The Platypus Conservation Initiative was established in 2016 for the purpose of reducing the risk of extinction to platypuses through research, improving management, and increasing awareness.
The platypus (Ornithorhynchus anatinus) is an Australian enigma, one of only five extant species of egg-laying mammals and the only species within the monotreme family Ornithorhynchidae. It is a semi-aquatic mammal, endemic to Australia, exhibiting both reptilian and mammalian characters: egg laying, fur, lactation, venomous spurs, and has electroreception. The platypus is such an evolutionarily distinct mammal, making it of exceptional scientific value and an irreplaceable component of national and global biodiversity.
Evidence for platypus declines
There is mounting evidence that populations are declining due to multiple stressors, including habitat loss and fragmentation and poor river management. The platypus is currently listed as “Near Threatened”, under the IUCN red listing. However, Australian legislation is still lagging whereby the platypus is not listed on any threatened species schedules in Australia, except in South Australia, where its natural distribution been dramatically reduced since European settlement.
Our research has shown a decline in both distribution and abundance of platypuses throughout many areas across the species’ range. Based on existing platypus observations, we found evidence of almost 30% decline in area of occupancy across their distribution and that declines were greater than 30% in more than a third of the species’ known range. We found that only 58.6% of areas where platypus have been reported previously, had records in the last 10 years (Hawke et al. 2019). Extensive knowledge gaps also exist across the species’ range and suggest declines may be greater. Historical data suggests that abundances in the past were likely greater than our contemporary estimates, suggestive of a shift in baseline understanding and evidence for declines since European colonisation (Hawke et al. 2019). Population viability analysis that integrates key threatening processes across the species’ entire range predict that under current climate and threats declines of 47-66% and 22-32% in abundance and population occupancy, respectively, resulting in extinction of local populations across about 40% of the range (Bino et al. 2020).
There has also been anecdotal evidence from the public of platypus declines and extinctions which significantly increased during the severe drought in 2019. During this time, we received emails and calls from members of the public raising concerns for platypuses in pools which were drying up. Communications reported stranded platypuses, mortality, and predation by invasive species. Given climate change and the predicted increased severity of droughts, these events are projected to become more frequent.
Threatening processes to platypuses
Platypus depend on freshwater habitats, which are increasingly degraded, making them especially vulnerable to modification of the natural dynamics of Australia’s riverine systems. Historic hunting and increasing evidence of recent local platypus population decreases and extinctions highlight a species facing considerable population risks. River regulation (dams, diversions), climate change, land use change, pollution and adhoc mortality from bycatch threaten the species.
Platypus populations appear to be different but connected mainly through aquatic dispersal (also some terrestrial). Reduced water availability, dam construction, water extraction, and habitat degradation all fragment platypus populations and considerably increase risks of overland dispersal by a species predominantly adapted to utilising aquatic and riparian habitats. Also, water extraction from Australia’s rivers, catalysed by dam construction, may increasingly fragment platypus populations likely increasing short-term extinction risks for isolated populations, and threatening the long-term viability of the species. Further, the vulnerability of suitable drought refugia with projected increasing climate change also represents a significant challenge for the long term survival of the species.
Threats to platypus populations are widespread and synergistic, including land clearing, bank erosion, sedimentation, urbanization, river regulation and fragmentation, fishing by-catch, predation, pollution, and climate change (Bino et al. 2019). Until 1912, thousands of platypuses were shot during the fur trade for their skins (9315 skins reported in Sydney markets between 1891-99), (Hawke et al. 2019). The Platypus Conservation Initiative has assessed the impacts of river regulation and fire to platypus populations, both of which have caused detrimental impacts to platypus. Downstream of dams, rivers with altered flow regimes supported fewer platypus numbers compared to upstream sections and adjacent free flowing rivers (Hawke et al. 2020, in press). These findings are concerning, given the distribution of the platypus overlaps significantly with Australia’s most regulated rivers. We have also undertaken surveys in areas impacted by the 2019/20 bushfires and compared captures rates and demographics to an adjacent control catchment unaffected by fire. Preliminary surveys indicate an impact of the fires to platypuses, with relatively low capture rates on the fire affected rivers and a sex bias towards males.
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The Platypus Conservation Initiative is a partnership with Taronga Zoo and a team of researchers from three universities (University of New South Wales, University of Melbourne, and University of Sydney), Cesar, and six State and Federal partners all involved in the conservation of platypus, with relevant expertise and management responsibilities.
Still in many areas, platypuses have not be observed at all or in recent years. To record sightings of platypus use the iNaturalist app: iNaturalist platypus project
Associated researchers on the Project:
University of NSW
- Prof. Richard Kingsford
- Dr Gilad Bino
- Dr Tahneal Hawke
- Prof. William Sherwin
- Dr Tom Grant
- Luis Mijangos Araujo
University of Sydney