Media Science communication The Conversation

The Conversation: Species don’t live in isolation: what changing threats to 4 marsupials tell us about the future

Once abundant, woylies – or brush-tailed bettongs – are now critically endangered. John GouldCC BY-SA

By William Geary (Deakin University), Adrian Wayne (The University of Western Australia), Euan Ritchie (Deakin University) and Tim Doherty (University of Sydney).

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Conserving native wildlife is a challenging task and Australia’s unenviable extinction record shows us we urgently need more sophisticated and effective approaches. 

Too often we focus on saving individual threatened species. But in the wild, species do not live neatly in isolation. They are part of rich ecosystems, relying on many other species to survive. To save species often means saving this web of life. 

Our new research models what’s likely to happen to four well-known Western Australian marsupials in the biodiversity hotspot of south-western Australia, by identifying key drivers of their populations over time. 

In the past, these species were most at risk from habitat loss. But when we ran our models forwards, we found all four species would be at more risk from climate change, which is bringing heightened fire risk and a drying trend to the region. Even better control of foxes – a major predator – did not offset the trend fully.

Our work adds further weight to efforts to protect ecosystems in all their complexity. The way species – including feral predators – interact takes place against a changing climate, fire regimes, and human-made change, like logging and grazing. 

To give native species their best chance of survival, we have to embrace ecosystem-based conservation, rather than focusing on rescuing individual species. 

What did we find?

We looked at long-term monitoring data to find out what was having the most impact on the woylie (brush-tailed bettong), chuditch (western quoll), koomal (western brushtail possum) and the quenda (southern brown bandicoot), four animals living in Upper Warren jarrah forests.

Our study species, left to right and clockwise: the koomal (western brushtail possum), chuditch (western quoll), quenda (southern brown bandicoot) and the woylie (brush-tailed bettong). The Department of Biodiversity, Conservation and Attractions (DBCA)

All four have undergone considerable population change over the last few decades and some are now threatened due to predation by foxes and feral cats, habitat loss and increased frequency of droughts and bushfires. To add to that, controlled burns, lethal fox control and timber harvesting have all taken place in our study region within this time. What we didn’t know was how these threats and conservation efforts interact. 

To find out, we built a complex statistical model of the ecosystem to pinpoint what was driving population change geographically and over time. 

We found the abundance of these species were affected most by the historical impact of habitat loss, as well as less food in the form of vegetation or prey due to the area’s ongoing decline in rainfall. 

Of the habitat lost here, most was cleared during the 19th and early 20th centuries. But now it has more or less stopped, the legacies of this change continue through the effects of habitat fragmentation and increased incursion by introduced species. That means the main falls in abundance took place decades ago. 

What about fire and foxes? These threats had less effect than habitat loss and rainfall declines, which we attribute to the broad management of both of these in the region. It was also difficult to quantify the effects of fox control because of the lack of control areas – essentially, comparable areas without poison baits in the region. 

Our work shows there’s not one simple answer for managing this ecosystem. Everything is connected. We need to embrace this complexity so that we can better pinpoint where our actions can make a difference.

This jarrah forest is typical of our study region. The Department of Biodiversity, Conservation and Attractions (DBCA)

What’s likely to happen?

While habitat loss was the major historical threat, the future looks to be different. Severe fire is set to increase and rainfall reduce due to climate change. This indicates all four species will see falling populations. 

Annual rainfall in south-western Australia has already fallen at least 20% below the historical average and further declines are expected. If severe fires arrive more often – and overlap with reduced rainfall – we could see even greater population loss. 

These threats mean local conservation managers will be less able to help. Controlling fox numbers may help at present, but in a drier, fierier future, things will get harder. 

Our modelling suggests that for woylie and koomal, lethal fox control could boost their resilience to severe fire and reduced rainfall, but not completely offset the expected losses.

Jarrah forests are now experiencing more bushfires. The Department of Biodiversity, Conservation and Attractions (DBCA)

What does this mean for ecosystem management?

It’s long been a goal for conservationists to manage ecosystems as a whole. In reality, this is often incredibly difficult, as we need to consider multiple threats (such as fire and invasive species) and conflicting requirements of different species, in the face of uncertainty about how some ecosystems work, as well as limited budgets

Ecosystems are complex webs of interacting species, processes and human influences. If we ignore this complexity, we can miss conservation opportunities, or see our actions have less effect than we expected. 

Sometimes, well-intended actions can actually produce worse outcomes for some species, such as fox control leading to a boom in wallabies who strip the forest of everything edible. 

Studies like ours wouldn’t be possible without the careful collection and synthesis of data over decades. As global climate change accelerates and the effects on ecosystems become increasingly unpredictable, conservation managers are flying blind if they do not have long-term monitoring to inform decisions on where and when to act. 

So what can our conservation managers do? They can help ecosystems survive by doing two things. First, keep managing the threats within our control – such as invasive predators and ongoing habitat loss – to help reduce damage from other threats. Second, model and anticipate the effects of future change, and use that knowledge to be as prepared as we can.

The Conversation
Media Science communication The Conversation

The Conversation: Labor’s plan to save threatened species is an improvement – but it’s still well short of what we need

Not a priority species: the endangered greater glider. Image credit: Josh Bowell/AAP

By Euan Ritchie (Deakin University), Megan C Evans (UNSW Sydney) and Yung En Chee (The University of Melbourne). 

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Australia’s dire and shameful conservation record is well established. The world’s highest number of recent mammal extinctions – 39 since colonisation. Ecosystems collapsing from the north to the south, across our lands and waters. Even species that have survived so far are at risk, as the sad list of threatened species and ecological communities continues to grow.

During the election campaign, Labor pledged to turn this around. On Tuesday, federal Environment Minister Tanya Plibersek announced what this would look like: a new action plan for 110 threatened species. The goal: no new extinctions. “Our current approach has not been working. If we keep doing what we’ve been doing, we’ll keep getting the same results,” Plibersek said.

But is this really a step change? Let’s be clear. This plan is a welcome improvement – especially the focus on First Nations rangers and Indigenous knowledge, clearer targets, better monitoring and the goal of protecting 30% of Australia’s lands and seas within five years.

But the funding is wholly inadequate. The A$225 million committed is an order of magnitude less than what we need to actually bring these threatened species back from oblivion. The grim reality is this plan is nowhere near enough to halt the extinctions. Here’s why.

There’s nowhere near enough funding

Conservation costs money. Recovering threatened species takes effort. Tackling the threats that are pushing them over the edge, from feral cats to land clearing, is expensive. “Measures of last resort”, such as captive breeding, creation of safe havens and translocations, takes more still.

How much is enough? Estimates put it at A$1.7 billion per year. This is around one-seventh of the money Australian governments spent on fossil fuel subsidies last financial year. If there’s funding for that, there should be funding for wildlife.

Make no mistake – starving conservation of adequate funding is a choice. For decades, Australia’s unique environment and wildlife have been thrown consolation crumbs of funding – even though they are our collective natural heritage, fundamental to human survival, wellbeing and economic prosperity, and a major draw card for tourists and locals. You can see the results for yourself: more extinctions and many more threatened species.

Picking winners means many species will lose

Labor’s plan is focused on arresting the decline of 110 species, and 20 places such as the Australian Alps, Bruny Island and Kakadu and West Arnhem Land.

Picking winners: the freshwater sawfish has been chosen as a priority species – while hundreds of others have not. AAP

Unfortunately, that’s a drop in the ocean. Combined, we now have more than 2,000 species and ecological communities listed as threatened. Picking species to survive betrays our remarkable, diverse and largely unique plants, animals and ecosystems. It suggests – wrongly – that we have to choose winners and losers, when in fact we could save them all.

The plan assumes recovering priority species may help conserve other threatened species in the same areas and habitats. This is questionable, given only around 6% of listed threatened species are slated to receive priority funding, and how much the needs of different species can vary even in the same habitats and ecosystems. Different species respond very differently to fire regimes, for instance.

Policies and laws are essential

Funding by itself isn’t enough. Unless all levels of governments enact and enforce effective policies aimed at conserving species and their homes, the situation will worsen. Australians are still waiting to see what reforms actually emerge from Graeme Samuel’s sweeping review of the main laws governing biodiversity and environmental protection.

Alignment of policies is vital. What’s the point of saving a rare finch from land clearing if you’re simultaneously opening up huge areas to fracking, polluting groundwater and adding yet more emissions to our overheated atmosphere? Despite Labor’s rhetoric on threatened species and climate change, they are still committed to more coal and gas.

Similarly, native vegetation clearing and habitat loss is barely mentioned in the threatened species plan. Yet these are leading causes of environmental degradation, as the 2021 State of the Environment Report makes clear.

If you want to save the critically endangered western ringtail possum and endangered black cockatoos, why would you approve the clearing of habitat vital to their existence? The Labor government did just that in July.

Conserving more land isn’t a panacea

Protecting 30% of Australia’s lands and oceans by 2030 sounds great. But protecting degraded farmland is not the same as protecting a biodiverse grassland or wetland. And establishing protected areas is not the same as effective management.

To get this right, the new areas must add to our existing conservation estates by adding species and ecological communities with little or no representation. They must help species move as they would have before European colonisation, by connecting protected areas separated by human settlement or farms. And there must be enough money to actually look after the land. There’s no point protecting ever-larger tracts of degraded, weed-infested, rabbit, deer, horse, pig, fox and cat-filled land.

The 50 million hectares of land and sea to be added by 2027 is supposed to come almost entirely from Indigenous Protected Areas. But again, where’s the funding? Right now, these land and sea areas get a pittance – a few cents per hectare per year.

It’s also important to support conservation on private land, where many threatened species live and where significant gains can be made. Maintaining wildlife on private land can also help farmers and landholders through pollination and seed dispersal as well as broader ecosystem health.

We need laws with teeth

If you liked it, you should have put a law around it. If the federal government is serious about ending extinctions, it should be enshrined in legislation. As it stands, “zero extinctions” is a promise with no clear way for us to see who is responsible or how the promise will be kept.

Too cynical? Alas, there’s a very real trend here. Successive governments have avoided accountability for losing species doing exactly this. They release strategies on glossy paper which note we all have a role to play in conservation – but strangely omit the part about who is responsible when a species dies out. If you want to save species, make human careers depend on species staying alive.

We know strong legislation and billions rather than millions of dollars are needed to stop extinctions. So far, the new government has announced inadequate funding, a non-binding strategy with an aspirational goal, and a seemingly rushed idea of a biodiversity market, dubbed “green Wall Street”, which made conservationists including the Wentworth Group of Concerned Scientists very concerned.

Tossing breadcrumbs to conservation is what we’ve done for decades. It’s a major reason why our unique species are in this mess. Time’s up.

The Conversation
Media Science communication The Conversation

The Conversation: Should we bring back the thylacine? We asked 5 experts

Image credit: Tasmanian Museum and Art Gallery

By Signe Dean, Science and Technology Editor, The Conversation.

This article is republished from The Conversation under a Creative Commons license. Read the original article.

In a newly announced partnership with Texas biotech company Colossal Biosciences, Australian researchers are hoping their dream to bring back the extinct thylacine is a “giant leap” closer to fruition.

Scientists at University of Melbourne’s TIGRR Lab (Thylacine Integrated Genetic Restoration Research) believe the new partnership, which brings Colossal’s expertise in CRISPR gene editing on board, could result in the first baby thylacine within a decade.

The genetic engineering firm made headlines in 2021 with the announcement of an ambitious plan to bring back something akin to the woolly mammoth, by producing elephant-mammoth hybrids or “mammophants”.

But de-extinction, as this type of research is known, is a highly controversial field. It’s often criticised for attempts at “playing God” or drawing attention away from the conservation of living species. So, should we bring back the thylacine? We asked five experts.

Axel Newton, Evolutionary Biologist at TIGRR Lab

YES, with a “but” (more on that shortly). The thylacine is one of the most tragic stories of the modern era, being actively hunted to extinction through a government bounty scheme. Unlike other extinct species, the thylacine was eradicated less than 100 years ago. Its habitat and ecological environment that it once thrived in is still intact.

I think we have an obligation to do everything in our power to bring back this remarkable animal, particularly as our forebearers were the direct cause of its disappearance. However, we also have an ethical and moral responsibility to ensure that the animal we resurrect is a 99%+ thylacine and not an almost-thylacine hybrid.

The largest challenge of this endeavour is reconstructing the genome of an extinct species without access to any living tissue (the difference between de-extinction and cloning). This equates to putting together a 3-billion-piece puzzle, with our hands tied behind our back.

Inevitably some argue that money used on this project could be put to better use through actively preserving habitats of animals on the brink. But this project will have enormous conservation benefits to already threatened species, and has the potential to generate significant advancements to human health.

The crux of this is through producing the genetic tools and methods to edit the DNA of stem cells, and then turn those stem cells back into an animal. This technology will not only meet our end goal of turning a surrogate marsupial cell into a thylacine, but in the process allow us to reintroduce genetic diversity into endangered populations. We could take bio-banked tissues of rare, endangered species, and produce animals to be reintroduced into the environment to increase beneficial genetic diversity. Not only this, but the work could be applied for targeted gene therapy to correct mutations underlying human health and cancer.

So, should we bring the thylacine back, yes. Not only for the fate of this incredible, lost species, but also the significant benefits this project will produce for humanity as a whole. As long as we keep the moral and ethical considerations at the forefront, we have an opportunity to correct the wrongs of the past.

Parwinder Kaur, Geneticist and Biotechnologist

MAYBE. It depends on the complex risks re-introductions of extinct species would have on our current ecosystems. Will such risks outweigh the potential benefits and fear unsuccessful environmental management actions?

Earlier this year, our DNA Zoo Australia team completed a chromosome-length 3D genome map of thylacine’s closest living relative: the numbat. This raised the tantalising prospect of piecing together the thylacine’s genetic sequence, which in turn would offer the possibility of reintroducing one of Australia’s most iconic lost species.

But the big question our team faced was: shall we go after resurrecting the dead, or help numbats first? Numbats are now struggling and on the verge of extinction, with fewer than 1,000 numbats left in the wild and the species officially listed as endangered. The answer was simple: focus on what we have first.

We live in exciting times when biotechnology offers various promising alternatives for achieving this purpose, and probably a better use of these techniques will be towards preserving critically endangered species on the verge of extinction.

In my opinion, focusing on de-extinction could compromise biodiversity conservation by diverting resources from preserving ecosystems and preventing newer extinctions. It is no trivial work in terms of resources and skills required to revive an extinct animal; given the low level of investments into conservation research, we need to be very careful as a scientific community to not prioritise preservation over resurrection.

Euan Ritchie, Wildlife Ecologist

MAYBE. There is much to consider with such an ambitious project. Most importantly, we must greatly increase efforts to save and recover living species, and it’s simply far cheaper and easier to conserve what we have than to attempt to resurrect species and their ecological roles.

This requires confronting the many causes for species decline & extinction, and, broadly speaking, our unsustainable existence and inability to share this planet with other species.

At current rates of species decline and extinction, de-extinction will not be able to come even close to resurrecting what we have destroyed. So which species do we try to bring back, and why? And, if it is even possible, will resurrected species behave the same way, will they perform the same ecological roles and affect ecosystems in the same way? I’m very doubtful.

However, we must stop perpetuating the idea that conservation is a zero-sum game, feeding a flawed narrative that we must choose which projects, species and ecosystems we support. A shortage of money isn’t the issue, values and priorities are. For perspective, it’s estimated Australia spent A$11.6 billion on fossil fuel subsidies in 2021–22, but recently only allocated A$10 million to 100 priority threatened species, fewer than 6% of the country’s listed threatened species.

It’s vital we maintain robust scrutiny and scepticism of ambitious projects, but we must also support scientists to push boundaries and take educated risks. And sometimes we learn, even when we ‘fail’.

Personally, I would love to see thylacines back in the wild, but I’m not optimistic we’ll see a self-sustaining and genetically diverse population of thylacines any time soon, if at all. If such projects are to proceed, I also hope that Indigenous people, and communities more broadly, are properly consulted and involved.

Julian Koplin, Bioethicist

YES. Most of us think we should protect ecosystems from damage and prevent animals from going extinct. This might be because we value nature for its own sake, or it might be because we think biodiversity is good for humans ourselves.

Importantly, both of these reasons also support de-extinction. One reason to bring back (approximations of) animals like the Tasmanian tiger and woolly mammoth is to help restore the ecosystems they used to live in; another is to bring humans a sense of wonder and awe, and perhaps even greater respect for the natural world. So, why not push ahead?

Perhaps the most serious ethical worry is that de-extinction is a poor use of resources; we could probably make a bigger difference to biodiversity by funding conservation efforts instead. But this objection isn’t decisive. The costs of de-extinction may come down over time.

Also, it’s unclear whether many people funding de-extinction efforts would otherwise have funded traditional conservation projects instead. We should keep an eye on the costs, but we shouldn’t reject de-extinction outright.

Corey Bradshaw, Ecologist

NO. While the scientific endeavour to demonstrate capacity to re-animate long-extinct species does have some merit, claiming that the approach will counter present-day extinction rates or could be used as a conservation tool is naïve.

Viable populations require thousands of genetically diverse individuals to be able to persist in the wild. There is simply no prospect for recreating a sufficient sample of genetically diverse individual thylacines that could survive and persist once released.

Also, large predators like thylacines require large home ranges to gather food, establish territories, and raise young. The reason they were driven to extinction in the first instance was due to perceived conflict with landholders, so even if the problem of genetic diversity could be solved, the social licence to re-establish a large population of predators is unlikely to be granted (consider the case of dingo persecution throughout most of Australia today).

Furthermore, the available habitats in Australia that could support a large population of thylacines have dwindled or been degraded radically since the early 19th Century. Combined with no-analogue climates of the immediate future due to global warming, it is unlikely that there would be sufficient available habitat to support a viable population.

The Conversation
The Conversation
Media Science communication The Conversation

The Conversation: 6 books about the climate crisis that offer hope

By Euan Ritchie (Deakin University), Erin O’Donnell (The University of Melbourne), Gregory Moore (The University of Melbourne), Kristen Lyons (The University of Queensland), Peter Christoff (The University of Melbourne), and Stefan Kaufman (Monash University).

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Coral bleaching, floods, bushfire, biodiversity decline and extinction – as we witness the effects of climate change, amid a stream of reports warning of the cost of government inaction, it is easy to feel overwhelmed.

How to counter the gloom? We asked six environmental experts to each nominate a book about the climate crisis that offers hope.

Euan Ritchie recommends All We Can Save: Truth, Courage, and Solutions for the Climate Crisis edited by Ayana Elizabeth Johnson and Katharine Keeble Wilkinson (2020)

Despair, disempowerment and division are all enemies of positive action, and crippling in the face of tremendous challenges such as the climate change crisis. All We Can Save is the antithesis of such emotions and concerns. Hope is a powerful motivator, especially when it’s delivered in such a creative, thoughtful, inclusive and diverse way.

Critically, All We Can Save brings together women’s voices, spanning culture, geography and ages. Women are still, shamefully, not heard nearly enough – and worse, actively suppressed in some instances and quarters. Society suffers because of this.

In this book, however, scientists, farmers, teachers, artists, journalists, lawyers, activists and others share their unique perspectives, through their essays, poetry and art. They explore how to confront the climate crisis, the damage already inflicted, but most importantly, how to bring about positive change and progress.

Food for the mind and soul, at at time when it’s needed more than ever.

Peter Christoff recommends Great Adaptations: In the Shadow of a Climate Crisis by Morgan Phillips (2021)

There is no point in pretending. There are no “good stories” about global warming. They are all framed by the crisis we refuse to talk about in Australia. We desperately need a national conversation about how to live in the perilous world forming around us.

Morgan Phillips’s Great Adaptations: In the Shadow of a Climate Crisis is not an Australian book. Its perspectives are international – British, European, Nepalese, North American.

Phillips doesn’t flinch from contemplating bleak prospects: systemic collapses, food and water insecurity, biodiversity decline. But his focus is neither on sheer doom, nor naive techno-optimism. He instead brings careful balance to his consideration of good adaptation and harmful (mal) adaptation.

He pushes us to think beyond fragmented reactions to individual climate catastrophes, such as droughts, fires, floods and storms – reactions that favour the wealthy and are based on the delusion that all will spring back to “normal”.

His aim is realistic “transformative adaptation”. He argues for enduring, flexible and equitable adjustments to nature’s new lottery. At the heart of his examples of success – from “fog harvesting” for water in arid Morocco to climate-responsive agro-forestry in Nepal – is the need for constant dialogue to guide adjustments to changing conditions.

Great Adaptations is a brilliant provocation for the discussion we must have.

Kristen Lyons recommends Who Really Feeds the World? The Failure of Agribusiness and the Promise of Agroecology by Vandana Shiva (2016)

The climate crisis has accentuated already unjust and ecologically unviable global food systems. Australia’s recent bushfires and floods, for example, destroyed crops, devastated food-producing landscapes and their communities, and disrupted transport networks. Each laid bare a corporate controlled food system characterised by escalating food prices, growing rates of hunger, and food insecurity.

How might fair and just food systems be fostered – systems that are resilient in the face of climate chaos?

In Who Really Feeds the World? The Failure of Agribusiness and the Promise of Agroecology, Vandana Shiva sets out principles and practices that may offer some solutions. Drawing on a range of examples from around the world, including the
Navdanya movement based in India (which she founded), Shiva presents agroecology, living soil, biodiversity and small-scale farming as life-affirming responses.

Small-scale farmers on small parcels of land already produce 70% of the world’s food. They really can feed the world.

The challenge then – one of many – is how we might breathe life into the principles advocated by this award-winning environmental activist, recipient of the Right Livelihood Award and Sydney Peace Prize. In an Australian context, this will include addressing the violent settler-colonial foundations upon which Australia’s agriculture and food systems have been built.

Erin O’Donnell recommends Fresh Banana Leaves: Healing Indigenous Landscapes through Indigenous Science by Jessica Hernandez (2022)

Raging fires, desperate droughts and unprecedented floods underscore the power and terror of the climate catastrophe. As we experience these brutal reminders of our dependence on healthy ecosystems, many of us are searching for a different way to reconnect with the world around us.

In Fresh Banana Leaves, Jessica Hernandez offers us the concept of “kincentric ecology”, in which the enduring relationship between Indigenous peoples and place is one of mutual interdependence.

She argues that “we are not separate from nature” and that “Indigenous peoples view their natural resources and surroundings as part of their kin, relatives, and communities”.

Hernandez’s book demonstrates the power of Indigenous science (and the leadership of Indigenous peoples) to help bring all of us back into good relations with nature. In doing so, she offers us a glimpse of a decolonised, just and sustainable future.

Stefan Kaufman recommends The Precipice: Exisiential Risk and the Future of Humanity by Toby Ord (2020)

In The Precipice, Toby Ord considers a range of “existential risks” that could, in the next few centuries, curtail the immense potential for long-term human flourishing. It leaves me perversely hopeful about climate change for three reasons.

Firstly, while acknowledging that climate change will cause immense suffering, Ord only identifies a few, relatively unlikely scenarios that leave humanity extinct or “stuck” barely surviving.

Secondly, he considers a range of human-generated and natural risks that are of even greater concern. Many of these risks are exacerbated by the increasing accessibility of powerful technologies once available only to elites, such as bio-engineering and artificial intelligence. These are all risks that we either create or will need to cooperate to mitigate; their occurrence and their level of impact are within our influence.

Thirdly, Ord makes a compelling case that we have many of the institutions, technologies and policy tools necessary to manage long-term existential risks. There is work all of us can do now to help. Climate change can make many other risks worse. Solving it requires solving others at the same time.

The Precipice leaves one with a sense that we will need to be better humans to make it through the next centuries, but a brighter future awaits. If we attain this future, we will deserve to, because we will have married our power and prosperity with civilisational maturity, compassion and wisdom.

Greg Moore recommends Trees and Global Warming: The Role of Forests in Cooling and Warming the Atmosphere by William J Manning (2020)

As climates change and Australia warms, trees are often seen as a panacea, but, as is invariably the case with ecosystems, things can be complicated.

As William J. Manning tells us in Trees and Global Warming, trees can warm as well as cool the atmosphere. The colour of their leaves (light or dark green) influences how much radiation is absorbed, transmitted and reflected, and how much they cool.

Manning is not looking at trees and forests through rose-coloured glasses, but through a strong scientific lens. They come out as winners when it comes to tackling climate change because, cultivated effectively, they can shade and cool, reduce the urban heat-island effect, sequester carbon, and much more.

Trees are an essential, cost-effective and sustainable part of living with climate change. We must protect the trees and forests that we have. Planting more trees is part of a quick and cheap solution, providing more liveable towns and cities across our continent.

The Conversation
The Conversation
Media Science communication The Conversation

The Conversation: ‘The sad reality is many don’t survive’ – how floods affect wildlife, and how you can help them

A koala joey was found drenched and trembling near the edge of the Brisbane River. It was one of the lucky animals to be rescued from the severe floodwaters. Image credit: WWF Australia

By Euan Ritchie (Deakin University) and Chris J Jolly (Macquarie University).

This article is republished from The Conversation under a Creative Commons license. Read the original article.

For over two decades, bull sharks have called a Brisbane golf course home after, it’s believed, a flood washed them into the course’s lake in 1996. Now, after severe floods connected their landlocked home back to the river system, these sharks have gone missing, perhaps attempting to seek larger water bodies.

This bizarre tale is one of many accounts illustrating how Australia’s wildlife respond to flooding. But the sad reality is many don’t survive. Those that do may find their homes destroyed or, like those bull sharks and others, find themselves displaced far from their original homes or suitable habitat.

The RSPCA and other wildlife care organisations have received hundreds of calls to help rescue and care for stranded animals. But the true toll on wildlife will remain unknown, in part because we know surprisingly little about the impacts of floods on wildlife.

Still, as many animals have amazing abilities to survive fire, so too do many possess the means to survive or even profit from floods. After all, Australia’s wildlife has evolved over millions of years to survive in this land of extremes.

How wildlife responds to floods

Floods rapidly turn land habitats into underwater habitats, allowing aquatic animals to venture into places you wouldn’t expect. Flooding during northern Australia’s annual wet season, for example, sees crocodiles occasionally turn up in people’s backyard pools.

Land-dwelling animals typically don’t fare as well in floods. Some may be able to detect imminent inundation and head for higher, drier ground. Others simply don’t have the ability or opportunity to take evasive action in time. This can include animals with dependent young in burrows, such as wombats, platypus and echidnas.

The extent to which flooding affects animals will depend on their ability to sense what’s coming and how they’re able to respond. Unlike humans who must learn to swim, most animals are born with the ability.

Echidnas, for example, have been known to cover large areas of open water, but fast flowing, powerful floods pose a very different proposition.

Animals that can fly – such as many insects, bats and birds – may be able to escape. But their success will also partly depend on the scale and severity of weather systems causing floods.

Many birds, for example, couldn’t get away from the heavy rain and seek shelter, ending up waterlogged. If birds are exhausted and can’t fly, they may suffer from exposure and also be more vulnerable to predators, such as feral cats and foxes.

During floods, age old predator-prey relationships, forged through evolution, can break down. Animals are more focused on self preservation, rather than their next meal. This can result in strange, ceasefire congregations.

For example, a venomous eastern brown snake was filmed being an unintentional life raft for frogs and mice. Likewise, many snakes, lizards and frogs are expert climbers, and will seek safety in trees – with or without company.

Some spiders have ingenious ways of finding safety, including spinning balloon-like webs to initiate wind-driven lift-off: destination dry land. This is what happened when Victoria’s Gippsland region flooded last year.

One of the challenges of extreme events is it can make food hard to find. Some animals – including microbats, pygmy possums, and many reptiles – may reduce their energy requirements by essentially going to “sleep” for extended periods, commonly referred to as torpor. This includes echidnas and Antechinus (insect-eating marsupials), in response to bushfire.

Might they do the same during floods? We really don’t know, and it largely depends on an animal’s physiology. In general, invertebrates, frogs, fish and reptiles are far better at dealing with reduced access to food than birds and mammals.

During floods species will share refuge such as trees. Damian Kelly Photography

What happens when floods recede?

Flooding may provide a bounty for some species. Some predators such as cats, foxes, and birds of prey, may have access to exhausted prey with fewer places to hide. These same predators may scavenge the windfall of dead animals.

Fish, waterbirds, turtles and other aquatic or semi-aquatic life may benefit from an influx of nutrients, increasing foraging opportunities and even stimulating breeding events.

Other wildlife may face harsher realities. Some may become trapped far from their homes. Those that attempt to return home will have to run the gauntlet of different habitats, roads, cats, dogs and foxes, and other threats.

Even if they make it home, will their habitats be the same or destroyed? Fast and large volumes of water can destroy vegetation and other habitat structures (soils, rock piles) in minutes, but they may take many years or decades to return, if ever.

Floodwaters can also carry extremely high levels of pollution, leading to further tragic events such as fish kills and the poisoning of animals throughout food chains.

How can you help?

Seeing wildlife in distress is confronting, and many of us may feel compelled to want to rescue animals in floodwaters. However, great caution is required.

Wading into floodwaters can put yourself at significant risk. Currents can be swift. Water can carry submerged and dangerous obstacles, as well as chemicals, sewage and pathogens. And distressed animals may panic when approached, putting them and yourself at further risk.

For example, adult male eastern grey kangaroos regularly exceed 70 kilograms with long, razor sharp claws and toe nails, and powerful arms and legs. They’ve been known to deftly use these tools to drown hostile farm dogs in dams and other water bodies.

So unless you’re a trained wildlife expert or animal carer, we don’t recommend you try to save animals yourself. There is more advice online, such as here and here.

If you’d like to support the care and recovery of wildlife following the floods, a number of organisations are taking donations, including WWF Australia, WIRES and the RSPCA.

What does the future hold?

While many Australian wildlife species are well adapted to dealing with periodic natural disasters, including floods, we and wildlife will face even more intense events in the future under climate change. Cutting greenhouse gas emissions can lessen this impact.

For common, widespread species such as kangaroos, the loss of individuals to infrequent, albeit severe, events is tragic but overall doesn’t pose a great problem. But if floods, fires and other extreme events become more regular, we could see some populations or species at increased risk of local or even total extinction.

This highlights how Earth’s two existential crises – climate change and biodiversity loss – are inextricably linked. We must combat them swiftly and substantially, together, if we’re to avoid a bleak future.

The Conversation