KooyongKootPlatypus reintroduction

Platypus in KooyongKoot (Gardiners Creek)? Graham Ross and Geoff Williams

By April 2, 2022April 16th, 2022No Comments

Can we return the Platypus to Gardiners Creek (KooyongKoot)?

Gardiners Creek (KooyongKoot) is a significant tributary of the Yarra River that flows through a highly urbanised landscape. Various initiatives have recently been announced to restore environmental values along the creek. These include the formation of the KooyongKoot Alliance, in which 20 Friends Groups are cooperating to act as a collective voice for the creek and its tributaries.

The alliance is working collaboratively with Stonnington, Whitehorse, Monash and Boroondara Councils, Melbourne Water, Deakin University and a number of sporting and community organisations to develop a Strategic Masterplan for this important community asset. This Plan will ultimately commit to a more holistic approach to managing the Creek and realizing its true potential.

This raises an intriguing possibility: could Gardiners Creek one day be home to the world’s strangest mammal, the platypus?

Director of the Australian Platypus Conservancy, Geoff Williams, said that returning the platypus to KooyongKoot would be a huge challenge but there were many positives associated with attempting to re-establish a population of this monotreme.

“The platypus is a key species in freshwater eco-systems,” said Geoff. “If you can make environmental conditions good enough to support a platypus population then you are pretty much getting things right for all the other species, both big and small, that live in such habitats. In addition, the platypus is a great conservation flagship – it is a very well-loved animal, so having the return of the platypus as a long-term aim can mobilise community support to improve the creek.”

Rehabilitation of other inner Melbourne creeks, such as Merri Creek and Darebin Creek, have been carried out over the past three decades with the specific aim of encouraging the platypus back. This work is now starting to pay off. In recent years sightings of platypus have increased in the lower reaches of these Yarra tributaries. However, there is no conclusive evidence yet that the species has become fully resident.

“We think that most platypus currently spotted in Merri and Darebin Creeks are probably vagrants from farther upstream in the main Yarra River system,” said Geoff. “The Yarra platypus population is quite strong, with breeding known to occur as far downstream as Lower Templestowe. This creates pressure on juveniles and non-breeding individuals to disperse to find territories of their own and some of these animals make their way into the inner suburban tributaries. At present they are probably only temporary visitors but eventually, if conditions continue to improve, they could become resident.”

In theory, this pattern might also be seen in Gardiners Creek if environmental conditions were similarly enhanced. However, dispersing platypus would have to traverse a much longer section of the inhospitable main Yarra channel in inner Melbourne before turning into KooyongKoot. This could be a significant barrier to natural recolonisation.

Getting platypus back into a rejuvenated Gardiners Creek may eventually have to rely on translocating animals from elsewhere to provide the initial founders of a KooyongKoot population. Translocation was used successfully by the Conservancy to re-establish a platypus population in Cardinia Creek to Melbourne’s east. A small group of surplus juveniles from the upper Yarra catchment could be transferred when conditions along Gardiners Creek had been upgraded to the required levels. However, the KooyongKoot population would be effectively isolated from the rest of the Yarra system. There would have to be a sufficient length of good habitat along the creek to support enough adult platypus – roughly 30 individuals – to ensure the long-term viability of the population. Upgrading on this scale would call for a concerted effort over many years from all councils and environment groups along the Gardiners Creek corridor.

In the meantime, the Australian Platypus Conservancy noted that KooyongKoot already possessed a very healthy population of the Australian water-rat, also known as rakali. This extremely attractive and intelligent native rodent functions as a top predator in aquatic habitats. The ecological role of the species is equivalent to that of the otters found on other continents. Rakali also has many otter-like features, including a thick coat of soft fur, a blunt and densely bewhiskered muzzle, partly webbed hind feet and a furry, tapering tail.

“Returning the platypus to Gardiners Creek would be an exciting prospect but it will take many years of hard work and immense commitment,” said Geoff Williams. “Improving environmental conditions will help rakali as well and so, in the interim, we can all take pleasure in having the “Aussie otter” in KooyongKoot.”

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