Crack-dwelling Whipsnake (Demansia rimicola)

Conservation status

New South Wales, Biodiversity Conservation Act 2016: Vulnerable.

Breeding season

Female reproductive cycles are strongly seasonal, with ovulation often occurring in spring. The timing of mating, egg laying, incubation and young emergence is not recorded, so plan clearing for potential risk in every month and apply additional care in spring.

Reproductive mode: Not recorded.

Clutch size: Not recorded.

Incubation: Not recorded.

Size at hatching or birth: Not recorded.

Age at maturity: Not recorded.

Nest or egg sites: Not recorded.

Breeding frequency: Female reproductive cycles are strongly seasonal, but the frequency of breeding is not recorded.

Confirm timing locally with the project ecologist or wildlife authority, and review rainfall and temperature triggers because these may alter surface activity and refuge use in cracking clay habitat.

• Mating: Mating months are not recorded for this species. Treat potential mating activity as possible throughout the year until local observations provide a narrower period.
• Gravid females: The documents do not report when females carry eggs or embryos. Spring ovulation is reported, but the duration of the gravid period is unknown, so gravid females may be encountered in any month.
• Egg laying: Egg laying has not been confirmed or assigned to particular months. Do not disturb potential refuge features or soil cracks in any month without checking them first.
• Incubation: Incubation duration and nest or egg sites are not recorded. If eggs are found, stop work nearby and obtain species-specific advice before continuing.
• Hatchlings: Hatching and juvenile emergence months are not recorded. Young snakes may therefore be present in any month, including near cracking clay refuges.
• Active period: The species is mostly diurnal and visually locates prey during the day. No seasonal activity limits are recorded, so treat adults as surface active throughout the year, with checks timed for daylight where practicable.
• Highest clearing risk: Every month carries clearing risk because shelter use, activity and young emergence are not seasonally defined. Spring, September to November, warrants additional attention because females often ovulate then, but no species-specific egg laying or hatchling peak is known.

Identification

This is a moderately large, stout whip snake with a brown to yellow-brown body and a characteristic head and neck pattern. It is venomous and should be identified from a safe distance by a trained person.

The head and nape are mid-brown, usually with darker flecks and spots. The body is mid-brown to mid yellow-brown, with darker pigment often concentrated along the lateral scale rows. The belly is usually yellow, with dark brown throat marbling and paired dark spots on the front of the ventral scales. Some recently collected New South Wales and Queensland specimens had a bright orange-red belly in life.

Snout to vent length: 155 to 740 mm, mean 488.1 mm

Tail length: 25.4 to 41.5% of snout to vent length, mean 31.8%

Ventral scales: 178 to 203, mean 190.2

Subcaudal scales: 68 to 96, mean 83.4

Identification: Key field characters

Look for a dark nape collar edged with pale markings, although the collar can become indistinct in adults. The pale postocular bar is sharply constricted and angled, giving the appearance of two pale blobs on the side of the face. Two rows of dark spots diverge across the anterior ventral scales.

• The dark nape band is usually broader than in Demansia angusticeps and Demansia olivacea.
• The species is larger and more robust than Demansia calodera and Demansia flagellatio.
• It has dark spots on the head dorsum and lacks the second dark nuchal band described for Demansia flagellatio.
• The head pattern is more sharply defined, and the pale postocular markings are more prominent, than in Demansia quaesitor.

Identification: Sex and field signs

Males have more subcaudal scales and relatively longer tails than females. The supplied documents do not provide reliable information on tracks, scats, calls, nests, sloughs or eyeshine, so these signs should not be used as primary identification features.

• Males: 73 to 93 subcaudal scales, mean 85.9; tail 28.2 to 41.5% of snout to vent length.
• Females: 68 to 89 subcaudal scales, mean 80.5; tail 27.9 to 33.8% of snout to vent length.
• Do not handle the snake for identification. Use photographs of the head, neck, side pattern and belly where this can be done safely.

Distribution: National range

The species is endemic to inland Australia and has a broad but discontinuous range associated with cracking clay soils. The supplied documents provide locality records and state records, but no population estimate or population trend.

The documented range extends from the southeast Kimberley in Western Australia, through the Northern Territory and Queensland, south-east to Goyder’s Lagoon in South Australia and the Tibooburra region of New South Wales. It extends east to Bindango Siding in Queensland and north-east to the Hughenden district.

• Western Australia: southeast Kimberley, including Smoke Creek, Flora Valley and the Argyle area.
• Northern Territory: Barkly and adjoining inland districts, including Avon Downs, Brunette Downs, Frewena, Anthony’s Lagoon and Victoria River Downs records.
• Queensland: inland and central western districts from Hughenden, Julia Creek, Longreach, Winton, Boulia and Tibooburra adjacent areas to Bindango Siding near Roma.
• South Australia: Goyder’s Lagoon and the Clifton Hills area.
• New South Wales: the Tibooburra region and Sturt National Park.

Distribution: Strongholds and population status

The records show repeated specimens from the Longreach and wider central western Queensland district, the Barkly region of the Northern Territory, the southeast Kimberley and the Tibooburra to Sturt National Park area. These are record concentrations, not confirmed population strongholds, because the documents do not provide abundance or survey-effort data.

Population size: Not reported in the supplied documents

Population trend: Not reported in the supplied documents

Known state range: New South Wales, Northern Territory, Queensland, South Australia and Western Australia

Erroneous or doubtful record: A Rollingstone record north of Townsville is considered erroneous because of its distance from other localities and the different habitat

Distribution: Project interpretation

A site outside the listed localities should not be treated as occupied solely because it contains cracking clay. Conversely, a lack of recent records should not be treated as evidence of absence. Check regional databases, previous environmental reports and local experts before clearing inland cracking clay habitat.

• Give particular attention to cracking clay plains and blacksoil areas in the Channel Country, Mitchell Grass Downs, Barkly and adjoining inland districts.
• Record the exact location, soil type, crack condition, photographs and weather conditions for every observation.
• Treat the New South Wales listing as a project constraint where work occurs in the species’ New South Wales range.

Habitat: Known habitat

The species is specifically associated with cracking clay soils in northern central Australia. The supplied material does not identify a definitive vegetation community, elevation limit or climate threshold.

The type description places Demansia rimicola in cracking clay soils of northern central Australia. Its common names also refer to blacksoil and Mitchell Grass Downs habitat. Records span inland plains and station country from the southeast Kimberley to western Queensland, the Barkly region, Goyder’s Lagoon and north-western New South Wales.

Primary substrate: Cracking clay soils

Named habitat associations: Blacksoil, Mitchell Grass Downs and Channel Country country

Elevation limit: Not reported

Climate limit: Not quantified in the supplied documents

Habitat: Features to retain during works

The documents do not quantify vegetation structure or cover requirements. During site assessment, map cracking clay areas as potential habitat and retain connected areas of native ground cover where practicable. Avoid assuming that apparently bare clay is unsuitable habitat.

• Map gilgai, clay depressions, drainage lines and areas with persistent soil cracking where they occur within the project footprint.
• Keep potential habitat connected across access tracks, compounds and cleared corridors where practicable.
• Inspect the ground surface, large cracks and nearby cover before machinery enters or soil is stripped.

Foraging habitat: Evidence gap

The supplied documents do not report diet, prey species, feeding times, feeding range or hunting behaviour for Demansia rimicola. Field planning should therefore rely on direct observations and general snake survey practice rather than assumed prey associations.

No prey, food plant, foraging distance or feeding method is given in the supplied sources. The species is an elapid whip snake, but its diet and foraging ecology should be confirmed from specialist or project-specific information before being used in impact assessment.

• Do not infer absence from a lack of visible prey or from sparse surface vegetation.
• Record the substrate, ground cover, weather, time and location when a snake is observed foraging.
• Search potential habitat across both open clay surfaces and adjacent cover because the documents do not define a preferred foraging microhabitat.

Breeding habitat: Breeding information

Breeding season, clutch size, incubation, maturity and lifespan are not reported in the supplied documents. No breeding feature has been confirmed for this species in the material provided.

The species description and distribution account do not provide observations of mating, eggs, young, gravid females, nesting sites or incubation. Project decisions should not rely on a presumed breeding season.

Breeding season: Not reported

Clutch or litter size: Not reported

Gestation or incubation: Not reported

Age at maturity: Not reported

Lifespan: Not reported

• Ask the project ecologist or wildlife authority for current species-specific breeding information before setting seasonal clearing controls.
• If eggs, hatchlings, gravid females or mating snakes are found, stop work in the immediate area and obtain species-specific advice.
• Record any breeding evidence with photographs, coordinates, soil description and the extent of the affected area.

Breeding habitat: Potential breeding habitat

No breeding microhabitat is identified. Because the species is associated with cracking clay soils, retain and inspect undisturbed clay areas and adjacent ground cover rather than removing them without further assessment.

• Do not fill, compact or seal large areas of cracking clay before they have been checked for snakes and other signs.
• Maintain links between clay habitat patches where practicable during construction planning.
• Use a qualified fauna spotter catcher for any animal capture or relocation.

Sheltering habitat: Known refuge association

The species name refers to its association with cracks in clay soil. The supplied documents do not confirm crack dimensions, retreat depth, burrow use or other shelter requirements.

Demansia rimicola was named from Latin words meaning crack-dweller, referring to its association with cracking clay soils. This supports treating soil cracks as potential refuge features during clearing, grading and earthworks.

Confirmed shelter type: Association with cracking clay soils

Crack or refuge dimensions: Not reported

Hollows, nests or burrows: Not reported

• Inspect open cracks, clay fissures and nearby surface cover before disturbance.
• Avoid driving or stockpiling materials over areas with substantial cracking where practicable.
• Do not insert hands, tools or camera equipment into cracks.

Sheltering habitat: Site controls

No species-specific refuge exclusion distance is provided. Use a staged clearing approach, retain undisturbed refuge areas where practicable and have a trained spotter catcher present when potential habitat is being cleared.

• Clear vegetation and surface debris in stages so animals can move away from machinery where safe and lawful.
• Check material piles, disturbed clay edges and construction trenches before moving or backfilling them.
• Provide safe egress from open trenches and inspect them regularly while they remain open.

Threats: Clearing and earthworks

The supplied documents establish the species’ close association with cracking clay soils and its Vulnerable listing in New South Wales, but do not quantify threats or population decline. The main project risk is loss or fragmentation of inland cracking clay habitat.

Clearing, grading, compaction, trenching and sealing of cracking clay soils can remove or alter habitat identified for this species. Risk is highest where works occupy broad, connected clay plains or remove the remaining habitat around known records.

• Avoid unnecessary clearing of cracking clay and blacksoil areas.
• Keep access tracks, laydown areas and compounds out of potential habitat where practicable.
• Inspect the work area immediately before clearing and use staged clearing with a fauna spotter catcher.

Threats: Fragmentation and roads

The documents do not quantify road mortality or fragmentation effects. Roads, rail corridors and linear infrastructure can nevertheless divide habitat and expose snakes to vehicle strike during movement between suitable clay areas.

• Use existing disturbed corridors where practicable rather than creating new routes through intact clay habitat.
• Manage vehicle speeds and inspect roads through known habitat for injured or dead snakes.
• Keep temporary fencing and stockpiles from creating traps or blocking movement routes.

Threats: Fire, predators, disease and hydrology

Specific effects of fire, introduced predators, disease and hydrology change are not reported in the supplied documents. Changes to flooding, drainage, soil moisture or cracking patterns may alter the clay habitat on which the species is associated.

• Obtain project-specific advice before changing drainage, floodplain flows or water retention across cracking clay habitat.
• Do not claim that fire, predators or disease are threats to this species without supporting local evidence.
• Record mortality, injury and unusual observations so regional threat information can be improved.

Survey methodology: 1. Habitat assessment and targeted searches

Demansia rimicola is associated with cracking clay soils across inland and northern central Australia. The supplied documents do not provide a species-specific survey guideline or a prescribed survey effort, so the project ecologist should set effort from the extent of cracking clay habitat, disturbance footprint, season and risk of encounter.

Map cracking clay soils and associated Mitchell Grass Downs, blacksoil and Channel Country habitat before selecting survey locations.

Walk the disturbance footprint and nearby retained habitat to identify soil cracks, dense ground cover, drainage lines and other places where a snake could shelter.

Search carefully around soil cracks and surface refuges, without filling, collapsing or unnecessarily widening cracks.

The species has been recorded from northern central Australia between the southeast Kimberley, Goyder’s Lagoon in South Australia, the Tibooburra region in New South Wales, and Queensland localities including the Hughenden district.

Survey methodology: 2. Spotlighting and active searches

Use night spotlighting and slow walking searches in suitable retained and impact-area habitat where access and safety allow.

Give particular attention to open ground, cracking clay, grass tussocks, track edges and habitat adjoining drainage features.

Record the time, date, weather, recent rainfall, soil condition, start and finish points, distance walked and observers for every search.

The supplied documents do not specify a required number of nights, hours, transect length or weather threshold. Set these values in the survey design and explain the basis for them in the report.

• Use suitably trained observers who can identify Demansia rimicola and distinguish it from other Demansia species recorded in the region.
• Do not rely on a single negative search where cracking clay habitat is extensive or poorly accessible.

Survey methodology: 3. Reptile refuge and pre-clearance searches

Complete systematic daytime searches of the disturbance area before clearing, including cracks, loose surface material, logs, rocks, grass tussocks and debris where these are present.

Use hand tools only where needed to lift loose refuges, and replace each item in its original position after inspection.

Inspect areas immediately before machinery enters them, because a snake may move into newly disturbed ground or temporary refuge during staging.

The species is a moderately large snake, with a recorded snout to vent length of 155 to 740 millimetres.

Recorded snout to vent length: 155 to 740 mm

Recorded mean snout to vent length: 488.1 mm

• Do not place funnel traps, pitfall traps or artificial refuges unless they are approved in the survey plan, suitable for the site and checked at the required frequency by authorised personnel.
• Do not handle a suspected Demansia rimicola during survey simply to confirm identification.

Survey methodology: Minimum effort and reporting

• Define the survey area to include the full impact footprint and nearby retained cracking clay habitat that could be used by displaced fauna.
• Document the search method, dates, start and finish times, observers, weather, recent rainfall, soil condition, distance or area searched, refuges inspected and survey limitations.
• Treat any observation, photograph, capture, road record or carcass as a significant fauna record and retain accurate coordinates, habitat photographs and an identification record.
• Submit confirmed records to the relevant state wildlife database and notify the project approval holder and relevant state agency where required.
• Check the current survey requirements and permit conditions for the state or territory in which the project occurs before finalising the effort.

Before habitat disturbance: Avoid and minimise

Plan the work around the species’ recorded habitat rather than relying only on broad vegetation mapping. The defining habitat association is cracking clay soil, and the documented range crosses five Australian states and territories.

• Avoid clearing cracking clay soil where practicable, particularly where it forms a large, continuous patch or connects retained areas.
• Retain connected areas of cracking clay, native ground cover and shelter features beside the work area.
• Keep vehicle movements, laydown areas, access tracks and spoil placement out of retained habitat.
• Do not use the erroneous coastal Rollingstone record as a basis for treating all Queensland habitat as suitable, because that record was considered erroneous in the taxonomic account.

Before habitat disturbance: Approvals and work planning

• Confirm the current state conservation status, development controls, wildlife permits and handling requirements before work starts.
• Check whether the action requires an EPBC Act referral or approval, and record the outcome in the project environmental documentation.
• Prepare a fauna management plan that identifies cracking clay habitat, survey methods, fauna roles, stop-work triggers, relocation arrangements and reporting responsibilities.
• Stage clearing so that habitat is removed progressively and fauna can move towards retained habitat rather than being surrounded by active works.
• Set the clearing window using local seasonal activity, access conditions and recent rainfall, because the supplied documents do not nominate particular months for this species.

Before habitat disturbance: Site preparation

• Complete and document a pre-clearance search immediately before each clearing stage.
• Mark no-go areas, retained cracking clay, access routes and any locations requiring a fauna spotter catcher.
• Install exclusion fencing only where it will direct animals towards retained habitat and will not block natural movement or trap snakes against the work area.
• Brief machinery operators on the species’ appearance, the exclusion zones, the spotter catcher’s authority and the stop-work procedure.

During habitat disturbance: Daily controls

Demansia rimicola is an elapid snake, so sightings must be managed by trained and authorised personnel. Machinery must not move until the spotter catcher has checked the work area and confirmed that the next task can proceed safely.

• Inspect the active work area, access routes and exclusion fencing at the start of each shift and after breaks or changes in the work front.
• Keep the fauna spotter catcher within a safe position to observe the clearing face, machinery and likely escape routes.
• Use staged, slow clearing towards retained habitat where safe, and avoid trapping animals between machinery, fencing, spoil or excavated edges.
• Keep cracks, loose soil and surface refuges intact until they have been inspected or are being removed under direct fauna supervision.
• Stop work if visibility is poor, the spotter catcher is not present, exclusion controls fail or machinery cannot be operated safely around an animal.

During habitat disturbance: Spotter catcher response

• The spotter catcher must direct the operator to stop and isolate machinery when a snake is sighted or suspected within the active work area.
• Do not allow untrained workers to approach, chase, corner, catch or kill the animal.
• Have only appropriately trained and authorised personnel handle the snake, using methods and equipment approved under the relevant state or territory requirements.
• Where relocation is authorised, move the animal only to suitable nearby retained habitat with cracking clay or comparable shelter, following the project fauna management plan.
• Do not relocate an animal across roads, into unsuitable habitat or outside the locally appropriate area without specific approval.

During habitat disturbance: Habitat features, injury and records

• Inspect logs, rocks, debris, burrows, soil cracks and dense grass before removal, and move or reinstate them only under spotter catcher direction.
• Treat excavations, trenches, pipes, stockpiles and machinery as potential temporary refuges and inspect them before covering, moving or starting work.
• Do not handle an injured snake unless the person is authorised and trained to do so safely.
• Place an injured animal with an approved wildlife rehabilitator or veterinarian as soon as practicable, and record the handover.
• Record every sighting, capture, relocation, injury, mortality, stop-work event and habitat feature removed, including coordinates, time, photographs and the people involved.

After habitat disturbance: Post-clearance checks

Post-clearance actions should confirm that no animals remain in the work area, that retained cracking clay habitat remains connected and that all fauna incidents have been closed out.

• Complete a final search of the cleared area, spoil margins, excavations, temporary fencing and retained habitat edges after each clearing stage.
• Inspect areas where cracking clay, grass cover, logs, rocks or other surface refuges were disturbed.
• Keep open trenches, pipes and similar hazards covered, ramped or checked at the frequency specified in the fauna management plan until they are closed.
• Remove temporary exclusion fencing only when the responsible ecologist confirms that it will no longer protect fauna or direct movement.

After habitat disturbance: Monitoring and reporting

• Monitor retained cracking clay habitat and any relocation areas at the frequency set by the approval, fauna management plan or risk assessment.
• Compare post-clearance observations with pre-clearance survey results and investigate any unexpected concentration of snakes, injuries or mortalities.
• Report confirmed records to the relevant state wildlife database and provide incident and monitoring reports to the approval holder and regulator where required.
• Review controls after each clearing stage and change the method if animals are repeatedly entering the work area.

After habitat disturbance: Offsets and compliance close-out

• Confirm whether state or Commonwealth approval conditions require an offset, restoration action or protection of additional cracking clay habitat.
• Retain survey data, photographs, permits, handling records, veterinary or rehabilitation records and close-out evidence for the project record.
• Do not describe habitat as successfully retained until the mapped area, condition, connectivity and management responsibilities have been verified.

Rehabilitation actions: Soil and habitat reinstatement

Rehabilitation should restore the soil and shelter structure that support a crack-dwelling snake. The primary species-specific target is functional cracking clay habitat with connected native ground cover, not simply tree planting.

• Reuse suitable local soil and reinstate natural levels and drainage so that cracking clay can reform where it was temporarily disturbed.
• Prevent compaction in rehabilitation areas and keep heavy vehicles, spoil and repeated pedestrian traffic out until the soil structure has recovered.
• Retain or reinstate locally appropriate native grass and ground-layer cover around cracking clay areas.
• Replace logs, rocks and other natural surface refuges in their original or ecologically suitable positions where they were removed for the works.
• Do not import soil, rubble or artificial refuge material unless it is approved by the project ecologist and does not introduce weeds or alter the soil profile.

Rehabilitation actions: Planting, weeds and fire

• Use locally native ground-cover and grass species suited to the site’s cracking clay soil and regional reference community, rather than selecting a generic planting mix.
• Control weeds before they dominate cracks, grass cover or movement paths, using methods that do not injure fauna or contaminate retained habitat.
• Manage fire in accordance with the local ecological fire strategy, avoiding unplanned high-intensity fire and protecting recovering ground cover.
• Maintain movement connections between rehabilitated areas and retained cracking clay habitat.

Rehabilitation actions: Monitoring and success measures

• Inspect rehabilitation after rainfall and during the locally suitable reptile activity period to check for soil cracking, erosion, compaction and ground-cover recovery.
• Use repeat searches and targeted spotlighting where safe, recording the same effort and conditions at each visit so results can be compared.
• Treat success as stable cracking clay soil, connected native ground cover, functioning shelter features, no persistent weed or erosion problem and no fauna mortality caused by the works.
• Continue monitoring and corrective maintenance for the period required by the approval or rehabilitation plan.

Sources

• Genus Demansia, repfocus.dk: http://www.repfocus.dk/Demansia.html
• Revision of the Small Tropical Whipsnakes previously referred to Demansia olivacea (Gray, 1842) and Demansia torquata (Günther, 1862) (Squamata: Elapidae), Australian Museum: https://journals.australian.museum/media/Uploads/Journals/18049/1488_complete.pdf
• Soil-crack whipsnake - Wikipedia, en.wikipedia.org: https://en.wikipedia.org/wiki/Soil-crack_whipsnake