1 Kejora

Northern Quoll Descriptive Essay

Geographic Range

Northern quolls (Dasyurus hallucatus) are native to a 150 kilometer band, across the northern Australian coast, from Pilbara in western Australia, to the northeast coast of Queensland. Since European settlement, the species has declined drastically over much of its range and has even become locally extinct on some Australian Islands. It is currently found in six isolated populations: in the Hamersley Range, northern and western Top End, North Cape York tip, Atherton Tableland and the Carnarvon Range. (Braithwaite and Begg, 1995; Braithwaite and Griffiths, 1994; Nelson and Gemmel, 2003; Oakwood, 2002; Woinarski, et al., 1999)

Habitat

Northern quolls are the most arboreal of the Australian quolls although they inhabit a variety of terrestrial habitats. They are most often found in rocky escarpments and open eucalyptus forests of lowland savannahs. This species has experienced an overall decline in population throughout its range; however, the savannah habitats have experienced the most drastic population decline. Northern quolls have been known to den in tree hollows, rock crevices, logs, termite mounds and goanna burrows. (Begg, 1981; Oakwood, 2000a; Oakwood, 2002)

Physical Description

Northern quolls are medium sized Dasyurids and the smallest of the Australian quolls. They are sexually dimorphic, with males larger than females. Males may weigh as much as 1,200 g, although they usually range between 400 to 900 g (an average of 760 g). Females range between 300 to 500 g (an average of 760 g). Their total length is similar, although males are slightly longer, ranging from 12.3 to 31 cm; whereas females range from 12.5 to 30 cm. Their tail is long relative to their body, the average tail length for males is 12.7 to 30.8 cm; whereas female tail lengths range 20 to 30 cm. (Braithwaite and Begg, 1995; Oakwood, 2002; Schmitt, et al., 1981)

In general, northern quolls are somewhat mouse-like in appearance. They have short coarse fur, with thin underfur. They are dusky grey-brown, with large white spots dorsally and cream to white fur ventrally. This species has well-defined serrated pads on their palms and soles and an unspotted tails. They have a hallux, with a total of five toes on their hind feet. Females have five to eight exposed teats, arranged in anterioposterior rows, surrounded by a marginal fold of skin (marsupium). (Begg, 1981; Braithwaite and Begg, 1995; Jones, et al., 2001)

Reproduction

Males and females are promiscuous. The mating season corresponds with the Australian dry season, occurring in May and June. Females are intra-sexually territorial, with no observed overlap in territory, most likely maintained by mutual avoidance. Feces markers are more commonly observed during the mating season, advertising female presence both to other females and males. Females are visited by multiple males during the mating season, with short encounters occurring at night in the female's den. It is rare for a female not to breed in any given year. Males are non-territorial and attempt to breed with as many females as possible during the breeding season, often traveling long distances from one female to another, monitoring the onset of estrus. The mating process has yet to be observed, although it appears to be quite aggressive, with females often showing distinct scars from males biting the back of their neck and clasping their sides during copulation. Males are the largest mammal and the only Dasyurid known to experience complete semelparity, usually dying within two weeks of mating. (Oakwood, 2000b; Oakwood, 2002)

After a 21 to 25 day gestation period, birth is completed synchronously among a single population within a four week period, with little annual variation. This period varies geographically, beginning as early as late May and ending as late as August. Evidence suggests that a combination of photoperiod and latitude affect the timing of this event for a given population. (Aitkin, et al., 1996; Nelson and Gemmel, 2003; Oakwood, 2000b)

When they are ready to give birth, females groom the area around their urogenital sinus, pouch and tail. Just before emergence of the young, a female will lift her posterior region and lick a cloudy mucus-like fluid, which is released from the urogenital sinus. During birth, females place their heads to the ground, keeping their urogenital sinus higher than the pouch region, with the base of their tail held away. The young are excreted in a gelatinous material and either drop to the ground or successfully climb their way along the mother to the pouch, aided by their senses and gravity. (Nelson and Gemmel, 2004)

Females may give birth to as many as 17 altricial offspring in one litter, although the average litter size is 5 to 8 and they have a maximum of 8 teats available for nursing young. The average weight of a newborn is 18 mg; with an average length of 5 mm. Offspring unsuccessful in latching to a teat soon perish. During birth, marginal ridges of skin develop around the teats and cover the young. Young are first released from this rudimentary pouch at two months of age for short periods of time. They are fully weaned at 4 months of age. Males and females become sexually mature at 11 months of age, although males reach their maximum weight at 7 months. (Nelson and Gemmel, 2003; Nelson and Gemmel, 2004; Nelson, 1992; Oakwood, 2000b)

Both sexes put forth most of their reproductive energy in their first breeding season, which is when they are at their highest fitness level. Females care for the young on their own because there is no paternal care. Little is known about parental care in this species, but studies indicate that the female will move from the rockier areas of her home range to the woodland areas near creeks when the young are around 2 months old. This is the time at which the young will first detach from their mother. The female will leave the young in a succession of nursery dens for periods of time, while foraging at night. When the young are weaned, the female will move them back to the rockier areas. Dispersal of young is not yet fully understood. (Oakwood, 2000b)

Lifespan/Longevity

Female northern quolls may live up to 3 years, although 1 to 2 years is more common. Males only live up to 1 year. Mating is extremely energetically costly for males, ultimately resulting in death within 2 weeks after mating. During the mating period, they experience weight loss, elevated androgens, loss of fur, and proliferation of parasites, increasing their risk of predation and vehicle collisions. (Cordoso, et al., 2009; Oakwood, 2000b; Oakwood, et al., 2001)

Behavior

Both male and female northern quolls are solitary and asocial. Males only contact females during short mating encounters. There is no evidence of a male dominance hierarchy and individuals appear to practice mutual avoidance in overlapping home ranges. Females are intra-sexually territorial to varying degrees. The size of an average female's territory is 35 ha. In low densities there is no overlap between female home ranges; however, in higher densities, foraging areas may overlap, with denning sites remaining mutually exclusive. A surviving young female of the last breeding season may inherit her mother’s territory when her mother dies, otherwise, young disperse into vacant areas and immediately take over rocky areas that become vacant when a neighbor dies. (Oakwood, 2002)

Males and females are nocturnal. Evidence of torpor and early morning lethargy has been observed in an individual male. This is not unexpected because torpor is common among marsupials inhabiting arid and tropical environments with variable resource availability. (Cooper and Withers, 2010; Oakwood, 2002)

Home Range

Males have a much larger home range than females, especially during the mating season. Males have an average home range area of 99 ha, whereas females average 35 ha.

Communication and Perception

Young northern quolls vocalize as early as 35-days-old by making stereotypic isolation calls. Hearing doesn’t develop until approximately 65 days, which promotes call development to a more adult-like vocalization. Call duration in young last 100 to 200 ms; while adult calls last 1 to 2 s. Young communicate vocally with their mother, providing information regarding location and stress level. Adult communication is in the form of a “hiss”, acknowledging an encounter. (Aitkin, et al., 1996)

Scent marking has been commonly observed in D. hallucatus to mark territories and advertise their presence to mates. Both females and males rub their ventral surfaces on objects in their environment, to disperse their scent. They also urinate on the feces of other individuals and deposit scat in prominent places. When feces by another individual is found, it is picked up, sniffed and examined. (Oakwood, 2002)

Food Habits

Dasyurus hallucatus is considered a carnivorous marsupial, although it primarily feeds on insects. Their diet also consists of other small mammals, birds, frogs, reptiles and sometimes fleshy fruits. Cane toads (Rhinella marina), an invasive species to Australia, are a food item of particular interest because their toxins appear to be a major cause of decline in northern quolls' populations, even in areas where they are managed. (O'Donnell, et al., 2010; Oakwood, 2002; Woinarski, et al., 2011)

Predation

Predators of D. hallucatus include dingos (Canis lupis dingo), feral cats (Felis catus) and snakes, such as olive pythons (Liasis olivaceus), king brown snakes (Pseudechis australis) and possibly avian predators, such as owls (Strigiformes). Physiological decline after mating is speculated to cause male northern quolls to become susceptible to lice infestations. (Oakwood, 2000a)

Ecosystem Roles

Northern quolls are predators of small mammals, which aides in the control of small mammal populations. They are also an ideal alternative host in the life cycle of many parasites. Although no particular parasitic species are known to favor northern quolls exclusively, males are commonly infested with lice (Boopia ucinata) before death. Other parasites that have been found on D. hallucatus include Bandicoot ticks (Haemaphysalis humerosa), trombiculid mites (Guntheria coorongensis) and fleas (Xenopsylla vexabilis). Sarcocystis species have been observed histologically in northern quolls. (Oakwood, 2000a)

Commensal/Parasitic Species

Economic Importance for Humans: Positive

A survey answered by scientists and wildlife handlers suggests that northern quolls, along with other quolls, have many characteristics that are ideal of a quality house pet. In addition, northern quolls may benefit agriculture by removing insect pests. (Nowak, 1991)

Economic Importance for Humans: Negative

Quolls can be an agricultural annoyance and have been known to destroy poultry. (Nowak, 1991)

Conservation Status

Northern quolls are considered ‘endangered’ under the International Union for Conservation of Nature (ICUN) list of threatened species. They have no special status in the appendices of the Convention on International Trade in Endangered Species (CITES). (Oakwood, et al., 2008)

Dasyurus hallucatus was originally identified by Gould in 1942, under the genus Satenellus. Some still suggest that D. hallucatus be placed in a separate genus due to its basal characteristics. (Braithwaite and Begg, 1995; Jones, et al., 2001)

Northern quolls are also known as the “little northern native cat”, “north Australian native cat”, and “njanmak”, a Mayali aboriginal word. (Braithwaite and Begg, 1995)

Contributors

Jenna Black (author), University of Manitoba, Jane Waterman (editor), University of Manitoba, Leila Siciliano Martina (editor), Animal Diversity Web Staff.

Glossary

Australian

Living in Australia, New Zealand, Tasmania, New Guinea and associated islands.

acoustic

uses sound to communicate

altricial

young are born in a relatively underdeveloped state; they are unable to feed or care for themselves or locomote independently for a period of time after birth/hatching. In birds, naked and helpless after hatching.

arboreal

Referring to an animal that lives in trees; tree-climbing.

bilateral symmetry

having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.

carnivore

an animal that mainly eats meat

chemical

uses smells or other chemicals to communicate

endothermic

animals that use metabolically generated heat to regulate body temperature independently of ambient temperature. Endothermy is a synapomorphy of the Mammalia, although it may have arisen in a (now extinct) synapsid ancestor; the fossil record does not distinguish these possibilities. Convergent in birds.

female parental care

parental care is carried out by females

forest

forest biomes are dominated by trees, otherwise forest biomes can vary widely in amount of precipitation and seasonality.

insectivore

An animal that eats mainly insects or spiders.

motile

having the capacity to move from one place to another.

native range

the area in which the animal is naturally found, the region in which it is endemic.

nocturnal

active during the night

polygynandrous

the kind of polygamy in which a female pairs with several males, each of which also pairs with several different females.

scent marks

communicates by producing scents from special gland(s) and placing them on a surface whether others can smell or taste them

seasonal breeding

breeding is confined to a particular season

semelparous

offspring are all produced in a single group (litter, clutch, etc.), after which the parent usually dies. Semelparous organisms often only live through a single season/year (or other periodic change in conditions) but may live for many seasons. In both cases reproduction occurs as a single investment of energy in offspring, with no future chance for investment in reproduction.

sexual

reproduction that includes combining the genetic contribution of two individuals, a male and a female

tactile

uses touch to communicate

terrestrial

Living on the ground.

territorial

defends an area within the home range, occupied by a single animals or group of animals of the same species and held through overt defense, display, or advertisement

tropical

the region of the earth that surrounds the equator, from 23.5 degrees north to 23.5 degrees south.

tropical savanna and grassland

A terrestrial biome. Savannas are grasslands with scattered individual trees that do not form a closed canopy. Extensive savannas are found in parts of subtropical and tropical Africa and South America, and in Australia.

savanna

A grassland with scattered trees or scattered clumps of trees, a type of community intermediate between grassland and forest. See also Tropical savanna and grassland biome.

temperate grassland

A terrestrial biome found in temperate latitudes (>23.5° N or S latitude). Vegetation is made up mostly of grasses, the height and species diversity of which depend largely on the amount of moisture available. Fire and grazing are important in the long-term maintenance of grasslands.

visual

uses sight to communicate

viviparous

reproduction in which fertilization and development take place within the female body and the developing embryo derives nourishment from the female.

References

Aitkin, L., J. Nelson, R. Shepherd. 1996. Development of hearing and vocalization in a marsupial, the northern quoll, Dasyurus hallucatus. Journal of Experimental Biology, 276: 394-402.

Begg, R. 1981. Small mammals of Little Nourlangi Rock, N.T. III. Ecology of Dasyurus hallucatus, the northern quoll. Australian Wildlife Research, 8: 73-85.

Braithwaite, R., A. Griffiths. 1994. Demographic variation and range contraction in the northern quoll, Dasyurus hallucatus (Marsupialia : >>Dasyuridae>>). Wildlife Research, 21: 203-217.

Braithwaite, R., R. Begg. 1995. Mammals of Australia: the northern quoll Dasyurus hallucatus Gould, 1842. Chatswood, New South Whales, Australia: Smithsonian Institution Press.

Cooper, M., P. Withers. 2010. Comparative physiology of Australian quolls (Dasyurus: Marsupialia). Journal of Comparative Biology, 180: 857-868.

Cordoso, M., M. Eldridge, M. Oakwood, B. Rankmore. 2009. Effects of founder events on genetic variation of translocated island populations: implications for conservation management of the northern quoll. Conservation Genetics, 10: 1719-1733.

Jones, M., R. Rose, S. Burnett. 2001. Dasyurus maculatus. Mammalian Species, 676: 1-9.

Nelson, J. 1992. Developmental Staging in a marsupial, Dasyurus hallucatus. Anatomoy of Embryology, 185: 335-354.

Nelson, J., R. Gemmel. 2004. Implications of marsupial births for an understanding of behvioural development. International Journal of Comparative Psychology, 17: 53-70.

Nelson, J., R. Gemmel. 2003. Birth in the northern quoll, Dasyururs hallucatus (Marsupialia : Dasyuridae). Australian Journal of Zoology, 51: 187-198.

Nowak, R. 1991. Walker's mammals of the world, 5th edition. Baltimore, Maryland: Johns Hopkins University Press.

O'Donnell, S., J. Webb, R. Shine. 2010. Conditioned taste aversion enhances the survival of an endangered predator inperiled by a toxic invader. Journal of Applied Biology, 47: 558-565.

Oakwood, M. 2000. Parasites of the northern quoll, Dasyurus hallucatus (Marsupialia : Dasyuridae) in tropical savannah, Northern Territory. Australian Journal of Zoology, 48: 79-90.

Oakwood, M. 2000. Reproduction and demography of the northern quoll, Dasyurus hallucatus in the lowland savannah of northern Australia. Australian Journal of Zoology, 48: 519-539.

Oakwood, M., A. Bradley, A. Cockburn. 2001. Semelparity in a large marsupial. Proceedings: Biological Sciences, 428: 407-411.

Oakwood, M., J. Woinarski, S. Burnett. 2008. "Dasyururs hallucatus" (On-line). ICUN Redlist of Threatened Species. Accessed November 01, 2012 at .

Oakwood, M. 2002. Spatial and social organization of a carnivorous marsupial Dasyurus hallucatus (Marsupialia : Dasyuridae). Journal of Zoology, London, 257: 237-248.

Schmitt, L., A. Bradley, C. Kemper, C. Kitchener, W. Humphreys, R. How. 1981. Ecology and physiology of the northern quoll, Dasyurus hallucatus (Marsupialia:Dasyuridae), at Mitchell Plateau, Kimberley, Western Australia. Journal of Zoology, 217: 539-558.

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

Woinarski, J., S. Legge, J. Fitzsimons, B. Traill, A. Burbidge, A. Fisher, R. Firth, I. Gordon, A. Griffiths, C. Johnson, N. McKenzie, C. Palmer, I. Radford, B. Rankmore, E. Ritchie, S. Ward, M. Ziembicki. 2011. The disappearing mammal fauna of northern Australia: context, cause, and response. Conservation Letters, 4: 192-201.

Advice to the Minister for the Environment and Heritage from the Threatened Species Scientific Committee (TSSC) on Amendments to the list of Threatened Species under the Environment Protection and Biodiversity Conservation Act 1999 (EPBC Act)
12 April 2005

1. Scientific name, common name (where appropriate), major taxon group

Dasyurus hallucatus (Northern Quoll)

2. Description

The Northern Quoll is the smallest of the four Australian quoll species. It has reddish brown fur, with its underside cream, white spots on its back and rump with the tail unspotted, and a pointy snout. The Northern Quoll is a solitary carnivorous marsupial that makes its dens in rock crevices, tree holes or occasionally termite mounds, and is predominantly nocturnal. Northern Quolls can weigh up to 1.2kg, with the males being larger than the females. They breed only once in the middle of the year with an average litter size of seven, the pups being born in the dry season. Northern Quolls have short life spans, with males living to approximately 1 year and the oldest recorded female in the wild being three years of age. In savanna landscapes, females maintain territories of about 35 hectares, with males estimated to range over 150 hectares. Northern Quolls consume a wide range of prey including beetles, grasshoppers, spiders, scorpions and centipedes. They also eat fruit, nectar, and are known to feed on carrion and human refuse. Northern Quolls hunt a wide variety of vertebrates including the Northern Brown Bandicoot, the Common Brushtail Possum, rats, Sugar Gliders, insectivorous bats, quails, bird eggs, snakes and frogs. Frogs are eaten regularly in the wet season with a least seven species taken, including large native frogs such as the Green Tree Frog, Litoria caerulea, and the Giant Frog, Cyclorana australis. As Cane Toads have moved into the Northern Quoll's range, they have also been added to the diet of the Northern Quoll.

3. National context

Historically, the Northern Quoll was common across northern Australia occurring almost continuously from the Pilbara, Western Australia to near Brisbane, Queensland. The species' preferred habitat consists of rocky escarpment, open forest and open woodland. A 75% reduction in the Northern Quoll's range between 1900-1990 has been suggested such that, during this time, the Northern Quoll has been reduced to six major geographical centres: Drummond Range, central Queensland; wet tropics Northern Queensland; northern Cape York Peninsula; northern and western Top End, Northern Territory; north Kimberley and Pilbara, Western Australia (Braithwaite and Griffiths 1994). The Northern Quoll is absent from Bathurst and Melville Islands but present on other smaller islands.

The Northern Quoll is listed as Vulnerable under the Territory Parks and Wildlife Conservation Act (Northern Territory). It is not listed under threatened species legislation in the States of New South Wales, Queensland or Western Australia.

EPBC Act criteria.

TSSC judges the species to be eligible for listing as endangered under the EPBC Act. The justification against the criteria is as follows:

Criterion 1 - It has undergone, is suspected to have undergone or is likely to undergo in the immediate future a very severe, severe or substantial reduction in numbers.

The Northern Quoll has undergone a substantial reduction in numbers and it is considered that this decline is likely to continue in the immediate future. There may be a number of factors that have contributed to the current status of the Northern Quoll, including changes in vegetation structure, fire frequency, and the introduction of exotic herbivores. Key threats to Northern Quoll populations are considered to be more extensive and frequent fires in northern Australia; predation following fire; and more recently poisoning by the Cane Toad, Bufo marinus.

A range of recent ecological studies have suggested that the Northern Quoll is vulnerable to extensive frequent fires now characteristic of much of the species' north Australian range. In a detailed radio-tracking study undertaken before the arrival of Cane Toads, it was reported that the main cause of Northern Quoll mortality at Kapalga, Kakadu National Park, was predation in the period following extensive fire (Oakwood 2000).

Northern Quolls are known to mouth Cane Toads causing the release of poison from the Cane Toad's parotoid glands (the swellings on each shoulder behind the eardrum). The poison is then ingested with the symptoms of death including bright red lips and or gums and can also include a red roof of mouth or bright red nose and nose bleeds, red ears, bleeding from the ears, a red eye, red skin pouch, bright purple teats and faeces around the anus (Oakwood 2003).

Based on analyses of distributional records, one study considered that there had been a 75% reduction in the range of the Northern Quoll over the period 1900-1990 and that the species' distribution had contracted to six major centres: Drummond Range area, central Queensland; wet tropics of northern Qld; northern Cape York Peninsula; northern and western Top End of the Northern Territory; north Kimberley; and Pilbara, Western Australia (Braithwaite and Griffiths 1994).

There are no historical data on abundance. Information on the current status of the Northern Quoll derives from anecdotal reports from Queensland including Cape York Peninsula, recent field research in Kakadu National Park, Northern Territory, and anecdotal reports and estimates of the likely impact of colonising Cane Toads in Western Australia.

Queensland

It is known that Cane Toads colonised Cape York between the mid 1980s to the mid 1990s with subsequent crashes in Northern Quoll populations. During 1994-95, the disappearance of Northern Quolls was reported at two monitored sites in northern Cape York Peninsula within three months of the arrival of Cane Toads, with no subsequent population return observed (Burnett 1997). Northern Quolls had previously been common at both these sites.

In northern Queensland populations of Northern Quoll are known to have survived for over fifty years in areas invaded by Cane Toads. Northern Quolls are still present in localised pockets, such as Cape Cleveland/Mt Elliott and Mareeba, in which Cane Toads have occurred for many years and it has been observed that such populations occur in small, high altitude areas associated with extremely rocky habitats. Northern Quolls are also thought to co-exist with reasonably high local densities of Cane Toads in several coastal sites in north Queensland. There is limited quantitative data on the extent and density of the remaining populations or the precise factors that have led to the survival of these remnant populations following Cane Toad invasion.

While Northern Quolls are still present in a number of localised areas in Queensland in which Cane Toads have been present for many years, and other factors may have contributed to the species decline in Queensland, including loss of habitat and predation following fire, they do not appear, to date, to be recolonising their former locations. There is no evidence that a recovery is occurring in these populations, or is likely to occur, following Cane Toad invasion, nor is their any information on the viability of these remnant populations. In particular, Northern Quoll appear not to have recovered in savannah areas, west of the eastern escarpment and in Cape York Peninsula.

Northern Territory

One study reported a major decline in the Northern Quoll over the period 1986-1999 at Kapalga within Kakadu National Park, Northern Territory (Woinarski et al. 2001). More recent studies in Kakadu National Park have demonstrated that local extinction of Northern Quolls is occurring following Cane Toad invasion.

Across a broad region of the south of Kakadu National Park, trapping success for Northern Quolls at 77 monitored sites was compared immediately before and after arrival of Cane Toads including 33 sites that had not yet been invaded by Cane Toads which was trapped over the same period. In the Cane Toad invaded sites there was a highly significant decline in the abundance of Northern Quolls, but no decline observed in the control sites (Watson and Woinarski 2003).

Over much the same period, another study systematically trapped and radio-tracked individual Northern Quolls around the Mary River district of Kakadu National Park, reporting local extinction of Northern Quolls within twelve months of the arrival of Cane Toads, and demonstrating large scale mortality of Northern Quolls directly attributable to poisoning by Cane Toads. 31% of recorded deaths appeared to have been caused by Cane Toad poisoning, there being no evidence of disease, heavy parasite infestation, or any other obvious changes at the site that could be responsible for the rapid decline (Oakwood 2004).

Comparable results have now been reported following the more recent (December 2003) arrival of Cane Toads in the East Alligator district, in the north of Kakadu National Park, (Oakwood 2004), where Northern Quoll numbers declined from 45 individuals in the wet season of 2002-03 to four individuals in March 2004 (i.e. within 3 months of Cane Toads arriving). Extensive trapping (4000 trap nights at 56 widely dispersed sites) in sandstone uplands (i.e. prime quoll habitat) in the south of Kakadu in February 2003 (about two years after the invasion of Cane Toads) resulted in no Northern Quolls being found (Watson and Woinarski 2004).

It has been estimated that the population of Northern Quolls in Kakadu National Park prior to the arrival of the Cane Toad was approximately 80 000 individuals and that this population had probably declined by approximately 20% by the time Cane Toads had colonised approximately 20% of Kakadu National Park. It is expected that similar declines will occur in remaining Northern Quoll populations in the Northern Territory as the Cane Toad invades their habitat.

Western Australia

In Western Australia. the Northern Quoll is restricted to the Pilbara and Kimberley regions. Between 1900-1990, Northern Quolls had apparently disappeared from the south east and south west Kimberley region and had undergone a substantial decline in the Pilbara.

In the Pilbara region, the species distribution is now considered to be fragmented and mostly confined to the larger conservation reserves as well as to the Burrup Peninsula. Populations are considered to have been declining since the mid 1980s with the precise causes unknown. Surveys in the Kimberley in the 1970s showed that the Northern Quoll was widespread there. More recent surveys, undertaken during 2003 and early 2004, confirmed that the Northern Quoll was still numerous in the high rainfall coastal habitat of the west Kimberley. However, populations in the more arid east Kimberley region have apparently undergone a dramatic decline over the past 30 years. The reasons for these declines are also uncertain although it is considered that altered fire regimes and the impact of cattle (both feral and managed) on the landscape may have played an important role.

Currently, Cane Toads are absent from Western Australia and therefore have not contributed to a decline in numbers from the western part of the species' range. Other factors operating may include the impact of predation following increasing fire frequency and intensity. These factors are not well documented and the degree of decline is unknown. Ecoclimatic modelling has estimated that the Cane Toad will colonise the remainder of the Northern Quolls mainland range in Western Australia and it is predicted that this will occur within the next 10-20 years (Sutherst et al. 1995). While some populations in the west Kimberley may survive, as parts of this area may not be suitable for Cane Toads, the fate of the Northern Quoll is considered precarious in Western Australia as the Cane Toad will invade its habitat within the next few years.

Offshore Islands

The Northern Quoll is absent from Bathurst and Melville Islands but occurs on other smaller islands in the Northern Territory (Vanderlin, Marchinbar, Inglis, Groote and North-east) and has also been translocated to Astell and Pobasso islands. In Western Australia, the Northern Quoll is known from Augustus, Bigge, Boongaree, Caffarelli, Carlia, Dolphin, Hidden, Koolan, Sir Frederick, Uwins, and Wollaston islands. It is likely that the Cane Toad, which tolerates high levels of salinity, will colonise some offshore islands, including those closer to shore or with favourable tides, where Northern Quolls are known to occur.

Summary

Northern Quoll populations demonstrate a normal fluctuation in numbers involving a slight decline through the dry season. It is considered that the Northern Quoll is likely to, and will continue to, decline over most of its mainland, and some of its island, range. Based on population crashes during the 1990s in Cape York Peninsula and more recently from Kakadu National Park, and projecting a similar decline as the Cane Toad advances across the remainder of the Quoll's range, and even allowing for the persistence of isolated pockets in Queensland and in some offshore islands, this reduction has been estimated at about 95% of the range, and hence total species population, covering the period 1980 to 2010.

Over the last 10 years, the population has almost entirely been lost from the north east Top End, Northern Territory; Cape York Peninsula; and the Einasleigh Uplands of northern Queensland. These areas have been estimated to constitute approximately 30-40% of the Northern Quoll's pre-toad distribution. The viability of these remnant populations in the wild is, at this stage, unknown.

Over the next 10 years, the rest of the mainland Top End population is expected to also disappear, along with much of the Kimberley mainland population. These areas are estimated to constitute a further 30% of the species' pre-toad distribution. With the exception of some of its island locations, an almost total Cane Toad colonisation of the Northern Quolls range is expected.

While the actual reduction in total individuals can not be directly calculated, it is clear that a considerable contraction in range has occurred and that the loss of a number of populations has been observed in Queensland and in Kakadu National Park.

While Northern Quolls are still present in a number of localised areas in Queensland in which Cane Toads have been present for many years, they do not appear, to date, to be recolonising their former locations and to date there is little evidence that any substantive recovery has occurred following Cane Toad invasion. More recent experimental evidence from the Northern Territory supports anecdotal reports from Cape York Peninsula and other areas of Queensland that Northern Quoll populations have been, and continue to be, severely affected by the presence of Cane Toads.

Threats to the species continue to operate, including those that may have been instrumental in the background decline of the last fifty years or more. Most noticeably however, are the catastrophic declines being observed as a result of the lethal ingestion of Cane Toad toxin. As there is no known remedy, at this stage, to the advance of Cane Toads across the rest of the species range, the Northern Quoll can be expected to continue to decline commensurate with the historical decline in Queensland, and recent population crashes in Cape York Peninsula during the late 1980s to early 1990s and in Kakadu National Park over the last two years.

The Northern Quoll has undergone a substantial reduction in numbers, and is likely to continue to undergo in the immediate future, an ongoing reduction in numbers. While determining the extent of the species historic decline is difficult due to limited baseline data, it is conservatively estimated that the species past population size reduction is greater than 30%. It is considered that a number of island populations will remain free from Cane Toad invasion but that even given this, the likely extent and rate of the species future decline is predicted to be in the order of a further 30% as Cane Toads colonise the remainder of the species' mainland distribution.

TSSC acknowledges that, due to uncertainties over the impact of Cane Toads and the likely extent of the future decline in the species, the conservation status of the Northern Quoll falls somewhere between the vulnerable and endangered categories. Due to the continuing and present threat posed by Cane Toads, and the fact that over time this threat would also qualify the species for listing under Criterion 3, the TSSC considers that the Northern Quoll should be listed in the endangered category.

Therefore, the species is eligible for listing as endangered under this criterion.

Criterion 2 - Its geographic distribution is precarious for the survival of the species and is very restricted, restricted or limited.

The Northern Quoll once occurred continuously across northern Australia, from the Pilbara, Western Australia, to near Brisbane, Queensland. Over the last ten years the loss of populations from most of the north eastern Top End of the Northern Territory, Cape York Peninsula and the Einasleigh Uplands of northern Queensland has been observed, constituting approximately 30-40% of the Northern Quoll's distribution prior to the invasion of its habitat by the Cane Toad.

One study has estimated that a 75% reduction occurred in the Northern Quoll's range between 1900-1990 and that, during this period, the Northern Quoll was reduced to six major geographical centres: Drummond Range, central Queensland; wet tropics Northern Queensland; northern Cape York Peninsula; northern and western Top End Northern Territory; north Kimberley and Pilbara, Western Australia (Braithwaite and Griffiths 1994).

The Northern Quoll is likely to continue to disappear over most of its mainland, and some of its island, range. Based on evidence from Cape York Peninsula and more recently Kakadu National Park (and allowing for persistence in the existing pockets in Queensland and in some offshore islands), this reduction is estimated at about 95% of the range (and hence total population) as it was in 1980, by about 2010.

The pre-toad mainland distribution of the Northern Quoll in the Northern Territory is estimated to be 249 207 km². The species also occurs on offshore island, notably on the two main islands of Groote and Marchinbar, which contribute a further distribution of 2 487 km². By 1990 the species was considered to occupy approximately 87% of its former range (216 854 km²). Following invasion of the Cane Toad the Northern Territory mainland distribution is estimated to have declined to 20% of the species' 1990 distribution by 2004 (i.e. 47 812 km²).

Over the next 10 years, it is likely that the rest of the mainland Top End population will also disappear, as will much of the Kimberley mainland population, estimated to represent a further loss of approximately 30% of the species' pre-toad distribution.

A significant reduction in the species' range has already occurred, and is likely to continue. In addition the loss of a number of populations has been observed and the species has been reduced to a number of disjunct locations across northern Australia. However, there is insufficient quantitative data available to indicate that the geographic distribution of the Northern Quoll is precarious for the survival of the species. Therefore, the species is not eligible for listing under this criterion.

Criterion 3 - The estimated total number of mature individuals is limited to a particular degree and: (a) evidence suggests that the number will continue to decline at a particular rate; or (b) the number is likely to continue to decline and its geographic distribution is precarious for its survival.

Past anecdotal reports and more recent experimental field data suggest that the number of mature individuals will continue to decline. No baseline data appears to exist for the species in Queensland and there are no historical data on the species' abundance. There are no direct estimates on how limited the number of mature individuals is, or to what degree this number is continuing to decline. Conversely, there is no data indicating how viable surviving populations in Queensland are and there has been no research to date verifying that any recovery has, or is likely to occur.

The population of Northern Quolls in Kakadu National Park has been estimated to be in the order of 80 000 individuals, of which 20% is thought to have been lost to date following the invasion of the Cane Toad. There are no figures on the size of the Western Australian population or on those populations that are known to occur on offshore islands.

There is insufficient quantitative data available, at this stage, on the number of mature individuals and the geographic distribution of the species is not considered to be precarious for the survival of the species. Therefore, the species is not eligible for listing under this criterion.

Criterion 4 - The estimated total number of mature individuals is extremely low, very low or low.

There is no quantitative data available against this criterion. Therefore, the species is not eligible for listing under this criterion

Criterion 5 - Probability of extinction in the wild

There is no quantitative data available against this criterion. Therefore, the species is not eligible for listing under this criterion.

5. Conclusion

Northern Quoll populations have been in decline for some time due to a number of factors. The invasion of Cane Toads throughout their range has accelerated this decline to a rapid rate. Other threatening processes are considered to have been operating, and continue to operate on the species, notably in the western part of the species range.

The response of Northern Quoll populations to colonising Cane Toads indicates that the species is likely to experience a very significant decline in both range and abundance as Cane Toads continue to invade more of its habitat. It has been predicted that the Cane Toad will colonise all of the Northern Quoll's natural range, with the exception of some island populations, within the next 10-20 years.

While remnant populations are known to survive in Queensland, where Cane Toads have been present for many years, there is no research that indicates the viability of these populations in the wild in the longer term, or what conditions have led to their survival, or whether similar conditions may exist either in the Northern Territory or in Western Australia. To date, there is no evidence indicating that a recovery is occurring, or is likely to occur in populations in Queensland; or any evidence to suggest that Northern Quoll populations have, or will, survive in Cane Toad invaded regions of the Northern Territory.

The Northern Quoll has experienced a substantial decline over the last ten years and it is expected that it will experience a very severe decline over the next ten years as Cane Toads invade the remainder of its mainland habitat.

The species is eligible for listing as endangered under criterion 1.

6. Recommendation

TSSC recommends that the list referred to in section 178 of the EPBC Act be amended by including in the list in the endangered category:

  • Dasyurus hallucatus (Northern Quoll)

Conservation Advice

Northern Quoll, Dasyurus hallucatus

The Northern Quoll is a solitary carnivorous marsupial, that makes its dens in rock crevices, tree holes or occasionally termite mounds, and is predominantly nocturnal. The species formerly occurred almost continuously and commonly across northern Australia from the Pilbara, Western Australia to near Brisbane, Queensland. It now occurs in a number of localised populations in Queensland, Northern Territory and Kimberley region (e.g. coastal Northern New South Wales, Queensland and Northern Territory, Western Australia NRM regions).

The Northern Quoll is absent from Bathurst and Melville Islands but occurs on other smaller islands in the Northern Territory (Vanderlin, Marchinbar, Inglis, Groote and North-east) and has also been translocated to Astell and Pobasso islands. In Western Australia, the Northern Quoll is known from Augustus, Bigge, Boongaree, Caffarelli, Carlia, Dolphin, Hidden, Koolan, Sir Frederick, Uwins, and Wollaston islands. It is likely that the Cane Toad, which tolerates high levels of salinity, will colonise some offshore islands, including those closer to shore or with favourable tides, where Northern Quolls are known to occur.

A number of factors are considered to be threatening the survival of the species:

  • inappropriate fire regimes;
  • predation following fire; and
  • lethal toxic ingestion of Cane Toad toxin.

Poisoning as a result of the ingestion of Cane Toad toxin is considered to have had a catastrophic impact on a number of Northern Quoll populations. The Cane Toad will most likely colonise much of the remainder of the Northern Quoll's natural mainland range over the next 10-20 years, and it is likely that this decline will continue.

The priority recovery and threat abatement actions required for this species are to:

  • minimise the impact of colonising Cane Toads on the species by:
    • investigating the use of physical barriers or other means, where feasible, to prevent the colonisation of key habitat areas;
    • undertaking translocation and management of Northern Quoll populations in safe havens where necessary;
  • identifying areas of critical habitat (e.g. island populations);
  • investigate the need to establish a captive breeding program for the species; and
  • investigate the status of the species in Queensland, including the reasons for its survival following Cane Toad invasion.

This list does not encompass all actions that may be of benefit to this species, but highlights those that are considered to be of the highest priority at the time of listing.

A Recovery Plan is not yet in place for the Northern Quoll. A nomination to list 'Predation, competition and lethal toxic ingestion caused by Cane Toads, Bufo marinus' is currently under consideration by the Threatened Species Scientific Committee. The Committee will also, at the time it provides advice on listing of the nominated key threatening process, advise on whether or not a national Threat Abatement Plan would be a feasible, effective and efficient way to abate this process.

Priority for the development of recovery plan: High.

Publications used to assess the nomination

Braithwaite, R.W., and Griffiths, A. (1994). Demographic variation and range contraction in the northern quoll Dasyurus hallucatus (Marsupialia: Dasyuridae). Wildlife Research21:203-17.

Burnett, S. (1997). Colonising cane toads cause population declines in native predators: reliable anecdotal information and management implications. Pacific Conservation Biology3:65-72.

Oakwood, M. (2000). Reproduction and demography of the northern quoll, Dasyurus hallucatus, in the lowland savanna of northern Australia. Australian Journal of Zoology48, 519-539.

Oakwood, M. (2004). The Effect of Cane Toads on a Marsupial Carnivore, the Northern Quoll, Dasyurus hallucatus. Report to Parks Australia.

Sutherst, R.W., Floyd, R.B., and Maywald, G.F. (1995). The potential distribution of the cane toad, Bufo marinus L. in Australia. Conservation Biology10, 294-299.

van Dam, R.A., Walden, D.J., and Begg, G.W. (2002). A preliminary risk assessment of cane toads in Kakadu National Park. Report 164.

Watson, M. and Woinarski, J. (2003). A preliminary assessment of impacts of cane toads on terrestrial vertebrate fauna in Kakadu National Park.

Watson, M., and Woinarski, J. (2003). Vertebrate monitoring and re-sampling in Kakadu National Park, 2002. Report to Parks Australia, Tropical Savannas Cooperative Research Centre, Darwin.

Watson, M., and Woinarski, J. (2004). Vertebrate monitoring and re-sampling in Kakadu National Park, Year 3, 2003-04. Report to Parks Australia, Tropical Savannas Cooperative Research Centre, Darwin.

Woinarski, J.C.Z., Milne, D.J., and Wanganeen, G. (2001). Changes in mammal populations in relatively intact landscapes of Kakadu National Park, Northern Territory, Australia. Austral Ecology26:360-370.

Woinarski, J.C.Z., Risler, J., and Kean, L. (2004). The response of vegetation and vertebrate fauna to 23 years of fire exclusion in a tropical Eucalyptus open forest, Northern Territory, Australia. Austral Ecology29, 156-176.

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