Wildlife Matters

Boosting genetic diversity at Mt Gibson wildlife sanctuary

20 Nov. 2018
© Brad Leue/AWC

By Carly Moir, Field Ecologist, and Brad Leue, Correspondent

Australian Wildlife Conservancy is continuing its major program of mammal reintroductions to Mt Gibson Wildlife Sanctuary. To date, eight species of threatened mammals have been reintroduced to the 7,832 hectare feral predator-free area at Mt Gibson, setting a new record for re-wilding projects in Australia. Each reintroduction is conducted in stages, drawing founders from a range of source populations, to help establish a genetically diverse population of each species.

Woylie translocation on track

Marking the end of a four-year translocation program, AWC ecologists have translocated the last tranche of one of Australia’s most threatened mammals, the Woylie (Bettongia penicillata), to Mt Gibson Wildlife Sanctuary.

Woylies were once widespread throughout southern and central Australia but are now found only in small, fragmented populations in southern Western Australia and within predator-free fenced areas including Scotia. These remnant populations have declined by up to 90 per cent in the last 20 years, mainly due to predation by feral cats.

Woylie at Mt Gibson. © Brad Leue/AWC © Brad Leue/AWC
AWC intern Rebecca O’Rourke releases a Woylie from Tone-Perup National Park into Mt GIbson Wildlife Sanctuary under the supervision of AWC field ecologist Noel Riessen (far right), and watched by Drew Bell, and Badimaya elder Ashley Bell, who is holding his grandson, Clayton. 

To conduct the translocation, AWC ecologists and staff from the Department of Biodiversity, Conservation and Attractions spent a week at Tone-Perup National Park trapping the animals, both within and outside the fenced area. At 4am each day the traps were checked and cleared. Health checks were performed on all Woylies and data was collected on breeding status, weight and pes (the length of the hind foot). This information was used to decide whether individuals were suitable for translocation. Animals selected for translocation were driven to Manjimup airstrip to board the plane that took them to their final destination.

The release team met the plane at the Mt Gibson airstrip and the animals were transferred to a special purpose holding room at the Neville Tichbon Field Research Station. Just before the release at sunset, Traditional Owner, Badimaya Elder Ashley Bell performed a Welcome to Country in which he highlighted the significance of local wildlife to Badimaya culture and the importance of the return of this species, and others, to the region.

A total of 56 Woylies were translocated to Mt Gibson in 2018, adding to the 106 individuals translocated to establish the population since 2015. The main purpose of the final translocation was to increase the genetic diversity of Mt Gibson’s Woylie population. Interbreeding with resident animals was promoted by releasing males and females at opposite ends of the designated release area. All Woylies were successfully released; most promptly hopping off into the night, while others took a little longer to take in their new surroundings.

Following this final translocation, the Mt Gibson population is estimated at over 350 individuals. AWC now protects 10 per cent of Australia’s remaining Woylie population at our Karakamia, Scotia, Yookamurra and Mt Gibson Wildlife Sanctuaries.

Greater Stick-nest Rats journey over land and sea

The first species reintroduced to Mt Gibson Wildlife Sanctuary in 2011 was the Greater Stick-nest Rat (Leporillus conditor). This guinea pig- sized native rodent has the amazing habit of building a communal home out of sticks and stones. Two species of Stick-nest Rat – the Greater and the Lesser – historically occurred across southern and central Australia, but were eliminated from the mainland by feral cats and foxes, along with competition from introduced herbivores. The Lesser Stick-nest Rat is extinct, while the Greater Stick-nest Rat survived only as a population of about 1,000 animals on the Franklin Islands, South Australia.

The population being established at Mt Gibson is important for the conservation of the species as it is one of only six populations that remain. As with many of Australia’s small to medium-sized native mammals, Greater Stick-nest Rats cannot survive in environments where feral cats and foxes are present.

AWC ecologists, in partnership with the South Australian Department of Environment and Water (SA DEW), recently undertook a challenging translocation of Greater Stick-nest Rats from St Peter Island, South Australia, to Mt Gibson. St Peter Island sits off the west coast of the Eyre Peninsula, approximately 25 kilometres south of Ceduna. Greater Stick-nest Rats were taken to the island by the South Australian Government in 1993 to establish an ‘insurance population’.

Greater Stick-nest Rat at Mt Gibson. Photo credit: Brad Leue © Brad Leue/AWC
The endangered Greater Stick-nest Rat was the first species to be translocated to Mt Gibson Wildlife Sanctuary. 

Over 11 nights in September 2018, a team of eight AWC staff and two staff from SA DEW undertook a complex logistical operation to capture and translocate 13 Greater Stick-nest Rats (seven males and six females) to Mt Gibson. AWC ecologists used both trapping and spotlighting to capture animals on St Peter Island. Traps were checked before sunrise and spotlighting was conducted throughout the night when the animals were most active.

During health checks, two of the seven males showed signs of trauma. A specialist wildlife vet was flown in to check the animals for any evidence of disease or pathogens. The results of blood tests and further examination concluded that the trauma was likely caused by aggressive interactions between males. With the health of the animals cleared, the translocation continued, although the males showing injuries were deemed not suitable for translocation and were released.

After arriving at Mt Gibson, 10 of the 13 animals to be released were fitted with small radio transmitters, allowing AWC ecologists to track and monitor the dispersal of the animals upon release. While animals groomed off their transmitters within days, the data showed some individuals travelled over three kilometres on their first night in the sanctuary.

Through the construction of feral-predator free areas, AWC is working to save Australia’s wildlife from extinction.

AWC acknowledges the major supporters of the Mt Gibson project: Michael Tichbon, Perth Zoo, Lotterywest, the Northern Agricultural Catchments Council NRM and Department of Biodiversity, Conservation and Attractions.

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