The Black Summer bushfires were devastating for wildlife, with an estimated three billion wild animals killed, injured or displaced. This staggering figure does not include the tens of thousands of farm animals who also perished.
The bushfire royal commission’s final report, released on October 30, recognised the gravity of the fires’ extraordinary toll on animals.
It recommended governments improve wildlife rescue arrangements, develop better systems for understanding biodiversity and clarify evacuation options for domestic animals.
While these changes are welcome and necessary, they’re not sufficient. Minimising such catastrophic impacts on wildlife and livestock also means reducing their exposure to these hazards in the first place. And unless we develop more proactive strategies to protect threatened species from disasters, they’ll only become more imperilled.
The royal commission recognised the need for wildlife rescuers to have swift and safe access to fire grounds.
In the immediate aftermath of the bushfires, some emergency services personnel were confused about the roles and responsibilities of wildlife rescuers. This caused delays in rescue operations.
To address this issue, the royal commission sensibly suggested all state and territory governments integrate wildlife rescue functions into their general disaster planning frameworks. This would improve coordination between different response agencies.
Another issue raised by the commission was that Australia does not have a comprehensive, central source of information about its native flora and fauna. This is, in part, because species listing processes are fragmented across different jurisdictions.
To better manage and protect wild animals, governments need more complete information on, for example, their range and population, and how climate change threatens them.
As a result, the royal commission recommended governments collect and share more accurate information so disaster response and recovery efforts for wildlife could be more targeted, timely and effective.
While promising, the measures listed in the royal commission’s final report will only tweak a management system for wildlife already under stress. Current legal frameworks for protecting threatened species are reactive. By the time governments intervene, species have often already reached a turning point.
Governments must act to allow wild animals the best possible chances of escaping and recovering on their own.
This means prioritising the protection and restoration of habitat that allows animals to get to safety. As a World Wildlife Fund report explains, an animal’s ability to flee the fires and find safe, unburnt habitat — such as mesic (moist) refuges in gullies or near waterways — directly influenced their chances of survival.
Wildlife corridors also assist wild animals to survive and recover from disasters. These connect areas of habitat, providing fast moving species with safe routes along which they can flee from hazards.
Hazard reduction activities, such as removing dry vegetation that fuels fires, were also a focus for the royal commission. These can coexist with habitat conservation when undertaken in ecologically-sensitive ways.
As the commission recognised, Indigenous land and fire management practices are informed by intimate knowledge of plants, animals and landscapes. These practices should be integrated into habitat protection policies in consultation with First Nations land managers.
The commission also suggested natural hazards, such as fire, be counted as a “key threatening process” under national environment law. But it should be further amended to protect vulnerable species under threat from future stressors, such as disasters.
Governments also need to provide more funding to monitor compliance with this law. Another new World Wildlife Fund report warns that unless it is properly enforced, a further 37 million native animals could be displaced or killed as a result of habitat destruction this decade.
And, as we saw last summer, single bushfire events can push some populations much closer to extinction. For example, the fires destroyed a large portion of the already endangered glossy black-cockatoo’s remaining habitat.
Pets and farm animals featured in the commission’s recommendations too.
During the bushfires, certain evacuation centres didn’t cater for these animals. This meant some evacuees chose not to use these facilities because they couldn’t take their animals with them.
To guide the community in future disasters, the commission said plans should clearly identify whether or not evacuation centres can accommodate people with animals.
Evacuation planning is crucial to effective disaster response. However, it is unfortunately not always feasible to move large groups of livestock off properties at short notice.
For this reason, governments should help landholders to mitigate the risks hazards pose to their herds and flocks. Researchers are already starting to do this by investigating the parts of properties that were burnt during the bushfires. This will help farmers identify the safest paddocks for their animals in future fire seasons.
Disasters are only expected to become more intense and extreme as the climate changes. And if we’re to give our pets, livestock and unique wildlife the best chance at surviving, it’s not enough only to have sound disaster response. Governments must preemptively address the underlying sources of animals’ vulnerability to hazards.
How we plan for animals in emergencies
Ashleigh Best, PhD Candidate and Teaching Fellow, University of Melbourne; Christine Parker, Professor of Law, University of Melbourne, and Lee Godden, Director, Centre for Resources, Energy and Environmental Law, Melbourne Law School, University of Melbourne
Kaya Klop-Toker, University of Newcastle; Alex Callen, University of Newcastle; Andrea Griffin, University of Newcastle; Matt Hayward, University of Newcastle, and Robert Scanlon, University of Newcastle
On an island off the Queensland coast, a battle is brewing over the fate of a small population of goats.
The battle positions the views of some conservation scientists and managers who believe native species must be protected from this invasive fauna, against those of community members who want to protect the goat herd to which they feel emotionally connected. Similar battles colour the management decisions around brumbies in Kosciuszko National Park and cats all over Australia.
These debates show the impact of a new movement called “compassionate conservation”. This movement aims to increase levels of compassion and empathy in the management process, finding conservation solutions that minimise harm to wildlife. Among their ideas, compassionate conservationists argue no animal should be killed in the name of conservation.
But preventing extinctions and protecting biodiversity is unlikely when emotion, rather than evidence, influence decisions. As our recent paper argues, the human experience of compassion and empathy is fraught with inherent biases. This makes these emotions a poor compass for deciding what conservation action is right or wrong.
We are facing a biological crisis unparalleled in human history, with at least 25% of the world’s assessed species at risk of extinction. These trends are particularly bad in Australia, where we have one of the world’s worst extinction records and the world’s highest rate of mammal extinctions.
The federal government recently announced it will commit to a new ten-year threatened species strategy, focused on eradicating feral pests such as foxes and cats.
When you first think about it, this idea sounds great. Why kill some animals to save others?
Well, invasive animals — those either intentionally or accidentally moved to a new location — are one of the biggest threats to global biodiversity.
Fortunately, endangered populations can recover when these pests are removed. Controlling pest numbers is one of the most effective tools available to conservationists.
Killing pests is at stark odds with the “do no harm” values promoted by the compassionate conservation movement.
Compassionate conservationists argue it’s morally wrong to kill animals for management, whereas conservation scientists argue it’s morally wrong to allow species to go extinct — especially if human actions (such as the movement of species to new locations) threaten extinction.
These conflicting moral standpoints result in an emotional debate about when it is justified to kill or let be killed. This argument centres on emotion and moral beliefs. There is no clear right or wrong answer and, therefore, no resolution.
In an attempt to break this emotional stalemate, we explored the biases inherent in the emotions of compassion and empathy, and questioned if increased empathy and compassion are really what conservation needs.
At first, compassion and empathy may appear vital to conservation, and on an individual level, they probably are. People choose to work in conservation because they care for wild species. But compassion and empathy come with strong evolutionary biases.
The first bias is that people feel more empathy toward the familiar — people care more for things they relate most closely to. The second bias is failure to scale-up — we don’t feel 100 times more sorrow when hearing about 100 people dying, compared to a single person (or species).
Evolution has shaped our emotions to peak for things we relate most strongly to, and to taper off when numbers get high — most likely to protect us from becoming emotionally overloaded.
Let’s put these emotions in the context of animal management. Decisions based on empathy and compassion will undoubtedly favour charismatic, relatable species over thousands of less-familiar small, imperilled creatures.
This bias is evident in the battle over feral horses in national parks. There is public backlash over the culling of brumbies, yet there is no such response to the removal of feral pigs, despite both species having similarly negative impacts on protected habitats.
If compassionate conservation is adopted, culling invasive species would cease, leading to the rapid extinction of more vulnerable native species. A contentious example is the race to save the endangered Tristan albatross from introduced mice on Gough Island in the south Atlantic.
Sealers introduced mice in the 1800s, and the mice have adapted to feed on albatross chicks, killing an estimated two million birds per year. Under compassionate conservation, lethal control of the mice would not be allowed, and the albatross would be added to the extinction list within 20 years.
What’s more, compassionate conservation advocates for a more hands-off approach to remove any harm or stress to animals. This means even the management of threatened fauna would be restricted.
Under this idea, almost all current major conservation actions would not be allowed because of temporary stress placed on individual animals. This includes translocations (moving species to safer habitat), captive breeding, zoos, radio tracking and conservation fencing.
With 15% of the world’s threatened species protected in zoos and undergoing captive breeding, a world with compassionate conservation would be one with far fewer species, and we argue, much less conservation and compassion.
In this time of biodiversity crisis and potential ecosystem collapse, we cannot afford to let emotion bias our rationale. Yes, compassion and empathy should drive people to call for more action from their leaders to protect biodiversity. But what action needs to be taken should be left to science and not our emotions.
Kaya Klop-Toker, Conservation Biology Researcher, University of Newcastle; Alex Callen, Post-doctoral researcher, University of Newcastle; Andrea Griffin, Senior Lecturer, School of Psychology, University of Newcastle; Matt Hayward, Associate professor, University of Newcastle, and Robert Scanlon, PhD Candidate in Restoration Ecology, University of Newcastle
Bushfires this season have left an estimated 1 billion dead animals in their wake, their carcasses dotting the blackened landscape.
The carcasses have already been flagged as a potential biosecurity threat, and the Australian Defence Force is tasked with collecting and burying the dead in mass graves.
There’s logic in this. Carcasses can harbour nasty diseases such as botulism that threaten human, livestock and wildlife health. They also provide food for invasive pests like feral cats and red foxes.
But carcasses can play a positive role as landscapes recover from fire, providing rich nutrients for other native animal, microbial and plant species.
The Morrison Government has announced a A$50 million package to help wildlife and habitat recover from the fires, and yesterday met leading wildlife experts and environment groups to get advice on the recovery process.
We suggest this process should examine carcass disposal methods other than burial, such as composting – effectively “recycling” the dead. It should also involve monitoring the carcasses that remain to understand both their positive and negative roles in fire-ravaged areas.
Carcasses feed a range of native animals, including goannas, wedge-tailed eagles and dingoes. Post-fire, they can provide an alternative source of food for struggling native predators and pollinators. And feeding hungry predators with carcasses could redirect them away from vulnerable prey.
Carcasses also feed insects such as flies, ants, beetles, and their larvae, and support important ecological processes such as pollination.
As they decompose, nutrients leach from carcasses into the surrounding environment and create “halos” of greenery in the landscape, where vegetation thrives around carcass sites. Their influence on soil and plant communities can last for years.
Carcasses are home to bacteria that help break down animal tissues. But some carcasses also harbour harmful pathogens that bring disease.
For a disease outbreak to happen, the animal must generally have already been carrying dangerous infectious agents, like Anthrax or the Hendra virus, before they died. And many of these pathogens will not survive long on dead hosts.
Leaving carcasses out in the open can also feed introduced predators such as feral cats and red foxes, putting small native animals at risk. Some weeds thrive in the nutrient-rich soils around carcasses too.
Introduced insects like the European wasp, which appeared en masse following fires in Kosciuszko National Park, also take advantage of carcass resources. These wasps are highly aggressive and attack and kill other native insects.
We know very little about the ecological role of carcasses in fire-affected areas, and it’s important that more research is carried out.
We know burnt animals can decompose faster than other carcasses and harbour different types of insect scavengers.
However the recent fires are likely to have wiped out entire scavenger communities, including larger scavengers like dingoes and eagles, that help to clean our landscapes of dead animals.
The effects of this are unknown, but could mean that carcasses stick around in the environment for prolonged periods, even months.
As climate change accelerates the number of natural disasters and mass animal deaths, more thought and planning must be put into carcass management.
In Australia, carcasses are often dealt with by not dealing with them: they’re left to rot. This happened for almost 100 feral horses that died last year at an empty water hole during a heatwave.
Animals culled in national parks and on farmlands are also often left to decay, untouched, as are the many dead animals that commonly line our country roads. But in landscapes where feral species are common, or where livestock or people are likely to encounter carcasses, leaving them alone isn’t the best option.
Carcasses are more often buried following disease outbreaks or when livestock die. We saw this during the 2019 Queensland floods, where thousands of drowned cattle were buried in mass graves.
Burial is a relatively inexpensive, fast and effective method of dealing with the dead. But it must be done carefully to avoid polluting groundwater sources and causing nutrients like nitrogen to build up.
Burying carcasses can also be compared to sending rubbish to the tip. Breakdown will be slow, and no useful end product is created.
An alternative option is to “recycle” carcasses by composting them. Composting can accelerate the decomposition of animal tissues and is environmentally friendly, capturing nutrients.
Composting kills most pathogens, whereas burial just moves the problem underground. It also suppresses smelly odours and doesn’t attract scavengers. The usable organic material resulting from the composting can also be applied to nutrient-poor soil.
Composting can be time-consuming and hard to get right. It requires careful monitoring of temperature and moisture content to ensure all disease-causing pathogens are killed, and odours are suppressed.
There’s also a “yuck” factor and the public would probably need convincing for the method to be widely adopted.
But whatever option we choose, it’s clear there’s more we can do with carcasses than simply burying them.
Emma Spencer, Ph.D. student, University of Sydney; Chris Dickman, Professor in Terrestrial Ecology, University of Sydney; Philip Barton, Honorary Senior Lecturer, Fenner School of Environment and Society, Australian National University, and Thomas Newsome, Lecturer, University of Sydney
One of the many difficulties faced by the pioneers of Australia’s sheep industry was finding a reliable shepherd. Among the convict labour available, for every two experienced farm labourers there were five convicted sheep, horse, cattle or poultry thieves.
The conditions were demanding. Convicts returning from pasture with fewer sheep than they left with faced a penalty of up to 100 lashes – close to a death sentence. Going bush was the only option for those unwilling to submit to the punishment back “inside”, as the settlements were called. Sheep were lost through negligence and misadventure, others to hungry dingoes.
Eradicating dingoes therefore had a double benefit for the graziers: they would reduce stock losses, and eliminate the need for (unreliable) convict labour.
Reverend Samuel Marsden announced the first plan for the destruction of the native dog in Sydney Town, 1811. On offer was a generous bounty of one gallon of spirits for each complete skin of a fully grown native dog.
(Incidentally, Marsden went on to introduce sheep to New Zealand, followed by the mysterious disappearance of the Maori kuri dog in following decades.)
Three years later, the first instance of using poison to eradicate the dingo was recorded in the Sydney Gazette. A “gentleman farmer” with extensive stock in the Nepean District initiated the operation. By applying arsenic to the body of a dead ox on his property, he managed to eradicate all the wild dogs from his landholding. The technique gathered a quiet following, though there were concerns that in the wrong hands this venture could inadvertently backfire on the penal colony.
In 1818 French scientist Pierre Joseph Pelletier successfully extracted beautiful but sinister crystals from the plant nux vomica. This discovery revolutionised toxicology: it enabled mass production of a highly toxic, stable and cheap poison known as strychnine.
The crystals were soon to be exported en masse around the world. Strychinine became an essential item in the Australian farmer’s toolkit, and by 1852 its use on landholdings was mandatory to control unwanted wildlife. In 1871 author Anthony Trollope wrote in his observations of Australian life:
On many large runs, carts are continually being taken round with (strychnine) baits to be set on the paths of the dingo. In smaller establishments the squatter or his head-man goes about with strychnine in his pocket and lumps of meat tied up in a handkerchief.
Over the course of the 19th century, the Australian economy became irreversibly dependent on this industrial agrochemical farming system.
The pace of Australia’s agricultural revolution was rapid; between 1822, when fine wool became NSW’s major export product, and 1850, the national flock numbers increased from 120,000 to 16 million. By 1892 the Australian sheep flock numbered 106 million.
A central Australian dingo extermination campaign was launched in 1897, to eradicate dingo and rabbit populations from South Australia’s arid zone. Described as the “Party of Poisoners”, the team travelled from Gawler Range to Wilpena Pound, covering an area 1,000km long by 480km wide. It took five months.
The poisoners dispensed phosphorised pollard and strychnine sticks and laid poisoned grain in lightly covered furrows. Meat baits were placed around the bases of the red and white mallee bush. Billabongs were poisoned. All species that might have competed for the scarce resources were effectively eliminated – carnivore and herbivore. Farming ultimately failed in the region. The natural biodiversity never recovered.
The legacy of Australia’s chemical-dependent farming over the past 200 years remains largely unacknowledged in conversations about the current biodiversity crisis. Australia has around 500 threatened animal species, and our rate of mammalian extinctions is unparalleled anywhere in the world. The main drivers of the crisis are attributed to introduced species, changed fire regimes, and land clearing.
In the history of agricultural expansion, it was the dingo that was the initial target of eradication campaigns. Land clearing worked in concert with the broad scale application of vertebrate pesticides. The expansion in the application, range, methods of delivery and quantity of poison and poisoned baits applied was rapid, using increasingly sophisticated machinery.
The effects reverberated throughout Australia’s ecosystems: the removal of the dingo, the top order predator, lead to the explosion of herbivore populations, more poisons, the establishment of introduced species and destabilising of the native ecosystem.
In the 1870s newspapers were reporting on the impact of herbivore populations including the introduced rabbit. The South Australian Advertiser, wrote in 1877:
We have destroyed the balance of nature in two ways simultaneously, by destroying the carnivore and introducing a new herbivorous animal of immense reproductive powers.
In the 21st century, more vertebrate poisons are dispensed by air in National Parks, than on private land – in efforts to protect biodiversity from invasive species.
My research examines how poison has been normalised in land management. The use of vertebrate pesticides has been supported by services and systems embedded within Australia’s social, political and legal framework for 200 years.
Applying more vertebrate pesticides to the environment to try and solve the problem, is arguably an extreme case of mistaking the poison for the cure.
Giant eucalypts play an irreplaceable part in many of Australia’s ecosystems. These towering elders develop hollows, which make them nature’s high-rises, housing everything from endangered squirrel-gliders to lace monitors. Over 300 species of vertebrates in Australia depend on hollows in large old trees.
These “skyscraper trees” can take more than 190 years to grow big enough to play this nesting and denning role, yet developers are cutting them down at an astounding speed. In other places, such as Victoria’s Central Highlands Mountain Ash forests, the history of logging and fire mean that less than 1.2% of the original old-growth forest remains (that supports the highest density of large old hollow trees). And it’s not much better in other parts of our country.
David Lindenmayer explains how these trees form, the role they play – and how very hard they are to replace.
Have you ever got on a flight and the person next to you started sneezing? With 37 million scheduled flights transporting people around the world each year, you might think that the viruses and other germs carried by travellers would be getting a free ride to new pastures, infecting people as they go.
Yet pathogenic microbes are surprisingly bad at expanding their range by hitching rides on planes. Microbes find it difficult to thrive when taken out of their ecological comfort zone; Bali might just be a tad too hot for a Tasmanian parasite to handle.
But humans aren’t the only species to go global with their parasites. Billions of animals have been flying, swimming and running around the globe every year on their seasonal migrations, long before the age of the aeroplane. The question is, are they picking up new pathogens on their journeys? And if they are, are they transporting them across the world?
With the rate of zoonotic diseases (pathogens that jump from animals to humans) on the rise, migratory animals have been under increasing suspicion of aiding the spread of devastating diseases such as bird flu, Lyme disease, and even Ebola.
These suspicions are bad for migrating animals, because they are often killed in large numbers when considered a disease threat. They are also bad for humans, because blaming animals may obscure other important factors in disease spread, such as animal trade. So what’s going on?
Despite the logical link between animal migration and the spread of their pathogens, there is in fact surprisingly little direct evidence that migrants frequently spread pathogens long distances.
This is because migratory animals are notoriously hard for scientists to track. Their movements make them difficult to test for infections over the vast areas that they occupy.
But other theories exist that explain the lack of direct evidence for migrants spreading pathogens. One is that, unlike humans who just have to jump on a plane, migratory animals must work exceptionally hard to travel. Flying from Australia to Siberia is no easy feat for a tiny migratory bird, nor is swimming between the poles for giant whales. Human athletes are less likely to finish a race if battling infections, and likewise, migrant animals may have to be at the peak of health if they are to survive such gruelling journeys. Sick travellers may succumb to infection before they, or their parasitic hitchhikers, reach their final destination.
Put simply, if a sick animal can’t migrate, then neither can its parasites.
On the other hand, migrants have been doing this for millennia. It is possible they have adapted to such challenges, keeping pace in the evolutionary arms race against pathogens and able to migrate even while infected. In this case, pathogens may be more successful at spreading around the world on the backs of their hosts. But which theory does the evidence support?
To try and get to the bottom of this question, we identified as many studies testing this hypothesis as we could, extracted their data, and combined them to look for any overarching patterns.
We found that infected migrants across species definitely felt the cost of being sick: they tended to be in poorer condition, didn’t travel as far, migrated later, and had lower chances of survival. However, infection affected these traits differently. Movement was hit hardest by infection, but survival was only weakly impacted. Infected migrants may not die as they migrate, but perhaps they restrict long-distance movements to save energy.
So pathogens seem to pose some costs on their migratory hosts, which would reduce the chances of migrants spreading pathogens, but perhaps not enough of a cost to eliminate the risk completely.
But an important piece of the puzzle is still missing. In humans, travelling increases our risk of getting ill because we come into contact with new germs that our immune system has never encountered before. Are migrants also more susceptible to unfamiliar microbes as they travel to new locations, or have they adapted to this as well?
To investigate the susceptibility of migrants, we went in a different direction and decided to look at the gut bacteria of migratory shorebirds – grey, unassuming birds that forage on beaches or near water, and that undergo some of the longest and fastest migrations in the animal kingdom.
Most animals have hundreds of bacterial species living in their guts, which help break down nutrients and fight off potential pathogens. Every new microbe you ingest can only colonise your gut if the environmental conditions are to its liking, and competition with current residents isn’t too high. In some cases, it may thrive so much it becomes an infection.
We found the migratory shorebirds we studied were exceptionally good at resisting invasion from ingested microbes, even after flying thousands of kilometres and putting their gut under extreme physiological strain. Birds that had just returned from migration (during which they stopped in many places in China, Japan, and South East Asia), didn’t carry any more species of bacteria than those that had stayed around the same location for a year.
Although these results need to be tested in other migratory species, our research suggests that, like human air traffic, pathogens might not get such an easy ride on their migratory hosts as we might assume. There is no doubt that migrants are involved in pathogen dispersal to some degree, but there is increasing evidence that we shouldn’t jump the gun when it comes to blaming migrants.
Alice Risely, PhD candidate in Ecology, Deakin University; Bethany J Hoye, Lecturer in Animal Ecology, University of Wollongong, and Marcel Klaassen, Alfred Deakin Professor and Chair in Ecology, Deakin University
Throughout history, humans have taken plants and animals with them as they travelled the world. Those that survived the journey to establish populations in the diaspora have found new opportunities as they integrate into new ecosystems.
These immigrant populations have come to be regarded as “invaders” and “aliens” that threaten pristine nature. But for many species, migration may just be a way to survive the global extinction crisis.
In our recently published study, we found that one of the Earth’s most imperilled group of species is hanging on in part thanks to introduced populations.
Megafauna – plant-eating terrestrial mammals weighing more than 100kg – have established in new and unexpected places. These “feral” populations are rewilding the world with unique and fascinating ecological functions that had been lost for thousands of years.
In New Zealand, a mere 800 years ago, a riot of giant flightless birds still grazed and browsed the landscape.
The loss of Earth’s largest terrestrial animals at the end of the Pleistocene was most likely caused by humans.
Sadly, even those large beasts that survived that collapse are now being lost, with 60% of today’s megafauna threatened with extinction. This threat is leading to international calls for urgent intervention to save the last of Earth’s giants.
Formal conservation distribution maps show that much of Earth is empty of megafauna. But this is only a part of the picture.
Many megafauna are now found outside their historic native ranges. In fact, thanks to introduced populations, regional megafauna species richness is substantially higher today than at any other time during the past 10,000 years.
Worldwide introductions have increased the number of megafauna by 11% in Africa and Asia, by 33% in Europe, by 57% in North America, by 62% in South America, and by 100% in Australia.
Australia lost all of its native megafauna tens of thousands of years ago, but today has eight introduced megafauna species, including the world’s only wild population of dromedary camels.
These immigrant megafauna have found critical sanctuary. Overall, 64% of introduced megafauna species are either threatened, extinct, or declining in their native ranges.
Some megafauna have survived thanks to domestication and subsequent “feralisation”, forming a bridge between the wild pre-agricultural landscapes of the early Holocene almost 10,000 years ago, to the wild post-industrial ecosystems of the Anthropocene today.
Wild cattle, for example, are descendants of the extinct aurochs. Meanwhile, the wild camels of Australia have brought back a species extinct in the wild for thousands of years. Likewise, the vast majority of the world’s wild horses and wild donkeys are feral.
There have been global calls to rewild the world, but rewilding has already been happening, often with little intention and in unexpected ways.
A small population of wild hippopotamuses has recently established in South America. The nicknamed “cocaine hippos” are the offspring of animals who escaped the abandoned hacienda of Colombian drug lord Pablo Escobar.
By insisting that only idealised pre-human ecosystems are worth conserving, we overlook the fact that these emerging new forms of wilderness are not only common but critical to the survival of many existing ecosystems.
Megafauna are Earth’s tree-breakers, wood-eaters, hole-diggers, trailblazers, wallowers, nutrient-movers, and seed-carriers. By consuming coarse, fibrous plant matter they drive nutrient cycles that enrich soils, restructure plant communities, and help other species to survive.
The wide wanderings of megafauna move nutrients uphill that would otherwise wash downstream and into the oceans. These animals can be thought of as “nutrient pumps” that help maintain soil fertility. Megafauna also sustain communities of scavengers and predators.
In North America, we have found that introduced wild donkeys, locally known as “burros”, dig wells more than a metre deep to reach groundwater. At least 31 species use these wells, and in certain conditions they become nurseries for germinating trees.
The removal of donkeys and other introduced megafauna to protect desert springs in North America and Australia seems to have led to an exuberant growth of wetland vegetation that constricted open water habitat, dried some springs, and ultimately resulted in the extinction of native fish. Ironically, land managers now simulate megafauna by manually removing vegetation.
It is likely that introduced megafauna are doing much more that remains unknown because we have yet to accept these organisms as having ecological value.
Like any other species, the presence of megafauna benefits some species while challenging others. Introduced megafauna can put huge pressure on plant communities, but this is also true of native megafauna.
Whether we consider the ecological roles of introduced species like burros and brumbies as desirable or not depends primarily on our own values. But one thing is certain: no species operates in isolation.
Although megafauna are very large, predators can have significant influence on them. In Australia, dingo packs act cooperatively to hunt wild donkeys, wild horses, wild water buffalo and wild boar. In North America, mountain lions have been shown to limit populations of wild horses in some areas of Nevada.
Visions of protected dingoes hunting introduced donkeys and Sambar deer in Australia, or protected wolves hunting introduced Oryx and horses in the American West, can give us a new perspective on conserving both native and introduced species.
Nature doesn’t stand still. Dispensing with visions of historic wilderness, and the associated brutal measures usually applied to enforce those ideals, and focusing on the wilderness that exists is both pragmatic and optimistic.
After all, in this age of mass extinction, are not all species worth conserving?
This research will be presented at the 2017 International Compassionate Conservation Conference in Sydney.
Erick Lundgren, PhD Student, Centre for Compassionate Conservation, University of Technology Sydney; Arian Wallach, Chancellor’s Postdoctoral Research Fellow, Centre for Compassionate Conservation, University of Technology Sydney; Daniel Ramp, Associate Professor and Director, Centre for Compassionate Conservation, University of Technology Sydney, and William Ripple, Distinguished Professor and Director, Trophic Cascades Program, Oregon State University