Kevin Minson

Kevin Minson


    Rediscovery of rare marsupial, Gilbert's potoroo

    7/12/1994 12:00 AM



    A small marsupial thought extinct for the past 125 years has been rediscovered at Two Peoples Bay Nature Reserve east of Albany.


    The animal, Gilbert's potoroo, was last recorded between Albany and the Pallinup River in 1869.


    Environment Minister Kevin Minson said today the find was made late last week by University of Western Australia students Elizabeth Sinclair and Adrian Wayne.


    CALM scientists positively identified the animals at the weekend.


    The researchers had trapped an adult female with pouch young and a juvenile male last Thursday and an adult male on Friday.  Another adult male was trapped yesterday.


    "The rediscovery of a species that has eluded science for more than 120 years is remarkable in itself," Mr Minson said.


    "But it also clearly demonstrates that when fox numbers are brought under control, we can prevent small native mammal species from becoming extinct."


    Ms Sinclair, a PhD student, is studying genetic variation in quokkas and has been searching for populations along the State's south coast, including Two Peoples Bay Nature Reserve.


    There had been several `signs' of animals but despite intensive searches and trapping, no quokkas were captured.


    But two unusual animals found in the traps last week could not be identified as anything that had been recorded in the reserve.


    Ms Sinclair and Mr Wayne discussed the animals with CALM officers Alan Danks and Leigh Whisson and after measurements were taken, it became clear that the species was likely to be the long lost Gilbert's potoroo.


    Experts from CALM's Wildlife Research Centre at Woodvale went to the reserve armed with material from the WA Museum's collection. That material helped confirm the identification.


    Gilbert's potoroo has been considered a subspecies of the long-nosed potoroo of south-eastern Australia and Tasmania.  The rediscovery now allows genetic comparisons to be made to see if the WA animals should be recognised as a separate species.


    The discovery of Gilbert's potoroo by Europeans was in 1840 at King George Sound by John Gilbert who collected mammals and birds in WA for the prominent naturalist John Gould.


    Gould later wrote he had not heard of the species being found in any part of the colony other than King George Sound.


    Apart from Gilbert's specimens, only two others were sent to museums between 1840 and 1869.  These had been collected in the Albany-Pallinup River areas.


    In 1975, the former Department of Fisheries and Wildlife began an extensive search for the animal and its relation, the broad-faced potoroo - also thought extinct.


    The search included Two Peoples Bay nature reserve but no evidence of the species was found.


    CALM wildlife scientist Dr Tony Start, who was part of the search, said sub-fossil remains of the animal had been found in a number of coastal caves along the Leeuwin-Naturaliste Ridge, including Mammoth Cave.  A bone fragment had also been found in a sand dune between Broke Inlet and Windy Harbour.


    CALM has controlled foxes inside the nature reserve since 1988 which has led to an increase in populations of other small mammals such as southern brown bandicoots.


    It is now thought that the Gilbert's potoroo may have survived in such small numbers that they were previously undetected, but fox control has allowed them to increase to levels where they now have turned up in traps set for other species such as quokkas.


    Fox control on other parts of the south-west such as Dryandra, Batallling, Julimara and Perup, has resulted in an upsurge in native wildlife numbers.


    Numbat sightings in Dryandra woodland have increased eleven-fold since fox baiting started in 1982.   The woodland is also the site of the biggest population of woylies, another direct result of fox control.


    Controlling fox numbers in Julimar conservation park near Toodyay has enabled chuditch to be re-introduced while at Batalling, east of Collie, populations of tammar wallabies are being re-established.


    Mr Minson said CALM's Threatened Species Unit - which was established in 1992 to manage recovery plans for rare and endangered species - was now working on plans to find out how widespread the potoroos were and what conservation action was needed.


    It is not the first time Two Peoples Bay has been the site of a rediscovered animal. The noisy scrub-bird was rediscovered there in 1961 after having been last recorded 72 years previously.  It was this find that led to the nature reserve being established in 1967.


    Mr Minson said it was remarkable that potoroos had been found in the same area as the noisy scrub-bird.


    "Two Peoples Bay is an amazing haven for thought-to-be-extinct species," he said.


    "CALM's management of the reserve to control fox numbers and protect large areas from wildfire, a strategy initiated for managing scrub-bird habitat, no doubt has had some more recent influence on the potoroos's survival."


    Media contact:  Caroline Lacy  222 9595/321 2222; Nigel Higgs CALM 389 8644; Elizabeth Sinclalir UWA Zoology Department 380 1468