Potorous gilbertii (Gould, 1841)

Russell A. Mittermeier & Don E. Wilson, 2015, Potoroidae, Handbook of the Mammals of the World – Volume 5 Monotremes and Marsupials, Barcelona: Lynx Edicions, pp. 600-628 : 628

8.

Gilbert's Potoroo

Potorous gilbertii

French: Potorou de Gilbert / German: Gilbert-Kaninchenkanguru / Spanish: Potoro de Gilbert

Taxonomy. Hypsiprymnus gilbertii Gould, 1841 ,

“ King George's Sound ,” south-west ern Western Australia.

Formerly regarded as a subspecies of P. tridactylus , but reinstated as a distinct species in 1996. Monotypic.

Distribution. Confined to a single population in Two Peoples Bay Nature Reserve (Mt Gardner), near Albany, in coastal far SW Western Australia. Successfully introduced to nearby Bald I.

Descriptive notes. Head-body 28:6-37.1 cm, tail 20-23.6 cm; weight 0.7-1.2 kg. A small potoroo with a heavily furred face. Reddish brown to grayish brown dorsally, paler ventrally. Densely furred on sides of face. Ears short, rounded, and well furred. Snout long and more fully furred than that of P. tridactylus . Hindfoot shorter than head. Tail short, sparsely furred distally, and dark. Diploid chromosome numberis 13 for males and twelve for females.

Habitat. Dense, long-unburnt heath and shrubland with a dense ground layer of sedges.

Food and Feeding. Mycophagous: ¢.90% of the diet is made up of fungi, primarily hypogeal (truffle-like), which are obtained by digging with the strong forepaws; some epigeal (above-ground) fungi also consumed. Remainder of the diet comprises invertebrates and plant material, including fruits.

Breeding. Females reach sexual maturity from nine months. They breed continuously, producing a single young which remains in the pouch for 3-4 months. The estrous cycle is 39 days; there is no information on duration of the gestation period. Embryonic diapause is likely. The young remains in its mother’s home range after weaning, until it disperses at 7-18 months.

Activity patterns. Nocturnal; emerges at dusk from daytime resting site (“squat”) under sedges to forage, returning before dawn. After an initial period of intense foraging, individuals will often rest before resuming activity.

Movements, Home range and Social organization. Lives in small groups (3-8 individuals) in patches of suitable habitat. Subadult and adult males occasionally disperse among groups. Home ranges are estimated at 3-6 ha for females and 15-25 ha for males. Individuals of the same sex show minimal overlap in home range, but substantial overlap occurs between the sexes.

Status and Conservation. Classified as Critically Endangered on The IUCN Red List and in Australia. Gilbert's Potoroo is one of Australia’s rarest mammals. Historically, it was more widespread in coastal far southwest Western Australia and was locally common. Its decline was most likely due to habitat loss from clearing and increased fire frequency. The species was previously believed extinct, having not been reported since the 1870s, until a small population of these potoroos was discovered in 1994 living at a single location in Two Peoples Bay Nature Reserve, near Albany. The surviving population is very small, numbering fewer than 40 individuals, and is threatened by introduced predators such as the Red Fox (Vulpes vulpes) and domestic/feral cats (Felis catus), combined with the loss of its long-unburnt (more than 50 years) habitat through wildfire or from the plant fungal disease Phytophthora, and stochastic processes. A Recovery Plan has been prepared and this aims at controlling introduced predators, excluding fire from the potoroo’s habitat, and establishing additional populations. A second population was successfully established via translocation in 2005-2007 on nearby Bald Island, east of Two Peoples Bay Nature Reserve, and a third was established in 2009 in a 380ha fenced enclosure in Waychinicup National Park, west of Bald Island. A captive population was established in 1996, but the species has failed to breed regularly in confinement.

Bibliography. Claridge et al. (2007), Courtenay & Friend (2004), Finlayson, Finlayson & Dickman (2010), Friend (2008a), Friend & Burbidge (2008), Johnston & Sharman (1976), Maxwell et al. (1996), Nguyen et al. (2005), Sinclair & Friend (2013), Sinclair & Westerman (1997), Sinclair, Danks & Wayne (1996), Sinclair, Murch et al. (2000), Stead-Richardson et al. (2010), Woinarski et al. (2014bt).

Figures

1. Rufous Bettong (Aepyprymnus rufescens), 2. Burrowing Bettong (Bettongia lesueur), 3. Eastern Bettong (Bettongia gaimardi), 4. Brush-tailed Bettong (Bettongia penicillata), 5. Northern Bettong (Bettongia tropica), 6. Long-footed Potoroo (Potorous longipes), 7. Long-nosed Potoroo (Potorous tridactylus), 8. Gilbert's Potoroo (Potorous gilbertii)

Distribution. Confined to a single population in Two Peoples Bay Nature Reserve (Mt Gardner), near Albany, in coastal far SW Western Australia. Successfully introduced to nearby Bald I.