The Black Summer bushfires of 2019–2020 that razed more than half of the landscape on Kangaroo Island in South Australia left an indelible mark on the island’s unique native biodiversity, which is still struggling to recover.
Flinders Chase National Park on Kangaroo Island after the 2019-2020 Black Summer fires (credit: CJA Bradshaw)
However, one big bonus for the environment’s recovery is the likely eradication of feral pigs (Sus scrofa). Invasive feral pigs cause a wide range of environmental, economic and social damages. In Australia, feral pigs occupy about 40% of the mainland and offshore islands, with a total, yet highly uncertain, population size estimated in the millions.
Feral pigs are recognised as a key threatening process under the Environment Protection and Biodiversity Conservation Act 1999, with impacts on at least 148 nationally threatened species and eight threatened ecological communities. They are a declared invasive species and the subject to control programs in all Australian jurisdictions.
Motion sensing cameras deployed during the eradication program capture feral pigs using their snouts to search for soil-borne food. This behaviour, called rooting, creates large areas of disturbed soil, killing native vegetation and spreading invasive weeds and pathogens (credit: PIRSA).
Human overpopulation is often depicted in the media in one of two ways: as either a catastrophic disaster or an overly-exaggerated concern. Yet the data understood by scientists and researchers is clear. So what is the actual state of our overshoot, and, despite our growing numbers, are we already seeing the signs that the sixth mass extinction is underway?
In a recent episode of The Great Simplification podcast, Nate Hagens was joined by global ecologist Corey Bradshaw to discuss his recent research on the rapid decline in biodiversity, how population and demographics will change in the coming decades, and what both of these will mean for complex global economies currently reliant on a stable environment.
Non-native species introduced mainly via increasing trade of goods and services have huge economic, health, and environmental costs. These ‘biological invasions’ involve the intentional or unintentional transport and release of species beyond their native biogeographical ranges, facilitating their potential spread.
However, there is limited information available demonstrating whether a country’s capacity to manage its invasive species is effective at limiting future damage.
Our new study published in the journal Ecological Economics found that while more affluent countries with higher economic activity are vulnerable to more damage from invasive species, they also have the highest potential to limit damages incurred by investing more in management. Consequently, a nation’s economic capability partially determines the efficacy of investing in the control and prevention of invasive species.
A global database set up by scientists to assemble data on the economic cost of biological invasions in support of effective government management strategies has grown to include all known invasive species.
Now involving 145 researchers from 44 countries — the current version of InvaCost has 13,553 entries in 22 languages and enables scientists to develop a clear picture about the major threats globally of invasive species to ecosystems, biodiversity, and human well-being.
Biological invasions are caused by species introduced on purpose or accidentally by humans to areas outside of their natural ranges. From cats and weeds, to crop pests and diseases, invasive species are a worldwide scourge.
Invasive species have cost over US$2 trillion globally since the 1970s by damaging goods and services, and through the costs of managing them, and these economic costs are only increasing.
A new synthesis published in the journal BioSciencedocuments the progress of the InvaCost endeavour.The study provides a timeline of the state of invasion costs, starting with prior flaws and shortcomings in the scientific literature, then how InvaCost has helped to alleviate and address these issues, and what the future potentially holds for research and policymakers.
Thanks to the collaborative and evidence-driven foresight of my colleagues at PIRSA Biosecurity and Landscape Boards, I was recently involved in more research examining the most efficient, cost-effective, and humane ways to cull feral dear in South Australia. The resulting paper is now in review in NeoBiota, but we have also posted a pre-print of the article.
Feral deer are a real problem in Australia, and South Australia is no exception. With six species of feral deer in the country already (fallowDama dama, redCervus elaphus, hogAxis porcinus, chitalA. axis), rusaC. timorensis, and sambarRusa unicolor deer), fallow deer are the most abundant and widespread. These species are responsible for severe damage to native plants, competition with native animals, economic losses to primary industries (crops, pastures, horticulture, plantations), and human safety risks from vehicle collisions. Feral deer are also reservoirs and vectors of endemic animal diseases and have the potential to transmit exotic animal diseases such as foot-and-mouth. If left uncontrolled, within 30 years the economic impacts of feral deer could reach billions of dollars annually.
Following my annual tradition, I present the retrospective list of the ‘top’ 20 influential papers of 2022 as assessed by experts in Faculty Opinions(formerly known as F1000). These are in no particular order. See previous years’ lists here: 2021, 2020, 2019, 2018, 2017, 2016, 2015, 2014, and 2013.
Last week, researchers at the University of Melbourne announced that thylacines or Tasmanian tigers, the Australian marsupial predators extinct since the 1930s, could one day be ushered back to life.
The thylacine (Thylacinus cynocephalus), also known as the ‘Tasmanian tiger’ (it was neither Tasmanian, because it was once common in mainland Australia, nor was it related to the tiger), went extinct in Tasmania in the 1930s from persecution by farmers and habitat loss. Art by Eleanor (Nellie) Pease, University of Queensland. Centre of Excellence for Australian Biodiversity and Heritage
Advances in mapping the genome of the thylacine and its living relative the numbat have made the prospect of re-animating the species seem real. As an ecologist, I would personally relish the opportunity to see a living specimen.
The announcement led to some overhyped headlines about the imminent resurrection of the species. But the idea of “de-extinction” faces a variety of technical, ethical and ecological challenges. Critics (like myself) argue it diverts attention and resources from the urgent and achievable task of preventing still-living species from becoming extinct.
The rebirth of the bucardo
The idea of de-extinction goes back at least to the the creation of the San Diego Frozen Zoo in the early 1970s. This project aimed to freeze blood, DNA, tissue, cells, eggs and sperm from exotic and endangered species in the hope of one day recreating them.
The notion gained broad public attention with the first of the Jurassic Park films in 1993. The famous cloning of Dolly the sheep reported in 1996 created a sense that the necessary know-how wasn’t too far off.
The next technological leap came in 2008, with the cloning of a dead mouse that had been frozen at –20℃ for 16 years. If frozen individuals could be cloned, re-animation of a whole species seemed possible.
After this achievement, de-extinction began to look like a potential way to tackle the modern global extinction crisis.
Following my annual tradition, I present the retrospective list of the ‘top’ 20 influential papers of 2021 as assessed by experts in Faculty Opinions(formerly known as F1000). These are in no particular order. See previous years’ lists here: 2020, 2019, 2018, 2017, 2016, 2015, 2014, and 2013.
Clues to understanding human interactions with global ecosystems already exist. The challenge is to read them more accurately so we can design the best path forward for a world beset by species extinctions and the repercussions of global warming.
This is the puzzle being solved by Professor Corey Bradshaw, head of the Global Ecology Lab at Flinders University. By developing complex computer modelling and steering a vast international cohort of collaborators, he is developing research that can influence environmental policy — from reconstructing the past to revealing insights of the future.
As an ecologist, he aims both to reconstruct and project how ecosystems adapt, how they are maintained, and how they change. Human intervention is pivotal to this understanding, so Professor Bradshaw casts his gaze back to when humans first entered a landscape – and this has helped construct an entirely fresh view of how Aboriginal people first came to Australia, up to 75,000 years ago.
Professor Bradshaw and colleagues identified and tested more than 125 billion possible pathways using rigorous computational analysis in the largest movement-simulation project ever attempted, with the pathways compared to the oldest known archaeological sites as a means of distinguishing the most likely routes.
The study revealed that the first Indigenous people not only survived but thrived in harsh environments, providing further evidence of the capacity and resilience of the ancestors of Indigenous people, and suggests large, well-organised groups were able to navigate tough terrain.
Back in June of this year I wrote (whinged) about the disappointment of writing a lot of ecological models that were rarely used to assist real-world wildlife management. However, I did hint that another model I wrote had assistance one government agency with pig management on Kangaroo Island.
Modelling by the Flinders UniversityGlobal Ecology Laboratory shows the likelihood and feasibility of feral pig eradication under different funding and eradication scenarios. With enough funding, feral pigs could be eradicated from Kangaroo Island in 2 years.
This basically means that because of the model, PIRSA was successful in obtaining enough funding to pretty much ensure that the eradication of feral pigs from Kangaroo Island will be feasible!
Why is this important to get rid of feral pigs? They are a major pest on the Island, causing severe economic and environmental impacts both to farms and native ecosystems. On the agricultural side of things, they prey on newborn lambs, eat crops, and compete with livestock for pasture. Feral pigs damage natural habitats by up-rooting vegetation and fouling waterholes. They can also spread weeds and damage infrastructure, as well as act as hosts of parasites and diseases (e.g., leptospirosis, tuberculosis, foot-and-mouth disease) that pose serious threats to industry, wildlife, and even humans.
South Australian legislation requires that all landholders cull feral deer on their properties. Despite this, feral deer abundance and distribution are increasing across South Australia. This arises because culling by land managers and government organisations is not keeping pace with rates of population growth, and some landholders are harbouring deer for hunting, whereas some deer escape from deer farms.
There are an estimated 40,000 feral deer in South Australia, and state government agencies are working to ramp up programs to cull feral deer before their numbers reach a point where control is no longer feasible.
Planning such large-scale and costly programs requires that government agencies engage economists to measure the economic impacts of feral deer, and to predict the value of these impacts in the future. That modelling is done regularly by governments, and in the case of pest-control programs, the modelling draws on models of feral deer population growth, farmer surveys about the economic, social, and environmental impacts of feral deer, and analyses of culling programs and trials of new culling techniques.
The economic models predict and compare both the current and future costs of:
deer impacts on pastures, crops, native plants, and social values (including illegal hunting)
culling programs that achieve different objectives (e.g., contain vs. reduce vs. eradicate)
The outputs of the models also inform whether there are sufficient public benefits from the investment of public funds into the culling of feral deer.
This PhD project will collate published and unpublished data to refine models of feral deer distribution and abundance under various culling scenarios. This project will drive both high-impact publications and, because this project builds extensive collaborations with government agencies, the results will inform the management of feral deer in South Australia.
You know you’ve made it to the big time in Australia when Behind The News does a story on your research. Practically every kid in Australia watches the show at some point during their school years.
Although this was produced last month, I thought I’d post the entire 4-minute video here for your viewing pleasure.
When you popularise your research story for kids, it really gets the message across well.
Sure, it’s a tough time for everyone, isn’t it? But it’s a lot worse for the already disadvantaged, and it’s only going to go downhill from here. I suppose that most people who read this blog can certainly think of myriad ways they are, in fact, still privileged and very fortunate (I know that I am).
Nonetheless, quite a few of us I suspect are rather ground down by the onslaught of bad news, some of which I’ve been responsible for perpetuating myself. Add lock downs, dwindling job security, and the prospect of dying tragically due to lung infection, many have become exasperated.
What can we do in addition to shifting our focus to making the future a little less shitty than it could otherwise be? I have a few tips that you might find useful:
Shamefully, Australia has one of the highest extinction rates in the world. And the number one threat to our species is invasive or “alien” plants and animals.
But invasive species don’t just cause extinctions and biodiversity loss – they also create a serious economic burden. Our research, published today, reveals invasive species have cost the Australian economy at least A$390 billion in the last 60 years alone.
Our paper – the most detailed assessment of its type ever published in this country – also reveals feral cats are the worst invasive species in terms of total costs, followed by rabbits and fire ants.
Without urgent action, Australia will continue to lose billions of dollars every year on invasive species.
Feral cats are Australia’s costliest invasive species. Source: Adobe Stock/240188862
Huge economic burden
Invasive species are those not native to a particular ecosystem. They are introduced either by accident or on purpose and become pests.
Some costs involve direct damage to agriculture, such as insects or fungi destroying fruit. Other examples include measures to control invasive species like feral cats and cane toads, such as paying field staff and buying fuel, ammunition, traps and poisons.
Our previous research put the global cost of invasive species at A$1.7 trillion. But this is most certainly a gross underestimate because so many data are missing.
As a wealthy nation, Australia has accumulated more reliable cost data than most other regions. These costs have increased exponentially over time – up to sixfold each decade since the 1970s.
Have you ever constructed a database and then published the findings, only to realise that after the time elapsed your database is already obsolete?
This is the reality of scientific information today. There are so many of us doing so many things that information accumulates substantially in months, if not weeks. If you’re a geneticist, this probably happens for many datasets on the order of days.
While our general databasing capacity worldwide has improved enormously over the last decade with the transition to fully online and web-capable interactivity, the world of scientific publication still generally lags behind the tech. But there is a better way to communicate dynamic, evolving database results to the public.
Enter the ‘living figure’, which is a simple-enough concept where a published figure remains dynamic as its underlying database is updated.
As someone who writes a lot of models — many for applied questions in conservation management (e.g., harvest quotas, eradication targets, minimum viable population sizes, etc.), and supervises people writing even more of them, I’ve had many different experiences with their uptake and implementation by management authorities.
Some of those experiences have involved catastrophic failures to influence any management or policy. One particularly painful memory relates to a model we wrote to assist with optimising approaches to eradicate (or at least, reduce the densities of) feral animals in Kakadu National Park. We even wrote the bloody thing in Visual Basic (horrible coding language) so people could run the module in Excel. As far as I’m aware, no one ever used it.
Others have been accepted more readily, such as a shark-harvest model, which (I think, but have no evidence to support) has been used to justify fishing quotas, and one we’ve done recently for the eradication of feral pigs on Kangaroo Island (as yet unpublished) has led directly to increased funding to the agency responsible for the programme.
According to Altmetrics (and the online tool I developed to get paper-level Altmetric information quickly), only 3 of the 16 of what I’d call my most ‘applied modelling’ papers have been cited in policy documents:
I’m pleased to announce the publication of a paper led by Kathryn Venning (KV) that was derived from her Honours work in the lab. Although she’s well into her PhD on an entirely different topic, I’m overjoyed that she persevered and saw this work to publication.
Feral cats occupy every habitat in the country, from the high tropics to the deserts, and from the mountains to the sea. They adapt to the cold just as easily as they adapt to the extreme heat, and they can eat just about anything that moves, from invertebrates to the carcases of much larger animals that they scavenge.
Cats are Australia’s bane, but you can’t help but be at least a little impressed with their resilience.
Still, we have to try our best to get rid of them where we can, or at least reduce their densities to the point where their ecological damage is limited.
Typically, the only efficient and cost-effective way to do that is via lethal control, but by using various means. These can include direct shooting, trapping, aerial poison-baiting, and a new ‘smart’ method of targeted poison delivery via a prototype device known as a Felixer™️. The latter are particularly useful for passive control in areas where ground-shooting access is difficult.
A live Felixer™️ deployed on Kangaroo Island (photo: CJA Bradshaw 2020)
A few years back the federal government committed what might seem like a sizeable amount of money to ‘eradicate’ cats from Australia. Yeah, good luck with that, although the money has been allocated to several places where cat reduction and perhaps even eradication is feasible. Namely, on islands.
They’re one of the most damaging environmental forces on Earth. They’ve colonised pretty much every place humans have set foot on the planet. Yet you might not even know they exist.
We’re talking about alien species. Not little green extraterrestrials, but invasive plants and animals not native to an ecosystem and which become pests. They might be plants from South America, starfish from Africa, insects from Europe or birds from Asia.
These species can threaten the health of plants and animals, including humans. And they cause huge economic harm. Our research, recently published in the journal Nature, puts a figure on that damage. We found that globally, invasive species cost US$1.3 trillion (A$1.7 trillion) in money lost or spent between 1970 and 2017.
The cost is increasing exponentially over time. And troublingly, most of the cost relates to the damage and losses invasive species cause. Meanwhile, far cheaper control and prevention measures are often ignored.
Yellow crazy ants, such as these attacking a gecko, are among thousands of invasive species causing ecological and economic havoc. Dinakarr, CC0, Wikimedia Commons
An expansive toll
Invasive species have been invading foreign territories for centuries. They hail from habitats as diverse as tropical forests, dry savannas, temperate lakes and cold oceans.
They arrived because we brought them — as pets, ornamental plants or as stowaways on our holidays or via commercial trade.
Let’s step back to 2015. In a former life when I was at another institution, I had the immense fortune and pleasure to spend six months on sabbatical in a little village just south of Paris working with my friend and colleague, Franck Courchamp, at Université Paris-Sud (now Université Paris-Saclay).
Sure, I felt a bit jammy living there with my daughter in a beautiful house just down the street from two mouth-watering pâtisseries and three different open marchés. We ate well. We picked mushrooms on the weekends or visited local châteaux. We went into the city and visited overwhelmingly beautiful museums at our leisure. We drank good champagne (well, I did, not my eight-year old). We had communal raclettes.
But of course, I was primarily there to do research with Franck and his lab, despite the obvious perks.
While I busied myself with several tasks while there, one of our main outputs was to put together the world’s first global database of the costs of invasive insects, which we subsequently published in 2016.
But that was only the beginning. With funding that started off the process with insects, Franck persevered and hired postdocs and took on more students to build the most comprehensive database of all invasive species ever compiled — InvaCost.
I cannot stress enough how massive an undertaking this was. It’s not simply a big list of all the cost estimates in existence, it’s also a detailed assessment of cost reliability, standardisation, and contextualisation. I’m not sure I would have had the courage to do this myself.
Herein we described how the economic costs of invasive alien species accumulated since 1970 are tremendous, and that they have been steadily increasing over time.
In some African countries, lion trophy hunting is legal. Riaan van den Berg
In sub-Saharan Africa, almost 1,400,000 km² of land spread across many countries — from Kenya to South Africa — is dedicated to “trophy” (recreational) hunting. This type of hunting can occur on communal, private, and state lands.
The hunters – mainly foreign “tourists” from North America and Europe – target a wide variety of species, including lions, leopards, antelopes, buffalo, elephants, zebras, hippopotamus and giraffes.
Debates centred on the role of recreational hunting in supporting nature conservation and local people’s livelihoods are among the most polarising in conservation today.
On one hand, people argue that recreational hunting generates funding that can support livelihoods and nature conservation. It’s estimated to generate US$200 million annually in sub-Saharan Africa, although others dispute the magnitude of this contribution.
On the other hand, hunting is heavily criticised on ethical and moral grounds and as a potential threat to some species.
Evidence for taking a particular side in the debate is still unfortunately thin. In our recently published research, we reviewed the large body of scientific literature on recreational hunting from around the world, which meant we read and analysed more than 1000 peer-reviewed papers.
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