Biodiversity

Species Profile and Threats Database


For information to assist proponents in referral, environmental assessments and compliance issues, refer to the Policy Statements and Guidelines (where available), the Conservation Advice (where available) or the Listing Advice (where available).
 
In addition, proponents and land managers should refer to the Recovery Plan (where available) or the Conservation Advice (where available) for recovery, mitigation and conservation information.

EPBC Act Listing Status Listed as Vulnerable
Recovery Plan Decision Recovery Plan required, included on the Commenced List (1/11/2009).
 
Adopted/Made Recovery Plans Quokka (Setonix brachyurus) Recovery Plan (Western Australia Department of Environment and Conservation (WA DEC), 2013) [Recovery Plan].
 
Other EPBC Act Plans Threat Abatement Plan for Predation by the European Red Fox (Department of the Environment, Water, Heritage and the Arts (DEWHA), 2008zzq) [Threat Abatement Plan].
 
Federal Register of
    Legislative Instruments
Declaration under s178, s181, and s183 of the Environment Protection and Biodiversity Conservation Act 1999 - List of threatened species, List of threatened ecological communities and List of threatening processes (Commonwealth of Australia, 2000) [Legislative Instrument].
 
State Government
    Documents and Websites
WA:Fauna Species Profiles - Quokka Setonix brachyurus (Quoy and Gaimard, 1830) (Western Australia Department of Environment and Conservation (WA DEC), 2010k) [Information Sheet].
Non-government
    Documents and Websites
The action plan for threatened Australian macropods 2011-2021 (World Wildlife Fund for Nature - Australia (WWF), 2011).
State Listing Status
WA: Listed as Vulnerable (Wildlife Conservation Act 1950 (Western Australia): September 2013 list)
Non-statutory Listing Status
IUCN: Listed as Vulnerable (Global Status: IUCN Red List of Threatened Species: 2013.1 list)
Scientific name Setonix brachyurus [229]
Family Macropodidae:Diprotodonta:Mammalia:Chordata:Animalia
Species author (Quoy and Gaimard,1830)
Infraspecies author  
Reference  
Distribution map Species Distribution Map

This is an indicative distribution map of the present distribution of the species based on best available knowledge. See map caveat for more information.

Illustrations Google Images

Scientific name: Setonix brachyurus

Common name:
Quokka

The Quokka is a small wallaby with thick, coarse, grey-brown fur with lighter underparts. Its snout is naked and its ears are short. Its short tail (25.8–31 cm long) tapers towards the end and is close-haired. There is evidence of sexual dimorphism (differences in size and shape between the male and female of a species), as males grow to 54 cm long and weigh up to 4.2 kg, whereas females grow to 50 cm and weigh up to 3.5 kg. The hind foot is 100–120 mm long (Cronin 1991; Strahan 1998).

The Quokka occurs on two offshore islands (Rottnest Island and Bald Island) and a number of mainland sites in south-west Western Australia (WA), ranging from just south of Perth to the Hunter River (Maxwell et al. 1996; Sinclair 1998). The distribution of this species is severely fragmented and there is little to no migration between populations.

A study in 2008 (Sinclair & Hyder 2009) of the Muddy Lakes area of the Swan Coastal Plain identified the presence of the Quokka, based on fresh scats and a recently-killed carcass. This finding is significant, as this sub-population is the only one known from the Swan Coastal Plain. However, the sub-population is highly isolated and likely to be very small. Threats to the sub-population remain and there is a chance that local extinction will occur in the future.

The Quokka is confirmed from ten locations, in which there are seven distinct sub-populations. All populations are considered important for the long-term survival of the species. However, mainland populations are particularly important as they contain the highest levels of genetic diversity (Alacs et al. 2003; DEC 2007). These seven sub-populations are: Rottnest island, Bald Island, Northern Jarrah Forests, Central Jarrah Forests, Southern Jarrah-Karri Forests, South Coast and Stirling Range (DEC 2007):

Population number Sub-population Locality Estimated population size Status Trend
1 Rottnest Island Rottnest Island 8–12 000 individuals Resilient to current levels of disturbance. Lower levels of genetic variation than mainland populations. Stable
2 Northern Jarrah Forest – state forests between Serpentine to Jarrahdale Chandler Road <50   Increasing
Rosella Road <10 Threat of localised extinction Decreasing
Kesners Swamp <50 Below estimated minimum viable population (MVP) Decreasing
Wild Pig Swamp   Presumed locally extinct Extinct
Holyoake   Presumed locally extinct Extinct
3 Central Jarrah Forest - state forests in the Harris River area Hadfield <50 Below estimated (MVP) Unknown
Hoffman   Presumed locally extinct Extinct
Victor Road <50 Threat of localised extinction Decreasing
4 Southern Jarrah-Karri Forest - state forests   >700 Threat of localised extinction Decreasing
5 South Coast Two Peoples Bay NR Unknown   Unknown
6 South Coast Mount Manypeaks NR >50 Presence noted in 2006 by scat analysis Unknown
7 Bald Island Nature Reserve (NR)   600–1000 Lower levels of genetic variation than mainland populations Stable
8 Stirling Range National Park (NP) Hume Peak >50 Geographically isolated populations. 150 records of occurrence. No quantitative estimates of population trends. Anecdotal evidence that populations are affected by wildfire, but increasing in size in response to Fox control. Increasing
Toolbrunup
Ellen Peak  
Bluff Knoll
9 South Coast Tinkelelup NR <50 Geographically isolated populations Unknown
10 South Coast Albany area Unknown Geographically isolated populations Unknown

The extent of occurrence of the Quokka was estimated to be 25 190 km² in 2007 (DEC 2007). This includes the populations on Rottnest Island and Bald Island. Area of occupancy was estimated at 5700 km² (using 5 km²) and 11 800 km² (using 10 km² grids), based on 1995–2007 location data (DEC 2007). The number of sites occupied by this species on the mainland is decreasing. The area of occupancy on the mainland has probably been reduced by at least 50% since the 1930s (Maxwell et al. 1996).

Mainland Quokka populations appear to be recovering at some locations, in response to feral species management programs (DEC 2007). The species is again being recorded from areas within parts of its former range, such as some outer metropolitan areas and the northern Darling Scarp. This may be attributed in large part to the combined efforts of Red Fox (Vulpes vulpes) baiting and feral Pig (Sus scrofa) control (DEC 2007).

Fossil deposits suggest that the Quokka originally occupied an area of approximately 49 000 km² in the south-west WA. They were widespread and abundant when Europeans colonised the region in 1829, but a noticeable and dramatic decline occurred over the following century (Hayward 2002), thought to have been primarily caused by the arrival of the Red Fox in the 1930s (Hayward et al. 2005a). There was another major population reduction in the period 1980–1992. The cause of this reduction is unknown, but could be related to habitat degradation and ongoing predation by the Red Fox (DEC 2007).

Forty fauna sites are regularly monitored under the Western Shield fauna recovery program which commenced in 1996 (DEC 2007). Quokkas have been captured at three of these sites. The following table summaries undertaken surveys. Blank cells indicate that data were not recorded (Barrett 1996a; DEC 2007):

Population Location Type of survey Date Number of trap nights Number of animals caught
1 Rottnest Island Tag and release 1972    
2 Mundaring to Walpole Rapid distribution survey September 2002   Present
2 Northern Jarrah forest Population estimates and habitat use July 1996    
2 Northern Jarrah forest Impact of Fox control on Quokka habitat use Spring 1993 to winter 1998    
2 Rosella Road, Jarrahdale Trapping 1995   4
1997   2
Spring 1998 to winter 1999 2690 1
2003 4607 1
2 Chandler Road, Jarrahdale Trapping Spring 1998 to winter 1999 3454 6 (and one pouch young)
2003 4976 8
2 Kesners Road, Dwellingup Trapping Summer 1998/99 to winter 1999 2978 20
2003 5842 21
2 Wild Pig Swamp, Dwellingup Trapping 1990   Sizeable
1995   Present
Summer 1998/1999 194 0
2003 194 0
2 Windy Ridge, Mornington district Trapping June 1992   16 
March 1993   5
Winter 1993   18
January 1994   19
August 1994   16
April 1995   15
January 1996   12
3 Hadfield, Harvey Trapping Summer 1998/1999 1002 23
Winter 1999 2595 21
2003    
3 Hoffman Trapping 2003 368 0
3 Victor Road, Harvey Trapping Autumn 1999 1020 8
Winter 1999 2654 11
2003    
4 Southern Jarrah Forest Occasional trapping/survey      
7 Bald Island Specimen collection/various surveys 1954    
1959    
1976    
1982    
1994    
8 Stirling Range NP Trapping 1970   Signs observed from hair tubes and scat analysis.

The Rottnest Island Quokka sub-population is estimated to be 8000–12 000 (Hayward et al. 2003; Waring 1956) and the Bald Island sub-population is estimated to be 200–600 (Main & Yadav 1971). There are no published estimates of mainland Quokka numbers, but the total adult population in the Northern and Central Jarrah Forest may be as few as 150 (Hayward et al. 2003). Reaching statistically accurate estimates is difficult because the species exists in many small, scattered sub-populations and is difficult to trap (Alacs et al. 2003). Many of the mainland populations are thought to consist of only a small number of individuals (Alacs et al. 2003; Sinclair & Morris 1996).

The Quokka Rottnest Island and Bald Island sub-populations are stable, although the extent of scrub cover decreased on Rottnest Island between 1930–1980 (Pen & Green 1983). On the mainland, the species is in decline at most sub-populations, with some of these at risk of localised extinction at some. Natural variation may also influence population trends, for example, extreme fluctuations in population size are known to occur at Rottnest Island, in response to water availability (DEC 2007).

Historically, the Quokka had population traits of a "classic metapopulation" (spatially separated populations with occasional inter-population migration). Traits include restriction to discrete habitat patches, occasional inter-patch movement, lack of correlation between the dynamics of each population, and reports of frequent localised extinctions and colonisations. The massive decline of the Quokka in the 1930s has resulted in populations that are the remnants of this original metapopulation (Hayward et al. 2003).

Captive populations

Quokkas are held in a number of captive populations, which include:

  • University of Western Australia animal care facility at Shenton Park (24 animals collected from Rottnest Island)
  • Perth Zoo (three animals from the mainland)
  • Caversham Wildlife Park (16 animals collected from Rottnest Island)
  • Broome Wildlife Park (three animals collected from Rottnest Island)
  • Cohuna Wildlife Park (four animals collected from Rottnest Island)
  • Quindalup Wildlife Park (three animals collected from Rottnest Island)

Karakamia Sanctuary in Chidlow (Australian Wildlife Conservancy) held five mainland Quokkas between 1996—1998 as part of a re-introduction program (Mawson 2004)

As a part of a re-introduction program, Harry Waring Marsupial Reserve in Jandakot received 673 Rottnest Quokkas between 1972—1988. All of these attempts at introduction to this site failed (DEC 2007).

Some sub-populations of the Quokka occur in areas that are managed for the conservation of flora, such as Two Peoples Bay Nature Reserve, Torndirrup National Park (NP), Mt Manypeaks NP and Stirling Range NP (Maxwell et al. 1996; Sinclair 1998). The other sub-populations occur in State Forest, which is not managed for conservation but is baited for foxes (DEC 2007). A table of sub-populations and land tenure is shown in the 'population information' section above.

Vegetation

The Quokka is a habitat specialist, preferring early seral (young) vegetation stages that have been burned within the previous ten years. This habitat meets dietary and predator refuge requirements (Hayward 2005). Bald Island, however, has a low frequency of fire during the past century and avoided Aboriginal burning for thousands of years due to its separation from the mainland (McCaw 1997; Storr 1965).

The Quokka also has relatively high water requirements, which necessitates close proximity to fresh water throughout the year (Hayward et al. 2005a). Hence, the species is often present in riparian and swamp habitat (Hayward et al. 2005a). 

The understorey structure of the habitats currently inhabited by the Quokka consist of dense, low vegetation (Hayward 2002) that provides refuge from predation by owls, the Fox (Vulpes vulpes) and the Cat (Felis catus). These covered/shady microhabitats may also be important during the hotter months, particularly on Rottnest Island, where animals converge in dense thickets of Gahnia spp. and Acanthocarpus spp. (Kitchener 1982).

The main habitat for mainland populations of the Quokka is dense riparian vegetation (Hayward et al. 2005a), but the species also uses a range of other habitat, including:

  • heath and shrubland on the mainland coast and offshore islands (Hayward 2005)
  • Swamp Peppermint (Taxandria linearifolia) dominated swamps in Jarrah (Eucalyptus marginata) forest (Hayward 2002).
  • swampy shrublands (Christensen et al. 1985 in Hayward et al. 2005c)
  • swordgrass-dominated understorey (Christensen et al. 1985 in Hayward et al. 2005c) 
  • regrowth areas of the Karri (E. diversicolor) forest (Christensen et al. 1985 in Hayward et al. 2005c)
  • Bullich (Eucalyptus megacarpa) swamp forest (Hayward 2002)
  • Paperbark (Melaleuca spp.) swamp (Hayward 2002).

Swamp Peppermint swamp shrublands are tall closed shrublands dominated by Swamp Peppermint, Gahnia decomposita and Astartea fascicularis with sedge dominated understorey (Hayward 2002).

Bullich or Paperbark swamp forests occur as small fragments within larger swamps in southern Jarrah (E. marginata) forests. In Bullich forest, the understorey includes Acacia linearifolia, Boronia molloyiae and Hypocalymna cordifolium (Hayward 2002). Paperbark swamp consists of small, species-rich pockets, dominated by Swamp Paperbark (Melaleuca rhaphiophylla), within Agonis swamp (Hayward 2002).

Site specific vegetation

In the Stirling Range NP, the Quokka is known to inhabit woodlands and flats (e.g. Jarrah and Marri (Corymbia calophylla) woodland). It also occurs in the peaks where the vegetation includes montane heath and thicket, and montane mallee at higher elevations. The latter vegetation community includes a Western Australian threatened ecological community known as the "Montane Mallee Thicket of the Stirling Range". This community occurs approximately 400 m above sea level on sandy clay-loam over sandstone and metamorphosed sandstone on the mid to upper slopes of mountains and hills in the Stirling Range, predominantly east of Red Gum Pass.

In the Albany-Fraser system (i.e. between Two Peoples Bay - Cheyne Beach) the Quokka occurs on coastal heath and thickets (Western Sheoak (Allocasuarina fraseriana), Hakea elliptica, Melaleuca striata and Anarthria scabra); swamps (Juniper Myrtle (Taxandria juniperina), Swamp Peppermint, Dryland Teatree (Melaleuca lanceolata) and Hakea nitida, Beaufortia sparsa and Gahnia trifida); and riparian systems (Bullich, River Banksia (Banksia littoralis) and Lepidosperma spp.) (DEC 2007).

In the Northern Jarrah Forest the Quokka is restricted to Agonis swamp shrubland habitats that form in the open, upper reaches of creek systems. This restriction was probably initially due to the high water requirements of the Quokka, but is likely to have been exacerbated by increased predation since the arrival of the fox (Hayward 2002).


Climate

Within the range of the Quokka, annual rainfall ranges from 600 mm in the farthest inland area to more than 1300 mm near the coast in the far south (near Northcliffe and Walpole). Most rain falls between May and October. Only limited summer rainfall is experienced along the south coast, but generally summers are dry (Christensen et al. 1985). Across most of the region, the rainfall over recent decades has been significantly less than that recorded earlier in the twentieth century (Bureau of Meteorology 2007).

Habitat Critical to the Survival of the Quokka

The draft Recovery Plan for the Quokka (DEC 2013) identifies habitat which is considered to be critical to the survival of the species. In the northern Jarrah forest, critical habitat are those areas which have a mosaic of recently burnt and long unburnt patches. In the southern forest, critical habitat has a low-density of near-surface fuel, a complex vegetation structure and a varied fire-age mosaic.

Quokkas are sexually mature at 18 months of age and live for about 10 years (Hayward et al. 2003). Captive-bred Quokkas have been found to become sexually mature at eight to nine months old (Shield 1968). Wild mainland Quokkas breed throughout the year, however a significant reduction in the number of births (anoestrus) occurs over summer and this coincides with a decline in female body weight. Despite this, the mainland Quokka is relatively fertile and is able to consistently wean two offspring per year, producing up to 17 young over a lifetime. However, the level of recruitment from pouch young to independence can be low and this may explain the apparent lack of population growth following the initiation of fox control (Hayward 2002; Hayward et al. 2003). Hayward and colleagues (2003) also found a high rate of pouch young mortality in the Northern Jarrah Forests: less than one in two pouch young survived to independence.

One day after the young is born, the female mates again and embryonic diapause begins (the embryo stays dormant in the female). If the young in the pouch dies within five months, the embryo resumes development and is born in 24—27 days. If the first young lives, the embryo degenerates when the female enters anoestrus over the summer period. Under good conditions the second embryo can resume growth after the first young is successfully raised. The young leaves the pouch between 6—7 months, but will return if alarmed or cold.

Quokkas exhibit a specific preference for early seral stages of vegetation (new young growth). They have been observed feeding in a burned swamp less than three months after a fire, reaching peak abundance 12 years after fire and then deserting that habitat at 15 years after the burn (Hayward et al. 2005a). Hayward (2005) relates this to the high nitrogen levels of new foliage.

In the Northern Jarrah Forest of Western Australia, the diet of the Quokka was investigated by microscopic examination of faecal pellets of known individuals, and comparison with a reference collection of plant epidermal tissue. Ninety-seven faecal pellet groups were collected from 53 individuals. From these samples, 29 different plant species were found, confirming that the Quokka is a browsing herbivore that favours leaves and stems. Of those 29 species, 11 species made up over 90% of the diet, and five species accounted for 71%. Thomasia species were the most common in the diet; Dampiera hederacea was also preferred, along with Bossiaea aquifolia, Mirbelia dilatata and Agonis linearifolia. There is seasonal variation in the diet of the Quokka, which can be attributed to increases in nutrient content of fresh growth associated with different seasons or vegetation seral stages (Hayward 2005).

On Rottnest Island, the diet of the Quokka is primarily succulents such as Arthrocnemum halocnemoides, Carpobrotus aequilaterus and Rhagodia baccata grasses and, to a much lesser extent, shrubs such as Acacia rostellifera and Scaevola crassifolia, and the sedge Gahnia trifida (Storr 1961). This diet was deficient in nitrogen and was often supplemented by human refuse, introduced stinkwort (Inula graveolens), and even snails. Quokkas have been observed climbing the outer branches of trees and shrubs of Rottnest Island to browse (Wake 1980 cited in Hayward 2005).

Rottnest Island

On Rottnest Island, Quokkas appear to maintain group territories (Kitchener 1995). Nicholls (1971) noted that for any individual animal the nocturnal and diurnal use areas were adjacent to each other for most of the year. In the dry season, the size of the feeding area increased, and in some cases in February and June, it changed completely. These changes in use areas were related to shelter, and distribution and seasonality of food plants.

Mainland

In mainland forests, the Quokka occurs in small colonies, often with no more than one or two dozen individuals being sighted together (Christensen et al. 1985). Mainland Quokkas rest in the sedge zone during the day and come out to feed at night, not only in the swamp, but also along swamp edges, where the ground cover is lower and more open (Storr 1963).

Based on a sample size of 58 animals from five remnant mainland populations in the Northern Jarrah Forest, mean overall home-range size was 6.39 ha and core home-range was 1.21 ha. Male core home-ranges were larger than those of females, although not when corrected for body mass (Hayward et al. 2005a). Nocturnal ranges were larger than diurnal ranges, reflecting nocturnal departures from the swamp refugia.

Telemetry confirmed trapping results that showed no movement between swamps or populations. The lack of dispersal is probably due to Quokka populations existing below carrying capacity and being philopatric (preferentially using the same site to breed or feed), as well as generally avoiding predators (Hayward 2002).

In mainland forests, Quokka colonies often make distinctive 'pads' or 'runnels' through the dense undergrowth that are easily recognisable if there are sufficient densities (Christensen et al. 1985). Transect counts of faecal pellet groups and runnels are cost-effective techniques for estimating relative population abundance (high medium and low) (Bain et al. 2009). The use of faecal pellet counts to estimate Quokka population size is cost-effective, quick and reduces disturbance of sub-populations (Hayward et al. 2005c). Hair analysis of fox scats can also be used for detection (Christensen et al. 1985).

Quokkas are relatively difficult to trap and the repeated trapping required for mark and recapture studies is time-consuming (Alacs et al. 2003; DEC 2007). Current Quokka capture methods rely on setting large numbers (up to 50) of large (0.5 x 0.5 x 0.9 m) wire cage traps (DEC 2007). However, Quokkas are most effectively caught by attracting them into a permanent enclosure baited with sown-improved pasture or pelleted feed (Walton & Richardson 1989).

Alacs and colleagues (2003) describe a technique using DNA acquired from scats to measure genetic differentiation among Quokkas.

Historic declines

Disease caused major declines to the Quokka in 1892, and again in 1919 and 1920 (Abbott 2001). Introduction of the Red Fox caused major declines in the 1930s (Abbott 2001). 

Current threats

Predation and habitat destruction through inappropriate fire regimes are thought to be the key drivers in the ongoing decline of the Quokka.

Rottnest Island

Although the population on Rottnest Island appears to be less susceptible to environmental change and disturbance than the populations on the mainland, it appears to be more susceptible to multiple factors acting together. Two factors in particular have probably contributed to declines: Fox predation and changed fire frequency. Absence of fire has reduced the availability of post-fire seral vegetation (DEC 2007).

Predation by the Fox and other predators

Fox predation is the main threat to the Quokka on the mainland (Maxwell et al. 1996). Road construction (i.e. logging haul roads) facilitate Fox predation and act as dispersal corridors (DEC 2007). Predator control programs have had success in some areas and have enabled the Northern Jarrah Forest populations to persist (DEC 2007). However, coordination of baiting is poor and regional efforts are required to avoid Fox re-invasion (DEC 2013). 

The Quokka is known to often expel its pouch young when pursued by Foxes, Cats or Dogs. This survival mechanism can negatively affect population growth over the long term if this strategy is used repeatedly (Robertshaw & Harden 1985, 1986, in Hayward et al. 2005b).

Habitat distruction caused by Pigs

Feral Pigs (Sus scrofa) destroy swamp and riverine habitat of the Quokka and compete with the species for resources. Feral Pigs also disturb the dense riverine vegetation, opening it up and allowing predators into otherwise inaccessible areas (DEC 2007). There have been anecdotal reports of areas, which previously supported Quokka populations, becoming unsuitable due to disturbance by the Feral Pig (DEC 2013).

Altered fire regimes

Low-intensity control burns generally burn the swamp edges without penetrating the swamp. This leads to a reduction in swamp vegetation without creating a mosaic of seral stages. Managing fire for Quokka conservation involves some burning of internal swamp habitat, as this is required to maintain the early seral vegetation stages favoured by the species. Suitable habitat for the Quokka is known to be destroyed by intense, broadscale, homogenising fires, or fires which result in midstorey collapse and overstorey death (DEC 2013).

Phytophthora dieback

As a species which depends on a complex forest structure, the Quokka is susceptible to the indirect impacts of the Phythophthera plant pathogen due to death of vegetation where the species occurs (DEC 2013). The loss of forest structure has the potential to increase the risk of predation of and loss of resources for the Quokka (DEC 2013).

Clearing and habitat fragmentation

Clearing of dense vegetation has contributed to the Quokka's decline because it progressively fragments the habitat. This increases the distance between suitable swamp habitats, and increases exposure to predators. Habitat clearing is attributable to agricultural developments (grazing and cropping), urbanisation, and logging. It has been noted that approximately 60% of Quokka records are within state forests or timber reserves, which are likely to be harvested in the future (DEC 2013).

Quokka populations now occur within 1 km of Dwellingup. The more open habitat in these areas increases the exposure of Quokkas to predation. The Wild Pig Swamp colony (part of the Northern Jarrah Forest sub-population) may have been affected by bauxite mining (via noise, road kill etc.), which has occurred within 20 m of the swamp around the upper reaches of the site. The disturbance may have contributed to the local decline of this colony (Hayward et al. 2003).

Altered hydrological regimes

Drying of swamp and riparian habitat has the potential to impact on the Quokka in areas where ground and surface water extraction occurs (DEC 2013). Forecast impacts of water extraction are predicted to go beyond the impact of climate change in some areas (CSIRO 2009 cited in DEC 2013).

Disease

Disease has been identified as being responsible for the deaths of individual Quokkas, but has not been causally-linked to widespread decline (de Tores et al. 2007 cited in DEC 2013). There are anecdotal records of large declines in native mammal species attributed to disease from the 1880s until 1920. This is possibly due to the presence of fleas and ticks, resulting from the introduction of sheep, horses, rats, mice, cats and dogs, which spread disease such as toxoplasma, to which some native animals are susceptible (Abbott 2001).

Recreational activities

High levels of human visitation have impacted on some sub-populations of the Quokka, particularly on Rottnest Island (DEC 2013). There is ongoing impacts from recreational activities and visitation, however, the actual effect of these impacts has not been quantified (but is likely to be low, as the Rottnest sub-population remains stable) (DEC 2013).

Road kills

In a 2005 study, road kills were identified as a major cause of death at five sites in the Northern Jarrah Forest (Hayward et al. 2005a).

Poor recruitment and limited genetic pool

As the mainland populations are small (sometimes only a few individuals) and are becoming increasingly isolated, the genetic variability is decreasing, which has the potential to affect recruitment and increase susceptibility to disease (Sinclair 2001). Sinclair (2001) notes that while island populations are much larger than on the mainland, they contain less of the species' genetic diversity. Sinclair (2001) considers it not in the best interests of long term population management to use island populations to augment mainland populations, due to differences in breeding patterns, ability to store fat, susceptibility to infection, and tolerance to naturally occurring fluoroacetate.

Climate Change

Regional changes in climate patterns have been observed. Between 1975 and 1996, rainfall decreased by 14% and runoff into Perth dams decreased by 48% from the long-term average. Between 1997 and 2005 the rainfall decline has been 21% and the runoff has been 64% less than the long term average. In the four years since 2001, rainfall was 36% less and runoff 88% less than the long-term average (McFarlane 2005). This is likely to have a detrimental impact on the Quokka, as their preferred habitat is swamp and marshland, which would contract with lowered rainfall. Gibson and colleagues (2010) modelled the predicted impact of climate change on the distribution of the Quokka which indicated that ongoing contraction of the extent of occurrence is likely.

Management actions completed or ongoing

Monitoring has been widespread previously (DEC 2007) but funding and coordination of ongoing monitoring is required (DEC 2013). Where Quokkas are known to occur in, or adjacent to, timber harvesting coups, special measures such as additional fox baiting are undertaken to protect the species (DEC 2007). For example, Fox baiting is in place for most of the known populations on the Darling Scarp, and at Two Peoples Bay NP and Stirling Range NP. Fox baiting is being extended to additional populations via the Western Shield program (the Western Australian Department's species recovery program) (DEC 2007).

Hazard reduction burns should be conducted in a manner that is beneficial to the Quokka and promotes understorey growth. Mosaic burns on a 5 to 10 year rotation have been recommended, but further research is required to determine the most suitable regime (DEC 2007).

The draft recovery pan

The overall objective of the draft recovery plan (DEC 2013) is the retention of the current distribution and abundance of the Quokka. The broad recovery actions identified in the plan are:

  • coordinate recovery actions
  • survey and monitor sub-populations
  • manage key sub-populations and habitat
  • improve understanding of current threats and the effectiveness of mitigation measures
  • translocation and captive breeding if required
  • education and communication.

Major studies on the Quokka include:

  • distribution and ecology: Alacs and colleagues (2003), Dunnet (1962), Hayward (2002, 2005), Hayward and colleagues (2003, 2004, 2005a, 2005b, 2005c), Holsworth (1967), Kitchener (1972), Rippey & Hobbs (2003), Shield (1959, 1963), Storr (1957), Storr and colleagues (1961)
  • reproduction and rearing: Bennets (1997), Miller (2005), Sharman (1955), Shield (1964, 1968), Shield and Woolley (1960)
  • behaviour and movement: Bonney and Wynne (2002), Packer (1962), Main and Yadav (1971), Nicholls (1971)
  • physiology: Chelvanayagam and colleagues (1998), Clark and Spencer (2006), Hart and colleagues (1985), Iveson and Bradshaw (1973), Shield and colleagues (1967), Sinclair (1998, 2001, 2001a)
  • recovery: Maxwell and colleagues (1994)

Documents that are relevant to the management of the Quokka can be found at the start of the profile.

The following table lists known and perceived threats to this species. Threats are based on the International Union for Conservation of Nature and Natural Resources (IUCN) threat classification version 1.1.

Threat Class Threatening Species References
Agriculture and Aquaculture:Agriculture and Aquaculture:Land clearing, habitat fragmentation and/or habitat degradation Setonix brachyurus in Species Profile and Threats (SPRAT) database (Department of the Environment and Heritage, 2006xi) [Internet].
Agriculture and Aquaculture:Livestock Farming and Grazing:Habitat loss and modification due to clearance of native vegetation and pasture improvements The Implications of Climate Change for Land-based Nature Conservation Strategies (Pouliquen-Young, O. & P. Newman, 1999) [Report].
Invasive and Other Problematic Species and Genes:Invasive Non-Native/Alien Species:Competition and/or predation Vulpes vulpes (Red Fox, Fox) Setonix brachyurus in Species Profile and Threats (SPRAT) database (Department of the Environment and Heritage, 2006xi) [Internet].
Natural System Modifications:Fire and Fire Suppression:Inappropriate and/or changed fire regimes (frequency, timing, intensity) Setonix brachyurus in Species Profile and Threats (SPRAT) database (Department of the Environment and Heritage, 2006xi) [Internet].
Species Stresses:Indirect Species Effects:Low numbers of individuals Setonix brachyurus in Species Profile and Threats (SPRAT) database (Department of the Environment and Heritage, 2006xi) [Internet].

Abbott, I. (2001). The Bilby Macrotis lagotis (Marsupialia: Peramelidae) in south-western Australia: original range limits, subsequent decline, and presumed regional extinction. Records of the Western Australian Museum. 20:271-305.

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This database is designed to provide statutory, biological and ecological information on species and ecological communities, migratory species, marine species, and species and species products subject to international trade and commercial use protected under the Environment Protection and Biodiversity Conservation Act 1999 (the EPBC Act). It has been compiled from a range of sources including listing advice, recovery plans, published literature and individual experts. While reasonable efforts have been made to ensure the accuracy of the information, no guarantee is given, nor responsibility taken, by the Commonwealth for its accuracy, currency or completeness. The Commonwealth does not accept any responsibility for any loss or damage that may be occasioned directly or indirectly through the use of, or reliance on, the information contained in this database. The information contained in this database does not necessarily represent the views of the Commonwealth. This database is not intended to be a complete source of information on the matters it deals with. Individuals and organisations should consider all the available information, including that available from other sources, in deciding whether there is a need to make a referral or apply for a permit or exemption under the EPBC Act.

Citation: Department of the Environment (2014). Setonix brachyurus in Species Profile and Threats Database, Department of the Environment, Canberra. Available from: http://www.environment.gov.au/sprat. Accessed Sun, 21 Sep 2014 00:34:03 +1000.