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Lace Monitor (Varanus varius)

The Lace Monitor, Varanus varius, is a large terrestrial and arboreal monitor found in forests, woodlands and tree-lined watercourses across eastern Australia. On development sites, mature trees, hollows, fallen timber, leaf litter, termite mounds and connected native vegetation may provide feeding, sheltering and breeding resources for a species listed as Endangered in Victoria.

Conservation status

Victoria, Flora and Fauna Guarantee Act 1988: Endangered.

Breeding season

Lace Monitors mate from late winter through spring and lay eggs mainly in late spring and summer. Eggs remain in nests for many months, so clearing can affect nests, inactive adults and hatchlings across much of the year.

Reproductive mode: Egg-laying.

Clutch size: Usually 4 to 15 eggs. Other reports give 6 to 12 eggs, an average of 8 eggs, or up to 20 eggs.

Incubation: About 6 to 9 months, with some reports of longer incubation.

Size at hatching: Approximately 25 to 28 cm.

Age at maturity: Captive Lace Monitors have bred at 7 to 8 years. Other sources suggest about 4 to 6 years for larger varanids.

Nest or egg sites: Most often active termite mounds, including arboreal and terrestrial mounds. Other reported sites include tree hollows, ground holes, burrows, hollow logs and decaying leaf or wood mould.

Breeding frequency: Usually once a year.

Confirm timing locally through records and pre-clearing surveys, because temperature affects winter activity, incubation duration and hatchling emergence.

  • Mating: Mating and male combat occur from late winter through spring and into early summer. Male combat has been recorded from August to October, while other sources place breeding from September to December or spring to early summer.
  • Gravid females: Females carry developing eggs between mating and laying. Eggs are laid about 35 days, or four to six weeks, after mating, so gravid females are most likely from October to January, with the strongest indication in November and December.
  • Egg laying: Egg laying occurs in late spring and summer, with December to January reported for temperate Lace Monitors. Females usually excavate active termite mounds, but ground holes, hollows and decaying plant material are also reported.
  • Incubation: Eggs remain in nests for about 6 to 9 months, and sometimes longer. Because clutches may be laid from November to February, eggs can be present in nests in every month, including active termite mounds that have been sealed by termites.
  • Hatchlings: Hatchlings generally emerge about 6 to 9 months after laying, giving an indicative emergence period from July to November for late spring and summer clutches. Young may remain at or near the mound for one to two weeks, and spend much of their first weeks in trees.
  • Active period: Adults are mainly active from September to May. Activity is generally reduced in winter, particularly from June to August in southern populations.
  • Winter inactivity: Lace Monitors in cooler parts of the range are inactive or have low activity from June to August. They shelter in tree hollows, under fallen trees and beneath large rocks, where they may be unable to escape machinery.
  • Highest clearing risk: Risk is highest from June to February because winter-sheltering animals, eggs in nests and emerging hatchlings may be affected. Egg-laying risk is greatest from November to February, while hatchling emergence is most likely from July to November.

Identification

Lace Monitors are large, dark monitors with a distinctive pale lacework pattern. They are active by day, climb well and may be encountered on the ground, in trees or around food and shelter resources.

Adults are generally dark grey to black, with cream, yellowish or pale grey spots, blotches and fine bands across the back, neck and tail. The tail is usually banded, with broader bands towards the tip. The head may have two or three pale bands across the snout, while dark bands extend from the lips beneath the chin and onto the throat.

The belly is cream to pale greyish yellow and may have darker bands. Juveniles are often more strongly marked than adults, sometimes with a bluish wash on the face and body and bright yellow within the pale bands.

Length: Up to about 2 m, including the tail.

Body form: Large monitor with powerful legs, strong curved claws, a long neck and a muscular tail.

Identification: Distinguishing features

The combination of large size, dark body, pale lacework or blotched pattern, banded tail and strong climbing ability is characteristic. Pattern and colour can vary, particularly between adults and juveniles, so photographs and measurements should be retained where identification may affect site decisions.

The supplied documents do not provide a diagnostic comparison with every other Australian Varanus species. Where the animal is seen briefly, is unusually small or has atypical markings, identification should be confirmed by an experienced reptile ecologist.

Identification: Field signs and behaviour

Lace Monitors are diurnal and may be seen climbing trunks, moving through the canopy, crossing the ground or investigating hollows and logs. Their forked tongue is used to collect chemical information while searching for resources.

An active termite mound with a side chamber may indicate a potential breeding site because females excavate the mound to lay eggs and termites later rebuild it over the eggs. The supplied documents do not provide validated measurements or descriptions for tracks, scats, sloughs, calls or eyeshine.

Distribution

The species has a broad but discontinuous distribution through wooded habitats of eastern Australia. Records extend from Cape York Peninsula to Gippsland, with additional records west of the Great Dividing Range and along the Murray River floodplain.

The national range includes Queensland, New South Wales, Victoria and parts of South Australia. In Queensland, the range extends north to Cape York Peninsula. In Victoria, records extend to Gippsland, the Wimmera, remnant woodlands north of the Great Dividing Range and the Murray River floodplain.

The supplied documents do not assign the species to a complete list of IBRA bioregions. The described habitat settings include foothill and coastal forests, dry and damp sclerophyll forests, Box-Ironbark Forest, Red Gum and Black Box Woodland, and mesic forested corridors along major watercourses through semi-arid country.

  • Queensland: eastern forests and woodlands, extending north to Cape York Peninsula.
  • New South Wales: eastern forests and woodlands, western NSW and river corridors including the Murray floodplain.
  • Victoria: Gippsland, foothill and coastal forests, remnant woodlands north of the Great Dividing Range, the Murray floodplain and the Wimmera.
  • South Australia: parts of the state associated with the species' western range, as described in the Victorian assessment.

Distribution: Strongholds and population status

East Gippsland was regarded as the Victorian stronghold before the 2019 to 2020 fires. A significant amount of habitat there was burnt, and the effect on the population had not been determined in the assessment supplied.

The Victorian assessment inferred a population reduction of 40 to 60 per cent over past, future and combined 24 to 45 year periods. It also inferred 5,000 to 20,000 mature individuals, but the supplied document does not establish that this estimate applies uniformly across the national range.

Estimated mature individuals: 5,000 to 20,000, as inferred in the Victorian assessment.

Inferred reduction: 40 to 60 per cent over 24 to 45 years for the assessment criteria used in Victoria.

Victorian status: Endangered.

National EPBC status: Not listed in the supplied project information.

Habitat: Habitat types

Lace Monitors use treed habitats that provide climbing surfaces, basking opportunities, prey, carrion and shelter. They can occupy both moist forest and woodland beside rivers in drier country.

Recorded habitat types include damp sclerophyll forest, dry sclerophyll forest, riparian forest, Box-Ironbark Forest, Red Gum Woodland and Black Box Woodland. The species also uses mesic, forested corridors along major watercourses through semi-arid areas.

The Central Hunter Valley eucalypt forest and woodland complex and Poplar Box Grassy Woodland are identified as habitats that may support Lace Monitors. These references show that the species can occur in both denser forest and open grassy woodland where suitable trees and other resources remain.

Habitat: Structural features

Retain mature trees, tree hollows, fallen timber, logs, leaf litter, rocks, termite mounds and connected patches of native vegetation where present. These features provide climbing, basking, refuge, feeding and potential breeding resources.

Trees also provide canopy cover and hollows, while litter, sticks and logs create sheltered ground conditions and habitat for prey. The species' large home ranges mean that a small retained patch may remain connected to feeding or sheltering sites outside the immediate work area.

Reported home range: 14 to 128 ha.

Habitat: Climate and elevation

The supplied documents do not give an elevation limit. They describe a distribution from tropical Cape York Peninsula to temperate Gippsland and use of both moist forest and semi-arid river corridors.

Activity is influenced by temperature because Lace Monitors are ectothermic and regulate body temperature by moving between warmer and cooler locations. Winter movement is reported to be lower than movement during warmer periods.

Foraging habitat: Diet

Lace Monitors are active predators and scavengers that search across the ground and in trees. They use a broad range of animal food and may investigate hollows, nests, burrows, logs and campgrounds for prey or carrion.

The diet includes carrion, small vertebrates, reptiles, birds, eggs, mammals, insects and other macroinvertebrates. This broad diet allows individuals to use different food resources as availability changes between sites and seasons.

The species is an apex predator in the supplied Victorian assessment and also acts as a scavenger. It therefore links prey communities and carrion resources within forest and woodland food webs.

Foraging habitat: Foraging locations and method

Lace Monitors search on the ground and in trees, climb to investigate hollows and use their forked tongue to detect chemical information. They typically locate small vertebrates in burrows, nests or hollows.

Retain trees, hollows, logs, litter, rocks and connected native vegetation around works because these features can support prey, carrion and access between feeding sites. Individuals may use large areas while repeatedly visiting important feeding and refuge sites.

Reported home range: 14 to 128 ha.

Breeding habitat: Breeding biology

Lace Monitors are egg-laying reptiles with an unusual association with active termite mounds. Breeding habitat must provide suitable termite mounds as well as connected treed habitat for adults and young.

Females excavate a chamber in the side of an active termite mound and lay the eggs. Termites rebuild the mound over the eggs, providing a protected and temperature-stable incubation environment. The female later returns to excavate the young.

Mating details and the exact timing of mating are not provided in the supplied documents. Breeding is described as occurring in summer.

Breeding season: Summer.

Clutch size: 4 to 15 eggs; 6 to 12 eggs is also reported.

Incubation: About 8 to 9 months.

Age at maturity: About 4 to 6 years is suggested for larger varanids; a Lace Monitor-specific value is not provided.

Lifespan: About 15 to 20 years is suggested for large monitors; longer survival is possible, but a Lace Monitor-specific maximum is not provided.

Young: Hatchlings emerge from the termite mound, and young Lace Monitors spend much of their early life in trees.

Breeding habitat: Breeding-site requirements

Active termite mounds are the defining breeding resource described for the species. Mounds should be retained and protected from direct disturbance, excavation, compaction, vibration and changes that could make them unsuitable.

Breeding females also require access through surrounding treed habitat. Retaining mature trees, hollows, logs, litter and connected vegetation helps maintain cover, feeding sites and movement routes for adults and young.

Sheltering habitat: Tree and canopy refuges

Lace Monitors shelter in and around trees and other forest structures. Their climbing ability allows them to use vertical habitat, while logs, rocks, litter and hollows provide additional cover and refuge.

Large trees provide climbing, basking and refuge sites. Tree hollows are used as shelter or investigated while foraging, and young animals spend much of their early life in trees.

Avoid removing mature trees and retain connected canopy where practicable. The supplied documents do not provide a minimum tree diameter, hollow entrance size or hollow height for Lace Monitor refuge sites.

Sheltering habitat: Ground cover and other shelter

Fallen timber, logs, rocks, leaf litter, burrows, nests and hollows contribute to shelter or provide access to prey. These features also support the invertebrates and small vertebrates that form part of the species' food supply.

Active termite mounds are breeding structures rather than general refuges, but they should be treated as sensitive habitat because eggs are incubated inside the mound for about 8 to 9 months.

Incubation period: About 8 to 9 months.

Home range: 14 to 128 ha.

Threats: Clearing and fragmentation

The Victorian assessment identifies habitat loss and damage, forestry operations, inappropriate fire regimes and fuel management as threats. Development can add direct habitat loss, fragmentation, vehicle mortality, disturbance and increased access by predators.

Clearing removes mature trees, hollows, logs, litter, termite mounds and prey habitat. Fragmentation can reduce movement between feeding, refuge and breeding sites for an animal with reported home ranges of 14 to 128 ha.

Prioritise retention of connected treed habitat, mature hollow-bearing trees, fallen timber, termite mounds and vegetated links to larger remnants. Inspect the wider work area rather than treating an isolated tree or mound as the only relevant habitat feature.

Threats: Fire and forestry

Inappropriate fire regimes and fuel management activities are identified threats. Significant habitat in East Gippsland was burnt in the 2019 to 2020 fires, but the population effect had not been determined in the assessment.

Forestry operations and other vegetation removal can damage the forest structure used for climbing, shelter, feeding and breeding.

Threats: Roads, machinery and construction activity

The supplied documents do not quantify road mortality or construction injury for Lace Monitors. As a field control, use fauna spotter catchers where required, inspect vegetation and ground structures before clearing, control vehicle speeds in retained habitat, and prevent machinery from entering retained trees, logs and termite mounds.

Do not feed Lace Monitors or leave food waste accessible, because food scraps and unsecured rubbish can alter foraging behaviour and attract animals to people and roads.

Threats: Predators and other pressures

Young animals are likely to be affected by predation from exotic animals. Habitat loss, reduced habitat availability and possible inbreeding among a small number of survivors are also identified concerns in the Victorian assessment.

No disease threat or hydrology-specific threat is identified in the supplied documents. Changes to watercourse vegetation or moisture conditions should nevertheless be assessed where works affect riparian forest or river corridors used by the species.

Survey methodology: 1. Daytime habitat inspection

The supplied documents do not provide a species-specific survey guideline or prescribed survey effort for Lace Monitors. Use a targeted, risk-based survey that covers trees, hollows, logs, termite mounds, ground shelters and connected native vegetation, and record the conditions and search effort clearly.

Inspect the proposed disturbance area and adjoining retained habitat before works begin.

Search trees, trunks, branches, hollows, fallen timber, leaf litter, rocks, termite mounds and ground cover for animals, tracks, scats, sloughed skin, burrows and feeding signs.

Give particular attention to mature treed habitats, riparian forest, dry and damp sclerophyll forest, box-ironbark forest, red gum and black box woodland, and wooded corridors along major watercourses.

Map habitat features and potential movement routes because Lace Monitors use both ground and trees and may move through large home ranges.

Adult length: Up to about 2 metres from snout to tail tip

Home-range size: About 14 to 128 hectares

Activity: Diurnal and ectothermic

Survey methodology: 2. Active searches and visual scans

Conduct systematic daytime searches along proposed clearing edges, access tracks, tree bases, fallen timber, termite mounds and retained vegetation adjoining the works.

Scan elevated branches, trunks and hollows because Lace Monitors are capable tree climbers and may shelter or forage above ground.

Repeat searches where access, visibility or weather has limited detection, and include both the disturbance footprint and nearby retained habitat that may receive displaced animals.

Record the search date, start and finish time, observers, area searched, weather, visibility, habitat features inspected and all detections.

Normal activity period: Daytime

Useful detection features: Trees, hollows, logs, rocks, leaf litter, termite mounds, prey remains and carrion

Survey methodology: 3. Targeted checks of breeding and refuge features

Inspect active termite mounds in and beside the disturbance area because females lay eggs in active termite mounds during summer.

Do not damage or open termite mounds during survey work unless this is authorised under the project fauna management plan and state requirements.

Inspect large trees, hollows, fallen timber, rocks and dense ground cover for adults and young animals, while avoiding unnecessary disturbance.

Use additional repeat daytime searches during warm conditions when animals are more likely to bask or move, and document temperature, cloud cover, wind, rain and recent fire conditions.

Breeding period noted in the assessment: Egg laying occurs in summer

Incubation information: Eggs may remain in a sealed termite mound for about 8 to 9 months

Survey methodology: Minimum effort and reporting

  • Use a qualified ecologist or fauna spotter catcher to set the search area and effort according to the habitat risk, proposed clearing method and visibility.
  • Do not claim that a site is free of Lace Monitors from a single negative search because the species can climb, use concealed shelters and move across large home ranges.
  • Where night work or night survey is proposed, treat it as supplementary only because the species is described as diurnal and the supplied documents give no prescribed spotlighting effort.
  • Submit confirmed records, including reliable negative or mortality records where required, to the relevant state wildlife database and comply with the data requirements of the state authority.
  • Retain maps, photographs, observer details, search conditions, effort, detections, handling records, release locations and permit details in the project file.

Before habitat disturbance: Avoid and minimise habitat loss

Plan the work around the species' use of mature trees, hollows, fallen timber, termite mounds and connected native vegetation. The Lace Monitor is not listed under the EPBC Act in the supplied information, but it is listed as Endangered in Victoria and is protected in New South Wales.

Known threats: Habitat loss and damage, forestry operations, inappropriate fire regimes and fuel management activities

Potential threat to young animals: Predation by exotic animals

  • Retain mature trees, hollow-bearing trees, fallen timber, rocks, leaf litter, active termite mounds and dense native vegetation wherever practicable.
  • Retain connected treed habitat and corridors, especially along watercourses, because individuals can use large home ranges and move between feeding, refuge and breeding resources.
  • Keep the disturbance footprint, vehicle movements, stockpiles, lighting and access tracks outside retained habitat wherever practicable.
  • Avoid removing active termite mounds during summer egg laying and obtain fauna advice before any mound must be disturbed.

Before habitat disturbance: Check approvals and plan the works

  • Check the current state listing and obtain any Victorian permit, approval or authorisation required for an Endangered species before works start.
  • Check whether the action may affect another protected matter or listed ecological community and obtain environmental advice on any EPBC Act referral requirement.
  • Prepare a fauna management plan that identifies the disturbance footprint, retained habitat, survey method, spotter catcher roles, stop-work triggers, handling limits, release areas and incident reporting.
  • Stage clearing so that retained habitat remains connected and animals have nearby cover while each work area is inspected and released.

Before habitat disturbance: Prepare and mark the site

  • Complete the pre-clearance inspection immediately before clearing and update the habitat map if trees, logs, termite mounds or other features have changed.
  • Mark no-go areas, retained trees, termite mounds, logs, rocks, refuge areas and movement corridors on the ground and in the site plans.
  • Install exclusion fencing where it can prevent entry into retained habitat without trapping Lace Monitors or blocking their movement to suitable refuge.
  • Brief operators on the species' appearance, tree-climbing ability, handling limits, release procedure, stop-work triggers and reporting requirements.

During habitat disturbance: Daily controls and machinery coordination

Use a spotter catcher and staged clearing process that gives animals a clear opportunity to move into retained habitat. Stop work when an animal or a high-risk habitat feature requires assessment.

  • Inspect the active work area, exclusion fencing, retained trees, termite mounds and likely refuge features at the start of each shift.
  • Keep the fauna spotter catcher within effective viewing distance of the active clearing and stop machinery when the spotter catcher directs the operator to stop.
  • Clear vegetation progressively towards retained habitat where the site layout allows, while avoiding pushing animals into machinery, roads, open excavations or unsuitable habitat.
  • Maintain low vehicle speeds, control unnecessary noise and vibration, and prevent access to retained habitat, stockpiles and open trenches unless they have been inspected.

During habitat disturbance: Habitat features and animal handling

  • Do not remove or destroy a hollow-bearing tree, active termite mound, large log, rock pile or other suspected refuge feature until it has been inspected and the fauna management plan allows the action.
  • Use trained and authorised personnel for capture, handling and relocation, and do not permit untrained workers to chase, restrain, feed or transport a Lace Monitor.
  • If an animal is found, stop nearby work, keep people and dogs away, allow an escape route to nearby retained habitat, and capture it only when the authorised fauna handler determines that capture is necessary.
  • Relocate a healthy animal only to suitable nearby retained habitat identified in the fauna management plan, and record the release location, time, condition and method.
  • Do not handle an animal by the tail or place hands near the jaws, and use approved equipment and procedures specified by the authorised handler.
  • Take an injured animal to an approved veterinarian or wildlife carer through the relevant state wildlife authority, and record the incident and transfer details.

During habitat disturbance: Stop-work triggers and records

  • Stop work immediately if a Lace Monitor is found within the active work area, trapped in an excavation, injured, unable to leave safely, or associated with a termite mound or other habitat feature that is about to be disturbed.
  • Stop work if exclusion fencing is damaged, a no-go area is entered, a retained tree or habitat feature is struck, or the fauna spotter catcher loses effective visibility of the work face.
  • Reassess the work method with the project ecologist before restarting and obtain any required authority direction or permit amendment.
  • Record every sighting, capture, relocation, injury, mortality, habitat feature disturbance, stop-work event and corrective action.
  • Photograph the animal or feature where this can be done without causing additional disturbance, and submit required records to the relevant state wildlife database.

After habitat disturbance: Complete post-clearance checks

Clearance is not complete until the work area and retained habitat have been checked, controls are repaired and records are closed out. Post-work actions should focus on surviving animals, retained habitat and movement between habitat patches.

  • Inspect the cleared area, tree bases, remaining trees, logs, rocks, termite mounds, stockpiles, trenches and drainage structures for Lace Monitors or trapped fauna before the site is handed to the next construction activity.
  • Inspect retained habitat beside the cleared area for displaced animals and damage to trees, hollows, logs, termite mounds, fencing and access controls.
  • Close, ramp or securely fauna-proof trenches and pits when they are not actively being worked, and inspect them at the frequency required by the fauna management plan.
  • Use an authorised fauna handler for any animal requiring capture, treatment or relocation.

After habitat disturbance: Monitor and maintain controls

Generation length: Estimated at 8 to 15 years

Population estimate in the Victorian assessment: About 5,000 to 20,000 mature individuals

  • Maintain no-go fencing, retained habitat buffers and movement corridors until construction risks have ended and the project environmental officer approves their removal.
  • Monitor retained habitat and rehabilitation areas for Lace Monitor sightings, road mortality, injured animals, predation signs, loss of mature trees, termite mound damage and weed or fire impacts.
  • Investigate changes in sighting frequency cautiously because detection depends on season, temperature, visibility, observer effort and access.
  • Continue vehicle, dog, waste and food controls around retained habitat and work compounds because feeding and rubbish can alter natural foraging behaviour and attract animals to people.

After habitat disturbance: Close-out and offsets

  • Provide the regulator, client and project ecologist with the final habitat map, survey effort, clearance records, handling and relocation records, injuries, mortalities, incidents and corrective actions.
  • Submit required records to the relevant state wildlife database and meet all approval conditions for monitoring and reporting.
  • Where an approval requires an offset or other compensatory measure, use the approved mechanism and ensure it protects or restores suitable treed habitat and habitat connectivity for Lace Monitors.
  • Review incidents and monitoring results before the next stage of works and amend the fauna management plan where controls were ineffective.

Rehabilitation actions: Restore habitat structure

Rehabilitation should restore the structure and resources used by Lace Monitors rather than only replanting cleared ground. Prioritise connected native treed habitat with mature-tree recruitment, refuge features, prey resources and suitable termite habitat.

Relevant habitat types: Damp sclerophyll forest, dry sclerophyll forest, riparian forest, box-ironbark forest, red gum and black box woodland

Habitat resources: Trees, hollows, shelter, prey, carrion and termite mounds

  • Replant locally appropriate native trees and understorey species that restore the relevant forest or woodland community, using the project ecologist's regional species list rather than a generic planting mix.
  • Retain existing mature trees and protect planted trees from browsing, machinery damage, compaction, fire and weed competition.
  • Reinstate suitable fallen timber, rocks, leaf litter and other ground cover in stable locations that do not create hazards for vehicles or workers.
  • Do not move active termite mounds or create artificial mounds without advice from the project ecologist and approval under the fauna management plan.

Rehabilitation actions: Reconnect and protect retained habitat

  • Restore native vegetation links between retained trees, watercourse corridors and adjoining woodland where these links were severed by the project.
  • Keep rehabilitation areas free from vehicle access, domestic dogs, food waste and unnecessary artificial lighting.
  • Manage invasive predators and pest animals in accordance with state requirements where monitoring identifies a risk to young Lace Monitors.
  • Use a fire management approach that avoids inappropriate fire regimes and protects established trees, fallen timber, hollows and termite mounds.

Rehabilitation actions: Monitor success

Species activity for monitoring design: Diurnal and generally less mobile in colder winter conditions

Breeding information relevant to monitoring: Females lay 4 to 15 eggs in active termite mounds during summer

  • Inspect rehabilitation areas during daytime searches for Lace Monitors, tracks, scats, feeding remains, tree use, shelter use and movement between retained habitat patches.
  • Repeat monitoring using the same mapped search areas, observer effort and recording method so results can be compared between seasons and years.
  • Measure survival and growth of planted trees, retention of logs and rocks, condition of termite mounds, weed cover, predator activity, fencing condition and connectivity to retained habitat.
  • Treat successful rehabilitation as establishment of safe, connected treed habitat with functioning refuge and food resources, not as a requirement to detect an animal on every visit.

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