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
Listing and Conservation Advices Commonwealth Listing Advice on Conilurus penicillatus (Threatened Species Scientific Committee (TSSC), 2008aea) [Listing Advice].
 
Commonwealth Conservation Advice on Conilurus penicillatus (Threatened Species Scientific Committee (TSSC), 2008afq) [Conservation Advice].
 
Recovery Plan Decision Recovery Plan required, it would assist in establishing the relative impact of the likely threats to this species and provide a coordinated approach to the management of this species (and other species with comparable management challenges) across Australia (20/11/2008).
 
Adopted/Made Recovery Plans
Other EPBC Act Plans Threat Abatement Plan for predation by feral cats (Department of the Environment, Water, Heritage and the Arts (DEWHA), 2008zzp) [Threat Abatement Plan].
 
Policy Statements and Guidelines Survey guidelines for Australia's threatened mammals. EPBC Act survey guidelines 6.5 (Department of Sustainability, Environment, Water, Population and Communities (DSEWPaC), 2011j) [Admin Guideline].
 
Federal Register of
    Legislative Instruments
Inclusion of species in the list of threatened species under section 178 of the Environment Protection and Biodiversity Conservation Act 1999 (67) (20/11/2008) (Commonwealth of Australia, 2008l) [Legislative Instrument].
 
State Government
    Documents and Websites
NT:Threatened Species Information Sheet: Brush-tailed Rabbit-rat Conilurus penicillatus (Woinarski, J. & B. Hill, 2012a) [Information Sheet].
State Listing Status
NT: Listed as Endangered (Territory Parks and Wildlife Conservation Act 2000 (Northern Territory): 2012 list)
WA: Listed as Vulnerable (Wildlife Conservation Act 1950 (Western Australia): September 2013 list)
Non-statutory Listing Status
IUCN: Listed as Near Threatened (Global Status: IUCN Red List of Threatened Species: 2013.1 list)
Scientific name Conilurus penicillatus [132]
Family Muridae:Rodentia:Mammalia:Chordata:Animalia
Species author Gould, 1842
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: Conilurus penicillatus

Common name: Brush-tailed Rabbit-rat

Other name: Brush-tailed Tree-rat

Conilurus penicillatus (Brush-tailed Rabbit-rat) is conventionally accepted (Gould 1842).

Three subspecies are recognised, with support from a specific study (Kemper & Schmitt 1992): C. p. melibius restricted to the Tiwi Islands (Bathurst and Melville) of the Northern Territory; C. p. penicillatus from the rest of its Australian range; and C. p. randi from New Guinea.

Both Australian subspecies (C. p. melibius and C. p. penicillatus) are covered in this profile.

The Brush-tailed Rabbit-rat is a robust rodent (Kemper & Firth 2008). It is most notable for its long (180 mm) and tufted (brush-like) tail. The end half to one third of the tail can be either black or white, with the ratio of these colour morphs varying among populations (Kemper & Schmitt 1992). Head and body length is 135–227 mm and the species weighs between 116–242 g (males) and 102–202 g (females). The Brush-tailed Rabbit-rat is grizzled grey to golden brown on the back, with a rufous patch on the neck. It is white to cream on the belly, often with a grey chest-patch (Van Dyck & Strahan 2008).

Animals from the Tiwi Islands have small ears and hindfeet and are more dark-bellied than in other regions (Van Dyck & Strahan 2008).

In Australia, the species is known from Queensland, the Northern Territory and Western Australia, where its distribution is restricted mostly to islands, coastal areas and areas of relatively high rainfall. The species may once have been more widespread in moister conditions and its current distribution may represent a relictual or retreating distribution following the post-glacial thermal maximum (Kemper & Schmitt 1992). The Brush-tailed Rabbit-rat is considered to be uncommon over its geographic range, although it can be locally abundant (Bradley et al. 1987; Calaby & Keith 1974a; Firth et al. 2006).

Queensland
In Queensland, the only record of the species was made in 1963 from Bentinck Island in the Gulf of Carpentaria, and there have been no subsequent records, surveys or studies (R.S.C. Firth 2007, pers. comm., cited in TSSC 2008aea).

Northern Territory
In the Northern Territory, the Brush-tailed Rabbit-rat has been recorded in near-coastal areas between Centre Island (in the Sir Edward Pellew group) in the east to near the mouth of the Victoria River in the west (NT DNREA 2007). The species has been recorded on Groote Eylandt, in south-east and eastern Arnhem Land, on Inglis Island (off Arnhem Land), on the Cobourg Peninsula, on the Tiwi Islands and in Kakadu National Park. However, there are no recent records from much of this historically recorded range (NT DNREA 2007) despite considerable survey effort (J.C.Z. Woinarski 2008, pers. comm., cited in TSSC 2008aea).

Western Australia
In Western Australia, the Brush-tailed Rabbit-rat is restricted to the northern Kimberley where its distribution is wide but patchy with several known populations (R. How 2007, pers. comm., cited in TSSC 2008aea). The species is known to be present from near King Sound to the Mitchell Plateau (Kemper & Schmitt 1992), a distributional range of about 400 km. Most records are from the Mitchell Plateau and nearby Prince Regent Nature Reserve (Abbott & Burbidge 1995; Bradley et al. 1987; Start et al. 2007). There appears to be a large gap in the species' distribution between the Kimberley and western Northern Territory (in the Cambridge Gulf region) where habitats such as mudflats, sand plains, rugged sandstone country, and black soil plains are considered unlikely to support the species, although further work is required to substantiate that it is truly absent (Kemper & Schmitt 1992).

Densities of one to six animals per hectare have been recorded (Kemper & Firth 2008) but such dense populations are not typical across the species' entire range (R.S.C. Firth 2007, pers. comm., cited in TSSC 2008aea).

Given the disjunct distribution of the species and some uncertainty about the persistence of certain populations (for example on Bentinck Island), the extent of occurrence of the Brush-tailed Rabbit-rat is difficult to calculate meaningfully (R.C.S. Firth 2007, pers. comm., cited in TSSC 2008aea). Similarly, it is difficult to calculate the species' area of occupancy, although a coarse estimate can be made by totalling the estimated areas of the regions where the species is thought to persist. In taking this approach, the sum of the Tiwi Islands (area 7481 km²), Inglis Island (81 km²), Groote Eylandt (2258 km²), Bentinck Island (138 km²), Cobourg Peninsula (2207km²), a small area in Kakadu National Park (0.15 km²) and probably a small area in the north of the Kimberley region (possibly 1000 km²) is about 13 000 km² (R.C.S. Firth 2007, pers. comm., cited in TSSC 2008aea).

There are two records of the subspecies C. p. randi from southern New Guinea, however very little is known of the status of the species there (R.S.C. Firth 2007, pers. comm., cited in TSSC 2008aea).

Firth (2008) and Smith (2009) conducted surveys for the Brush-tailed Rabbit-rat on Groote Eylandt as part of a proposal for drilling in exploration leases by GEMCO (GEMCO 2010). Firth (2008) reported no trapping or sighting of Brush-tailed Rabbit-rats in the two areas (in western Groote Eylandt) surveyed in 2008, while Smith (2009), in his more extensive survey of Groote Eylandt, made four new recordings of the Brush-tailed Rabbit-rat, concluding that their distribution across Groote Eylandt is patchy and they appear to be present in low numbers. Prior to Smith's survey (Smith 2009), the previous record for this species on this island came from November 2006 when one was seen by a ranger co-ordinator while driving tracks east of Kings Crossing (Ward 2006 in Firth 2008).

Northern Territory
Historically, the Brush-tailed Rabbit-rat has been recorded in the Northern Territory from near-coastal areas from close to the mouth of the Victoria River in the west to the Pellew Islands in the east. However, there are no recent records from much of its historically recorded range (NT DNREA 2007) despite considerable survey effort (J.C.Z. Woinarski 2008, pers. comm., cited in TSSC 2008aea).

The most detailed information on the status and trend for the Brush-tailed Rabbit-rat on the mainland of the Northern Territory is for the population in the Kakadu National Park area (R.S.C. Firth 2007, pers. comm., cited in TSSC 2008aea). Early explorers commented that the Brush-tailed Rabbit-rat was widespread and common in the Northern Territory (Kemper & Firth 2008), with Dahl (1897) commenting "in Arnhem Land [it] is everywhere common in the vicinity of water". Supporting this assessment, the collector J.T. Tunney obtained 40 individuals near the South Alligator River (now within Kakadu National Park) in 1902–03 (Thomas 1904).

During the 1960s and early 1970s the species was still relatively common, as indicated by Calaby (1973a) who stated it was "a reasonably common species, found chiefly in woodland with suitable hollow tree shelters". Based on more quantitative surveys of Kakadu National Park in the early 1980s, Braithwaite (1985) stated "this beautiful uncommon species is likely to be widespread in open forest and woodland". However, despite extensive surveys having been undertaken throughout Kakadu National Park from the late 1980s until the present, no Brush-tailed Rabbit-rats have been recorded. The only place where the species is known to persist is at the Mardugal campground (Firth et al. 2005, 2006b) where it has probably been a collateral beneficiary of localised fire management to maintain campground infrastructure (R.S.C. Firth 2007, pers. comm., cited in TSSC 2008aea).In 2009 the Mardugal campground site was re-surveyed (following the same methods as Firth 2007) and no Rabbit-rats were recorded.

This evidence suggests that the species has changed from a status of 'common' to virtually extinct in the Kakadu National Park area in around 100 years. Although this decline cannot be dated with certainty, the evidence suggests it began in the 1960s and has continued since 1983 to the present (R.S.C. Firth 2007, pers. comm., cited in TSSC 2008aea), most substantially in the last 20 years (Woinarski et al. 2001). If this trend continues, the species is likely to become extinct in Kakadu National Park in the next 10–20 years (R.S.C. Firth 2007, pers. comm., cited in TSSC 2008aea).

The Brush-tailed Rabbit-rat has also apparently disappeared from other parts of its historical range on the mainland of the Northern Territory. For example, it has been recorded from the Victoria River region (C. Kemper 2008, pers. comm., cited in TSSC 2008aea), in the Darwin-Katherine region and in south-east Arnhem Land. However, there are no recent (post 1950) records from these areas despite considerable survey effort (J.C.Z. Woinarski 2008, pers. comm., cited in TSSC 2008aea).

Apart from the small population that persists at Mardugal campground in Kakadu National Park, the only other known population of the species on mainland Northern Territory is on the Cobourg Peninsula, an area which has been considered a 'stronghold' for the species (R.S.C. Firth 2007, pers. comm., cited in TSSC 2008aea). However, a predictive assessment of the impact of fire frequency on the population of the Brush-tailed Rabbit-rat on the Cobourg Peninsula concluded that extinction of the species in this area is likely within 10 years under current fire management regimes (Firth et al. 2010).

The Brush-tailed Rabbit-rat is known from several islands off the mainland of the Northern Territory, of which the population found on the Tiwi Islands is considered a 'stronghold' for the species (R.S.C. Firth 2007, pers. comm., cited in TSSC 2008aea; Firth et al. 2006). However, the subspecies on the Tiwi Islands has undergone decline due to plantation forestry and is likely to continue to decline should conversion of habitat to plantation timber continue as planned (S. Ward 2008, pers. comm., cited in TSSC 2008aea). A plantation of 100 000 ha has been foreshadowed, potentially representing 30% of the range of the subspecies on the Tiwi Islands (R.S.C. Firth 2007, pers. comm., cited in TSSC 2008aea), which would be in areas of high-quality habitat for the Brush-tailed Rabbit-rat (J.C.Z. Woinarski 2008, pers. comm., cited in TSSC 2008aea).

The species has been recorded on Groote Eylandt, although it has probably declined there due to manganese mining and may continue to decline should proposed extensions proceed. The species was not recorded during surveys of the island from 2006–08 and its status on Groote Eylandt is therefore uncertain (J.C.Z. Woinarski 2008, pers. comm., cited in TSSC 2008aea). However a recent survey undertaken in 2009 across Groote Eylandt, the focus of which was threatened species (including the Rabbit-rat) recorded Rabbit-rats at three different locations (R.S.C. Firth 2010, pers. comm).

The Brush-tailed Rabbit-rat was also recorded on Centre Island (off Arnhem Land, in the Sir Edward Pellew Group), but has apparently become extinct, possibly due to the introduction of Feral Cats (Felis catus) (R.S.C. Firth 2007, pers. comm., cited in TSSC 2008aea). During a survey of the Wessel and English Company Islands group off Arnhem Land between 1993–96 the species was noted as being patchily "very abundant" in a range of eucalypt woodlands on Inglis Island, although it was not recorded on any of the other islands (Woinarski et al. 1999).

Western Australia
Whilst there is a paucity of routine, published survey data to accurately assess changes to the distribution and abundance of the Brush-tailed Rabbit-rat over time in the Kimberley region (R. How 2007, pers. comm., cited in TSSC 2008aea), the available data including surveys of islands off the Kimberley region (A. Start 2007, pers. comm., cited in TSSC 2008aea), and recent surveys of the Mitchell River region, indicate that the species is relatively rare in Western Australia (I. Radford 2007, pers. comm., cited in TSSC 2008aea).

Surveys in the Kimberley region in the 1970s identified three sites where the species occurred. Surveys of this area in 2003–04 confirmed the species was still present at two of these sites and established the species' presence at an additional site (Start et al. 2007). Start and colleagues (2007) concluded that there was no evidence of change in the species' distribution and abundance in the Kimberley. However, this conclusion was qualified by noting that comparisons to previous survey effort were qualitative and that declines due to altered fire regimes, introduced stock, feral predators and weeds may occur in future (Start et al. 2007). In 2007, mammal trapping studies conducted in the Mitchell River region failed to record the species (I. Radford 2007, pers. comm., cited in TSSC 2008aea). However, some habitats where Brush-tailed Rabbit-rats were known to have been recorded in the past, were not sampled during this study. Extensive trapping conducted in 2007 during a survey of the Kimberley islands also failed to locate the species (A. Start 2007, pers. comm., cited in TSSC 2008aea). While this evidence indicates absence of the species in these locations, its does not necessarily indicate a decline in the species' numbers (TSSC 2008aea).

The species may decline in the Kimberley region due to proposed bauxite mining which could impact on two of the known populations on the Mitchell Plateau, should it progress to the production stage (R. How 2007, pers. comm., cited in TSSC 2008aea).

The Brush-tailed Rabbit-rat appears to have quite specific habitat requirements. It is largely restricted to mixed eucalypt open forest and woodland, or on dunes with Casuarina, seeming to prefer habitats that are not burnt annually, that have an understorey of predominantly perennial grasses and a sparse-to-moderate middle storey (Firth et al. 2006; Firth 2007; Kemper & Firth 2008).

The Brush-tailed Rabbit-rat is often active at dusk (Kemper & Firth 2008), and shelters during the day in tree hollows, hollow logs and, very infrequently, in the crowns of pandanus or sand-palms (Firth et al. 2006b).

The species has a small home ranges of approximately 1 ha (Firth et al. 2006b).

The Brush-tailed Rabbit-rat breeding season is long (March–October) (Kemper & Firth 2008) and the litter size tends to be two (Taylor & Horner 1971). In captivity, males, females and young share the nest and this suggests that social bonding and tolerance are features of the species' behaviour. Near-maximum weight is reached by about three months and females are sexually mature, on average, after 11 weeks (Kemper & Firth 2008). Some wild animals have lived for over two years (Kemper & Firth 2008), and the species' longevity may be as high as five or six years (R.S.C. Firth 2007, pers. comm., cited in TSSC 2008aea). One captive-bred Brush-tailed Rabbit-rat lived for 4.5 years before being released in the wild (Weigl 2005).

The only recorded predators of the Brush-tailed Rabbit-rat are Carpet Pythons (Morelia spilota variegate) and Northern Quolls (Dasyurus hallucatus) (Firth 2004; Kemper & Firth 2008), although the species is likely to be vulnerable to a wide range of predators including owls (order: Strigiformes), snakes (suborder: Serpentes), Goannas (Genus: Varanus), Dingos (Canis lupus dingo) and Feral Cats (J.C.Z. Woinarski 2008, pers. comm., cited in TSSC 2008aea).

The species is for the most part granivorous, with a diet composed primarily of seed from perennial grasses. Leaves, plant stems and insects comprise a smaller proportion of the species' diet (Firth et al. 2005).

Threats to the Brush-tailed Rabbit-rat include habitat alteration due to inappropriate fire regimes and grazing by introduced herbivores, habitat destruction resulting from forestry (~ 30,000 ha on Melville Island) and mining (though habitat destruction from mining is very minimal) operations and predation by Feral Cats. These threats are likely to have impacted, to various degrees, across the species' range, although there is a lack of specific data to demonstrate this for some threats (K. Johnson 2008, pers. comm., cited in TSSC 2008aea), and researchers note the need to quantify their relative impact (D. Fordham & B. Brook 2007, pers. comm., cited in TSSC 2008aea).

Habitat alteration
It is possible that broad-scale habitat change, resulting from altered fire regimes and grazing by introduced herbivores, may have contributed to the apparent decline in the Brush-tailed Rabbit-rat (NT DNREA 2007). Studies by Russell-Smith and colleagues (2003) have demonstrated that frequent burning in eucalypt forests in northern Australia (the habitat of the Brush-tailed Rabbit-rat) leads to a reduction in grass species diversity and an increase in understorey dominance by a small number of annual grasses, notably the now regionally pervasive annual Sorghum spp. This increased dominance of a small number of annual grasses and reduces the year-round availability variety of seed, particularly from those perennial grasses that are important components of the diet of the Brush-tailed Rabbit-rat (Firth et al. 2005). An increase in Sorghum spp. is likely to trigger a fire-grass cycle of ever increasing fire intensities (Rossiter et al. 2003). Increased fire intensities and/or frequency will also lead to reduction in the incidence, size and productivity of understorey shrubs that produce fleshy fruits, a dietary component that may be critical for the species at certain times of the year (R.S.C. Firth 2007, pers. comm., cited in TSSC 2008aea) and destroys hollow logs required for denning (Firth et al. 2006b).

In addition to Sorghum spp., the spread of other exotic grasses, particularly Gamba Grass (Andropogon gayanus) and Mission Grass (Pennisetum polystachyon), which exacerbate the cycle of intense late dry season fires, is also a potential threat to the species (S. Ward 2008, pers. comm., cited in TSSC 2008aea).

Recent research that models the risk of extinction to the species posed by various fire regimes predicts that, without active fire management, the remaining populations of Brush-tailed Rabbit-rat on the mainland of the Northern Territory are likely to be extinct within 10 years (Firth et al. 2010). This as-yet unpublished predictive assessment was based on capture-mark-recapture data from the population of the species in Garig Gunak Barlu National Park on the Cobourg Peninsula. Three fire regime scenarios were tested: no fire, an annual intense event in the late dry season and a rare intense event in the late dry season. Each modelled scenario resulted in the likely extinction of the Brush-tailed Rabbit-rat on the Cobourg Peninsula due to a homogenisation of the landscape, reducing food availability and foraging success (D. Fordham & B. Brook 2007, pers. comm., cited in TSSC 2008aea). The authors concluded that it is reasonable to expect similar rates of decline in other populations of the Brush-tailed Rabbit-rat that experience late dry season wildfires and temporally invariant regimes (D. Fordham & B. Brook 2007, pers. comm., cited in TSSC 2008aea). It is likely that a regime of low incidence of fire is suitable for the species, which is probably obtainable by undertaking early season, small-scale, patchy burns (TSSC 2008aea).

Grazing by introduced herbivores may be impacting on the habitat of the Brush-tailed Rabbit-rat. This effect may be similar to that of fire in that removal of ground cover through grazing and trampling can result in the loss of shelter for small mammals, such as Brush-tailed Rabbit-rats, from predators (I. Radford 2007, pers. comm., cited in TSSC 2008aea). However, Firth (2010, pers. comm) states that introduced grazers have probably not contributed to the decline to any real extent, as there has long (since the late 19th century) been an abundant population of swamp buffalo on Melville Island, where the Brush-tailed Rabbit-rat is also abundant (though their status needs to be re-assessed post forestry). On Cobourg Peninsula there are many introduced grazers (banteng, horses and swamp buffalo) and pigs which are in abundance and have a long history (e.g. banteng mid 19th century) with the Brush-tailed Rabbit-rat (Firth 2007). In fact at the last remaining site in Kakadu National Park horses and pigs are also present; and the decline reported for the Brush-tailed Rabbit-rat in Kakadu National Park matches a period during which buffalo and other feral stock numbers were dramatically reduced (R.S.C. Firth, 2010, pers. comm.).

Habitat destruction
Firth and colleagues (2006) reported that the subspecies on the Tiwi Islands was likely to undergo substantial decline over a short period of time due to clearance of its habitat for plantation timber. Between 2000–07, 25 000 ha of tall eucalypt forest on the Tiwi Islands was cleared. Another 6000 ha was approved for clearance in 2007 and a total plantation of 100 000 ha has been foreshadowed, which would be in areas of high-quality habitat for the Brush-tailed Rabbit-rat (J.C.Z. Woinarski 2008, pers. comm., cited in TSSC 2008aea). This potentially represents 30% of the range of the subspecies on the Tiwi Islands (R.S.C Firth 2007, pers. comm., cited in TSSC 2008aea). The subspecies is likely to decline both through the direct impact of habitat clearance, but also due to changed fire regimes and increases in exotic grasses, both of which are indirectly related to forestry development (R.S.C Firth 2007, pers. comm., cited in TSSC 2008aea). However just recently the forestry company operating on the Tiwi Islands has become insolvent as such no more clearing is planned (total area cleared was approximately 30 000 ha) (R.S.C. Firth, 2010, pers. comm.).

Although the population size and habitat preferences of the species on Groote Eylandt are unknown, it is likely that the species has declined there to some extent because of the clearing of eucalypt woodland for manganese mining. Proposed extension to mining activities may threaten the species further, as the extension would be in the area where the species has been most recently recorded (S. Ward 2008, pers. comm., cited in TSSC 2008aea). However in 2009, surveys were undertaken across Groote Eylandt, the focus of which was threatened species (including the Brush-tailed Rabbit-rat). Brush-tailed Rabbit-rats were recorded at three different locations (R.S.C. Firth, 2010, pers. comm). All three locations are in areas well away from any proposed mining (R.S.C. Firth, 2010, pers. comm).

Similarly, proposed bauxite mining, should it progress to the production stage, may impact on two of the known populations of this species on the Mitchell Plateau (R. How 2007, pers. comm., cited in TSSC 2008aea).

Feral Cats
Brush-tailed Rabbit-rats are of a size that makes them attractive prey for Cats (S. Ward 2008, pers. comm., cited in TSSC 2008aea). The maintenance of populations of the species on islands which are free of Cats suggests that predation by Feral Cats may have been the causal factor in the decline in the species' range on the mainland of the Northern Territory (NT DNREA 2007). Further, there is circumstantial evidence to suggest that the recent arrival of Cats in the Sir Edward Pellew Islands group coincided with the decline and possible extinction of the Brush-tailed Rabbit-rat in that area (R.S.C. Firth 2007, pers. comm., cited in TSSC 2008aea). The species was recorded from Centre Island by Keith (1968) and Calaby (1976) during a broad-based fauna survey, however subsequent surveys have not recorded the species despite targeted searching (Johnson & Kerle 1991; Taylor et al. 2004). This decline corresponds reasonably well with reports from Aboriginal landholders of these islands about the introduction of Cats to these islands within the last 20–30 years (R. Taylor 2007, pers. comm., cited in TSSC 2008aea).

However, there is a paucity of data regarding the occurrence of Feral Cats within the range of Brush-tailed Rabbit-rats (A. Start 2007, pers. comm., cited in TSSC 2008aea) and a lack of empirical evidence to demonstrate that they are a direct threat to the species (C. Kemper 2008, pers. comm., cited in TSSC 2008aea). Predation by cats on the mainland may have also contributed to the decline, however cats are present on the Tiwi Islands, and at both of the last known Northern Territory mainland sites (Cobourg Peninsula and at the Mardugal campground site in Kakadu National Park). Although this suggests that cats are probably not the main factor driving the decline, they may nonetheless be having some predation impacts (Firth 2007).

Other threats and factors
It is possible that disease may be a threat to the species (NT DNREA 2007), but lack of data would render any assessment of this conjectural at best (A. Start 2007, pers. comm., cited in TSSC 2008aea). Climate change may impact on the species by increasing the incidence of destructive cyclones throughout the species' range (R.S.C. Firth 2007, pers. comm., cited in TSSC 2008aea), although cyclones may also be beneficial for the species by increasing tree-fall and resulting in more logs for shelter (C. Kemper 2008, pers. comm., cited in TSSC 2008aea).

It is also possible that some of the variation in the species' numbers may be due to long-term fluctuations in mammal abundance in the wet-dry tropics, a phenomenon for which there is some evidence but little quantitative information collected over a relevant time scale (R. How 2007, pers. comm., cited in TSSC 2008aea).

Should the Brush-tailed Rabbit-rats' distribution contract to islands, then demographic, stochastic and genetic factors may threaten the species. Although genetic diversity in Brush-tailed Rabbit-rat populations is unknown, Australian marsupial island populations typically harbour significantly lower genetic diversity and are more inbred than their mainland counterparts (Eldridge et al. 1999, 2004). Such genetic factors are considered to contribute to the extinction-proneness of island populations worldwide (Frankham 1998).

Minister's Reasons for Recovery Plan Decision
There should be a recovery plan for the Brush-tailed Rabbit-rat, as it would assist in establishing the relative impact of the likely threats to this species and provide a coordinated approach to the management of this species (and other species with comparable management challenges) across Australia.

The Commonwealth Conservation Advice on Conilurus penicillatus (TSSC 2008afq) outlines the following research priorities:

  • Collate, evaluate and make available, unpublished historical data.
  • Develop and maintain a monitoring program across the species' national range. This program may incorporate:
    • surveys using baselines that have been established for faunal surveys on Cobourg Peninsula, the Tiwi Islands and in Kakadu National Park (DNREA 2007)
    • surveys at appropriate spatial and temporal scales across the species' known and potential distribution in the Kimberley region
    • in addition to the current WA DEC Kimberley Islands survey, surveys to determine the species' current distribution on islands throughout its range, in particular islands where the species has previously been recorded but where no recent records have been made (i.e. Bentinck Island)
    • surveys of suitable habitat and potential habitat to locate any additional populations, for example on the mainland adjacent to the Sir Edward Pellew Group and Bentinck Island.
  • More precisely assess population size, distribution, ecological requirements and the relative impacts of threatening processes such as, inappropriate fire regimes, habitat modification by introduced herbivores and predation by Feral Cats on the species.

In addition, the Commonwealth Conservation Advice on Conilurus penicillatus (TSSC 2008afq) outlines the following priority actions:

  • Monitor known populations to identify key threats and the effectiveness of management actions, where appropriate.
  • Investigate formal conservation arrangements such as the use of covenants, conservation agreements or inclusion in reserve tenure.
  • Develop and implement a management plan for the control of Gamba Grass and Mission Grass in regions where the species occurs.
  • Ensure the implementation of the Threat Abatement Plan for predation by feral cats (DEWHA 2008adg).
  • Work with Aboriginal landowners to maintain effective quarantine actions for island populations, most particularly relating to preventing the introduction and establishment of cats on the islands where the species occurs.
  • Develop and implement a suitable fire management strategy across the range of the Brush-tailed Rabbit-rat. It is likely that a regime of low incidence of fire is suitable for the species, which is probably obtainable by undertaking early season, small-scale, patchy burns.
  • Provide maps of known occurrences to local and state rural fire services and seek inclusion of mitigative measures in bush fire risk management plan(s), risk register and/or operation maps.
  • Continue to raise awareness of the Brush-tailed Rabbit-rat within the relevant land management authorities and within the local community. Target audiences include:
    • The Anindilyawaka Land Council, managers of the Indigenous Protected Area that includes Groote Eylandt
    • Relevant land managers on the Tiwi Islands
    • Relevant land managers in the Kimberley region.
  • Evaluate the possibility of establishing translocated populations, either on currently uninhabited islands and/or in appropriately managed conservation reserves.
  • Ensure that the species is considered in any proposed expansion to manganese mining operations on Groote Eylandt.
  • Ensure that the species is considered in any proposals for the mining of bauxite on the Mitchell Plateau.
  • Ensure that habitat clearance for plantation forestry on the Tiwi Islands does not compromise population viability.

The Threatened Species Information Sheet: Brush-tailed Rabbit-rat Conilurus penicillatus (NT DNREA 2007) outlines the following conservation objectives and management:

  • Maintain a monitoring program in at least two sites, which can also measure responses to management actions. The baseline for this monitoring has now been established, with recent studies on Cobourg Peninsula, the Tiwi Islands and in Kakadu National Park.
  • Work with Aboriginal landowners to maintain effective quarantine actions for island populations, most particularly relating to maintaining at least some of these islands cat-free.
  • Develop effective captive population breeding programs, and evaluate the possibility of establishing translocated populations (either to currently uninhabited islands or to appropriately managed conservation reserves). Such a program is currently being undertaken through the Territory Wildlife Park.
  • Ensure that habitat clearance for plantation forestry on the Tiwi Islands does not compromise population viability.

The Commonwealth Conservation Advice on Conilurus penicillatus (TSSC 2008afq) provides a brief biological overview and management recommendation. In addition the Threat Abatement Plan for predation by feral cats (DEWHA 2008adg) and the Threatened Species Information Sheet: Brush-tailed Rabbit-rat Conilurus penicillatus (NT DNREA 2007) are available.

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:Livestock Farming and Grazing:Grazing pressures and associated habitat changes Commonwealth Listing Advice on Conilurus penicillatus (Threatened Species Scientific Committee (TSSC), 2008aea) [Listing Advice].
Biological Resource Use:Logging and Wood Harvesting:Habitat disturbance due to foresty activities Commonwealth Conservation Advice on Conilurus penicillatus (Threatened Species Scientific Committee (TSSC), 2008afq) [Conservation Advice].
Biological Resource Use:Logging and Wood Harvesting:Habitat loss, modification and degradation due to timber harvesting Commonwealth Listing Advice on Conilurus penicillatus (Threatened Species Scientific Committee (TSSC), 2008aea) [Listing Advice].
Climate Change and Severe Weather:Climate Change and Severe Weather:Climate change altering atmosphere/hydrosphere temperatures, rainfall patterns and/or frequency of severe weather events Commonwealth Listing Advice on Conilurus penicillatus (Threatened Species Scientific Committee (TSSC), 2008aea) [Listing Advice].
Climate Change and Severe Weather:Habitat Shifting and Alteration:Habitat loss, modification and/or degradation Commonwealth Listing Advice on Conilurus penicillatus (Threatened Species Scientific Committee (TSSC), 2008aea) [Listing Advice].
Climate Change and Severe Weather:Habitat Shifting and Alteration:Habitat modification, destruction and alteration due to changes in land use patterns Commonwealth Listing Advice on Conilurus penicillatus (Threatened Species Scientific Committee (TSSC), 2008aea) [Listing Advice].
Energy Production and Mining:Mining and Quarrying:Habitat destruction, disturbance and/or modification due to mining activities Commonwealth Conservation Advice on Conilurus penicillatus (Threatened Species Scientific Committee (TSSC), 2008afq) [Conservation Advice].
Energy Production and Mining:Mining and Quarrying:Habitat modification through open cut mining/quarrying activities Commonwealth Listing Advice on Conilurus penicillatus (Threatened Species Scientific Committee (TSSC), 2008aea) [Listing Advice].
Invasive and Other Problematic Species and Genes:Invasive Non-Native/Alien Species:Competition and/or habitat degradation Andropogon gayanus (Gamba Grass) Commonwealth Listing Advice on Conilurus penicillatus (Threatened Species Scientific Committee (TSSC), 2008aea) [Listing Advice].
Invasive and Other Problematic Species and Genes:Invasive Non-Native/Alien Species:Competition and/or habitat degradation Pennisetum polystachion (Mission Grass, Perennial Mission Grass, Missiongrass, Feathery Pennisetum, Feather Pennisetum, Thin Napier Grass, West Indian Pennisetum, Blue Buffel Grass) Commonwealth Listing Advice on Conilurus penicillatus (Threatened Species Scientific Committee (TSSC), 2008aea) [Listing Advice].
Invasive and Other Problematic Species and Genes:Invasive Non-Native/Alien Species:Competition and/or habitat degradation caused by Sorghum sp. Commonwealth Listing Advice on Conilurus penicillatus (Threatened Species Scientific Committee (TSSC), 2008aea) [Listing Advice].
Invasive and Other Problematic Species and Genes:Invasive Non-Native/Alien Species:Competition and/or habitat degradation caused by exotic pasture species Commonwealth Listing Advice on Conilurus penicillatus (Threatened Species Scientific Committee (TSSC), 2008aea) [Listing Advice].
Invasive and Other Problematic Species and Genes:Invasive Non-Native/Alien Species:Competition and/or predation Felis catus (Cat, House Cat, Domestic Cat) Commonwealth Listing Advice on Conilurus penicillatus (Threatened Species Scientific Committee (TSSC), 2008aea) [Listing Advice].
Commonwealth Conservation Advice on Conilurus penicillatus (Threatened Species Scientific Committee (TSSC), 2008afq) [Conservation Advice].
Invasive and Other Problematic Species and Genes:Invasive and Other Problematic Species and Genes:Predation, competition, habitat degradation and/or spread of pathogens by introduced species Commonwealth Conservation Advice on Conilurus penicillatus (Threatened Species Scientific Committee (TSSC), 2008afq) [Conservation Advice].
Invasive and Other Problematic Species and Genes:Invasive and Other Problematic Species and Genes:Presence of pathogens and resulting disease Commonwealth Listing Advice on Conilurus penicillatus (Threatened Species Scientific Committee (TSSC), 2008aea) [Listing Advice].
Natural System Modifications:Fire and Fire Suppression:Inappropriate and/or changed fire regimes (frequency, timing, intensity) Commonwealth Listing Advice on Conilurus penicillatus (Threatened Species Scientific Committee (TSSC), 2008aea) [Listing Advice].
Commonwealth Conservation Advice on Conilurus penicillatus (Threatened Species Scientific Committee (TSSC), 2008afq) [Conservation Advice].

Abbott, I. & A.A. Burbidge (1995). The occurrence of mammal species on the islands of Australia: a summary of existing knowledge. CALMScience. 1:259-324.

Bradley, A.J., C.M. Kemper, D.J. Kitchener, W.F. Humphreys & R.A. How (1987). Small mammals of the Mitchell Plateau region, Kimberley, Western Australia. Australian Wildlife Research. 14:397-413.

Braithwaite, R.W. (1985). The Kakadu fauna survey: an ecological survey of Kakadu National Park. Canberra: Australian National Parks & Wildlife Service.

Calaby, J.H. (1973a). Mammals In Alligator Rivers Region Environmental Fact-finding Study: Wildlife. Canberra, ACT: CSIRO.

Calaby, J.H. (1976). Mammals in a survey of the fauna of the lower McArthur River Region Northern Territory. Canberra, ACT: CSIRO.

Calaby, J.H. & K. Keith (1974a). Mammals in fauna survey of the Port Essington district, Cobourg Peninsula, Northern Territory of Australia. Canberra, ACT: CSIRO.

Dahl, K. (1897). Biological notes on north-Australian mammalia. Zoologist, Series 4. 1:189-216.

Department of Sustainability, Environment, Water, Population and Communities (DSEWPaC) (2011j). Survey guidelines for Australia's threatened mammals. EPBC Act survey guidelines 6.5. [Online]. EPBC Act policy statement: Canberra, ACT: DSEWPAC. Available from: http://www.environment.gov.au/epbc/publications/threatened-mammals.html.

Department of the Environment, Water, Heritage and the Arts (DEWHA) (2008zzp). Threat Abatement Plan for predation by feral cats. [Online]. Department of the Environment, Water, Heritage and the Arts. Available from: http://www.environment.gov.au/biodiversity/threatened/publications/tap/cats08.html.

Eldridge, M.D.B., J.E. Kinnear, K.R. Zenger, L.M. McKenzie & P.B.S. Spencer (2004). Genetic diversity in remnant mainland and "pristine" island populations of three endemic Australian macropodids (Marsupialia): Macropus eugenii, Lagorchestes hirsutus and Petrogale lateralis. Conservation Genetics. 5:325-338.

Eldridge, M.D.B., J.M. King, A.K. Loupis, P.B.S. Spencer, A.C. Taylor, L.C. Pope & G.P. Hall (1999). Unprecedented low levels of genetic variation and inbreeding depression in an island population of the black-footed rock-wallaby. Conservation Biology. 13: 531-541.

Firth, R (2008). Surveys for the Threatened Northern Hopping-mouse, Northern Quoll and Brush-tailed Rabbit Rat on GEMCO Eastern Exploration Leases (Groote Eylandt). A report prepared for Coffey Natural Systems and GEMCO (submitted with Referral EPBC 2010/5455). EWL Sciences Pty Ltd.

Firth, R.S.C (2010). Personal Communication.

Firth, R.S.C. (2004). Carpet python (Morelia spilota variegata) predation on the brush-tailed rabbit-rat (Conilurus penicillatus melibius) on Melville Island, Northern Territory. Herpetofauna. 34:105-106.

Firth, R.S.C. (2007). Ecology and conservation status of the brush-tailed rabbit-rat Conilurus penicillatus. Ph.D. Thesis. Darwin, Northern Territory: Charles Darwin University.

Firth, R.S.C., Brook, B.W., Woinarski, J.C.Z., & Fordham, D.A. (2010). Decline and likely extinction of a northern Australian native rodent, the brush-tailed rabbit-rat Conilurus penicillatus. Biological Conservation.

Firth, R.S.C., E. Jefferys, J.C.Z. Woinarski & R.A. Noske (2005). The diet of the brush-tailed rabbit-rat Conilurus penicillatus from the monsoonal tropics of the Northern Territory, Australia. Wildlife Research. 32:517-524.

Firth, R.S.C., J.C.Z. Woinarski & R.A. Noske (2006b). Home range and den characteristics of the brush-tailed rabbit-rat Conilurus penicillatus in the monsoonal tropics of the Northern Territory, Australia. Wildlife Research. 33:397-408.

Firth, R.S.C., J.C.Z. Woinarski, K.G. Brennan & C. Hempel (2006). Environmental relationships of the Brush-tailed Rabbit-rat Conilurus penicillatus and other small mammals on the Tiwi Islands, northern Australia. Journal of Biogeography. 33:1820-1837.

Frankham, R. (1998). Inbreeding and extinction: island populations. Conservation Biology. 12:665-675.

Groote Eylandt Mining Company (GEMCO) (2010). EPBC 2010/5455. [Online]. Groote Eylandt Mining Company (GEMCO). Available from: http://www.environment.gov.au/cgi-bin/epbc/epbc_ap.pl?name=public_notifications&limit=999999&text_search=2010%2F5455.

Johnson, K.A. & J.A. Kerle (1991). Flora and vertebrate fauna of the Sir Edward Pellew group of islands, Northern Territory. Report to the Australian Heritage Commission. Alice Springs, Northern Territory: Conservation Commission of the Northern Territory.

Keith, K. (1968). Mammals of the Pellew Islands. Mimag (House journal of Mount Isa Mines Ltd). 19:19-21.

Kemper, C.M. & L.H. Schmitt (1992). Morphological variation between populations of the brush-tailed tree-rat (Conilurus penicillatus) in northern Australia and New Guinea. Australian Journal of Zoology. 40:437-452.

Kemper, C.M. & R.S.C. Firth (2008). Brush-tailed Rabbit-rat. In: Van Dyck, S. & R. Strahan, eds. The Mammals of Australia. Chatswood, NSW: Reed New Holland.

Northern Territory Department of Natural Resources, Environment and the Arts (NT DNREA) (2007). Threatened Species Information Sheet: Brush-tailed Rabbit-rat Conilurus penicillatus. [Online]. Darwin, Northern Territory: Department of Natural Resources, Environment and the Arts. Available from: http://www.nt.gov.au/nreta/wildlife/animals/threatened/pdf/mammals/brushtailed_treerat_vu.pdf.

Rossiter, N.A., S.A. Setterfield, M.M. Douglas & L.B. Hutley (2003). Testing the grass-fire cycle: alien grass invasion in the tropical savannas of northern Australia. Diversity and Distributions. 9:169-176.

Russell-Smith, J., P.J. Whitehead, G.D. Cook & J.L. Hoare (2003). Response of Eucalyptus-dominated savanna to frequent fires: lessons from Munmarlary, 1973-1996. Ecological Monographs. 73:349-375.

Smith, J (2009). Surveys for Northern Hopping-mouse, Northern Quoll and Brush-tailed Rabbit Rat across Groote Eylandt. A report prepared for GEMCO (submitted as part of EPBC Referral 2010/5455). EWL Sciences Pty Ltd.

Start, A.N., A.A. Burbidge, N.L. McKenzie & C. Palmer (2007). The status of mammals in the North Kimberley, Western Australia. Australian Mammalogy. 29:1:1-16.

Taylor, J.M. & B.E. Horner (1971). Reproduction in the Australian tree-rat Conilurus penicillatus (Rodentia: Muridae). CSIRO Wildlife Research. 16:1-9.

Taylor, R., J. Woinarski, A. Charlie, R. Dixon, D. Pracy & S. Rhind (2004). Report on mammal survey of the Pellew Islands 2003. Darwin, Northern Territory: Lianthawirriyarra Sea Ranger Unit, Department of Infrastructure, Planning and Environment, and Tropical Savannas CRC.

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Threatened Species Scientific Committee (TSSC) (2008aea). Commonwealth Listing Advice on Conilurus penicillatus. [Online]. Department of the Environment, Water, Heritage and the Arts. Available from: http://www.environment.gov.au/biodiversity/threatened/species/pubs/132-listing-advice.pdf.

Threatened Species Scientific Committee (TSSC) (2008afq). Commonwealth Conservation Advice on Conilurus penicillatus. [Online]. Department of the Environment, Water, Heritage and the Arts. Available from: http://www.environment.gov.au/biodiversity/threatened/species/pubs/132-conservation-advice.pdf.

Van Dyck, S. & R. Strahan (2008). The Mammals of Australia, Third Edition. Page(s) 880. Sydney: Reed New Holland.

Woinarski, J.C.Z., C. Palmer, A. Fisher, R. Southgate, P. Masters & K. Brennan (1999). Distributional patterning of mammals on the Wessel and English Company Islands, Arnhem Land, Northern Territory, Australia. Australian Journal of Zoology. 47:87-111.

Woinarski, J.C.Z., D.J. Milne & G. Wanganeen (2001). Changes in mammal populations in relatively intact landscapes of Kakadu National Park, Northern Territory, Australia. Austral Ecology. 26:360-370.

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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). Conilurus penicillatus in Species Profile and Threats Database, Department of the Environment, Canberra. Available from: http://www.environment.gov.au/sprat. Accessed Mon, 22 Sep 2014 10:18:43 +1000.