Did You Know? Platypus Population is Slowly Declining in Australia

Platypus is one of Australia’s most beloved species, and that’s with good reasons. First of all, they’re super cute—they’re like a hybrid of otter and duck—and it’s going to be so hard to resist petting them when you spot them in the wild.

Second, they exist only around the continent and nowhere else. Third, platypus is one of the last remaining monotremes (egg laying mammals) left on Earth. And, we’ve only begun to discover its wealth of secrets, from life-saving antibiotics in its milk to potential diabetes cures in its venom.

Sadly, since they’re seen quite regularly enough, they didn’t get that much of attention until biologists began to realise that these quirky mammals aren’t doing so well, and they probably weren’t all along.

Tahneal Hawke, a PhD candidate at the University of New South Wales and a researcher with the Platypus Conservation Initiative stated, “The platypus has declined right in front of our noses. We have a huge area across the range of the platypus where we literally don’t know if they’re even there or in what numbers if they are.”

Based on Hawke’s study that surveyed centuries of historical data of platypus found in rivers and streams throughout eastern Australia and Tasmania, it’s revealed that the species’ population has been plummeting in number, due to hunting, habitat loss, and climate change.

What’s sad is that scientists actually started sounding alarms of the platypus’ decline as early as the 1980s, but they weren’t taken seriously. Then, as more and more data from long-term monitoring programs set up in the 1980s and ‘90s came up, and people’s thought of the indestructible species began to crumble away.

“We’ve been monitoring platypus since 1995 and the decline is certainly evident,” said Tiana Preston, an environmental water resources planner for the Victoria state agency Melbourne Water.

Undetected loss

In 2016, IUCN reassessed the platypus and they estimated that populations have dropped by about 30 per cent on average overall since Europeans arrived. And now, the species’ status has changed to near threatened.

Some scientists think that the status is an understatement. The study’s co-author Gilad Bino, a research fellow at the University of New South Wales explained, “There isn’t a tonne of great data, but the data we have suggests that our estimate of where that baseline is wrong. I wouldn’t be surprised if the numbers have halved or even more.”

Such losses had been under the radar for so long partly because platypuses are shy, nocturnal creatures that are difficult to find and count, so not seeing them doesn’t stand out as strange. However, this decline could have been missed ecause the animals were considered common enough that no one kept track of them. And over time, everyone forgot how many there used to be, so they just assumed the numbers hadn’t changed much.

Hunted down


Before, platypuses roam freely, maybe occasionally hunted by the natives but not on a large scale. Well, when Europeans came to Australia in the 17th century, platypuses became a favourite of fur traders for their soft, waterproof skins.

As a result, that hunting business boomed for centuries until hunting was outlawed in the early 20th century. “There was one particular record that we found that suggested a single furrier had sold 29,000 platypus skins,” said Hawke.

These platypuses continued to be seen in the same watersheds, with the exception of severe losses in South Australia. Now, in that state, this species is listed as endangered, but it’s not covered under any federal threatened species legislation.

It seemed that the animals are so resilient that those continuous hunting didn’t seem to lead to drastic declines. But, Hawke said that we shouldn’t be complacent about that. It’s not easy to know how exactly this species has declined, because there’s no data of how many of them used to be.

Additionally, research into platypus populations is spotty both geographically and historically. As mentioned before, they’re nocturnal and elusive, so daytime surveys tend to miss them. Tracking them through prints or droppings is also not possible, since they spend most of their time in the water. “Platypus are notoriously difficult to study,” Preston said.

Learning from the past


In order to get a better understanding of how much the species has declined, Hawke and colleagues dug through 258 years’ worth of historical documents, over 11,000 records in all, to piece together what she could about the animals’ past numbers and distribution, and then compared that with all the modern data they could find.

The team couldn’t calculate firm numbers from such variable data, but they could come up with the conclusion that there are a lot fewer platypuses now than there once were. A century ago, there were some places where one can see them in a day, and now one must do an exhaustive nighttime surveying. If one is lucky, that is.

“For species like platypus, whose population declines happened before ecologists started studying them, these types of historical observations are extremely valuable. It is an excellent use of historical data to understand the population dynamics of an iconic species,” said Loren McClenachan, a historical ecologist with Maine’s Colby College.

However, some platypus researchers think that historical sources are just too unreliable to make claims about past populations. Peter Temple-Smith and Frank Carrick stated that we need more robust surveys to determine if areas with fewer reported sightings really have fewer animals.

“Historical reports can be very important to understanding current ecology, but do require considerable care in interpretation,” said Carrick. Bino agreed that combining such different types of data wasn’t easy before stating that the team’s goal was never to put some exact number on how much the animals have declined.

What the future holds

One thing is certain; platypuses are struggling and will continue to decline if nothing changes. From the study, Hawke’s team suggests that large dams are important to these animals. If managed poorly, a single dam can essentially wipe out the platypuses living above and below it.

If we understand the nuances of threats like this, we can help researchers determine the best ways to protect the animals and we can also take action to preserve these unique mammals. “We are all concerned that it continues to be conserved as a flagship species for eastern Australian waterways after 160 million years of evolution—especially since it is the last extant species of its evolutionary line,” said Temple-Smith.

After all, we want to keep platypuses around for sure.

 

Source

https://www.nationalgeographic.com.au/animals/the-silent-decline-of-the-platypus-australias-beloved-oddity.aspx

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