The secret life of echidnas reveals a world-class digger vital to our ecosystems

Christine Cooper, Curtin University and Christofer Clemente, University of the Sunshine Coast

Echidnas may not seem the most active of animals. Waddling around, they spend much of their time dozing and hiding. But in research published today in the Journal of Experimental Biology, we show that echidnas dig huge amounts of soil, and play a crucial role in Australia’s ecosystems.

By attaching miniature GPSs and accelerometers to echidnas in Western Australia, we found that these mammals move on average 200 cubic metres of soil each year. For the 12 echidnas we studied, this is the equivalent of an Olympic-sized swimming pool.

Attaching tiny tracking devices to echidnas is harder than it sounds.

Zoology gets small

Short-beaked echidnas are one of few surviving species of monotreme; unique mammals that reproduce by laying eggs. As well as a strange anatomy, they have an unusually low body temperature and metabolism.

We were interested in how the echidna’s unusual limbs influenced their walking and digging, and how this in turn was related to patterns of activity and their potential ecosystem impact.

So we attached tiny custom-made accelerometers to the spines of wild echidnas at Dryandra Woodland, in Western Australia. We also attached GPS units to monitor their location, and radio-transmitters so we could find them again.

The miniaturisation of electronic devices has changed the way we study wildlife. We can get details about wild animals’ behaviour in their natural habitat that we couldn’t previously. This is now revealing more information not only about the biology of these species, but the roles they play in ecosystems.

Echidna fitted with an accelerometer and GPS unit, and a radio-tracking transmitter
Christine Cooper

The accelerometers were about the size of a wrist-watch, hand-soldered with a microscope and tiny soldering iron. These let us determine exactly when and for how long echidnas were resting, walking and digging.

Our biggest challenge was getting to the echidnas again so we could remove their tracking devices. Echidnas spend much of their time sheltering in inaccessible caves, rocky crevices and hollow logs and are mostly active at night, especially during summer. We studied echidnas during the hot West Australian summer, when temperatures rose to 45℃, and during spring when it was 25℃ cooler.

Tracking an echidna to a rock cave at Dryandra Woodland
William Parkinson

Walk like an echidna

Our data revealed that echidnas take shorter and slower strides compared with similar-sized mammals. Unlike most other mammals, they take more strides rather than increasing the length of their strides to walk faster. This reflects the anatomy of the limbs, which are adapted to digging rather than rapid movement and as a consequence, echidnas cannot walk very fast, with a maximum speed of 2.3 kilometres per hour, and have a characteristic waddling gait.

But their covering of sharp spines offers good protection from predators. Indeed you don’t need to be able to run quickly if nothing can eat you. This armour of spines and the echidna’s ability to dig rapidly into the ground or roll into a tight, spikey ball is one reason that echidnas have not suffered the same dramatic decrease of many other Australian mammals.

Echidnas are also not as vulnerable to the ravages of introduced predators that are often the final straw for native mammals already threatened by increasing aridity, land clearing, altered fire regimes and competition with introduced herbivores.

Removing the accelerometer and GPS from an echidna to download the data and re-charge the batteries.
Kellie McMaster

When echidnas were active, they spent most of the time digging and looking for food. Compared to many other animals, echidnas have longer activity times, presumably due to the time required to find their food of ants and termites; echidnas eat about 40,000 individual ants and termites a day.

Echidnas spend a similar amount of time foraging in both spring and summer, but during spring they move more slowly and are more likely to ramble, at a leisurely 1 kilometre per hour, from their rest sites to foraging areas. But in summer, they sprint at their top speed directly to and from feeding sites, presumably to minimise activity during hot weather.

The importance of digging

The considerable time that echidnas spend digging and the area over which they dig means that they act as important “bioturbators”. They turn over the soil which reduces compaction, improves soil mixing and water penetration, incorporates leaf litter and other organic matter into the soil, and reduces run-off and erosion.

Therefore, bioturbators such as echidnas are “ecosystem engineers”. They play a crucial role in the environment as their digging can make for better soils, and in turn influence plant growth and species diversity.

Echidna digging for termites, Dryandra Woodland
Christine Cooper

Echidnas are particularly important ecosystem engineers in Australian landscapes, as many of the other native mammals that once performed this function are rare or have become extinct, and so are no longer doing this essential role. Echidnas have one of the widest distributions of any native Australian mammal.

Their persistence in almost all Australian habitats means that their extensive digging is a critical component of maintaining ecosystem function throughout the Australian continent.

Christine Cooper, Senior Lecturer, Department of Environment and Agriculture, Curtin University and Christofer Clemente, Lecturer in Animal Ecophysiology, University of the Sunshine Coast

This article was originally published on The Conversation. Read the original article.

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Teaching reptiles to avoid cane toads earns top honour in PM’s science prizes

Michael Hopkin, The Conversation

A conservation biologist who is bidding to help Australia’s native animals learn to give cane toads a wide berth has been awarded the 2016 Prime Minister’s Prize for Science.

University of Sydney professor Rick Shine was given the award for his work in using evolutionary principles to boost the effectiveness of real-world conservation.

One example is his innovative use of “teacher toads” – small cane toads deployed in areas where native animals are threatened by the poisonous invaders. These small toads aren’t big enough to kill but are unpleasant enough to encourage animals such as quolls and lizards to steer clear of eating bigger cane toads in future.

Invading cane toads are spreading westwards across tropical Australia and have now reached the northern parts of Western Australia, growing bigger and faster as they go. By deliberately releasing smaller cane toads ahead of the invasion front, the project aims to give native animals a better chance of avoiding being caught on the hop.

Professor Shine’s research has also explored ways to stop cane toads reproducing, by lacing traps with pheromones from other species that attract cane toad tadpoles.

Originally a reptile biologist, Professor Shine began studying cane toads after one arrived at a site on the Adelaide River near Darwin, making him realise the significance of the threat the toads posed.

“The creatures like snakes and lizards that dominate our ecosystems, they’re the ones we have to focus on, they’re the ones we need to understand if we want to keep Australia’s ecosystems functioning,” he said.

Rick Shine on his love of reptiles.

UNSW Australia conservation ecologist Mike Letnic said that Professor Shine has been a role model for many scientists, particularly biologists tackling big questions about evolution and conservation.

“For me the biggest contribution he has made is in studying the rapid evolution of some species such as snakes, and obviously the work on cane toads feeds into that. The big challenge is whether you can harness that evolution for biological control,” he said.

“With cane toads it is not just the selection process but also the spatial sorting – faster, fitter toads are skewing selection by being at the invasion front.”

Cash and plastic

Other award recipients include Michael Aitken of the Capital Markets Cooperative Research Centre, who won the Prime Minister’s Prize for Innovation for his use of financial data to identify ways to improve Australia’s health markets.

Having initially developed ways to detect fraud in financial markets, Professor Aitken then turned his attention to spotting inefficiencies in health spending.

He and his colleagues have identified examples of “low-value treatments”, which are over-prescribed relative to the benefits they deliver – such as prostate screening and surgeries for chronic arthritis.

“We are looking at maybe A$20 billion per year that could be directed to improve health care in areas of genuine want,” he said. “These might be treatments that are of no great benefit. But surgeons are paid to do surgery – and if they don’t do surgery they don’t get paid, so they do it.”

Professor Aitken said you can learn a lot by studying the “low-hanging fruit” of health financial data to spot treatments that are being over-prescribed. But he then asks clinical experts to evaluate the evidence base for the treatments themselves.

Michael Aitken explains his data-driven approach.

Another scientist being honoured for innovation is Colin Hall of the University of South Australia, who has created a high-tech, all-plastic replacement for standard car wing mirrors.

His design is lighter and more sustainable than the conventional metal-and-glass design, but it had to pass a succession of stringent tests designed to mimic harsh motoring conditions before being adopted by the car industry.

“The hardest was the salt test – it had to be sprayed with very salty hot water for ten days,” Hall said.

Other tests included a thermal shock test in which the mirrors had to cycle rapidly between -40℃ and 80℃, 200 times in a row, to ensure they could handle temperature changes.

Colin Hall’s high-tech plastics have passed the test.
Prime Minister’s Prizes for Science/WildBear

Hall’s earlier research focused on designing high-tech plastics for spectacles. But while a pair of glasses might be replaced within a year, cars are designed to last at least a decade, which means the industry is very strict about which designs it approves.

Hall hopes that, in time, all of the metal components on cars can be replaced with plastic alternatives, thereby doing away with the highly polluting electroplating processes currently used in car production.

Peptides, proteins and ecosystems

Other prizewinners include Richard Payne of the University of Sydney, whose work on re-engineering protein molecules found in nature promises to give us new ways to treat stroke, malaria, tuberculosis and even cancer, and has earned him the Malcolm McIntosh Prize for Physical Scientist of the Year.

University of Queensland conservation scientist Kerrie Wilson has won the Frank Fenner Prize for Life Scientist of the Year, for her work on evaluating “ecosystem services” – the benefits provided by natural resources such as clean air, water and food.

Perth teacher and former geoscientist Suzy Urbaniak has won the prize for excellence in secondary school science teaching, while the award for primary school science education went to Sydney-based Gary Tilley.

The winners, who will share a prize pool of A$750,000, will receive their prizes from Prime Minister Malcolm Turnbull and Science Minister Greg Hunt at a dinner in Parliament House this evening.

Michael Hopkin, Environment + Energy Editor, The Conversation

This article was originally published on The Conversation. Read the original article.