Recovering Gilbert’s potoroo – walking a tightrope with Australia’s rarest mammal
Gilbert’s potoroo is known only from a small population at Two Peoples Bay Nature Reserve near Albany, Western Australia. Recent conservation efforts have focussed on developing means to increase numbers without detrimental effect on the viability of the wild population. This paper investigates alternative approaches to this problem and describes preliminary results.
Captive breeding has had limited success. Although initially promising, breeding ceased after six years, after production of only eight young. Attempts to restore fecundity have involved different regimes of housing and pairing, disease investigation and ongoing reviews of captive diet. As an alternative to intensive husbandry, a 14-hectare predator-protected enclosure has been built and a captive pair will be transferred there in winter 2007.
Other methods proposed to increase potoroo numbers involve regular removal of animals from the wild. Accurate demographic information is necessary to ensure that removal is not causing damage to the population. In the wild, the survival of young from pouch emergence to sexual maturity is between 20% and 40%, so there are “surplus” young with which might be harvested sensibly for cross-fostering, hand-rearing and wild-to-wild translocation.
Several pouch young have been cross-fostered to captive long-nosed potoroos, with success following the establishment of a long-nosed potoroo captive colony 15 km from Two Peoples Bay Nature Reserve. Two individuals have been removed from their wild mother’s pouch and hand-reared before transfer to the captive colony. This method is labour-intensive and requires development of an optimal nutritional regime. Seven adult animals have been translocated from the wild to Bald Island, 40 km east of Albany to establish a second population. Preliminary results indicate that there are sufficient resources on the island to support a colony. A project to establish another mainland population, within a large area of natural bush surrounded by a predator-proof fence, is being developed.