The Platypus is a unique and fascinating creature. It is one of two species of monotreme (egg-laying mammals) found in Australia, the other being the Short-beaked Echidna. The Platypus is found in and around freshwater ecosystems, including permanent streams, rivers, lakes and even dams. Platypus prefer habitats with intact vegetated creekbanks with overhanging plants, earthen banks and streams with a depth between 1-5m. Platypus also require habitat connectivity to support breeding, dispersal and to ensure that they have access to adequate food sources in response to changing conditions such as flood and drought.
Localised declines have been recorded across the country and the Platypus is now listed as ‘near threatened’ on the International Union for Conservation of Nature (IUCN) Red List of Threatened Species. They are also vulnerable to local extinctions if waterways are not managed properly. The main threatening processes impacting upon Platypus populations are urbanisation and agriculture, which result in habitat degradation, habitat fragmentation and decline in movement between populations. They are also vulnerable to predation from both natural predators, such as goannas and Wedge-tailed Eagles, and introduced predators such as foxes, cats and dogs.
The Platypus can be an elusive critter that is difficult to monitor due to their shyness and nocturnal habit. There are a few tell-tale signs of their presence, such as ripples, bubbles and the presence of burrows. However, positive sightings are a rare occurrence. Therefore, identifying and monitoring populations has been a challenge and accurate information on population trends is limited.
The Wildlife Preservation Society of Queensland’s (WPSQ) PlatypusWatch network has been working in collaboration with Councils in SEQ, including Ipswich City Council, to undertake environmental DNA (eDNA) testing. The Platypus signature and test, using eDNA, was developed by cesar Australia. Some eDNA testing can detect the presence of a species from a single drop of water or a speck of dust. In this case, a sample of water can be taken from the environment to a laboratory where a test determines whether it contains the DNA of the Platypus.
Much like a crime scene, the Platypus leaves DNA behind them as they swim, crawl and walk. DNA can be obtained from Platypus skin cells, hair, faeces and mucous that is shed into the water. The Platypus DNA is retained in the water for approximately three days, so a positive result means that a Platypus was present in that general location within the previous three days. Half a glass of water is all that is needed to detect the presence of a Platypus. eDNA testing is a true game-changer in Platypus conservation.
eDNA testing can produce significantly less false-negative results than the observation surveys that were previously undertaken by WPSQ and is an effective method of quickly determining the presence of Platypus within waterways. eDNA Platypus surveys are unobtrusive as samples can be taken in any location and no contact is required with the animals.
In Ipswich the results have been very interesting, suggesting numerous populations in unlikely spots and no evidence in locations of seemingly suitable habitat. The Mid-Brisbane catchment is emerging as a hotspot for activity and may well be a source for dispersing populations.
While eDNA currently doesn’t currently provide information on numbers or populations, or data on health status, sex or abundance, it does provide data on the presence and absence and therefore distribution range over large areas. Therefore, eDNA is currently used as a tool that can be used alongside other traditional methods of Platypus surveys, such as trapping and surveying, depending on the intent of the study.
The exciting news is that this technology is not only available for the Platypus but can be used to confirm the presence of hundreds of different species of animals. Second generation eDNA is looking at things like estimating densities and identifying and tracking movements of individuals. It will be fascinating to see how this technology will progress and be integrated into management practices in the future.
Conservation Partnerships Officer
Ipswich City Council
References & Further Reading
Carrick FN, Grant TR & Temple-Smith PD (2008). Family Ornithorhynchidae: Platypus, in S. Van Dyck and R. Strahan (eds), The Mammals of Australia, 3rd Ed, New Holland.
cesar Australia – http://cesaraustralia.com/biodiversity-conservation/environmental-dna-edna/
Griffiths J, Kelly T, van Rooyen A & Weeks A (2014). Distribution and relative abundance of platypuses in the greater Melbourne areas: survey results 2013/14. Report to Melbourne Water. cesar.
Goldberg CS, Pilliod dS, Arkle RS & Waits LP (2011). Molecular detection of vertebrates in stream water; demonstration using Rocky Mountain tailed frogs and Idaho great salamanders. PLoS ONE, 6(7).