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Western Ring-tailed Possum (Pseudocheirus occidentalis)

The western ring-tailed possum is a small, nocturnal and highly arboreal marsupial found only in south-western Western Australia. It is listed as Critically Endangered under the EPBC Act and in Western Australia, so clearing, canopy breaks, loss of food trees, removal of dreys or hollows, and poorly managed construction near occupied habitat require careful controls.

Conservation status

Commonwealth, EPBC Act 1999: Critically endangered.

Western Australia, Biodiversity Conservation Act 2016: Critically endangered.

Breeding season

The pattern below combines the general coastal pattern with the more seasonal jarrah forest pattern. Breeding can occur throughout the year in some populations, but most births occur from late autumn to winter and dependent young may remain with the mother into spring or summer.

Month values are ordered January to December: 0 means not typical, 1 means occurs, and 2 means a typical peak. Local breeding timing varies between coastal peppermint habitat and inland jarrah forest.

  • Breeding: Most births occur from late autumn to winter. In inland jarrah forest, 77 per cent of recorded births occurred in May and June, with the remainder in October and November. Coastal populations can breed throughout the year, with reported peaks in April to June and October to December.
  • Young: Young remain in the pouch for about three months and may continue to suckle and depend on the mother until 6 to 7 months old. Young born in autumn or winter therefore remain dependent through winter and spring, and some into early summer.
  • Movement and dispersal: The species is generally resident within a home range, but requires connected canopy for movement. Male young are reported to disperse, while female young tend to remain within the natal range. Fragmented habitat can force movement on the ground.
  • Highest clearing risk: Clearing can harm the species in any month because adults use habitat throughout the year and coastal populations can breed throughout the year. Risk is highest from April to November when breeding, pouch young and dependent young are common, and when condition and mortality can be poor in some inland populations.

Identification

Look for a dark, small-bodied possum moving through the canopy at night, with a long, slender, strongly prehensile tail ending in a pale or white tip. It is usually detected by spotlighting, dreys, feeding signs or evidence beneath occupied trees rather than by ground tracks or calls.

The coat is usually very dark brown above, sometimes dark grey, with cream or grey fur below. The ears are short and rounded. The tail is approximately as long as the head and body, slender, strongly prehensile and white tipped.

Head and body: 300 to 400 mm.

Tail: 300 to 410 mm.

Weight: Approximately 700 to 1,300 g.

Identification: Distinguishing features

The most likely similar species is the common brushtail possum, Trichosurus vulpecula. The western ring-tailed possum is smaller, has shorter and usually darker fur, smaller rounded ears, and a slender ringtail rather than a broad brush tail.

  • Do not identify an animal from tail colour alone. Confirm the combination of body size, dark coat, rounded ears and slender white-tipped prehensile tail.
  • In south-western Western Australia, the western ring-tailed possum is one of the two large possums likely to be encountered in overlapping habitat.

Identification: Field signs

Dreys are leaf and branch nests, often about the size of a soccer ball. They may occur in tree canopies, low shrub thickets, sedges, rushes or grass trees. Tree hollows can also be used, particularly inland and more than about 4 km from the coast.

Other useful signs include scratches on tree trunks and scats beneath trees containing dreys or hollows. The supplied documents do not provide a diagnostic description of tracks, calls or eyeshine, so these should not be used alone for identification.

  • Search all potential habitat resources during the day, including dreys, hollow-bearing trees, food trees, canopy connections and signs below trees.
  • Use stagwatching at likely dreys and hollows, and spotlight suitable vegetation at night. For sites up to 5 ha, the national survey guidance lists daytime habitat searches, sign searches, stagwatching and spotlighting as appropriate methods.

Distribution: State and bioregional range

The species is endemic to south-western Western Australia. Its former range was much larger, but current occurrence is patchy and concentrated in coastal peppermint and tuart habitat, southern forests and several inland forest or riverine populations.

The only state or territory identified for the species is Western Australia. The current known range includes coastal areas between Bunbury and Albany, the Swan Coastal Plain near Busselton, inland populations near Collie, Harvey and the Upper Warren near Manjimup, and south coast localities extending east of Albany.

  • Relevant IBRA regions are the Swan Coastal Plain, Northern Jarrah Forest, Southern Jarrah Forest, Warren and Esperance Plains.
  • The historical range extended from near Geraldton to the Hampton Tableland and, around colonial settlement, from just north of Perth to east of Albany, including Pingelly and Borden.

Distribution: Strongholds and subpopulations

The largest remaining concentration is around Busselton and the southern Swan Coastal Plain, where dense peppermint woodland and peppermint and tuart associations remain. Other important populations occur in coastal habitat from Bunbury to Albany, the Upper Warren near Manjimup, jarrah and marri forest near Collie, and riverine peppermint near Harvey.

  • Known or re-established populations and release sites include areas near Busselton, Leschenault Conservation Park, Yalgorup National Park, Lane Poole Reserve, Karakamia Sanctuary and Perup Sanctuary.
  • A record of presence does not necessarily demonstrate a secure or persistent population. This is particularly relevant to isolated or recently translocated populations.

Distribution: Population status

The total population size is unknown. Available estimates indicate fewer than 8,000 mature individuals in the wild, with a decreasing trend. The calculated area of occupancy was less than 800 km² using records from 1990 to 2013, although this may overestimate current occupancy.

Estimated mature individuals: Fewer than 8,000 in the wild.

Calculated area of occupancy: Less than 800 km², based on 1990 to 2013 records.

Trend: Decreasing.

Range contraction: Approximately 80 to 90 per cent of the former range has been lost or no longer supports the former distribution.

Habitat: Vegetation communities

Habitat varies between coastal, inland forest and south coast populations, but suitable sites generally provide nutritious foliage, secure daytime shelter and continuous or closely connected canopy. Any habitat where the species occurs naturally is considered habitat critical to survival in the recovery plan.

Coastal populations are associated mainly with peppermint, Agonis flexuosa, woodland and forest, often with a tuart, Eucalyptus gomphocephala, canopy. Inland populations use jarrah, Eucalyptus marginata, and marri, Corymbia calophylla, forest and woodland. Other documented habitat includes coastal heath, myrtaceous heath and shrubland, bullich, Eucalyptus megacarpa, dominated riparian vegetation, karri forest, sheoak woodland, wandoo forest and mallee.

  • Give priority to long-unburnt, mature peppermint remnants with dense foliage and high canopy continuity.
  • Retain lightly disturbed or unlogged jarrah and marri forest with low fragmentation, low-intensity fire history and mature shelter trees.
  • Treat riparian peppermint and bullich vegetation as potential habitat, not as cleared or low-value vegetation solely because it is narrow or linear.

Habitat: Structural features

Suitable habitat combines food foliage, dreys or other nest structures, hollow-bearing trees where available, and canopy continuity that allows movement without frequent trips to the ground. Adjacent habitat patches can be connected by retained or restored vegetation corridors.

  • Map mature peppermint, jarrah, marri and tuart trees, hollow-bearing trees, dreys, dense understorey and canopy gaps before clearing.
  • Retain connected canopy wherever practicable. A decrease in canopy continuity, food availability, refuge sites or dispersal ability is identified as a potential significant impact.
  • Include private bushland and roadside or drain vegetation in habitat assessments where it forms part of a movement corridor.

Habitat: Climate and elevation

The species occupies the Mediterranean-climate forests and woodlands of south-western Western Australia. The supplied documents do not define a species-wide elevation limit. One jarrah forest life-history study was conducted at 220 to 280 m above sea level, with approximately 700 mm mean annual rainfall and warm, dry summers and cool, wet winters.

  • Do not exclude habitat from assessment because it is outside the elevation or rainfall conditions of the jarrah study site.
  • Assess local vegetation structure, food availability, shelter and canopy connectivity rather than relying on elevation alone.

Foraging habitat: Diet and food plants

Western ring-tailed possums are folivorous and feed mainly in the canopy at night. The dominant food plant changes between coastal and inland populations, so food trees should be identified at each project site rather than inferred from a single regional diet.

Peppermint leaves, Agonis flexuosa, form approximately 90 to 95 per cent of the diet in the Busselton area and are also used to build dreys. Inland animals mainly feed on jarrah foliage, with marri also an important food source. In urban areas, animals may feed on garden plants, rose flowers and leaves, and cultivated fruit.

  • Retain mature peppermint trees and their connected canopy in coastal habitat.
  • Inland, retain jarrah and marri trees and assess the foliage available across the proposed clearing area and nearby retained habitat.
  • Do not treat cultivated garden feeding as evidence that native food habitat is unimportant.

Foraging habitat: Foraging behaviour and range

Animals feed, rest and socialise mainly in tree canopies and are rarely seen on the ground. They use scent trails on branches during nocturnal social activity and may move between several nest sites within a home range.

Coastal peppermint home range: About 0.5 to 1.5 ha.

Some eucalypt forest home range: About 2.5 ha.

Northern jarrah forest home range: At least 5.6 ha.

Home-range overlap: Adjacent home ranges can overlap by up to 70 per cent.

  • Assess canopy continuity across the entire work area, including access tracks, laydown areas, drainage corridors and temporary compounds.
  • In dense coastal peppermint forest, allow for home ranges of about 0.5 to 1.5 ha. Home ranges are about 2.5 ha in some eucalypt forests and at least 5.6 ha in northern jarrah forest.
  • Treat canopy gaps as potential movement barriers because fragmented habitat can force animals to travel on the ground, increasing exposure to predators.

Breeding habitat: Breeding biology

Breeding occurs in or near suitable canopy habitat with reliable foliage and secure dreys or hollows. Most litters contain one young, but two or three young can occur.

Females usually raise one young, although litters of two or three have been recorded. The young remains in the pouch for about three months, then continues to suckle and depend on the mother until about 6 to 7 months of age. Inland breeding is more seasonal than coastal breeding, with most births in May and June and a smaller peak in October and November.

Breeding season: Most births occur from late autumn to winter; coastal populations may breed throughout the year.

Litter size: Usually one young; two or three can occur.

Pouch period: Approximately three months.

Dependence: Young may suckle until approximately 6 to 7 months of age.

Age at maturity: Individuals have been observed breeding from approximately 12 months of age.

Recorded longevity: At least 4 years has been recorded in jarrah forest; a precise typical lifespan is not provided.

  • Avoid clearing, tree felling, heavy vibration and canopy severance around occupied dreys and hollow-bearing trees during the breeding and dependent-young period.
  • If a female with a pouch young, a dependent young or an occupied drey is detected, stop work in the immediate area and follow the project fauna handling and exclusion procedure.

Breeding habitat: Breeding habitat features

Breeding habitat needs connected canopy, nutritious foliage and secure nest structures. Dreys are common near the coast, while hollows and balga, Xanthorrhoea preissii, can provide shelter in inland jarrah forest.

Nest sites used by an adult: Usually three to eight different dreys or hollow trees during a year.

  • Inspect dreys, hollow-bearing trees and dense understorey before vegetation disturbance.
  • Retain food trees and canopy links around known or potential breeding sites.
  • Do not assume that a vacant-looking drey is unused without appropriate inspection, as adults may use several nest sites during a year.

Sheltering habitat: Dreys and canopy shelter

Daytime shelter is usually above ground, in a leafy drey or tree hollow. Shelter choice changes with distance from the coast and with the availability of mature trees and dense ground or shrub vegetation.

Dreys are nests made from branches and leaves and are often about the size of a soccer ball. They occur in tree canopies and in low shrub thickets, sedges, rushes and grass trees. Adults generally rest alone and may use three to eight nest sites in a year.

Typical drey size: Approximately the size of a soccer ball.

Number of nest sites used: Usually three to eight sites per adult per year.

  • Search the full clearing footprint and a suitable buffer for dreys before work begins.
  • Mark and retain trees supporting dreys, as well as connected trees that provide access to alternative nest sites.
  • Inspect dense low vegetation, including sedges, rushes and grass trees, where ground-level or low nests may occur.

Sheltering habitat: Hollows and inland refuges

Eucalypt hollows are used for resting where available. Beyond about 4 km from the coast, hollows are used more often than dreys. In inland jarrah forest, tree hollows and balga can be important daytime refuges.

  • Retain hollow-bearing trees, including trees that are dead or partly dead where they remain safe and stable.
  • Do not remove hollow-bearing trees without a species-specific assessment and an approved management response.
  • Where nest boxes or alternative refuges are proposed, install and monitor them under a qualified fauna management plan. A documented infrastructure project used at least 12 nest boxes and six rope bridges as conditions to retain movement and shelter opportunities, but these measures do not replace habitat avoidance.

Sheltering habitat: Ground exposure and movement

The species is rarely seen on the ground. Loss of canopy continuity can force animals to descend when moving between trees, increasing exposure to foxes, cats, dogs and vehicles.

  • Keep vegetation corridors continuous across roads, drains, work compounds and cleared strips where practicable.
  • Use fauna spotter catchers during staged clearing and inspect trees and ground cover before machinery enters the work area.
  • Manage night traffic and lighting near occupied habitat, particularly where canopy gaps or roads cannot be avoided.

Threats: Clearing and fragmentation

The main project-related risks are loss and fragmentation of habitat, canopy breaks, removal of food and shelter trees, predation after displacement, and injury or death during clearing or night traffic. Threats can interact, so avoiding habitat loss remains preferable to relying on relocation or revegetation after clearing.

Clearing for urban development is identified as a major current threat, especially around Busselton. Fragmentation reduces safe movement, removes food and nest sites, and increases exposure to predators. Loss of old trees is particularly difficult to reverse because suitable hollows can take hundreds of years to form.

  • Avoid clearing occupied or suitable peppermint, tuart, jarrah and marri habitat wherever practicable.
  • Retain mature food trees, hollow-bearing trees, dreys, dense understorey and canopy corridors.
  • Treat reductions in canopy continuity, food availability, refuge availability or dispersal ability as potential significant impacts under project approvals.

Threats: Predators, roads and pets

Red foxes and feral cats are major introduced predators. Dogs can also injure or kill possums near urban works. Predation is more likely when animals are forced to the ground by canopy gaps or habitat fragmentation. A jarrah forest study recorded 84 per cent of deaths between April and September, with predation the cause of 81 per cent of deaths and foxes and cats implicated in many cases.

Seasonal mortality in one jarrah study: 84 per cent of deaths occurred between April and September.

Predation in that study: Predation caused 81 per cent of deaths; at least 16 animals were likely killed by foxes or cats.

  • Control access by domestic dogs and cats around occupied habitat and worker accommodation.
  • Use fauna fencing and canopy connections where approved and appropriate, while checking that fencing does not trap animals in the work area.
  • Set low night-time speed limits, use wildlife-aware traffic controls and avoid unnecessary vehicle movements through occupied habitat.

Threats: Fire, timber harvesting and disease

Changed fire regimes can reduce shelter and alter the structure of suitable habitat. Timber harvesting has been associated with reduced survivorship and declining sightings in some jarrah forest populations. Phytophthora cinnamomi and other plant diseases can alter forest condition and food or shelter resources.

  • Plan fire breaks, prescribed burning and construction ignition controls to retain long-unburnt mature habitat and protect known refuges.
  • Manage timber clearing and pruning so that canopy links, mature trees and low understorey are retained.
  • Apply clean-down and hygiene controls where Phytophthora or other soil-borne plant pathogens may be present.

Threats: Relocation and residual project impacts

Relocation has been used for possums displaced by development, but its success is not assured and has not been demonstrated consistently. Released animals may suffer high mortality, fail to recruit or remain dependent on ongoing predator control. Relocation should therefore not be treated as a substitute for avoiding occupied habitat.

  • Use a qualified wildlife ecologist and fauna spotter catcher to develop a capture, handling, release and monitoring plan before clearing.
  • Prioritise avoidance, staged clearing and retention of connected habitat before considering relocation.
  • Obtain the required state and Commonwealth approvals and assess whether the action may have a significant impact on the listed species.

Survey methodology: 1. Daytime habitat and sign searches

Survey western ringtail possums, Pseudocheirus occidentalis, before clearing or construction where suitable habitat occurs. Use a stratified design that targets peppermint and tuart vegetation near the coast, and jarrah, marri, wandoo or other eucalypt forest inland.

Search the whole work area, or representative sites within it, for food trees, dreys, hollow bearing trees, tree scratches and scats beneath trees. These searches help locate survey effort and identify habitat that must be retained or managed.

In coastal areas, focus on mature peppermint, Agonis flexuosa, woodland and peppermint or tuart, Eucalyptus gomphocephala, associations. Inland, inspect jarrah, Eucalyptus marginata, marri, Corymbia calophylla, wandoo and other eucalypt forest, including hollow bearing trees.

Recommended site size in the survey guideline: Up to 5 hectares, with surveys replicated within habitat types or plant communities for larger sites

Typical home range: About 0.5 to 1.5 hectares in dense coastal peppermint forest, about 2.5 hectares in eucalypt forests, and at least 5.6 hectares in northern jarrah forest

  • Map dreys, hollow bearing trees, continuous canopy, dense understorey, food trees and likely movement routes before works begin.
  • Search trees and the ground below them for dreys, scratches and scats, noting that dreys are commonly used near the coast while hollows become more important at sites more than 4 kilometres from the coast.
  • Record habitat condition, canopy continuity, food tree species, nest sites and connections to retained vegetation.

Survey methodology: 2. Spotlighting

Spotlight suitable vegetation at night because the species is nocturnal and highly arboreal. Search tree canopies, trunks, dreys, hollow entrances and canopy links rather than relying on ground searches.

Use a consistent route and record search area, start and finish times, weather, wind, rain, moon conditions, observers, spotlight type and all detections. Repeat effort across each habitat type and along proposed clearing edges.

Activity period: Nocturnal

Published project method example: Two vehicle driven transects were spotlighted for 6 to 9 consecutive nights from mid March to early June in a research programme

  • Use spotlighting with daytime habitat searches, because possums may be missed when they are resting in dreys or hollows.
  • Give particular attention to peppermint dominated vegetation near Busselton and other coastal areas, and to mature jarrah and marri forest inland.
  • Treat a sighting as evidence of use of the surrounding connected habitat, not only the tree in which the animal was seen.

Survey methodology: 3. Stagwatching at nest sites

Watch identified dreys and hollow entrances around dusk to detect animals emerging. Use this method where daytime searches identify likely nest sites or where clearing may affect hollow bearing trees.

Record the nest type, tree species, tree condition, height if measured, signs of recent use and the direction of connected canopy. Do not approach or open a hollow to improve detection.

  • Use stagwatching as a targeted method for mapped dreys and hollows, not as a substitute for searching the full work area.
  • Schedule observations during suitable weather and stop or repeat the observation if rain, strong wind or poor visibility prevents reliable detection.
  • Protect a tree or drey from disturbance until the fauna ecologist has assessed its use and the proposed control measures.

Survey methodology: 4. Arboreal trapping and other detection methods

Arboreal cage or Elliott B trapping can confirm presence and distinguish species where spotlighting and sign searches are inconclusive. It must be designed, approved and supervised by a suitably authorised person.

Place traps in suitable canopy habitat and check them at the frequency required by the relevant animal ethics, wildlife and project approvals. Provide protection from weather and overheating, and remove traps when conditions are unsafe.

Published arboreal trapping example: A 500 metre by 500 metre grid with 121 arboreal trap points, spaced 50 metres apart, was used in a research study

Published research effort: 3,308 trap nights and additional hand captures over 18 months, not a general project survey requirement

  • Do not use trapping as a routine first response when non capture methods can answer the survey question.
  • Use hair sampling devices only where an appropriately designed method and specialist identification are available, noting that the guideline identifies the species as a possible target for hair sampling.
  • Do not infer absence from a failed trap or spotlight survey because the species is difficult to detect and conventional mark recapture is not considered appropriate for estimating its population size.

Survey methodology: Minimum effort and reporting

  • Cover all habitat types and the full proposed disturbance area, with additional effort in mature peppermint, tuart, jarrah and marri vegetation, continuous canopy and areas containing dreys or hollows.
  • For a site of 5 hectares or less, use the guideline methods of habitat resource searches, sign searches, stagwatching and spotlighting, adding arboreal trapping where presence must be confirmed or individuals must be captured under approval.
  • For sites larger than 5 hectares, replicate surveys within each habitat type or plant community and explain the sampling design and limitations in the report.
  • Report every detection, drey, hollow, scat, scratch, injured animal, mortality and relocation with coordinates, date, time, observer, method, habitat and photographs where safe to obtain.
  • Submit records to the relevant Western Australian wildlife database or, in another state or territory, the relevant state or territory wildlife database, in accordance with the database requirements and project approvals.
  • Provide the survey report, spatial data, photographs, permit details, weather conditions, effort and limitations to the proponent and relevant regulators before clearing starts.

Before habitat disturbance: Avoid and minimise habitat loss

Avoid clearing western ringtail possum habitat first, then minimise unavoidable disturbance. The species depends on food foliage, refuge sites and connected canopy, and its remaining populations are fragmented across south western Western Australia.

Retain mature peppermint woodland and peppermint or tuart associations near the coast, and mature jarrah, marri and other suitable eucalypt forest inland. Retain all naturally occupied habitat unless approval clearly authorises its disturbance.

Maintain continuous canopy and safe connections between retained vegetation. Loss of canopy continuity can force possums to the ground and increase exposure to foxes, cats and other predators.

Retain dreys, hollow bearing trees, dense understorey, grass trees, sedges, rushes and other structures used for daytime shelter.

Main coastal food: Peppermint leaves form about 90 to 95 per cent of the diet in the Busselton area

Key habitat attributes: High nutrient foliage, suitable protection and nesting structures, canopy continuity and linkages between suitable habitat patches

  • Redesign access tracks, drainage, compounds and work areas to avoid mapped dreys, hollows, food trees and canopy links.
  • Keep clearing to the approved footprint and prevent unauthorised vehicle movement, stockpiling, lighting and storage in retained habitat.
  • Use site specific ecological advice to set buffers around occupied or potentially occupied trees and dreys, because the documents do not prescribe one universal buffer distance.

Before habitat disturbance: Approvals and work planning

Confirm the current EPBC Act listing before works. The supplied project records identify the species as Critically Endangered, while older survey and recovery documents describe it as Vulnerable, so use the current official listing for the referral decision.

Refer an action under the EPBC Act if it may have a significant impact on this nationally listed species. Obtain all required Western Australian or other state and territory wildlife, clearing, capture, handling and relocation approvals before work begins.

  • Check the EPBC Act protected matters process, state clearing approval and any conditions attached to the project approval.
  • Prepare a fauna management plan that identifies habitat, survey results, exclusion zones, spotter catcher roles, stop work triggers, handling arrangements, release sites, injury response and reporting.
  • Stage clearing so fauna can move into retained connected habitat and so the spotter catcher can inspect each work area before machinery enters.
  • Plan work to avoid periods of heavy rain, extreme heat and unsafe conditions for nocturnal arboreal fauna, and use the approved project timing if a regulator has specified one.
  • Do not assume that relocation solves habitat loss, because translocation success for this species has not been consistently demonstrated.

Before habitat disturbance: Site preparation

Complete the approved pre clearance survey shortly before works, because dreys and animal use can change. Recheck trees and habitat features if clearing is delayed or the footprint changes.

Mark retained trees, occupied or potentially occupied dreys, hollow bearing trees, canopy links, exclusion zones and no go areas on the ground and in the construction drawings.

Install exclusion fencing where it can safely keep machinery, vehicles and people out of retained habitat. Inspect fencing daily and after storms.

Brief operators on the species, marked exclusion zones, night driving risks, speed limits, lighting controls and the requirement to stop when fauna is detected.

  • Remove rubbish, loose wire and other entanglement hazards from the work area before machinery arrives.
  • Keep retained vegetation connected and protect roots, trunks and canopy from vehicle damage, trenching, fill, dust and unnecessary pruning.
  • Ensure the fauna spotter catcher has authority to direct machinery and that the supervisor will enforce stop work instructions.

During habitat disturbance: Daily controls and clearing sequence

Use a fauna spotter catcher and a clearly briefed machine operator as a single work team. The spotter catcher must have a clear view of the work face and authority to stop the activity immediately.

Inspect the work area at the start of each shift, including trees, dreys, hollow entrances, dense understorey and the ground beneath trees. Repeat the inspection after overnight work, weather changes or a break in clearing.

Clear in small, controlled stages from the edge towards retained habitat, where approved, so animals have an opportunity to move into safe connected vegetation.

Keep machinery outside marked exclusion zones and use a spotter catcher to check the next tree or section before felling, pushing, mulching or trenching.

Use low vehicle speeds at night and during access through retained habitat, because the species is nocturnal and may cross roads or move between trees.

  • Stop work if the spotter catcher loses visibility of the work face, if exclusion fencing fails, or if machinery approaches a mapped habitat feature without clearance.
  • Keep domestic animals, food waste and unnecessary night lighting away from retained habitat and release areas.
  • Control dust, noise, vibration and avoidable canopy damage near retained habitat.

During habitat disturbance: Handling trees and habitat features

Inspect hollow bearing trees, dreys, logs, rocks, grass trees, sedges, rushes and dense shrubs before they are disturbed. The species may use dreys near the coast and tree hollows, balga and other shelter structures inland.

Do not cut, shake, burn or fell a hollow bearing tree or drey until the approved fauna procedure has been applied and a suitably authorised person has assessed it.

Retain habitat features in place where possible. If an approved procedure requires removal, lower logs or other features carefully and inspect them for fauna before moving them.

Treat canopy severance as a potential fauna impact even when no animal is seen, because the species relies on canopy continuity for movement and predator avoidance.

  • Do not place spoil, logs, rocks, equipment or waste against retained trees or across canopy movement routes.
  • Do not fill or block a hollow, drey or nest box that is being retained or used as a temporary refuge.
  • Obtain project ecologist approval before moving a drey, hollow feature or occupied habitat feature.

During habitat disturbance: If a possum is found

Stop the relevant activity and keep people, machinery and dogs away from the animal. Allow the fauna spotter catcher to assess the situation without chasing the possum.

Only a person authorised under the relevant state or territory approval should capture, handle, transport or release the animal.

Release a healthy animal only to an approved nearby retained habitat area with suitable canopy, food and shelter, unless the permit or fauna management plan specifies another location.

Place an injured, sick, orphaned or heat stressed animal in a secure, quiet container and contact the approved wildlife carer, veterinarian or wildlife authority immediately. Do not provide food, water or medication unless directed by an authorised wildlife professional.

Do not relocate a possum across roads, cleared land or unsuitable habitat, and do not release it into an area without suitable shelter and predator management.

Typical litter: Usually one young, with two or three reported

Pouch and dependence: Young emerge from the pouch at about 3 months and may remain dependent on the mother for 6 to 7 months

  • Use a stop work trigger for any live possum, dependent young, injured animal, occupied drey or occupied hollow within the disturbance area.
  • Record the animal identification, condition, capture and release times, coordinates, habitat, handler, permit, destination and follow up action.
  • Report deaths, injuries, failed releases and unexpected concentrations of animals to the project ecologist and regulator as required by approval conditions.

After habitat disturbance: Clearance verification and monitoring

Complete clearance verification before the site is handed to construction. Then check that retained habitat, movement routes and fauna controls remain functional throughout the project.

Undertake a final post clearance inspection of felled trees, mulched vegetation, logs, hollows, dreys and the ground beneath trees before the area is released for construction.

Reinspect retained habitat and canopy connections after storms, vibration, pruning, trenching or changes to the work footprint.

Monitor retained habitat and release areas using the approved combination of spotlighting, nest and hollow checks, sign searches and other methods suited to the site.

Compare detections, mortality, habitat condition and use of dreys or hollows with the pre disturbance baseline. Do not treat a single presence record as evidence of population persistence.

  • Continue fauna exclusion, speed, lighting and access controls until the environmental officer confirms they are no longer needed.
  • Repair damaged fencing, replace failed nest boxes and remove construction materials from retained habitat promptly.
  • Investigate any decline in detections, roadkill, predation signs, canopy breaks or loss of food trees and adjust controls through the fauna management plan.

After habitat disturbance: Reporting, approvals and offsets

Keep a complete register of clearing, habitat retained, trees and dreys affected, animals detected, captures, releases, injuries, deaths, incidents, monitoring results and corrective actions.

Submit required records and reports to the approval authority and the relevant state wildlife database. Include spatial data and the methods and effort used.

Implement approved offsets, rehabilitation or revegetation commitments where residual impacts remain. Offsets do not replace avoidance and minimisation.

Example project mitigation: A Busselton drain project avoided 5.72 hectares through redesign and proposed 2.16 hectares of clearing, with 10.89 hectares of habitat rehabilitation and revegetation as an offset

Example fauna structures: The same project proposed at least 6 rope bridges and 12 nest boxes in suitable locations

  • Check that offset and rehabilitation areas contain suitable food trees, shelter, canopy continuity and links to other habitat before works are signed off.
  • For EPBC Act actions, demonstrate compliance with approval conditions and the approved conservation advice.
  • Retain photographs, maps, permits, chain of custody records and veterinary or wildlife carer records in the project environmental file.

Rehabilitation actions: Rebuild food and shelter habitat

Rehabilitation should rebuild the food, shelter and canopy connections used by western ringtail possums. Planting and maintenance must be matched to the local population and vegetation community.

Plant locally appropriate peppermint, Agonis flexuosa, in coastal western ringtail possum habitat, and retain or restore jarrah, Eucalyptus marginata, marri, Corymbia calophylla, tuart and other locally suitable food trees where they form part of the population's habitat.

Use dense native understorey, sedges, rushes and grass trees where they are characteristic of the site and provide drey or refuge structure.

Reinstate canopy links between retained patches and revegetation areas. Prioritise links that allow movement without forcing possums onto the ground.

Retain suitable fallen timber, logs and other natural shelter features where they do not create a construction or fire hazard.

Peppermint diet contribution in the Busselton area: About 90 to 95 per cent of the diet

Drey and refuge use: Individuals may use 3 to 8 nest sites in a year, including dreys or hollow trees

  • Use local provenance plants where required by the approval or rehabilitation specification.
  • Protect new plantings from browsing, weeds, vehicles and drought until they are established.
  • Do not rely on isolated nest boxes or rope bridges where the surrounding habitat cannot provide food and connected cover.

Rehabilitation actions: Nest boxes, bridges and habitat features

Install nest boxes or rope bridges only where they are specified by the approved design and placed by a suitably qualified ecologist in locations connected to retained habitat.

Use nest boxes as supplementary shelter, not as a substitute for retaining mature hollow bearing trees and natural dreys.

Monitor bridges, boxes and retained hollows for use, damage, overheating, pests and maintenance needs.

Replace or repair artificial structures when monitoring shows they are unsafe or no longer connected to usable canopy.

  • Record the location, design, installation date, height, tree condition and inspection results for each nest box or bridge.
  • Avoid placing artificial refuges where they expose animals to roads, cats, foxes, construction lighting or isolated cleared ground.
  • Retain natural hollows because suitable hollows can take hundreds of years to form.

Rehabilitation actions: Weeds, predators and fire

Control weeds that suppress peppermint, jarrah, marri or native understorey regeneration, while avoiding herbicide or machinery impacts on occupied habitat.

Manage foxes and feral cats in accordance with approved predator control programmes and relevant threat abatement requirements. Monitor the fauna response rather than assuming baiting has improved survival.

Prepare fire management with the species' habitat structure in mind. Avoid high intensity or frequent fire in retained mature habitat and protect long unburnt areas identified as habitat critical to survival.

Use fire planning that retains canopy continuity, refuge sites and food foliage, with site specific advice for the local vegetation community.

  • Inspect rehabilitation areas for predator tracks, cat activity, fox activity, roadkill and loss of canopy links.
  • Coordinate weed, predator and fire management across retained habitat and rehabilitation areas rather than treating each patch in isolation.
  • Do not use prescribed burning as a routine clearing method in occupied habitat.

Rehabilitation actions: Success measures and adaptive management

Set measurable success criteria for plant survival, canopy connection, refuge availability, weed cover, predator activity and western ringtail possum use.

Monitor rehabilitation with the same core methods used before disturbance, including spotlighting, drey and hollow checks, sign searches and habitat condition assessments.

Continue monitoring long enough to detect establishment of vegetation and repeated use of restored habitat, as a single sighting does not demonstrate a viable population.

Review the rehabilitation design if food trees fail, canopy connections remain discontinuous, artificial refuges are unused, predator activity increases or possum detections decline.

  • Report monitoring results, failures and corrective actions to the approval authority where required.
  • Use independent ecological review where approval conditions require it or where monitoring identifies unexpected mortality or habitat decline.
  • Document whether the project met its approved rehabilitation and offset completion criteria.

Sources