Orange Leaf-nosed Bat (Rhinonicteris aurantia)

Conservation status

Commonwealth, EPBC Act 1999: Vulnerable.

Queensland, Nature Conservation Act 1992: Vulnerable.

Western Australia, Biodiversity Conservation Act 2016: Vulnerable.

Northern Territory, Territory Parks and Wildlife Conservation Act 1976: Near threatened.

Breeding season

Timing differs between northern monsoonal populations and the arid Pilbara form. The Pilbara pattern below is the most relevant guide for works in Western Australia, while northern populations may use roosts differently during the wet season.

Surveys and work planning should account for year-round roost use, the physiological sensitivity of the species and local differences between Pilbara, Kimberley, Northern Territory and Queensland populations.

• Breeding: Mating occurs around July, during the dry season. In the Pilbara, breeding is thought to occur in year-round roosts.
• Young: Births usually begin in December or January. Young are independent by late February, although non-volant young have been reported in early March.
• Roost contraction and movement: In the Pilbara, bats contract into the deepest roosts during the hottest and driest period, approximately August to December. In northern populations, many bats may leave some large caves during the wet season from November to February.
• Highest clearing risk: The highest risk is December to March, when births, lactation and dependent young occur, with additional risk from August to December when Pilbara bats are concentrated in relatively few deep roosts. Disturbance to roosts can be harmful in any month.

Identification

This bat is distinctive when seen closely or recorded with a suitable bat detector. Identification should rely on several features because pale fur and brief flight views can be confused with other small bats.

It is a small bat with short fur, small pointed ears and a fleshy, diamond-shaped noseleaf surrounding the nostrils. Fur is usually bright orange, lighter on the belly and chest, but individuals or whole colonies can be pale orange, pale yellow, white, pale grey, light brown, lemon or fawn. The wing membranes are dark brown. Males and females are generally similar in size and external appearance.

Weight: 6.5 to 11.2 g reported in Queensland guidance, with other sources reporting 8 to 11 g or about 9.5 g.

Forearm: 45 to 50 mm.

Noseleaf: Diamond-shaped, with a scalloped upper part.

Identification: Separating similar bats

In the Pilbara, a captured bat with a noseleaf is readily identified because there are no other small local bats with the same feature. In northern Australia, the diamond-shaped noseleaf separates it from northern leaf-nosed bats, Hipposideros stenotis, which have a more square-shaped noseleaf. The Orange Leaf-nosed Bat has shorter, higher-frequency pulses than H. stenotis.

In a spotlight beam, orange fur and agile, low flight can suggest the species, but pale individuals may not be separable by sight. Confirm records with acoustic analysis where possible.

Pilbara call: CF-FM call with a characteristic frequency usually about 117 to 125 kHz, with an average near 121 kHz.

Northern call: Usually about 109 to 117 kHz, up to 10 kHz lower than the Pilbara form.

Pulse: A constant-frequency component lasting about 5 to 8 milliseconds, followed by a steep downward frequency-modulated sweep of about 20 kHz.

Identification: Field signs and survey recognition

The most useful field sign is the distinctive echolocation call. Calls have a short CF component followed by a downward FM sweep and can be identified from good-quality full-spectrum recordings. The species flies in a sinuous, zigzagging pattern, often within a few centimetres to 3 m of the ground, and may approach small light sources such as a headtorch.

Guano, urine staining and other signs may occur at cave or mine roosts, but daytime entry can cause abandonment. Night visitation at a cave entrance does not by itself prove that the structure is a daytime roost.

• Use passive detectors overnight at potential roost entrances, pools, gullies, gorges and rocky outcrops.
• For active monitoring, walk likely habitat for at least 2 hours after sunset with a recording bat detector.
• Do not trap cave or mine entrances simply to confirm presence. If capture is required for another approved purpose, harp traps are preferred and must be monitored closely.

Distribution: National range

The species is endemic to Australia. The Pilbara form is an isolated population separated from northern populations by the Great Sandy Desert, while the species as a whole extends across several northern Australian regions.

Rhinonicteris aurantia occurs in the Pilbara and Kimberley regions of Western Australia, the Top End and Gulf country of the Northern Territory, and north-western Queensland. The Pilbara form occurs through the Pilbara and adjoining parts of the Ashburton and Little Sandy Desert bioregions.

Within the Pilbara, records are concentrated in rocky country with caves or abandoned underground mines. Records also occur along drainage lines and in some flat areas, but detection is generally lower away from rocky outcrops.

Western Australia: Pilbara, adjoining Ashburton and Little Sandy Desert areas, and Kimberley populations.

Northern Territory: Top End and parts of the Gulf of Carpentaria region.

Queensland: North-west Queensland near the Northern Territory border, including the Camooweal and Lawn Hill areas.

Biogeographic separation: Pilbara and northern populations have been isolated across the Great Sandy Desert for many thousands of years.

Distribution: Strongholds and population information

Known Pilbara strongholds include natural caves in the Hamersley Ranges and eastern Pilbara, caves in Barlee Range Nature Reserve, rocky uplands of Karlamilyi National Park, and disused gold and copper mines in the eastern Pilbara. The species may appear widespread because individuals visit many caves and forage over broad areas, while detections can come from one or a few roosts.

Population trend is unknown. The IUCN assessment describes colonies from a few individuals to several thousand, with typical colonies ranging from a few individuals to the low hundreds. Only two large colonies were known at the time of that assessment, and the larger historical counts were not verified with robust counting methods.

Pilbara permanent roosts: The 2022 review reported 48 confirmed permanent category 1 and 2 diurnal roost sites, with a further 17 known and 31 predicted sites yet to be found.

Pilbara roost types: Thirty-eight known or suspected permanent roosts were in natural caves in banded iron formations, six were in disused underground gold or copper mines, and four were not yet defined.

Colony size: Reported colonies range from a few individuals to several thousand. Typical colonies are from a few individuals to the low hundreds.

Population trend: Unknown.

Habitat: Roosting and broader habitat

The species is limited more by access to suitable subterranean roost microclimates than by one particular vegetation community. Foraging records occur across open and wooded habitats, but roosting and nearby flight paths are the main considerations for development assessment.

The bat uses caves, rock fissures and disused underground mine workings in rocky country. Important Pilbara settings include banded iron formations of the Hamersley Ranges, granite boulder piles and greenstone ranges in the eastern Pilbara, and folded silcrete formations near the southern Pilbara. Deep structures that remain warm and humid are most suitable.

The species can occur in flat terrain, especially along medium and major drainage lines radiating from rocky uplands, but records are less likely more than a few kilometres from rocky outcrops that contain caves. Shallow caves may be used seasonally or as night refuges, while deeper structures support year-round occupation.

Dry-season roost conditions: About 28 to 32 degrees Celsius and 85 to 100 percent relative humidity are reported for suitable cave roosts.

Important geology: Banded iron formations, granite boulder piles, greenstone ranges, folded silcretes and suitable abandoned underground mines.

Roost access: Structures may be entered at night without being used as daytime roosts, so entrance detection alone does not confirm roost occupancy.

Habitat: Vegetation and climate setting

Foraging habitat includes open savannah woodland, sparse tree and shrub savannah, hummock grassland, spinifex grassland, open forest, monsoon rainforest, mangroves, palm forest, black soil grassland, gullies, gorges and watercourses. In the Pilbara, pools in rocky gullies, gorges and larger watercourses are regular detection locations.

In the arid Pilbara, the bat contracts into the deepest roosts during the hottest and driest period, when shallower structures may not retain suitable humidity. In wetter periods, more shallow caves and temporary refuges may become available.

Foraging habitat: Diet and feeding behaviour

The Orange Leaf-nosed Bat catches insects in flight. It commonly forages close to roosts, over water and along drainage features, but may travel several kilometres and possibly at least 10 km from a day roost.

The diet is mainly moths and beetles, with other insects taken opportunistically. Short-term termite emergences and other seasonal insect concentrations may also be important. The species forages in open air around vegetation rather than gleaning from foliage.

Bats emerge after dusk, often later than Finlayson's Cave Bat and the Common Sheath-tailed Bat when they share a roost. Some individuals remain near the entrance for about 2 hours, repeatedly entering and leaving, possibly feeding on insects around the entrance or following other bats.

Main prey: Moths and beetles.

Seasonal prey: Termites and other insects during short-term emergences.

Flight height: Usually within a few metres of the ground, sometimes within centimetres of the ground and commonly up to 2 to 3 m.

Flight style: Highly agile, with a sinuous zigzag pattern of turns.

Foraging habitat: Foraging areas and range

Regular foraging settings include gullies, gorges, rocky pools, larger watercourses, open woodland and hummock grassland. Watercourses and pools can be important survey locations even where no day roost is present.

The 2022 review found that the species is more commonly recorded within 20 km of permanent diurnal roosts. Other evidence indicates a nightly flight range of at least 10 km and possibly more, so clearing or lighting projects should assess habitat well beyond the roost entrance.

Common detection distance: More commonly encountered within 20 km of permanent diurnal roosts.

Potential nightly range: At least 10 km and possibly more.

• Retain connected flight paths between known or potential roosts, drainage lines, pools and open foraging areas.
• Assess low-level flight risk where new roads, haul roads, lighting or power infrastructure cross routes between rocky roosting areas and watercourses.
• Do not treat a lack of roost detection at a detector site as evidence that nearby foraging habitat is unused.

Breeding habitat: Breeding biology

Breeding depends on stable subterranean roost conditions and access to suitable humid sites during pregnancy, birth and lactation. Breeding details are best documented for northern populations, with the Pilbara cycle assumed to be similar but less well studied.

The species has a seasonally monoestrous breeding cycle. Mating occurs during the dry season, and females give birth during the wet season when insect availability is higher. In the Pilbara, breeding is thought to occur in roosts occupied throughout the year, although some caves become unsuitable during the hottest and driest months.

In the Northern Territory, females leave some known mating roosts during late pregnancy, birth and weaning, and maternity roosts have not been confirmed. This does not establish tree roosting, which has not been confirmed in any population.

Mating: Around July, or during the dry season.

Litter size: One young.

Gestation: About 150 days.

Births: Usually December or January, with non-volant young also reported in early March.

Female maturity: About 7 months.

Male maturity: About 16 months.

Life expectancy: Unknown, but estimated at about 10 years.

Breeding habitat: Breeding habitat requirements

Breeding sites need warm, humid, stable subterranean conditions that reduce water loss. Deep caves and mine workings are particularly important in the Pilbara because the species cannot enter torpor and loses water rapidly.

Pregnant and lactating females may be especially sensitive to disturbance. Entry into an occupied roost can cause a mass exodus or abandonment, which may expose bats to less suitable microclimates and increase mortality risk.

Generation length: Expected to be about 6 years.

Breeding roost pattern in the Pilbara: Breeding is thought to occur in roosts where bats are present year-round.

• Treat a confirmed or suspected diurnal roost as a breeding site unless qualified survey evidence shows otherwise.
• Avoid cave or mine entry, trapping and noisy works at roost entrances, particularly from late pregnancy through weaning.
• Assess nearby drainage, seepage and groundwater conditions because humidity within some temporary roosts depends on water availability.

Sheltering habitat: Day roosts

Day roosts are mainly caves and abandoned underground mines with restricted, humid internal chambers. The species also uses temporary night refuges and shallower structures, but these may not support breeding or year-round survival.

The bat roosts in colonies on cave or mine ceilings, with individuals maintaining small territories and spacing of about 12 to 15 cm. In the Pilbara, confirmed permanent roosts include natural caves in banded iron formations and disused gold and copper mines. Some natural caves have narrow internal spaces or constrictions that may help retain the required microclimate and limit access by predators.

Deep structures are most important during the hot, dry period from about August to December. Caves that are too shallow, dry, flooded or unstable may be used only seasonally or may not be suitable.

Roost spacing: Individuals in clusters maintain about 12 to 15 cm between one another.

Main roost structures: Natural caves, fissures and abandoned underground mine workings.

Permanent Pilbara roosts: The 2022 review reported 48 confirmed permanent category 1 and 2 diurnal roost sites.

Sheltering habitat: Temporary refuges and roost assessment

Individuals may use shallower caves or other underground structures as temporary night refuges while foraging several kilometres from the day roost. Bats also commonly enter caves at night that they do not occupy during the day, so a detector recording at an entrance cannot by itself identify a day roost.

The species is highly sensitive to people entering roosts. Daytime entry can cause bats to leave and may result in abandonment for weeks or months. Roost confirmation should therefore use non-invasive emergence, return or acoustic methods wherever possible.

• Search geological maps, aerial imagery and field features for caves, fissures, mine adits, shafts, gorges, gullies, cliff lines and rocky outcrops.
• Use overnight detectors at entrances as an initial, low-disturbance method, then confirm daytime occupancy using an approved method that distinguishes bats leaving the roost from bats entering during night foraging.
• Do not backfill, flood, gate or alter an old mine opening without assessing its use by this species and other cave bats.

Threats: Clearing, mining and roost loss

The main project risk is loss or disturbance of a small number of subterranean roosts that may support many bats. Low-level flight, attraction to lights and physiological sensitivity add risks from roads, lighting, capture and poorly timed works.

Iron ore mining can remove natural caves in ironstone country, while mine rehabilitation can backfill shafts and adits used as roosts. Old mines may also deteriorate, collapse or flood. Loss of a deep roost can affect a colony because suitable alternatives may be scarce or outside the nightly flight range.

Clearing around roosts can remove nearby gullies, pools, drainage lines and open foraging areas. Repeated detections may represent bats from one or a few roosts, so local abundance should not be inferred from detector records alone.

• Map and protect all caves, mine workings and likely underground structures before clearing or blasting is planned.
• Maintain suitable roost access and internal microclimate. Do not block, flood, collapse or alter entrances without species-specific advice.
• Assess cumulative loss across nearby projects, not only the area proposed for direct clearing.

Threats: Disturbance, roads and infrastructure

The species is highly sensitive to people entering roosts, trapping at entrances, drilling, noise and vibration. Disturbance can cause a colony to leave for weeks or months or move to a less suitable roost. Inappropriate cave gating has killed large numbers of bats.

Roadkill occurs because bats fly low and are attracted to lights. Sporadic losses may be small at a regional scale, but a busy haul or access road near a roost or regular foraging area can cause local decline. Artificial lighting can draw bats towards traffic and other hazards.

• Keep people, vehicles, drilling and blasting away from known and suspected roost entrances, using buffers based on site-specific acoustic, vibration and occupancy information.
• Avoid lighting cave entrances, drainage crossings and low flight paths. Use the minimum lighting needed for safety and direct light away from habitat.
• Plan traffic controls where roads pass close to roosts, pools, gullies or known flight paths.

Threats: Predators, fire, hydrology and disease

Natural predators include Olive Pythons, Brown Tree Snakes, King Brown Snakes and Ghost Bats. Ghost Bats may share caves and can take smaller bats, particularly where roosting space is accessible.

Changes to groundwater seepage, drainage or flooding can reduce the humidity of temporary roosts or damage permanent mine and cave habitat. Poor fire management may reduce the quality of foraging habitat around a roost. The supplied documents do not identify a species-specific disease as a major population threat, but capture and handling carry zoonotic risks, including Australian bat lyssavirus, and must follow approved health procedures.

• Prevent avoidable changes to seepage, pools and drainage near roosts and temporary refuge caves.
• Manage fire in accordance with local ecological advice so that foraging habitat and roost access are not degraded.
• Use vaccinated, trained personnel for any approved handling and release bats promptly at night.

Survey methodology: 1. Passive acoustic monitoring

Use non-invasive acoustic surveys first, then confirm potential daytime roosts without entering occupied caves or mines during the day. This species is easy to miss if surveys rely only on capture, because its calls have a short detection range and it often visits caves at night without roosting there during the day.

Place full-spectrum or other suitable bat detectors for full nights in likely habitat, including cave and mine entrances, rocky outcrops, gullies, gorges, pools, drainage lines and open foraging areas.

Use high sensitivity settings and retain the original recordings for verification. The call is a distinctive constant-frequency and frequency-modulated pulse, usually 5 to 8 milliseconds long, with a characteristic frequency of about 109 to 117 kHz in northern populations and about 118 to 128 kHz, commonly 121 kHz, in the Pilbara form.

High-frequency calls have a short detection range, usually about 2 m in Queensland guidance and typically a few metres in the Pilbara. Place detectors where bats are likely to pass close to the microphone.

Survey over suitable nights rather than windy, cold or rainy nights. Repeat surveys in wet and dry seasons where seasonal use of roosts or foraging areas is possible.

For broad project areas, use about one recording site per 500 to 800 ha, with 2 to 4 recording nights at sites with the highest habitat rating. Repeat the survey in both wet and dry seasons.

Survey methodology: 2. Active acoustic monitoring and spotlighting

Walk likely habitat with a hand-held detector for at least 2 hours after sunset, especially around cave and mine entrances, gullies, gorges, rocky outcrops and pools.

Keep a continuous recording for later verification and retain a GPS track showing the route and survey effort.

The bat often flies low, usually within 3 m of the ground, in a zigzag pattern. It may approach a small light source, allowing close detection with a hand-held detector.

Use spotlighting only as an aid to detection and identification. Orange fur can be distinctive, but pale yellow, white, grey or light brown individuals may resemble other bats. Confirm records from echolocation calls where possible.

Minimum active effort: 8 detector hours per 100 ha, over at least 4 nights

Recommended timing: At least 2 hours after sunset

Survey methodology: 3. Roost searches and occupancy confirmation

Search maps, aerial imagery, geology and landform data before fieldwork, then inspect gorges, gullies, fissures, rocky outcrops, cliff lines and disused underground mines for potential roost habitat.

Do not treat a bat detector record at a cave or mine entrance as proof of a daytime roost. The species commonly enters structures at night while foraging or using a temporary night roost.

Where occupancy must be confirmed, use non-invasive emergence or return observations, acoustic monitoring, cameras, or the cloth-barricade method described in the survey guidance. If using a cloth barricade, place detectors on both sides, monitor for no more than 2 hours after sunset, and remove the cloth as soon as presence is confirmed.

Do not enter a suspected occupied roost during the day. The species can abandon a roost for weeks or months after intrusion, and disturbance during dry periods can increase mortality if suitable alternative roosts are unavailable.

Do not trap or net cave or mine entrances simply to establish presence or occupancy.

Roost searches: At least 2 hours per survey day, subject to local terrain and access

Occupancy assessment: Up to 2 hours per roost when using the cloth-barricade method

Survey methodology: 4. Capture only where justified

Avoid capture for presence or absence surveys because acoustic detection is usually safer and more effective for this species.

If capture is required for an authorised purpose, use harp traps away from cave and mine entrances where practicable. Mist nets are readily avoided in open flight paths.

Check harp traps at least twice during the night and monitor traps constantly at cave or mine entrances. Keep capture and processing time as short as possible.

Place each bat in a dry calico bag without overcrowding, process it promptly, and release it close to the capture point while it is dark, preferably within 2 hours.

Only trained, vaccinated and authorised personnel should handle bats. Apply Australian bat lyssavirus safety procedures.

Optional trapping effort: 8 trap nights per 100 ha, over at least 4 nights

Preferred release time: During the same night, ideally within 2 hours of capture

Survey methodology: Minimum effort and reporting

• Use passive acoustic monitoring, active acoustic monitoring and targeted searches for caves and mines where suitable habitat occurs.
• Repeat surveys in wet and dry seasons when the project could affect seasonal roosts, foraging areas or movement between roosts.
• Record detector type, microphone position, sensitivity, dates, weather, start and finish times, GPS tracks, habitat, call files, spotlighting effort, roost observations and any capture details.
• Have an experienced bat ecologist verify suspected records from full recordings, because night visitation of non-roost caves can give a misleading result.
• Map all confirmed and suspected roosts, nearby foraging habitat and movement routes, while managing sensitive location information appropriately.
• Submit verified records and survey data to the relevant state or territory wildlife database and the Australian Government species information system where appropriate.
• Document survey limitations, including microphone range, weather, access constraints, incomplete roost searches and any seasonal gap.

Before habitat disturbance: Avoid and minimise

Treat caves, mines and their surrounding foraging areas as habitat that may support this species even when no colony is visible. The species is physiologically fragile and highly sensitive to roost disturbance, so avoidance should be the first project control.

• Retain all known and suspected daytime roosts, including natural caves, fissures and disused underground mine workings.
• Avoid blasting, drilling, excavation, vibration, lighting, noisy works and public access near a roost until a bat ecologist has assessed the risk and suitable controls are approved.
• Retain gullies, gorges, rocky outcrops, drainage lines, pools and other areas used for low foraging flights, especially within several kilometres of a roost.
• Maintain usable connections between roosts, temporary night roosts, water sources and foraging areas. In the Pilbara, individuals may travel at least 10 km nightly and may move between roosts by using suitable underground structures.
• Do not gate, backfill, flood or collapse a mine or cave that may provide roost habitat without an approved species management approach.

Before habitat disturbance: Approvals and project planning

• Check the current EPBC Act listing before work starts. The Pilbara form is listed as Vulnerable nationally, and an action that may significantly affect it may require referral to the Australian Government.
• Check the current state or territory listing, wildlife legislation, survey requirements, handling rules and permit conditions for the project location.
• Prepare a fauna management plan that identifies roosts, foraging habitat, buffers, lighting, noise, vibration, access, seasonal constraints, stop-work triggers, response personnel and reporting requirements.
• Stage clearing and construction so that retained roosts and nearby foraging areas remain available throughout the works.
• Obtain specialist advice before any proposal to relocate a colony, alter a cave entrance, install a gate or construct an artificial roost.

Before habitat disturbance: Site preparation

• Complete the targeted survey and roost occupancy assessment before clearing, excavation, blasting, drilling, road construction or changes to mine workings.
• Mark confirmed and suspected roost entrances, cave-bearing geology, gullies, drainage lines, pools, access restrictions and no-go areas on approved construction plans and in the field.
• Use exclusion fencing or physical barriers where they can protect roost entrances and foraging habitat without blocking bat flight paths or altering cave airflow.
• Brief the fauna spotter catcher, supervisors and machinery operators on the species identification features, low flight height, sensitivity to disturbance and emergency stop-work procedure.
• Schedule work to avoid disturbance during breeding and dry periods when alternative humid roosts may be limited. In the Pilbara, bats contract into deeper roosts during hot, dry conditions, particularly from about August to December.

During habitat disturbance: Daily work controls

Keep a fauna spotter catcher involved in daily controls wherever works could affect caves, mines, rocky habitat, drainage lines or low-flying bats. Stop work if a roost, bat or unexpected habitat feature is found and obtain ecological direction before restarting.

• Inspect exclusion fencing, roost barriers, lighting controls and marked no-go areas before each shift.
• Keep machinery, vehicles, workers and visitors out of roosts and away from entrances unless the approved management plan specifically allows access.
• Do not enter an occupied cave or mine during the day, shine lights into a roost, block an entrance, trap an entrance or create sudden noise and vibration near a roost.
• Use directional, shielded lighting and switch off unnecessary lights near roosts, water points and flight paths.
• Keep dust, smoke, blasting fumes, spoil, sediment and contaminated water away from cave entrances, pools, gullies and drainage lines.
• The fauna spotter catcher must remain in communication with the operator, stand in a safe position with a clear view of the work zone, and direct machinery to stop before approaching an animal or habitat feature.

During habitat disturbance: Habitat feature handling

• Do not remove, fill, gate, collapse or alter a cave, mine adit, shaft, fissure or rock pile without approval from the project ecologist and relevant regulators.
• Treat logs, rocks, burrows, tree hollows, drainage depressions and pools as fauna habitat during clearing, but recognise that this species is primarily an obligate cave and underground-roosting bat and is not confirmed to roost in trees in the supplied sources.
• If clearing affects watercourses, pools or riparian vegetation used for foraging, retain flow paths, avoid sediment entry and prevent lighting from shining across the water.
• Do not relocate rocks, logs or other features into a cave entrance or movement route unless the approved fauna management plan specifies their placement.
• Keep any temporary access, spoil and drainage works outside marked roost buffers and do not change the temperature, humidity or airflow of a retained roost.

During habitat disturbance: Animal response, stop work and records

• If a bat is found, stop the immediate activity, keep people and machinery back, and contact the authorised fauna spotter catcher and project ecologist.
• Do not handle, chase, net or capture the bat unless the person is trained, vaccinated, authorised and the action is permitted by the relevant approval.
• Allow a flying bat to leave without interference. If a grounded or injured bat requires intervention, place it in a dry calico bag only under authorised direction, minimise handling and arrange prompt assessment by a veterinarian or licensed wildlife carer.
• Do not release a bat into an unassessed cave or mine. If relocation is authorised, use nearby retained habitat selected by the ecologist and release it during darkness.
• Stop work and establish a no-go area if a daytime roost, roosting colony, repeated bat emergence, injured bat, unexpected cave or mine opening, collapse or change in roost airflow is found.
• Record the date, time, GPS location, activity, weather, species evidence, photographs, call files, people involved, machinery status, response, release or referral details and the person who authorised recommencement.
• Notify the relevant regulator and follow the approval conditions for any mortality, injury, roost disturbance, colony displacement or other reportable incident.

After habitat disturbance: Post-clearance checks

Keep controls in place after clearing and construction. A site can remain unsuitable even when no bat is seen, because roost abandonment and delayed mortality may follow disturbance.

• Inspect the work area and retained habitat for injured or dead bats, damaged cave entrances, blocked flight paths, altered drainage, sediment deposition, lighting spill and vibration or blasting damage.
• Check all retained roost entrances and nearby foraging areas using non-invasive observation and acoustic monitoring at the times specified in the fauna management plan.
• Reinspect areas where bats were detected during construction, including pools, gullies, drainage lines, mine entrances and natural caves.
• Remove temporary fencing, access tracks and equipment only after the ecologist confirms that their removal will not expose roosts or disturb flight paths.

After habitat disturbance: Monitoring and reporting

• Monitor confirmed and suspected roost activity for the period required by the approval or management plan, using consistent detector locations, settings, dates and weather records.
• Compare activity and emergence timing with pre-construction data where those data exist. Investigate a sustained reduction in activity, delayed return, changed emergence behaviour or evidence of abandonment.
• Maintain buffers, access restrictions, lighting controls and noise and vibration controls for as long as the roost and foraging habitat remain at risk.
• Report survey results, incidents, mortalities, injuries, roost status, corrective actions and rehabilitation progress to the project manager, relevant state or territory agency and the Australian Government where required.
• Update the relevant state or territory wildlife database with verified records and clearly identify whether a record represents a daytime roost, night visitation or a foraging detection.

After habitat disturbance: Offsets and residual impacts

• Demonstrate that roost avoidance and on-site controls were considered before relying on an offset or other compensatory measure.
• If a residual impact remains, obtain regulator advice on any offset, artificial roost, land protection or management action required under the approval.
• Do not count a newly built artificial roost as a replacement until its temperature, humidity, access, safety and bat use have been demonstrated over an appropriate monitoring period.
• Protect any offset or retained roost site from future mine closure, flooding, cave collapse, clearing, uncontrolled access, inappropriate gating and altered fire or water regimes.

Rehabilitation actions: Restore roost and foraging habitat

Rehabilitation should restore the conditions around retained roosts rather than treat planting alone as replacement habitat. The main requirement is a secure, warm and humid underground roost connected to suitable low-flight foraging areas.

Typical roost conditions reported for northern populations: About 28 to 32°C and 85 to 100% relative humidity during the dry season

Pilbara nightly movement potential: At least 10 km, and possibly more

• Retain and protect natural caves, fissures, ironstone formations, granite boulder piles and safe disused mine workings that can provide suitable roost microclimates.
• Where an approved artificial roost is required, design it with specialist bat advice to provide stable temperature, high humidity, suitable depth, secure access, an appropriate entrance and protection from people, predators and flooding.
• Reinstate drainage lines, pools, rocky gullies, gorges and nearby riparian vegetation used for foraging, while preventing sediment, pollutants and altered water flows from entering caves or pools.
• Use locally appropriate native vegetation for the project region, including native riparian and open woodland or grassland species that support insect prey. The supplied sources do not prescribe a universal planting list for this species.
• Do not claim tree hollows, nest boxes, logs or general terrestrial habitat as roost replacement unless monitoring shows that the species uses them. Tree roosting has not been confirmed in the supplied sources.

Rehabilitation actions: Manage threats around restored sites

• Control weeds and maintain native vegetation around gullies, watercourses, pools and roost approaches so that foraging habitat remains available.
• Manage fire in accordance with the approved ecological fire regime for the local vegetation and avoid fire entering roost entrances or removing vegetation around important foraging areas.
• Prevent feral cats and other predators from accessing artificial roosts and manage domestic animal access where it threatens colonies.
• Keep roads, haul routes, lights, blasting, drilling, public access and noisy activities away from restored and retained roosts.
• Do not backfill or gate a mine opening without confirming that the design will retain bat access, airflow and microclimate, and will not cause mass mortality.

Rehabilitation actions: Monitor rehabilitation success

• Set measurable success criteria for roost temperature and humidity, entrance condition, water and sediment control, native plant establishment, weed cover, predator activity and bat use.
• Use passive detectors and, where safe, emergence observations to monitor whether bats use the restored roost and nearby foraging areas across wet and dry seasons.
• Treat repeated detection near an entrance as evidence of use only after confirming whether the structure is a daytime roost or a night-visitation site.
• Investigate reduced activity, failure of the roost to maintain suitable humidity or temperature, flooding, altered airflow, predator access and public intrusion, then apply corrective action.
• Continue monitoring for the period required by the approval and report results to the project manager and relevant authorities.

Sources

• Rhinonicteris aurantia (Pilbara form) â Pilbara Leaf-nosed Bat, Australian Government DCCEEW: https://environment.gov.au/cgi-bin/sprat/public/publicspecies.pl?taxon_id=82790
• review-pilbara-leaf-nosed-bat-ecology-threats.docx, Australian Government DCCEEW: https://www.dcceew.gov.au/sites/default/files/documents/review-pilbara-leaf-nosed-bat-ecology-threats.docx
• The IUCN Red List of Threatened Species™, iucnredlist.org: https://www.iucnredlist.org/species/pdf/209539734
• Orange leaf-nosed bat Rhinonicteris aurantia, Queensland Government: https://www.qld.gov.au/__data/assets/pdf_file/0021/68007/orange-leafnosed-bat.pdf
• Survey guidelines for Australia's threatened bats, Australian Government DCCEEW: https://www.agriculture.gov.au/sites/default/files/documents/survey-guidelines-bats.pdf