SCIENCE
WHERE HAVE ALL THE PLATY…PODES(?) GONE? Words: Dr Qamar Schuyler Nearly every Hobartian has a story about ‘the platypus in the Rivulet’ – the last time they saw it, theories about whether it has disappeared after recent major works, the best time to find it… frankly though, none of these reports have helped me, as I have yet to see a platypus in the wild. To get some spotting tips and learn more about this beguiling creature, I spoke to platypus researchers Josh Griffiths (based in Melbourne) and Sarah Munks (UTAS). If you’ve ever wondered what it would be like to be a platypus researcher, it’s pretty much like any other career in the sciences – not nearly as glamorous as Hollywood would have you believe! Historically, collecting accurate data on these little cuties required lots of trapping surveys, often in cold, wet, dark conditions. Just to be able to reliably detect the presence of animals in a single waterway would require pulling between 6-10 all-nighters, dressed to the nines in your fanciest waders. As you can imagine, it’s impossible (and prohibitively costly) to conduct these surveys everywhere, so distribution data is limited in scope. But Josh and his team are using some exciting new technology which has revolutionised not only platypus research, but wildlife research in general. Environmental DNA, or eDNA, relies on the fact that everywhere we (and other animals) go, we shed our DNA, through mucous, skin cells, hair, and many other sources. By testing the water that an animal has been in, you can pick up traces of its DNA for as long as 7 days after the animal has left. Now, just scooping up a couple of water samples gives you the same accuracy as all of those long, wet nights. Instead of just sampling a few select rivers, scientists can survey entire watersheds! And even more excitingly, the sample collection technique is simple enough that individuals and community groups can easily be trained to collect samples in their local waterways. Josh has now sampled across most of Victoria and southern New South Wales with this new technology, and he has some pretty depressing news. My bucket list item has gotten a lot harder to tick over the past few decades. Platypus populations have declined significantly, both in numbers as well as in the locations they can be found. In fact, a proposal to list them as “Vulnerable to Extinction” in Victoria is currently under public comment. The causes for their decline are predominantly human-induced. The increase in extreme climatic events (both drought and flooding), removal of water from aquatic systems, and building in-stream dams and reservoirs all change the flow of rivers and affect food availability. Removal of vegetation around waterways and subsequent erosion of riverbanks not only affects the 28
platypuses’ ability to dig extensive burrows (up to 30m long!), but perhaps more critically, reduces woody debris and organic matter, habitat for their invertebrate prey species. Development also fragments river systems, leaving populations more vulnerable to local depletion. Which brings us back to the platypus in the Rivulet – a habitat which essentially ends where the rivulet is directed underground in the middle of the CBD. Josh gently reminds me that it’s not “the” platypus - there would certainly be more than one living there, but when pressed to say how many, he really can’t. While there have been studies of platypus ecology and distribution in Tasmania, not a lot is known about population trends here. Tasmania is considered a stronghold for the platypus, we have plenty of waterways, good habitat, and enough rainfall. However, local changes in land use and habitat degradation lead scientists to hypothesize that numbers may be on the decline in parts of Tasmania, especially in areas most impacted by drought. Sarah says that it is critical to conduct more monitoring of platypus populations in Tasmania, particularly in areas that will be vulnerable to climate change. So how can we help these critters to survive? Josh offers a few tips – use less water, follow the “snip it and bin it” technique – cut all of your enclosed rings (hair ties, rubber bands, milk rings, etc) before binning them to prevent entanglement. Practice responsible fishing – remove your line when it gets snagged, and never use enclosed yabby traps. If you are lucky enough to see a platypus in the wild, reporting your sighting on the platypusSpot website or app (www.platypusSpot.org) will help researchers better understand where they live. And if you really wanna go big? Josh and Sarah estimate that collecting eDNA data for platypus populations across all of Tasmania would be relatively inexpensive, especially if citizen scientists were involved in gathering the samples. All it would take is a couple of big sponsors and maybe some grassroots efforts by school kids and community groups…just putting it out there! Oh…and as for what we call more than one platypus – according to Josh, the technically correct term is indeed platypodes, from the Greek, though the more commonly used “platypuses” will also suffice! This article is part of a series featuring early career researchers; scientists in the beginning phase of their careers. Follow Qamar on Twitter @Qamarsky
