laying timing are unknown.

Sheltering habitat: Known refuges

The species shelters in woody brigalow features. It retreats behind bark or into holes and cracks when disturbed, and may depend on the larger stems and fallen wood present in mature forest.

At night, individuals have been found on brigalow stems, branches and fallen timber. When disturbed, they retreat behind bark or into holes and cracks in timber.

• Inspect loose bark, tree cracks, cavities and fallen timber before felling, pushing or relocating woody debris.
• Retain standing mature brigalow stems and large fallen timber wherever practicable.
• Use slow, staged clearing and allow a spotter catcher to check each woody feature immediately before disturbance.
• Do not move occupied logs or dismantle bark refuges unless this is part of an approved fauna management procedure.

Sheltering habitat: Feature size and availability

The sources do not provide measurements for shelter diameter, crack width, tree size or fallen-log size. Surveys did not find the species in young regrowth, which may indicate a need for the larger stems and fallen wood found in mature brigalow forest.

Known shelter type: Bark, holes and cracks in brigalow timber, including standing stems and fallen wood

Measured refuge dimensions: Not available

Most suitable documented structure: Larger stems and fallen wood in thick mature brigalow forest

Threats: Clearing and fragmentation

The main development-related risks are loss of mature brigalow habitat, isolation of remnants and fire entering fragmented forest. A single severe fire may affect either remaining subpopulation and remove suitable habitat for years.

More than 99 percent of the former brigalow forest in the Arcadia Valley has been cleared, mainly for cattle grazing. The remaining habitat is restricted to two small, isolated patches separated by about 54 km of cleared pasture.

• Avoid clearing mature brigalow forest, including standing dead timber, fallen timber and edge vegetation.
• Survey small brigalow remnants rather than assuming they are unoccupied because they are isolated or small.
• Treat the two known remnants as one highly vulnerable management unit when assessing cumulative clearing and fire risk.

Threats: Fire and weeds

Fire is identified as the most severe current threat. Moderate or high intensity fire entering from adjacent forest or grazing land could reduce or temporarily remove habitat, and a single fire could potentially destroy a remaining subpopulation.

• Prevent construction activities, machinery and temporary works from increasing ignition risk at remnant edges.
• Manage fire entry points and buffel grass where authorised, because buffel grass can carry fire into brigalow.
• Plan works to avoid creating continuous fine fuels between cleared areas and brigalow remnants.
• Remember that even if brigalow suckers after fire, the standing stems, foliage and ground debris used by the gecko may be unavailable for years.

Threats: Predators and other pressures

Feral cat predation is a potential threat because cats commonly prey on Australian reptiles, although its impact on this species has not been measured. The supplied sources do not identify disease, road mortality or hydrology change as documented threats.

• Control domestic and feral cat access to occupied remnants where this is part of an approved site or reserve management program.
• Record any cat detections, carcasses or predation evidence near occupied habitat.
• Do not infer that roads, disease or altered drainage are harmless. Assess them site by site, but distinguish observed impacts from threats not documented for this species.

Survey methodology: 1. Targeted night spotlighting

Arcadia velvet geckos are nocturnal, arboreal reptiles associated with mature brigalow forest. The available documents do not provide a formal species-specific survey guideline or prescribed survey effort, so project surveys should target night activity on mature brigalow stems, branches and fallen timber, with additional effort where habitat is difficult to inspect.

Survey after dark when geckos are active on brigalow stems, branches and fallen timber.

Search mature, fairly closed-canopy brigalow forest and mixed brigalow forest first, because the species has only been found in these habitats.

Inspect tree trunks, branches, fallen timber, bark, holes and cracks where geckos may perch or retreat when disturbed.

Use a slow, systematic search by experienced observers and record the search route, start and finish times, weather, habitat condition and all detections.

Give additional attention to mature stems and fallen wood because the species may require these features for refuge; it has not been detected in adjacent young brigalow regrowth.

Activity: Nocturnal

Typical adult snout to vent length: 62 to 79 mm, with an average of 71 mm

Total length: Up to 130 mm

• There is no published species-specific number of spotlighting nights or hours in the supplied documents.
• Repeat night searches across suitable retained habitat rather than relying on one visit, particularly where the habitat patch is small, isolated or affected by fire, weeds or clearing.
• Use photographs and diagnostic features to confirm records where capture is unnecessary, including the yellowish back, pale midline, linear dorsal markings and V-shaped or Y-shaped white nape marking.

Survey methodology: 2. Habitat-led searches

Map and search every mature brigalow patch, including narrow remnants, regrowth edges and small fragments between larger patches.

Search habitat that connects or lies between known or potential patches, because the two known subpopulations are separated by 54 km of cleared grazing land and small intervening remnants may still be significant.

Extend searches to brigalow remnants in the central and southern Arcadia Valley, brigalow north of the valley and remnants east of the valley when the project is in or near those areas.

Do not exclude a site solely because a previous search was negative, because the species was not found at Nuga Nuga National Park in a targeted November 2022 survey but may not yet be extinct there.

Known sites: Expedition National Park, Lonesome section, and Nuga Nuga National Park

Known brigalow patch sizes: About 7 km² at Lonesome and about 2 km² at Nuga Nuga

Estimated extent of occurrence: 61 km²

Estimated remaining potential habitat: About 9 km² across the two known patches

• Record the area searched in hectares or square metres, the length of each transect, the number of observers and the number of nights and hours searched.
• Record absence results separately from habitat observations, including whether mature stems, fallen timber, bark refuges and cracks were present and searchable.
• Inspect adjacent non-brigalow woodland, rock outcrops and young regrowth when required by the approval or risk assessment, while recognising that previous searches in these habitats did not find the species.

Survey methodology: 3. Detection and handling during survey

Treat a gecko seen on a stem, branch or log as a potential Arcadia velvet gecko until it has been identified against nearby Oedura species.

Check the V-shaped or Y-shaped white nape marking and the linear dorsal streaks, spots and dark markings, because Oedura elegans, O. monilis and O. tryoni occur nearby and may be confused with this species.

Avoid dislodging animals from bark, holes or timber during searches.

Use non-invasive photography where possible and retain location coordinates, date, time, observer, habitat, perch type and identification confidence.

• Do not collect or relocate an animal during a survey unless the person is authorised under the relevant permit and project fauna management plan.
• If capture is necessary for confirmation, use the least stressful method available and release the animal promptly in the same retained habitat unless an approved relocation procedure applies.
• Record whether the animal was on a live brigalow stem, branch or fallen timber, because these features are relevant to habitat management.

Survey methodology: Minimum effort and reporting

• Use targeted night searches over all mature brigalow habitat that may be disturbed, with repeat visits where detection conditions, access or habitat visibility are poor.
• Document the actual effort, including dates, months, nights, search hours, observers, transect lengths, area searched, weather and habitat condition; do not report an absence without describing this effort.
• Plan surveys for the local period when nocturnal reptiles are active, and use November as an example of a documented survey month rather than as a prescribed survey window.
• Submit confirmed records, photographs and negative survey results to the relevant Queensland or other state wildlife database and to the project approval record.
• Escalate any detection, suspected detection or material habitat discrepancy to the project ecologist and approval holder before clearing proceeds.
• Check the current state survey and threatened species requirements before fieldwork, because the supplied documents do not include a formal survey guideline for this species.

Before habitat disturbance: Avoid and minimise

Avoiding loss of mature brigalow is the safest project measure. The species is known from only two isolated subpopulations, and a single severe fire could potentially affect either remaining patch.

Known separation between subpopulations: About 54 km of cleared grazing land

Historical habitat loss in the Arcadia Valley: More than 99% of brigalow forest cleared; remaining brigalow-dominated vegetation is less than 1% of former extent in the area

• Redesign the activity to retain mature brigalow forest, especially fairly closed-canopy patches with large stems, branches, bark refuges, holes, cracks and fallen timber.
• Keep all known or detected habitat outside the disturbance footprint and protect the smallest intervening brigalow remnants where practicable.
• Maintain vegetated links between retained brigalow patches where they exist, and avoid creating additional cleared edges through the habitat.
• Do not clear young regrowth or non-brigalow habitat as a substitute for retaining mature brigalow, because the species has not been detected in adjacent young regrowth, surrounding non-brigalow woodland or rock outcrops.
• Prevent additional fire-prone edges and buffel grass spread around retained brigalow.

Before habitat disturbance: Approvals and project planning

EPBC status: Critically Endangered, effective from 21 December 2023

Queensland status: Critically Endangered

• Check whether the proposed action requires referral under the EPBC Act because the Arcadia velvet gecko is listed as Critically Endangered nationally.
• Check Queensland or other relevant state threatened species, wildlife handling and clearing requirements before survey, capture, relocation or clearing.
• Obtain advice on the applicable state wildlife database and reporting obligations for the project location.
• Prepare a fauna management plan that identifies retained brigalow, no-go areas, survey effort, fauna spotter catcher authority, handling limits, relocation sites, stop-work triggers and incident reporting.
• Stage clearing so that retained habitat is protected before machinery enters the site and so that unexpected detections can be managed without rushing.

Before habitat disturbance: Site preparation

• Complete the pre-clearance survey and mark the approved disturbance boundary, retained brigalow, mature stems, fallen timber and other habitat features before machinery arrives.
• Use visible exclusion fencing or equivalent no-go controls where these controls can be installed without damaging retained brigalow or its root zone.
• Brief machinery operators and supervisors on the species identification features, habitat controls, daily inspection process and stop-work procedure.
• Inspect retained habitat for buffel grass, fire entry points and conditions that could carry fire into the patch, then include controls in the site fire plan.
• Confirm the release or holding arrangements for any animal found, including the authorised handler, nearby retained habitat and veterinary or wildlife carer contacts.

During habitat disturbance: Daily controls

Clearing should proceed only within the approved footprint and under direct fauna supervision where required. The main operational risk is loss of standing brigalow, fallen timber and bark refuges through clearing or fire.

• Inspect exclusion fencing, no-go markers, access routes and retained brigalow before work starts each day.
• Keep machinery, vehicles, spoil, fuels and temporary materials outside retained habitat and marked exclusion areas.
• Prevent ignition sources and uncontrolled fire from entering brigalow, and stop work if smoke, fire or a fire-weather event threatens retained habitat.
• Remove or control buffel grass and other fine fuels only under an approved method that does not damage retained brigalow or its refuges.
• Keep a fauna spotter catcher, supervisor and machinery operator in direct communication while habitat is being disturbed.

During habitat disturbance: Fauna spotter catcher and machinery

• Use the fauna spotter catcher to inspect each work area immediately before disturbance and to watch stems, branches, bark, holes, cracks and fallen timber as they are approached.
• Direct the operator to stop, hold position and wait for instructions whenever the spotter catcher identifies a gecko, potential gecko or habitat feature that needs inspection.
• Clear vegetation progressively and slowly enough for the spotter catcher to inspect exposed surfaces and retreat sites before machinery moves on.
• Do not allow machinery to crush or drag retained logs, standing stems or bark features outside the approved footprint.
• Only an appropriately authorised person should capture, handle or relocate the animal.

During habitat disturbance: If an animal is found

• Stop work in the immediate area and establish a quiet exclusion zone around the animal and its refuge.
• Photograph and identify the animal where this can be done without handling it.
• Do not chase an animal into a crack, hole or bark refuge, and do not handle it unless the authorised fauna handler considers handling necessary and lawful.
• If relocation is approved, move the animal to nearby retained brigalow habitat with comparable stems, bark refuges and fallen timber, following the project fauna management plan and permit conditions.
• Take an injured animal to a veterinarian or authorised wildlife carer as soon as practicable, and record the injury, location, treatment and outcome.
• Resume work only after the authorised fauna handler and project ecologist confirm that the stop-work trigger has been cleared.

During habitat disturbance: Stop-work triggers and records

• Stop work if an Arcadia velvet gecko is found, if the species cannot be confidently ruled out, or if clearing is outside the approved footprint.
• Stop work if exclusion fencing or habitat markers fail, if machinery threatens retained brigalow, or if fire enters or threatens the habitat patch.
• Record every detection, attempted detection, relocation, injury, death, escape, fire event and breach of the fauna management plan.
• For each record, include date, time, coordinates, habitat, perch or refuge feature, photograph, identification, handler, action taken and final outcome.
• Notify the project ecologist, environmental officer and approval holder promptly, then report incidents to regulators where approval conditions require it.

After habitat disturbance: Post-clearance checks

Post-clearance work should confirm that retained brigalow and its habitat features remain intact. Monitoring should focus on whether the retained patch continues to provide mature stems, fallen timber and low-fire-risk conditions.

• Complete a final inspection of the disturbance boundary, retained brigalow, marked habitat features and exclusion controls.
• Search the cleared edge and retained habitat for injured, displaced or trapped geckos and report any animal under the project fauna procedure.
• Check that clearing has not removed standing stems, branches, fallen timber, bark refuges, holes or cracks from retained habitat.
• Remove temporary materials and repair damaged exclusion fencing without entering or disturbing retained habitat unnecessarily.
• Record the final cleared area, retained area, habitat condition and all fauna incidents.

After habitat disturbance: Monitoring and reporting

Documented survey result requiring follow-up: Targeted surveys in November 2022 found moderate density at Lonesome but did not find the species at Nuga Nuga

• Repeat targeted night searches in retained mature brigalow where required by the approval, fauna management plan or risk assessment.
• Use the same search areas, route descriptions and recording fields as the pre-clearance survey so results can be compared.
• Monitor buffel grass, fire entry points, canopy condition, standing stems and fallen timber around the retained patch.
• Report confirmed records and monitoring results to the relevant state wildlife database and to the approval holder.
• Update the risk assessment if the gecko is detected outside the expected area, if a subpopulation appears absent, or if retained habitat is damaged.

After habitat disturbance: Controls and offsets

• Maintain no-go areas, fire controls, weed controls and access restrictions for as long as specified in the approval or fauna management plan.
• Apply any approved offset or compensatory habitat measure only in accordance with the EPBC decision, Queensland requirements and project conditions.
• Do not treat an offset as a substitute for retaining mature brigalow habitat within the project area where avoidance is practicable.
• Keep survey, clearing, handling, incident, monitoring and rehabilitation records together for audit and future site management.

Rehabilitation actions: Rebuild brigalow habitat

Rehabilitation should rebuild mature brigalow habitat structure and reduce the threats identified for the species. Recovery will take time because the gecko has been associated with thick brigalow forest and may require larger stems and fallen wood for refuge.

Known habitat: Thick brigalow forest and mixed brigalow forest

Known refuge features: Brigalow stems, branches, fallen timber, bark, holes and cracks

• Replant or encourage regeneration of brigalow and mixed brigalow forest using locally appropriate provenance and an approved restoration design.
• Prioritise dense, closed-canopy structure and the development of stems, branches, bark refuges and fallen timber rather than relying only on ground cover.
• Retain naturally fallen timber where safe, and place salvaged logs only where they will not create a fire, access or safety hazard.
• Do not clear regenerating brigalow during routine maintenance unless the action is approved and its effect on future gecko habitat has been assessed.

Rehabilitation actions: Fire, weeds and predators

• Manage buffel grass and other fine fuels at habitat edges so fire is less likely to carry into retained or rehabilitated brigalow.
• Use a fire management plan that recognises that even moderate fire can remove the standing foliage, stems and ground debris used as gecko habitat.
• Avoid high-intensity fire in retained and rehabilitated brigalow, because fire can kill brigalow and remove suitable habitat for years even where suckering occurs.
• Monitor for feral cats and apply approved predator management where required, because feral cat predation is a potential threat to Australian reptiles and its effect on this species is unknown.
• Control weed invasion without damaging mature stems, fallen timber or other refuges.

Rehabilitation actions: Monitoring and success measures

• Monitor plant survival, brigalow regeneration, canopy development, stem and fallen-timber availability, buffel grass cover, fire damage and feral cat activity.
• Use repeat nocturnal searches to test whether rehabilitated areas are developing the mature brigalow structure associated with the species.
• Set success measures in the rehabilitation plan for retained and regenerating brigalow area, survival of plantings, weed and fuel control, fire incidents and habitat-feature retention.
• Do not claim habitat recovery from planting alone; assess whether the site has developed the mature stems, branches, bark refuges and fallen timber used by the species.
• Submit confirmed detections and monitoring results to the relevant state wildlife database and retain them with the project rehabilitation records.

Sources

• THREATENED SPECIES SCIENTIFIC COMMITTEE, Australian Government DCCEEW: http://www.environment.gov.au/biodiversity/threatened/species/pubs/91704-conservation-advice-21122023.pdf
• Arcadia velvet gecko (Oedura lineata), All Angles Creatures, allanglescreatures.com: https://www.allanglescreatures.com/species/oedura-lineata