A scarcity of analysis into platypus numbers is leaving the long-lasting mammal weak to extinction, an skilled has warned.
The platypus is predominantly discovered alongside the Nice Dividing Vary, throughout the japanese seaboard and in an remoted pocket of South Australia.
It can be discovered near main inhabitants centres reminiscent of within the Yarra River, simply 10 kilometres from Melbourne’s CBD.
In 2014 the Worldwide Union for Conservation of Nature (IUCN) raised the standing of the platypus from least involved to near-threatened.
However Centre for Environmental Stress and Adaptation Analysis (CESAR) senior ecologist Josh Griffiths mentioned no-one actually knew for certain what number of platypuses there have been within the wild.
“The issue is no-one’s actually wanting,” Mr Griffiths mentioned.
“And that is one of many actual points with platypus conservation — there is no such thing as a dependable approach of estimating platypus numbers, even at an area scale.
“There’s a lot of areas the place they’re extraordinarily weak.”
Getting correct numbers is tough
Mr Griffiths mentioned finding out the monotreme by means of conventional catch-and-release strategies had confirmed ineffective.
“Partly since you do not catch lots of them, but in addition after you have caught them they appear to keep away from the nets, so it’s totally arduous to catch them once more, and it means you possibly can’t get an correct estimate of numbers.”
He mentioned whereas he was pretty sure there have been tens of 1000’s of platypuses in Australian waterways, the quantity might be as excessive as 100,00Zero or as little as 20,000.
“We do not know if there’s half as many as there have been 200 years in the past, [or] a 10th of what there was 200 years in the past. They might have elevated for all we all know,” he mentioned.
Researchers will now use DNA studies to track platypus numbers in the wild. (Supplied: Gary Lewis)
What threatens platypus numbers?
Australian Platypus Conservancy biologist Geoff Williams mentioned habitat destruction, local weather change, predation and direct human contact have been the principle threats to the platypus.
This yr, 9 platypuses died in Victorian waterways after drowning in unlawful enclosed yabby nets, the second-worst yr since information started in 2010.
However Mr Williams mentioned the precise variety of deaths might be significantly increased.
“We suspect the variety of deaths is simply absolutely the tip of the iceberg,” he mentioned.
“The overwhelming majority of [platypus] mortalities don’t get reported [because] most individuals are utilizing them [the nets] illegally.”
Mr Williams questioned figures from Victoria’s Division of Setting, Land, Water and Planning estimating that solely 5 per cent of platypus deaths have been reported.
“The true quantity might be maybe 1 per cent for all we all know,” he mentioned.
“Consequently it is provided that any individual by chance discovers a web and has a glance in it and finds a lifeless animal that we are likely to get studies.
“The explanation the numbers are typically increased in Victoria in all probability does not mirror the actual fact the issue is any worse — it merely displays the truth that Victoria has a greater system for retaining observe of this stuff.”
An enormous illegal drum net was found on the banks of Gunbower Creek in northern Victoria, a hotspot for platypus deaths. (Supplied: Swan Hill Fisheries Authority)
First nationwide platypus DNA survey
CESAR has simply launched a three-year nationwide survey of platypus numbers in partnership with the College of Melbourne and the San Diego Zoo in america.
Mr Griffiths mentioned the survey would absorb Victoria and New South Wales, and transfer away from catch-and-release strategies to a DNA sampling method.
“We will now go and take water samples and search for traces of DNA,” he mentioned.
“And that allows us to do that large-scale analysis over about 1,00Zero websites … and that is by no means been capable of be performed earlier than.
“It’s going to be taking a look at locations the place we all know they was once 20 or 50 years in the past — are they nonetheless there now?”
What’s being carried out to help platypus numbers?
In 1994, Challenge Platypus was established to behave as an umbrella organisation for 11 Landcare teams within the higher Wimmera catchment to ship large-scale environmental restore tasks.
Challenge supervisor Allistair Stephens mentioned whereas the venture was in a roundabout way concerned in counting platypus numbers, works have been geared toward supporting a “wholesome habitat for that type of pinnacle species”.
Mr Stephens mentioned current DNA testing of water within the Wimmera’s higher catchment revealed there have been no platypuses there, and he remained pessimistic about their future.
He mentioned an absence of rainfall was a significant menace to platypuses, who favored deep river swimming pools with loads of protection and steady banks.
“We will do all that we will do to try to maintain issues trending in the proper route so far as bettering habitat, however it’s so depending on rainfall, and there is not a heck of lots we will do to enhance that,” Mr Stephens mentioned.
Platypuses disappearing from complete waterways
Mr Griffiths mentioned 20 to 30 years in the past, platypuses have been pretty widespread throughout western Victoria’s Wimmera catchment.
However he mentioned the millennium drought had resulted within the catchment’s complete platypus inhabitants dying out, aside from the McKenzie River, which obtained environmental flows.
“They’ve disappeared from the entire Wimmera River itself … they usually’ve additionally disappeared from the decrease a part of the Murray Darling,” he mentioned.
“And it may’t simply be these areas the place they’re on a downward trajectory, however as a result of they are not on any of the states’ threatened species lists they do not get particular consideration.”