The Times Australia
The Times World News

.
The Times Real Estate

.

how living with predators could help native species survive

  • Written by Katherine Moseby, Associate Professor, UNSW
how living with predators could help native species survive

When we release a group of endangered animals into the wild, we always hope they will survive. They usually don’t. We find bilby carcasses under bushes, bettongs ripped apart by feral cats, and tufts of rock wallaby fur in fox scats.

Over the last 25 years I’ve seen the devastation caused by introduced foxes and cats firsthand during attempts to conserve our threatened mammals. At one of my research sites, Arid Recovery[1], we have tried again and again to protect bilbies, bettongs and wallabies outside fences.

Unfortunately, our native animals have not co-evolved with these canny predators and simply don’t have the anti-predator[2] behaviours or physical traits needed to avoid them.

So what to do? After years of discouraging results, we’re trying something new. We want to help our native marsupials evolve to become warier and better at surviving. Not in fenced-off sanctuaries – but in the wild, alongside these extraordinarily clever predators.

A feral cat hunting at night in central Australia
Too lethal: A feral cat hunting at night in central Australia. Author provided

Why are our native mammals such easy prey?

If our native marsupials had more time to adapt, we wouldn’t have to do this. But rabbits, foxes and cats operate like an unholy trinity. European settlement brought high rabbit numbers. These animals competed with native marsupials for food and became food for cats and foxes – inflating their numbers in turn. The damage was exacerbated by widespread land clearing and overgrazing.

Read more: From the frontline: saving Australia's threatened mammals[3]

Our mammal extinctions to date include burrowing or smaller marsupials, including wallabies, bandicoots and rodents mostly within the critical weight range[4] of 35 grams to 5.5 kilograms. Those smaller or larger are safer. Those in the middle? Cat and fox food.

The problem we are faced with in conservation is doubly difficult, because to protect the most vulnerable species – Shark Bay bandicoots, burrowing bettongs, greater stick-nest rats – we have to breed them in islands of safety. They live behind high fences while the predators roam outside.

When you breed animals in captivity, they become even more naive about predators. So what’s the solution? Do we simply keep stocks of these rare marsupials on life support?

Researchers release a burrowing bettong in the Arid Recovery sanctuary in South Australia Researchers release a burrowing bettong in the Arid Recovery sanctuary in South Australia. Author provided

We spend millions of dollars a year controlling cats and foxes by trapping, shooting and baiting them. Much less effort has gone into improving the responses of prey animals.

If our native mammals are to claw back any part of their previous range, they will eventually need to co-exist with cats and foxes in more places in the wild. And to do that, they need our help.

Can we really speed up adaptation?

To date, most efforts to improve naive prey animals’ responses to predators pair an unpleasant experience with a predator cue. Rubber bands, water pistols, loud noises or physically chasing animals are paired with cues like taxidermied foxes, models, cat odour or vocalisations. Unfortunately, results are generally poor or short lived.

In response to these challenges, we have been testing a more interventionist approach – in situ predator exposure[5]. This is where we expose threatened mammals to low densities of real predators over long time periods to accelerate natural selection and direct learning through real predator encounters.

For the six years we have been running this experiment in South Australia, the approach has yielded some promising results.

We placed bilbies and burrowing bettongs into a fenced paddock and added low numbers of feral cats. Then we waited. Over the next six years, we compared their physical and behavioural traits over time with a control population not exposed to predators.

Greater bilby at night
Greater bilby photographed at the Arid Recovery centre. Alexandra Ross, Author provided

Read more: Why Australia needs to kill cats[6]

We found cat-exposed bilbies became warier and sought areas of thicker cover within only a couple of years. Not only that, they had higher survival rates[7] than control bilbies when both were reintroduced to an area where cats were present.

Within 18 months, predator-exposed bettongs became significantly harder[8] to approach at night. Remarkably, their hind feet became longer relative to control populations over several years and they had significantly faster reaction times during escapes from predators[9], though not yet fast enough to show a significant difference in survival between control and cat-exposed populations.

In short, exposing naive prey to predators changed behaviour and in some cases survival after just a few generations. This is positive news.

You might be wondering why this doesn’t just happen naturally in wild populations. In some cases it does. Many native mammals now recognise and respond to dingoes[10], which have only been in Australia for a few thousand years. The problem is that cat and fox densities are likely too high to enable prey to adapt before local extinction occurs.

Anti-predator behaviour can be lost within only a few[11] generations, studies have shown. It’s heartening to know it can also be regained quickly.

burrowing bettong Burrowing bettongs were once extremely common across Australia’s interior. Photo by Andrew Freeman, Author provided

Will these changes endure?

What we need to know is if these changes are due to plasticity or selection. If it’s plasticity, it means the changes and learning experienced by individual bilbies and bettongs may not be passed on to the next generation.

If selection is at work, it means ongoing predator exposure could result in changes to the genetic makeup of the species, with further improvements and adaptations over time.

So which is it? Our initial results suggest selection may be occurring in some traits such as hind foot length. Similar efforts to teach northern quolls to avoid cane toads[12] have found learned behaviour can be inherited.

This kind of assisted evolution is also being trialled in corals[13] to give them the adaptations necessary to survive our warming oceans.

To achieve the dream of successful coexistence between introduced predators and our native mammals, we will need a range of approaches. These include better predator control methods to reduce numbers, improved habitat quality for our mammals, and enhanced prey responses.

We urgently need a better understanding of predator thresholds[14] – the level of predation at which native species can maintain stable or increasing populations while applying enough selective pressure to evolve new behaviours and traits. Under these conditions we could expect some (but not all) native species to eventually adapt to introduced predators.

After spending the last three decades watching our native animals continually decline, we are now at the point where we need to carefully explore new options with an open mind.

References

  1. ^ Arid Recovery (aridrecovery.org.au)
  2. ^ anti-predator (researchers.mq.edu.au)
  3. ^ From the frontline: saving Australia's threatened mammals (theconversation.com)
  4. ^ critical weight range (pubmed.ncbi.nlm.nih.gov)
  5. ^ in situ predator exposure (onlinelibrary.wiley.com)
  6. ^ Why Australia needs to kill cats (theconversation.com)
  7. ^ higher survival rates (besjournals.onlinelibrary.wiley.com)
  8. ^ significantly harder (besjournals.onlinelibrary.wiley.com)
  9. ^ escapes from predators (doi.org)
  10. ^ respond to dingoes (www.researchgate.net)
  11. ^ lost within only a few (royalsocietypublishing.org)
  12. ^ avoid cane toads (pubmed.ncbi.nlm.nih.gov)
  13. ^ corals (www.pnas.org)
  14. ^ predator thresholds (digital.library.adelaide.edu.au)

Read more https://theconversation.com/so-you-want-to-cat-proof-a-bettong-how-living-with-predators-could-help-native-species-survive-170450

The Times Features

Best Deals on Home Furniture Online

Key Highlights Discover the best deals on high-quality outdoor furniture online. Transform your outdoor space into a stylish and comfortable oasis. Explore a wide range of d...

Discover the Best Women's Jumpers for Every Season

Key Highlights Explore lightweight jumpers for spring and summer, ensuring breathability and ease. Wrap up warm with cozy wool jumpers for the chilly autumn and winter season...

Uncover the Elegance of Gorgeous Diamond Tennis Necklaces

Key Highlights Diamond tennis necklaces are a timeless piece of jewelry that exudes elegance and sophistication. They feature a continuous line of brilliant-cut diamonds, cre...

Dental Implants vs. Dentures: Which Is Better for You?

When it comes to replacing missing teeth, two of the most common options are dental implants and dentures. Both have their advantages and disadvantages, so choosing between them ...

What Neck Pain Really Means (And Why It’s More Than Just Poor Posture)

Neck pain is often brushed off as something temporary — a tight spot after a long day at the desk or a poor night’s sleep. But when the discomfort keeps returning, it could be a ...

The Work of Gosha Rubchinskiy: Fashion, Culture, and Youth

From Designer to Cultural Architect Gosha Rubchinskiy is not just a fashion designer—he's a cultural force. Born in Moscow in 1984, Rubchinskiy began his career in fashion in t...

Times Magazine

The Essential Guide to Transforming Office Spaces for Maximum Efficiency

Why Office Fitouts MatterA well-designed office can make all the difference in productivity, employee satisfaction, and client impressions. Businesses of all sizes are investing in updated office spaces to create environments that foster collaborat...

The A/B Testing Revolution: How AI Optimized Landing Pages Without Human Input

A/B testing was always integral to the web-based marketing world. Was there a button that converted better? Marketing could pit one against the other and see which option worked better. This was always through human observation, and over time, as d...

Using Countdown Timers in Email: Do They Really Increase Conversions?

In a world that's always on, where marketers are attempting to entice a subscriber and get them to convert on the same screen with one email, the power of urgency is sometimes the essential element needed. One of the most popular ways to create urg...

Types of Software Consultants

In today's technology-driven world, businesses often seek the expertise of software consultants to navigate complex software needs. There are several types of software consultants, including solution architects, project managers, and user experienc...

CWU Assistive Tech Hub is Changing Lives: Win a Free Rollator Walker This Easter!

🌟 Mobility. Independence. Community. All in One. This Easter, the CWU Assistive Tech Hub is pleased to support the Banyule community by giving away a rollator walker. The giveaway will take place during the Macleod Village Easter Egg Hunt & Ma...

"Eternal Nurture" by Cara Barilla: A Timeless Collection of Wisdom and Healing

Renowned Sydney-born author and educator Cara Barilla has released her latest book, Eternal Nurture, a profound collection of inspirational quotes designed to support mindfulness, emotional healing, and personal growth. With a deep commitment to ...

LayBy Shopping