NSW Scientific Committee - final determination
The Scientific Committee has found that:
1. The Dusky Hopping-mouse is a nocturnal, mostly granivorous native rodent of weight range 30-50g (Dickman 1993). The species has a long tail (range 115-150mm) relative to its body (range 80-110mm). The dorsal fur of the species is usually pale orange, although colour varieties are known to range from light fawn to russet orange (Watts 2000). The Dusky Hopping-mouse is distinguished from other species of Notomys by the presence of a circular throat pouch surrounded by stiff white hairs (Dickman 1993). The species inhabits vegetated sand dunes and excavates tunnels that are up to 5m in length, which are accessed via vertical 1m deep shafts. Nesting is communal with up to five individuals sharing a tunnel system (Watts 2000).
2. Prior to 2003, no confirmed records of the Dusky Hopping-mouse were known from New South Wales (NSW) since at least 1845. The species was recorded by Charles Sturt in 1845 at a location between Fort Grey (NSW) and Lake Blanche (South Australia), although the exact location of the sighting is not known (Dickman 1993). Sub-fossil Notomys remains were collected from Mutawintji National Park in the central far-west of NSW (Ellis 1993) and were most likely the remains of N. fuscus (M. Ellis pers. comm.). Two Australian Museum specimens were collected from South Australia in 1977 at Tilcha Bore and Rotten Swamp, both of which lie within 30km of the NSW border. Further, the species has been recorded only 12km from the NSW border near Tilcha (P. Bird pers. comm., cited by Dickman 1993). Hence, and given the occurrence of similar habitat in the far north-west corner of NSW, the occurrence of the species within NSW prior to European settlement is thought to be highly likely (Dickman 1993). Therefore, the Dusky Hopping-mouse was presumed extinct in NSW.
3. In September and November 2003, twelve Dusky Hopping-mouse individuals (two females and ten males) were captured in pitfall traps at two locations in Sturt National Park in the extreme north-west corner of NSW (I. Witte, pers. comm.). Therefore, the species can no longer be presumed extinct in NSW. Suitable habitat extends throughout Simpson-Strzelecki Dunefields Bioregion.
4. The chief threats to the Dusky Hopping-mouse in north-western NSW are probably the loss and degradation of habitat by rabbits and pastoral activities (Dickman 1993). Although the degree of threat posed by introduced predators such as foxes and cats is not known, their impact on Dusky Hopping-mouse populations may be significant. Such threats would exacerbate the inherent threats faced by such an apparently restricted and small population.
5. In view of the above the Scientific Committee is of the opinion that the Dusky Hopping-mouse Notomys fuscus (Jones, 1925) is likely to become extinct in nature in New South Wales unless the circumstances and factors threatening its survival or evolutionary development cease to operate.
Associate Professor Paul Adam
Chairperson
Scientific Committee
Proposed Gazettal date: 25/06/04
Exhibition period: 25/06/04 - 06/08/04
References:
Dickman CR (1993) 'The biology and management of native rodents of the arid zone in NSW.' NSW National Parks and Wildlife Service, Species Management Report No. 12, Hurstville, NSW.
Ellis M (1993) Extension to the known range of the Fawn Hopping-mouse Notomys cervinus in New South Wales. Australian Zoologist 29, 77-78.
Watts CHS (2000) Dusky Hopping-mouse Notomys fuscus (Jones 1925). In 'The Mammals of Australia.' (Ed. R Strahan) pp. 575-576. (Reed Books Australia: Chatswood)
A notice of determination to provisionally list this species as an endangered species was gazetted on 17/10/03.