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Broad-shelled Turtle (Chelodina expansa)

The broad-shelled turtle is a large, long-necked freshwater turtle of permanent rivers, deep billabongs, lakes and connected wetlands in eastern and south-eastern Australia. On development sites, risks are greatest where works affect permanent water, submerged logs, vegetated banks, nesting areas, riparian vegetation or movement between rivers and wetlands.

Conservation status

Victoria, Flora and Fauna Guarantee Act 1988: Endangered.

South Australia, National Parks and Wildlife Act 1972: Vulnerable.

Breeding season

Broad-shelled Turtles nest mainly from autumn into winter, with the clearest nesting record for March to May. Eggs remain in nests for about 192 to 650 days, so clearing risks continue well beyond the nesting period, including during hatchling emergence after rain.

Reproductive mode: Egg laying. Females leave the water, excavate a nest, lay their eggs, seal the nest and return to the water.

Clutch size: 5 to 30 eggs, typically 10 to 15.

Incubation: About 192 to 650 days. Low temperatures can delay embryonic development and allow eggs to overwinter in the nest.

Size at hatching: Carapace length 34.5 to 37.9 mm; mass approximately 7.9 to 12.88 g.

Age at maturity: Males mature at 9 to 11 years. Females mature at 14 to 15 years.

Nest or egg sites: Nests are commonly about 42 m to 100 m from the water, but females can travel up to 1 km. Sites include sandy ridges and soft or moderately vegetated soil.

Breeding frequency: Not recorded.

Confirm timing locally before works, particularly after rainfall and where temperatures, water levels or dry conditions may trigger nesting, hatchling emergence or movement to other water sources.

  • Mating: Mating timing is not recorded for this species. March to July is shown as a general reproductive-planning window around the documented autumn and winter nesting period, not as evidence of a mating peak.
  • Gravid females: The timing of gravid females is not recorded. Females carrying eggs may be encountered during the March to August nesting period, including during overland searches for nest sites.
  • Nesting: Nesting is mainly March to May, with nesting around April in the River Murray region. It can continue through winter and occur occasionally in spring, especially after rainfall.
  • Incubation: Eggs can remain in nests for about 192 to 650 days, commonly spanning winter and extending into the following year. Low temperatures can cause embryonic diapause and delay hatching.
  • Hatchlings: Hatchlings are reported mainly from later spring through summer, generally September to February, and emerge after rain. Another account records emergence in the following autumn, so local emergence can extend beyond this window.
  • Active period: Adults are most active during the warmer months, approximately October to April. Trapping records from the Murray River also document activity from October to April when water temperatures are above 18°C.
  • Winter inactivity: The species does not hibernate or brumate, but movement and feeding decrease during the cooler winter months, mainly June to August. Embryos, rather than adult turtles, may enter diapause in cold nests.
  • Highest clearing risk: Risk peaks from March to May when females are nesting and moving overland. Nests remain at risk for 192 to 650 days, while hatchlings may emerge from September to February and can be killed on roads or during movement to water.

Identification

This is Australia's largest snake-necked turtle. It is usually found in water and can be difficult to detect because it occupies turbid water and remains submerged for long periods.

Adults have a very long neck, a broad and relatively flat head, and a large shell that is usually about twice as long as it is wide. The neck has loose, baggy skin and can extend beyond the length of the carapace.

The carapace can reach 40 to 50 cm. Females are larger and heavier than males, reaching up to 6 kg, while males reach up to 4 kg.

Identification: Distinguishing features

Compared with the eastern long-necked turtle, the broad-shelled turtle is generally much larger. Its plastron is narrow and does not have the distinct black lines between the plates seen in the eastern long-necked turtle.

The plastron does not fully cover the legs, head and tail when they are retracted. The broad head, very long neck and large body are useful field characters when the animal is handled by an authorised and trained person.

  • Males are smaller and mature earlier than females.
  • A mature male has a long tail that extends beyond the rear margin of the carapace.
  • Females have smaller tails than males.

Identification: Field signs

The most useful field signs are the animal itself, nest holes and nesting activity on sandy or soft banks above flood level. Females may travel over land to nest, so searches should include suitable banks beyond the immediate water edge.

Nests are small holes dug in the ground, commonly 30 to 55 m from the water in Victoria and reported more broadly at 30 to 300 m from the water's edge. Eggs may remain in the nest through winter after hatching.

  • Do not rely on tracks, scats, calls, sloughs or eyeshine for detection because these signs are not described as reliable identification features in the supplied sources.
  • Treat any suspected nest, nesting female or turtle crossing route as a sensitive location and keep machinery and vehicle movement away until the site has been assessed.

Distribution: National range

The broad-shelled turtle occurs across south-eastern and eastern Australia, mainly in lowland freshwater systems. Its distribution is associated with river networks, permanent wetlands and connected billabongs rather than a single vegetation community.

The species occurs through the Murray-Darling Basin and in coastal rivers of south-eastern Queensland, from the Logan-Albert drainage north to the Fitzroy drainage. Offshore populations are reported from Fraser, Moreton and Stradbroke islands.

In southern Australia, records include the Murray River system and associated wetlands in Victoria, New South Wales and South Australia. The species is also reported from the lower Murray River and Riverland region.

States and regions: Victoria, New South Wales, South Australia and Queensland, including the Murray-Darling Basin and south-eastern Queensland coastal river systems.

Bioregional pattern: Lowland inland river systems, billabongs and connected wetlands, plus coastal river systems of south-eastern Queensland.

Elevation or climate limit: The supplied sources describe lowland and inland river systems but do not provide a defined elevation limit.

Distribution: Strongholds and trend

Important areas include the Murray-Darling river network, the Murraylands and Riverland region, and connected rivers, backwaters, oxbows, anabranches, ponds and swamps. The Edward-Wakool system is a documented monitoring area where wetland connectivity and flow affect turtle distribution.

The species has lower population densities than sympatric freshwater turtles. Declines have been reported in the Murray-Darling Basin, although the supplied documents do not provide a national population estimate or a quantified rate of decline.

Population size: No national population estimate is provided in the supplied sources.

Population trend: Declines have been reported, but no national rate of decline is given.

Legal status in the supplied material: Not listed under the EPBC Act; Endangered in Victoria and Vulnerable in South Australia.

Habitat: Waterway habitat

Broad-shelled turtles depend on permanent freshwater habitats, including river channels and connected off-channel wetlands. They are most often associated with deep, turbid water and submerged structures.

Suitable habitat includes permanent rivers, deep billabongs, lakes, backwaters, oxbows, anabranches, ponds and swamps. The species is commonly associated with water deeper than 2 to 3 m, although studies have recorded it across a range of river habitats.

The species is rarely observed out of water and is often found in water too turbid for underwater observation. In the River Murray region, it depends on permanent water bodies and seldom emerges except to lay eggs.

Typical water depth: Usually deeper than 2 m, with more than 3 m preferred or commonly reported in Victorian and South Australian guidance.

Water character: Turbid, permanent water is typical.

Habitat: Structure and vegetation

Key habitat features include submerged logs, tree roots, dead trees, snags, water weeds and moderate vegetation cover along the banks. These features provide concealment, ambush positions and nesting habitat.

Connectivity between the main river channel, billabongs, wetlands and floodplain habitats supports movement and access to suitable habitat. Works that remove snags, simplify banks or isolate wetlands can reduce habitat value.

Habitat: Development-site application

Before clearing or in-water works, inspect permanent water, deep pools, connected wetlands, vegetated banks and areas with submerged logs or roots. Retain these features where practicable and maintain aquatic connections during construction.

Do not assume that an apparently isolated wetland is unsuitable. The species may enter or leave off-channel habitats when flows reconnect them to a river.

Foraging habitat: Diet and method

The broad-shelled turtle is a carnivorous ambush hunter. It feeds underwater, usually from cover in turbid permanent water.

The diet includes fish, frogs, crustaceans, shrimps, aquatic insects and carrion. The turtle waits among water weeds, submerged timber or other cover and strikes rapidly by extending its neck and opening its jaws.

Carrion feeding may help remove dead fish and other animals from the water. Food availability can be affected by changes in aquatic vegetation, water quality, flow and the condition of connected wetlands.

  • Retain submerged logs, roots, dead trees and aquatic vegetation where these occur in permanent water.
  • Avoid releasing sediment, chemicals, concrete washout or other contaminants into pools and connected wetlands.

Foraging habitat: Foraging area

The supplied documents do not define a foraging-range size. Radio tracking in the Murray River recorded male movements of up to 25 km over approximately two and a half years through the main channel, backwaters, connected swamps and inlets.

These movements show that feeding habitat can extend across connected river and wetland systems. Barriers, low flows and isolated pools may limit access to food and refuge habitat.

Recorded movement distance: Males travelled up to 25 km during a study of approximately two and a half years.

Breeding habitat: Breeding biology

Breeding occurs in autumn, when females leave permanent water to lay eggs in elevated ground. The long incubation period means nests can remain exposed to construction, predators and changing water levels for many months.

Nesting season: March to May, with nesting around April in the River Murray region.

Clutch size: Approximately 5 to 30 eggs; around 20 eggs is reported in South Australia.

Nest location: Usually above flood level, approximately 30 to 55 m from water in Victoria and more broadly 30 to 300 m from the water's edge.

Incubation: Approximately 200 to 650 days. Embryos can enter diapause during cold conditions, resulting in incubation of about one year.

Sexual maturity: Males mature at about 9 to 11 years; females mature after 14 years.

Lifespan: Not stated in the supplied sources.

Breeding habitat: Nesting habitat

Females require suitable open or lightly vegetated ground above flood level, often on sandy banks or other soft substrates. Moderate vegetation cover along the bank is associated with nesting habitat.

Nests can be inundated by high flows, dam releases or rising storage levels. Because incubation is prolonged, a nest may be exposed to these risks for many months.

  • Survey banks, floodplain margins and elevated sandy or soft ground within at least 300 m of permanent water during March to May.
  • Keep vehicles, stockpiles, trenching and earthworks away from suspected nest sites.
  • Plan water releases, dewatering and bank works so that nesting banks are not flooded during incubation.

Sheltering habitat: Aquatic refuges

This species shelters in deep permanent water rather than in terrestrial dens or tree hollows. Cover in the water is important because the turtle is cryptic and relies on ambush hunting.

Important refuges include deep pools, turbid water, submerged logs, tree roots, dead trees, snags and aquatic vegetation. The species may use main channels, backwaters, oxbows, anabranches, connected swamps and inlets.

Broad-shelled turtles seldom emerge except to nest. They do not hibernate, although low temperatures can cause embryos to enter diapause within the nest.

Reported refuge depth: Usually more than 2 m, with more than 3 m commonly reported for preferred permanent water habitat.

  • Retain large woody debris and submerged root structures in permanent pools unless removal is required for a demonstrated safety reason.
  • Avoid isolating deep pools from connected river and wetland habitats during low-flow periods.
  • Use turtle-safe fish traps and ensure trapped turtles can reach an air pocket.

Sheltering habitat: Terrestrial shelter and nests

The supplied sources do not describe permanent terrestrial refuges, burrows, dens, hollows or shelter sizes for this species. Terrestrial use is mainly associated with nesting and movement between water and nesting areas.

Nesting females and nests are vulnerable while on land. Foxes may kill nesting females and dig up eggs.

  • Inspect banks, floodplain margins and access tracks for nesting females and nest holes before earthworks.
  • Keep lighting, traffic and machinery away from the water edge and likely nesting areas during autumn nesting.

Threats: Hydrology and habitat change

The main risks are loss of permanent water, reduced river and wetland connectivity, nest predation, road mortality, fishing entanglement, poor water quality and altered flow. These risks can act together because the species matures slowly and has low reproductive output.

Water extraction, dams and weirs can reduce flow volume, increase drying, alter flow variability and disconnect rivers from wetlands and floodplains. Drying of permanent pools can remove shelter and feeding habitat.

High flows, sudden releases and changed water levels can inundate nests. Low flows can reduce access to connected wetlands, while altered water quality, salinity, sedimentation, turbidity and temperature can affect health, food resources and reproduction.

  • Maintain water in permanent pools and retain connections between rivers, billabongs, wetlands and floodplains.
  • Manage dewatering, diversion and environmental releases to avoid sudden isolation or inundation of turtle habitat and nests.
  • Prevent sediment, saline water, chemical runoff and other poor-quality discharges from entering permanent water.

Threats: Clearing, construction and fragmentation

Removal of riparian vegetation, bank disturbance, loss of snags and channel modification can reduce shelter, foraging cover and nesting habitat. Fragmentation also limits movement between populations and connected wetlands.

Most freshwater turtle movement is aquatic. Barriers and low flows can therefore restrict movement more strongly than they do for species that regularly migrate over land.

  • Treat permanent pools, connected wetlands, vegetated banks and submerged timber as habitat during site planning.
  • Keep construction access routes out of likely nesting banks and avoid creating barriers at wetland connections.
  • Use fauna spotter catchers and turtle-safe exclusion or relocation procedures where turtles are found during works.

Threats: Roads, predators and equipment

Vehicles can kill turtles when they cross roads, particularly during nesting movements and after rain. Foxes kill adults on land and dig up nests to eat eggs.

Fishing nets, funnel traps and other structures can drown turtles. Weirs and sudden water releases can also cause injury or death.

  • Use turtle warning signage, reduced vehicle speeds and targeted spot checks near water crossings during March to May.
  • Protect identified nests from foxes and exclude vehicles from nesting banks.
  • Use turtle-safe fishing gear and provide an air pocket in any permitted trap.

Threats: Fire and disease

The supplied documents do not identify a species-specific fire response or provide a disease profile for the broad-shelled turtle. Fire planning should still avoid damaging riparian vegetation, nesting banks and water quality through ash, sediment or chemical runoff.

Novel diseases are recognised as a general threat to Australian freshwater turtles. Any sick, injured or dead turtle found during works should be isolated from handling and reported to the project ecologist or relevant wildlife authority.

  • Do not conduct burns or place firebreaks through known nesting banks without ecological assessment.
  • Prevent contaminated equipment, water and handling materials from moving between turtle sites.

Survey methodology: 1. Trapping in aquatic habitat

Survey broad-shelled turtles in permanent rivers, deep wetlands, billabongs and connected backwaters before clearing or construction. The species is cryptic, rarely seen out of water and commonly occurs in turbid water, so trapping and repeat surveys are more suitable than visual searches alone.

Use baited aquatic traps in the waterbody and in connected river habitat. Suitable trap types include cathedral traps, fyke nets and commercially available crab pots, as used in the Edward-Wakool monitoring program.

Set traps for up to four days per session and check them regularly to reduce the time turtles remain enclosed and to maintain access to air.

Identify each captured turtle to species and sex, measure and weigh it, mark it only under an approved research or wildlife authority, and release it at the capture location unless an authorised fauna management plan specifies otherwise.

Reference trapping design: Six sites, with two replicates each of permanent, disconnected and sporadically connected wetlands.

Trapping effort in the reference program: Five traps in the wetland and five traps in the adjacent river, for up to four days per session.

Reference sampling sessions: October, December, February and April.

  • Target permanent waterbodies, deep pools, billabongs, backwaters, anabranches, ponds and swamps connected to the river system.
  • Place trap arrays in both the project waterbody and adjacent connected river habitat where both habitats may be affected.
  • Use aquatic vegetation, submerged logs, tree roots and deep water as priority sampling features because broad-shelled turtles use these habitats.

Survey methodology: 2. Repeat seasonal aquatic surveys

Repeat trapping across the active period rather than relying on one visit. The reference program used October, December, February and April sessions to compare distribution through the year.

Prioritise surveys before works, after periods of reconnection or flooding, and before a waterbody is isolated or drained. Environmental flows can affect access to disconnected wetlands and the distribution of turtles.

Record water depth, flow or connection status, turbidity, aquatic vegetation, submerged timber, bank vegetation and evidence of drying at every survey location.

  • Survey permanent water and connected backwaters first where access is limited, because this species depends on permanent water and is more likely to remain in permanent or sporadically connected wetlands than in disconnected wetlands.
  • Treat a zero catch cautiously because the species is cryptic, occurs at low population density and can be difficult to detect in turbid water.
  • Do not infer absence from a single failed trapping session.

Survey methodology: 3. Movement and environmental DNA methods

Use acoustic telemetry only where movement information is required and the work is covered by the relevant animal ethics and wildlife approvals. The reference program fitted acoustic transmitters to 3 to 5 turtles per site and monitored movement for 12 months.

Use receiver stations at the wetland connection, the deepest part of the wetland and the adjacent river connection when assessing movement between a wetland and river.

Use environmental DNA as a supplementary presence or distribution method, not as a replacement for trapping where individual condition, sex or relocation decisions are required.

Reference telemetry duration: October 2019 to October 2020, or 12 months.

Reference receiver array: Three receiver stations per wetland, with two in the wetland and one in the adjacent river.

Reference eDNA timing: Spring to early summer 2019 to 2020, with laboratory work and analysis over the following 3 to 6 months.

  • For eDNA, use contamination controls, positive controls, an internal positive control and adequate replication of water samples and PCR replicates.
  • Record the sampling location, waterbody connection, date, water conditions and laboratory result for every eDNA sample.
  • Interpret eDNA detections with the project ecologist because a detection does not establish the number, life stage or exact location of turtles.

Survey methodology: Minimum effort and reporting

  • Prepare a site-specific survey design before works begin, using repeat aquatic trapping where suitable habitat is present and documenting why any recommended method cannot be used.
  • Use the reference effort of five wetland traps and five adjacent-river traps for up to four days, repeated in representative seasons, where the project scale and approvals allow it.
  • Include all survey locations, dates, trap numbers, trap nights, checking times, weather, water conditions, habitat features, captures, recaptures, injuries and releases in the report.
  • Submit verified records and negative survey results to the relevant state wildlife database, such as the Victorian Biodiversity Atlas or the applicable South Australian or other state repository.
  • Report the species as Chelodina expansa, broad-shelled turtle, and retain photographs or other verification for unusual records and all state-listed fauna records.
  • Obtain advice from the relevant state wildlife authority before trapping, marking, telemetry, handling or relocating turtles.

Before habitat disturbance: Avoid and minimise habitat loss

Plan around the species' dependence on permanent, deep aquatic habitat and its use of connected rivers, billabongs and wetlands. Avoid isolating or drying suitable water and retain the structures and bank vegetation used for shelter, feeding and nesting.

Retain permanent waterbodies, deep pools and connected backwaters wherever practicable. The species is associated with permanent water and commonly uses water deeper than 2 to 3 metres.

Retain submerged logs, tree roots, dead trees, aquatic vegetation and moderate bank vegetation. These features provide cover, ambush habitat or nesting habitat.

Maintain both longitudinal connection along the river and lateral connection between the main channel, wetlands, billabongs and floodplain areas.

  • Avoid filling, draining, dewatering or isolating permanent pools and connected wetlands.
  • Keep large snags in the water unless removal is required for an approved safety reason.
  • Avoid removing vegetated banks used for nesting, particularly during the autumn nesting period.
  • Design crossings, cofferdams, access tracks and temporary diversions to avoid trapping turtles in isolated pools or preventing movement through the waterway.

Before habitat disturbance: Approvals and work planning

Confirm the approval pathway before works start. Chelodina expansa is not listed under the Commonwealth EPBC Act, but it is listed as Endangered in Victoria and Vulnerable in South Australia.

Check the relevant state and territory legislation, wildlife permits, animal ethics requirements and authority conditions for the project location.

Prepare a fauna management plan that identifies aquatic habitat, nesting banks, connection points, exclusion areas, rescue arrangements, authorised handlers, release sites and reporting requirements.

Victoria status: Endangered.

South Australia status: Vulnerable.

Commonwealth status: Not listed under the EPBC Act.

Nesting period: Generally March to May, with nesting around autumn.

  • Seek an EPBC referral decision if another listed matter or an indirect impact brings the project within the Act, even though this species itself is not listed under the EPBC Act.
  • Schedule in-water works and dewatering to avoid the autumn nesting period where practicable, and obtain specialist advice where timing cannot be avoided.
  • Stage works so that suitable retained water remains available and turtles are not forced into unsafe or isolated areas.
  • Include stop-work criteria for a turtle found in the work area, unexpected dewatering, loss of a connection to retained habitat, or a suspected injury or mortality.

Before habitat disturbance: Pre-clearance preparation

Complete the aquatic survey and pre-clearance inspection before machinery enters the work area. Mark retained water, connection points, submerged timber, nesting banks and no-go areas on plans and on the ground.

Install exclusion fencing only where it will not block movement between retained aquatic habitat and the river or wetland. Keep fencing out of the water unless it is specifically designed and approved for aquatic fauna management.

Brief the fauna spotter catcher, machine operators and supervisors on the species' appearance, handling limits, release procedure and stop-work triggers.

  • Inspect the full work footprint and access routes for turtles, nests, stranded individuals and waterbody changes before each clearance stage.
  • Identify a nearby retained release area with permanent, deep, turbid water, cover and a suitable bank, and obtain project approval for its use before works begin.
  • Place rescue equipment, ventilated transport containers, shade, damp materials and contact details for the project ecologist and veterinarian at the work front.
  • Do not use a single pre-clearance inspection as evidence that the waterbody is free of turtles.

During habitat disturbance: Daily controls and spotter catcher duties

Use a controlled, staged work system around water. The fauna spotter catcher should work directly with the site supervisor and machinery operators, with authority to stop work when a turtle or unsafe aquatic condition is found.

Inspect the work area, retained habitat, access routes, exclusion fencing and water connections at the start of each shift and after changes in water level or flow.

Keep machinery, spoil, fuels, concrete washout and sediment controls out of retained water and nesting banks.

Require the fauna spotter catcher to remain close enough to see the active work face and to communicate immediately with operators by an agreed stop signal or radio call.

Use a staged approach to vegetation removal, dewatering and bank works so that turtles can be detected and safely moved before the next stage begins.

  • Keep an up-to-date fauna register at the site office and work front.
  • Record the location, time, activity, person who found the turtle, identification, condition, action taken and release location for every observation or capture.
  • Check traps, exclusion devices and isolated pools at the frequency specified in the approval or fauna management plan.
  • Stop work if a turtle is found in the active footprint, if a turtle becomes stranded, or if works could cut off its connection to retained water.

During habitat disturbance: Habitat feature handling

Treat permanent water, deep pools, connected wetlands, submerged logs, tree roots, aquatic vegetation and vegetated banks as fauna habitat during construction.

Do not remove submerged timber or drain a pool until the fauna management plan has specified the inspection, rescue and relocation process.

Manage dewatering progressively and inspect isolated pools, pump sumps, trenches and low points for turtles before filling, backfilling or compacting.

Protect autumn nesting banks from unnecessary disturbance and inspect excavated soil or stockpiles for nests before movement.

  • Use turtle-safe fish and fauna traps where trapping is approved, and provide turtles with access to air when they are enclosed.
  • Do not leave open trenches, pits, pipes or tanks that can trap turtles overnight unless they are securely covered or fitted with fauna escape measures.
  • Prevent sediment, chemicals and contaminated water from entering retained habitat because water quality, salinity, turbidity and chemical runoff can affect turtles.
  • Retain or reinstate large logs and other submerged cover where removal is unavoidable.

During habitat disturbance: If a turtle is found

Stop the relevant activity and keep machinery and people clear until the fauna spotter catcher or another authorised person has assessed the turtle.

Handle the turtle only when authorised and trained, using two hands on either side of the carapace and plastron. Keep handling quiet and brief.

Do not pull on the head or limbs, and do not force a retracted turtle to extend its body.

Place an animal awaiting assessment in a secure, well-ventilated container with suitable humidity, shade and no standing water during transport.

Preferred release habitat: Permanent watercourses or waterbodies, generally deeper than 2 to 3 metres, with turbid water and submerged cover.

Activity temperature from Victorian guidance: Usually above 18 degrees Celsius, with occasional activity above 16 degrees Celsius.

  • Release a healthy adult as soon as practicable at its original location, or at the nearest approved retained habitat with permanent water and appropriate cover if the original location is unsafe.
  • Release a broad-shelled turtle into deep permanent water at the edge of a vegetated bank, rather than onto dry ground or into a temporary shallow pool.
  • Refer an injured, weak, bleeding or unresponsive turtle to the project ecologist and veterinarian or authorised wildlife carer without delay.
  • Do not provide medication or release an injured animal without veterinary or authorised wildlife advice.
  • Stop work and escalate to the project manager, ecologist and relevant authority for any mortality, nest discovery, repeated turtle entry into the work area, or loss of aquatic connectivity.

After habitat disturbance: Post-clearance checks and monitoring

Confirm that retained and restored aquatic habitat remains connected and usable after construction. Continue checks until temporary controls are removed and the work area is stable.

Inspect the cleared footprint, dewatering areas, access tracks, pits and retained water immediately after each work stage and before demobilisation.

Repeat aquatic trapping or other approved monitoring where the project removed, isolated or altered suitable habitat. Compare results with the pre-work survey using the same methods and effort where practicable.

Monitor water depth, permanence, connection to the river, turbidity, aquatic vegetation, submerged cover, bank vegetation and evidence of turtle movement.

  • Check that no turtle remains in isolated pools, sediment basins, pump sumps, trenches or temporary structures.
  • Maintain exclusion fencing, fauna escape devices and waterway controls until the fauna spotter catcher and project ecologist agree that they are no longer needed.
  • Investigate any decline in captures, dead turtles, stranded turtles or loss of connection to retained habitat.

After habitat disturbance: Reporting and compliance

Provide the regulator and asset owner with the final fauna register, survey data, capture and release records, incidents, mortalities, photographs, maps and rehabilitation results.

Submit verified records to the relevant state wildlife database and retain the database submission reference in the project file.

Report non-compliance, injury, mortality, nest disturbance and unexpected habitat loss in accordance with approval conditions and the fauna management plan.

  • Document the number of trap nights, survey dates, water conditions, captured species, sex, measurements, marks, release sites and any recaptures.
  • Map retained and disturbed habitat, wetland connection points, nesting banks, submerged timber and restoration areas.
  • Keep veterinary records and wildlife carer outcomes for every injured turtle transferred from the site.

After habitat disturbance: Offsets and residual impacts

Assess residual impacts after avoidance, minimisation and rehabilitation measures have been applied.

Use the relevant state offset or approval framework if permanent habitat loss, fragmentation or damage remains and an offset is required.

Ensure any offset or compensatory action protects habitat that is permanent, connected, deep enough for the species and capable of retaining submerged cover and suitable banks.

  • Do not treat an offset as a substitute for retaining permanent water, river connectivity or suitable habitat within the project area.
  • Set measurable requirements for any offset, including protection status, water permanence, connection, habitat features, monitoring period and corrective actions.

Rehabilitation actions: Waterbodies and habitat structure

Restore permanent aquatic habitat and its connections, not just the bank surface. Broad-shelled turtles need deep water, submerged cover, aquatic prey habitat and vegetated banks for nesting.

Reinstate permanent pools and maintain water depths suited to the species, with project-specific depths informed by the reference habitat and approval conditions. Victorian guidance identifies habitat deeper than 2 metres, while South Australian guidance describes waterbodies deeper than 3 metres.

Re-establish connections between the main channel, billabongs, wetlands and backwaters where construction has interrupted them.

Retain or place large logs, root structures and dead trees in the water where safe and approved. These features provide shelter and ambush habitat.

Re-establish aquatic vegetation and moderate vegetation cover along banks without blocking turtle movement or reducing the open water needed for deep pools.

Reference nesting distance: Females may nest 30 to 55 metres from the water in Victorian guidance, and more than 500 metres from the river is reported for South Australia.

Reference nesting season: March to May, around autumn.

Reference egg number: Approximately 5 to 30 eggs in Victorian guidance, and approximately 20 eggs in the South Australian fact sheet.

  • Use local native aquatic and bank plant species suitable for the waterbody and region, selected with the relevant state authority or restoration ecologist.
  • Do not introduce non-native plants or materials that can degrade water quality or obstruct the waterway.
  • Shape banks to provide stable, vegetated nesting areas above expected flood levels while avoiding designs that direct floodwater across active nests.
  • Avoid creating shallow, isolated ponds as the only replacement habitat.

Rehabilitation actions: Predator, weed and fire management

Control foxes around nesting banks in accordance with approved vertebrate pest management requirements because foxes dig up nests and can kill turtles on land.

Control weeds and prevent sediment, salinity and chemical runoff from entering restored water.

Manage fire, access and stock impacts so that bank vegetation, nests and refuge habitat are not damaged during the nesting and incubation period.

  • Protect known nests from predators only under an approved, species-appropriate program.
  • Do not remove all bank vegetation or submerged cover when controlling weeds.
  • Inspect restored pools after drought, flood or fire and repair erosion, barriers and loss of connection.

Rehabilitation actions: Monitoring and success measures

Monitor restored sites through repeat wet-season and dry-season inspections, with aquatic trapping where approved and suitable.

Use the pre-work survey as the baseline and compare catch per unit effort, species presence, sex, body condition, water permanence, connection, depth, aquatic vegetation and submerged cover.

Continue monitoring for the period required by the approval or rehabilitation plan, and apply corrective actions if habitat dries, connection is lost, water quality declines or turtles are injured or absent.

Reference movement distance: Male broad-shelled turtles have travelled up to 25 kilometres within the main channel, backwaters, connected swamps and inlets over roughly two and a half years.

Reference telemetry effort: Three to five transmittered turtles per site, monitored for 12 months.

  • Record turtle detections, trap effort, recaptures, movement evidence, nests, predation, mortality and habitat condition at every monitoring event.
  • Use acoustic telemetry only where an approved movement study is needed and animal ethics and wildlife approvals are in place.
  • Consider eDNA as an additional detection method, with positive controls, an internal positive control and adequate sample and PCR replication.
  • Report monitoring results to the relevant authority and submit verified species records to the relevant state wildlife database.

Sources