Trapped in the light

31 03 2025

Night is the peak activity period for many animal species. In the Western Andes of Ecuador, the Chocó golden scarab flies between forest patches during the night, but urban lighting interferes with their paths and jeopardises populations already struggling to persist in fragmented native forests.


Urban development has created a network of illuminated infrastructure that allows our society to function day and night without interruption. It is no surprise that with so much artificial light, we increasingly have to move farther away from towns and cities to see a sky full of stars.

Light pollution poses a challenge for nocturnal species that have adapted to living in the dimness of night (1, 2) — see documentaries about the impacts of artificial light on wildlife and insects, and a related scientific talk. This problem might be one of the causes of the global decline in insects (3, 4), in turn negatively affecting their role in maintaining agricultural systems through pest control, pollination, and soil quality (5). These concepts are featured by the documentaries The Insect Apocalypse and The Great Death of Insects.

Chocó golden scarab (Chrysina argenteola) walking on forest litter in La Maná (Cotopaxi, Ecuador). Growing to up to 4 cm in length, this species inhabits the tropical rainforest of the Chocó region in the Western Andes (10), where it is frequently attracted to artificial lights at night. The striking colour of this ‘jewel scarab’ is an optical illusion. The exoskeleton is covered with overlapping layers of chitin that polarise light and reflect hues of blue, gold, green, silver, or reddish tones, depending on the species (16). The metallic sheen appears to deter bird predation (17) and might serve as camouflage as well as aid in individual recognition (11). The eyes of insects are ‘compound’ — composed of 100s to 1000s of tubular eyelets (‘ommatidia’), each with its own cornea and lens (18), and all collectively contributing to insect vision. In nocturnal species like the golden scarab, the photoreceptor cells (at the base of each ommatidium) respond more slowly to light compared to diurnal species, allowing the former to collect more nocturnal light per unit of time before forming an image (19). However, just as staring at the sun blinds us, eyes adapted for night vision become overwhelmed by excessive artificial light, disrupting the behaviour of these species. Below the scarab image are two photographs contrasting the day and night landscapes of the same location in Pedro Vicente Maldonado (Pichincha, Ecuador) within the species’ distribution range. Photos courtesy of Martín Bustamante (animal) and Luis Camacho (city).

When flying, nocturnal insects orient their backs toward the sky, using the light of the moon and stars as a reference (6) (explained here and here). However, when they encounter artificial lights, they can no longer distinguish up from down, and so they can become disoriented, flying erratically, like a moth circling a streetlight.

It is estimated that a third of the insects attracted to artificial light die from collisions, burn injuries, exhaustion, and/or predation (7). In the tropics, finding countless dead insects at the base of urban lights is a common scene. Equally important is that artificial light also hinders migration, foraging, and the search for mates in many nocturnal species (1, 8, 9).

Nocturnal jewels

Camacho and collaborators evaluated the effect of artificial lighting at night on the Chocó golden scarab (Chrysina argenteola) (10). This species inhabits the tropical rainforests of the Western Andes from Ecuador to Colombia, and is a member of the group known as ‘jewel scarabs‘ due to their metallic body coloration (11). Because of its nocturnal habits and the larvae’s dependence on wood for food (12), the golden scarab has been increasingly affected by the loss of native forest in combination with light pollution from rural and urban expansion.

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The (new) birds and the bees

20 01 2025

‘Nuff said





5000 piggies, 500 piggies, 100 piggies, … and there there was none

4 12 2024

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).

In a new article published in Ecosphere, a collaboration between PIRSA Biosecurity and the Global Ecology Laboratory at Flinders University analysed optimal strategies for culling feral pigs. 

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Human impact, extinctions, and the biodiversity crisis

22 08 2024

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.

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Assessing the massive costs of biological invasions to Australia and the world

6 09 2023

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 BioScience documents 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.  

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Open Letter: Public policy in South Australia regarding dingoes

28 08 2023

08 August 2023

The Honourable Dr Susan Close MP, Deputy Premier and Minister for Climate, Environment and Water, South Australia

The Honourable Claire Scriven MLC, Minister for Primary Industries and Regional Development, South Australia

Dear Ministers,

In light of new genetic research on the identity of ‘wild dogs’ and dingoes across Australia, the undersigned wish to express concern with current South Australia Government policy regarding the management and conservation of dingoes. Advanced DNA research on dingoes has demonstrated that dingo-dog hybridisation is much less common than thought, that most DNA tested dingoes had little domestic dog ancestry and that previous DNA testing incorrectly identified many dingoes as hybrids (Cairns et al. 2023). We have serious concerns about the threat current South Australian public policy poses to the survival of the ‘Big Desert’ dingo population found in Ngarkat Conservation Park and surrounding areas.

We urge the South Australian Government to:

  • Revoke the requirement that all landholders follow minimum baiting standards, including organic producers or those not experiencing stock predation. Specifically
    1. Dingoes in Ngarkat Conservation park (Region 4) should not be destroyed or subjected to ground baiting and trapping every 3 months. The Ngarkat dingo population is a unique and isolated lineage of dingo that is threatened by inbreeding and low genetic diversity. Dingoes are a native species and all native species should be protected inside national parks and conservation areas.
    2. Landholders should not be required to carry out ground baiting on land if there is no livestock predation occurring. Furthermore, landholders should be supported to adopt non-lethal tools and strategies to mitigate the risk of livestock predation including the use of livestock guardian animals, which are generally incompatible with ground and aerial 1080 baiting.
  • Revoke permission for aerial baiting of dingoes (incorrectly called “wild dogs”) in all Natural Resource Management regions – including within national parks. Native animals should be protected in national parks and conservation areas.
  • Cease the use of inappropriate and misleading language to label dingoes as “wild dogs”. Continued use of the term “wild dogs” is not culturally respectful to First Nations peoples and is not evidence-based.
  • Proactively engage with First Nations peoples regarding the management of culturally significant species like dingoes. For example, the Wotjobaluk nation should be included in consultation regarding the management of dingoes in Ngarkat Conservation Park.

Changes in South Australia public policy are justified based on genetic research by Cairns et al. (2023) that overturns previous misconceptions about the genetic status of dingoes. It demonstrates:

  1. Most “wild dogs” DNA tested in arid and remote parts of Australia were dingoes with no evidence of dog ancestry. There is strong evidence that dingo-dog hybridisation is uncommon, with firstcross dingo-dog hybrids and feral dogs rarely being observed in the wild. In Ngarkat Conservation park none of DNA tested animals had evidence of domestic dog ancestry, all were ‘pure’ dingoes.
  2. Previous DNA testing methods misidentified pure dingoes as being mixed. All previous genetic surveys of wild dingo populations used a limited 23-marker DNA test. This is the method currently used by NSW Department of Primary Industries, which DNA tests samples from NSW Local Land Services, National Parks and Wildlife Service, and other state government agencies. Comparisons of DNA testing methods find that the 23-marker DNA test frequently misidentified animals as dingo-dog hybrids. Existing knowledge of dingo ancestry across South Australia, particularly from Ngarkat Conservation park is incorrect; policy needs to be based on updated genetic surveys.
  3. There are multiple dingo populations in Australia. High-density genomic data identified more than four wild dingo populations in Australia. In South Australia there are at least two dingo populations present: West and Big Desert. The West dingo population was observed in northern South Australia, but also extends south of the dingo fence. The Big Desert population extends from Ngarkat Conservation park in South Australia into the Big Desert and Wyperfield region of Victoria.
  4. The Ngarkat Dingo population is threatened by low genetic variability. Preliminary evidence from high density genomic testing of dingoes in Ngarkat Conservation park and extending into western Victoria found evidence of limited genetic variability which is a serious conservation concern. Dingoes in Ngarkat and western Victoria had extremely low genetic variability and no evidence of gene flow with other dingo populations, demonstrating their effective isolation. This evidence suggests that the Ngarkat (and western Victorian) dingo population is threatened by inbreeding and genetic isolation. Continued culling of the Ngarkat dingo population will exacerbate the low genetic variability and threatens the persistence of this population.

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Best and worst countries by different environmental indicators

15 06 2022

I’ll preface this post with a caveat — the data herein are a few years old (certainly pre-COVID), so things have likely changed a bit. Still, I think the main message holds.


Many years ago, I compiled seven different national-level measures of environmental degradation to show that countries with the largest human populations, and hence, the largest economies, had done the most environmental damage — not only to their own resources, but to the world’s in general.

That last observation is important because there are really two main ways to quantify a country’s environmental performance. First, there is its relative environmental damage, which essentially means what proportion of its own resources a country has pilfered or damaged. This type of measure standardises the metrics to account for the different areas of countries (e.g., Russia versus Singapore) and how much of, say, forests, they had to start with, and what proportion of them they have thus far destroyed.

Looking at it this way, small countries with few large-scale industries came out in the lead as the least-damaged environmentally — the least environmentally damaged country according this metric is Cape Verde (followed by Central African Republic, Swaziland, Niger, and Djibouti).

However, another way to look at it is how much of the overall contribution to the world’s environmental damage each country is responsible, which of course implies that the countries with the highest amounts of resources damaged in absolute terms (i.e., the biggest, most populous ones) disproportionately contribute more to global environmental damage.

Using this absolute metric, the countries with the greatest overall damage are Brazil (largely due to the destruction of the Amazon and its other forests), the USA (for its greenhouse-gas emissions and conversion of its prairies to farmland), and China (for its water pollution, deforestation, and carbon emissions). On the flip side, this means that the smallest countries with the fewest people are ranked ‘better’ because of their lower absolute contribution to the world’s total environmental damage.

Looking more closely at how countries do relative to each other using different and more specific measures of environmental performance, the best-known and most-reported metric is the ecological footprint. This measures the ecological ‘assets’ that any particular population of people requires to produce the natural resources it consumes and to absorb its wastes.

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Bane of the bees

19 04 2022

Bees are essential for pollination, but their critical function can be perturbed by pesticides. The detrimental effects of those chemicals accumulate through a bee’s life, and become stronger if females cannot collect pollen from wildflowers.

Our childhood experiences partly determine our health, personality, and lifestyle when we are adults, and our experiences accumulate over time. Accumulation also occurs in any living being and can explain why some populations and species adapt to their environments better than others.

Migratory birds are a clear example. Thousands can travel to their breeding grounds after wintering elsewhere, and those coming from regions laden with resources (e.g., food, shelter, water) will have a greater reproductive success than those that migrated from resource-poor regions (1). In ecology, these ‘carry-over’ effects can take place between seasons, but also across the different phases of the life cycle of a plant or animal (2).

From larvae to adults

Clara Stuligross and Neal Williams have studied the carry-over effect of pesticides on the blue orchard bee Osmia lignaria in California (3). Instead of the typical hives constructed by the honey bee (Apis mellifera), solitary blue orchard bees make lines of brood cells with mud partitions, glued into holes and crevices of branches and trunks from fallen trees (see videos herehere, & here).

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Influential conservation papers of 2021

5 01 2022

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, 201920182017201620152014, and 2013.


Amazonia as a carbon source linked to deforestation and climate change — “… confirms what the sparse forest inventory has suggested, that climate change and land-use change is driving Amazonian ecosystems toward carbon sinks. … the research team provides a robust estimate of the carbon dynamics of one of the world’s most important ecosystems and provides insights into the role of land use change and potentials for mitigating direct carbon losses in the future.

Organic and conservation agriculture promote ecosystem multifunctionality — “… a very clear insight into the trade-offs between the different ecosystem services and indicate that yield and product quality are lower in organic systems compared to conventional systems, yet organic systems have higher economic performance due to higher product prices and subsidies.

Biodiversity of coral reef cryptobiota shuffles but does not decline under the combined stressors of ocean warming and acidification — “… even with similar richness, community function is very likely to be perturbed by ocean warming/acidification with unpredictable impacts on economically important species such as fish and corals.

Local conditions magnify coral loss after marine heatwaves — “… show that climate-induced coral loss is greater in areas with elevated seaweed abundance and elevated sea urchin densities, both of which commonly result from local overfishing … effective local management can synergize with global efforts to mitigate climate change and help coral reefs survive the Anthropocene.

Large ecosystem-scale effects of restoration fail to mitigate impacts of land-use legacies in longleaf pine savannas — “… while restoration can have major benefits in longleaf savannas, land-use legacies have clear effects on many aspects of the ecosystem.

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An eye on the past: a view to the future

29 11 2021

originally published in Brave Minds, Flinders University’s research-news publication (text by David Sly)

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.

Two recent papers he co-authored — ‘Stochastic models support rapid peopling of Late Pleistocene Sahul‘, published in Nature Communications, and ‘Landscape rules predict optimal super-highways for the first peopling of Sahul‘ published in Nature Human Behaviour — showed where, how and when Indigenous Australians first settled in Sahul, which is the combined mega-continent that joined Australia with New Guinea in the Pleistocene era, when sea levels were lower than today.

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.

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And this little piggy went extinct

24 11 2021

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.

Well, now that report has been published online and I’m permitted to talk about it. I’m also very happy to report that, in the words of the Government of South Australia’s Department of Primary Industries and Regions (PIRSA),

Modelling by the Flinders University Global 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.

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PhD opportunity in control strategies of feral deer

30 09 2021

In collaboration with Biosecurity South Australia, the Global Ecology Lab at Flinders University is happy to announce a wonderful new PhD opportunity in feral deer control strategies for South Australia.

The project is tentatively entitled: Refining models of feral deer abundance and distribution to inform culling programs in South Australia

Feral fallow deer (Dama dama) digging in a mallee fowl (Leipoa ocellata) mound © Lee Williams

The project brief follows:

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.

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The very worn slur of “neo-Malthusian”

7 09 2021

After the rather astounding response to our Ghastly Future paper published in January this year (> 443,000 views and counting; 61 citations and counting), we received a Commentary that was rather critical of our article.

A Malthusian slur

We have finally published a Response to the Commentary, which is now available online (accepted version) in Frontiers in Conservation Science. Given that it is published under a Creative Commons Attribution License (CC BY), I can repost the Response here:


In their comment on our paper Underestimating the challenges of avoiding a ghastly future, Bluwstein et al.2 attempt to contravene our exposé of the enormous challenges facing the entire human population from a rapidly degrading global environment. While we broadly agree with the need for multi-disciplinary solutions, and we worry deeply about the inequality of those who pay the costs of biodiversity loss and ecological collapse, we feel obligated to correct misconceptions and incorrect statements that Bluwstein et al.2 made about our original article.

After incorrectly assuming that our message implied the existence of “one science” and a “united scientific community”, the final paragraph of their comment contradicts their own charge by calling for the scientific community to “… stand in solidarity”. Of course, there is no “one science” — we never made such a claim. Science is by its nature necessarily untidy because it is a bottom-up process driven by different individuals, cultures, perspectives, and goals. But it is solid at the core. Scientific confluence is reached by curiosity, rigorous testing of assumptions, and search for contradictions, leading to many — sometimes counter-intuitive or even conflicting — insights about how the world works. There is no one body of scientific knowledge, even though there is good chance that disagreements are eventually resolved by updated, better evidence, although perhaps too slowly. That was, in fact, a main message of our original article — that obligatory specialisation of disparate scientific fields, embedded within a highly unequal and complex socio-cultural-economic framework, reduces the capacity of society to appreciate, measure, and potentially counter the complexity of its interacting existential challenges. We agree that scientists play a role in political struggles, but we never claimed, as Bluwstein et al.2 contended, that such struggles can be “… reduced to science-led processes of positive change”. Indeed, this is exactly the reason our paper emphasized the political impotence surrounding the required responses. We obviously recognize the essential role social scientists play in creating solutions to avoid a ghastly future. Science can only provide the best available evidence that individuals and policymakers can elect to use to inform their decisions. 

We certainly recognise that there is no single policy or polity capable of addressing compounding and mounting problems, and we agree that that there is no “universal understanding of the intertwined socio-ecological challenges we face”. Bluwstein et al.2 claimed that we had suggested scientific messaging alone can “… adequately communicate to the public how socio-ecological crises should be addressed”. We did not state or imply such ideas of unilateral scientific power anywhere in our article. Indeed, the point of framing our message as pertaining to a complex adaptive system means that we cannot, and should not, work towards a single goal. Instead, humanity will be more successful tackling challenges simultaneously and from multiple perspectives, by exploiting manifold institutions, technologies, approaches, and governances to match the complexity of the predicament we are attempting to resolve.

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Climate change will also make us more stupid

31 08 2021

Most people are at least vaguely aware that climate change isn’t good for us.

Let’s consider the obvious direct health effects, like heat exhaustion and stroke, dehydration, increased inhalation of particulate matter from bushfires and other pollutant sources, greater expression of allergies, higher incidence of cardiovascular and respiratory diseases, greater injury rates, and higher probability of disease transmission from flooding events (see review here).

Let’s not forget the rising incidence of mental illness either.

Then there are the climatic events that increase the probability of dying violently like in a bushfire or a flood, getting caned in a major storm by debris, personal injury from storm surges exacerbated by rising sea levels, or dying slowly due to undernutrition from crop failures.

Some of the more indirect, yet just-as-insidious repercussions are those climate-driven events that worsen all of the above, such as increasing poverty, rising violent interactions (both individual-level and full-on warfare), loss of healthcare capability (less infrastructure, fewer doctors), and increased likelihood of becoming a refugee.


So, when someone says increased warming at the pace we’re witnessing now isn’t a problem, tell them they’re full of shit.

But wait! There’s more!

Yes, climate change will also make us more stupid. Perhaps one of the lesser-appreciated byproducts of an increasingly warmer world driven by rising greenhouse-gas concentrations is the direct effects of carbon dioxide on a variety of physiological functions.

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Pest plants and animals cost Australia around $25 billion a year — and it will get worse

2 08 2021
AAP

Corey J. A. Bradshaw, Flinders University and Andrew Hoskins, CSIRO

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


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.


Read more:
Attack of the alien invaders: pest plants and animals leave a frightening $1.7 trillion bill


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.

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No, you can’t argue the Medieval warm period is evidence that today’s climate change isn’t all that bad

23 04 2021
As this reconstructed village shows, Vikings made it as far as Newfoundland during the Medieval warm period. Wikimedia/Dylan Kereluk, CC BY-SA


Frédérik Saltré, Flinders University and Corey J. A. Bradshaw, Flinders University


What was the Medieval warm period? What caused it, and did carbon dioxide play a role?

We are living in a world that is getting warmer year by year, threatening our environment and way of life.

But what if these climate conditions were not exceptional? What if it had already happened in the past when human influences were not part of the picture?

The often mentioned Medieval warm period seems to fit the bill. This evokes the idea that if natural global warming and all its effects occurred in the past without humans causing them, then perhaps we are not responsible for this one. And it does not really matter because if we survived one in the past, then we can surely survive one now.

But it’s just not that simple.


Read more: 2,000 years of records show it’s getting hotter, faster


The Medieval climate anomaly

This Medieval period of warming, also known as the Medieval climate anomaly, was associated with an unusual temperature rise roughly between 750 and 1350 AD (the European Middle Ages). The available evidence suggests that at times, some regions experienced temperatures exceeding those recorded during the period between 1960 and 1990. Read the rest of this entry »





Attack of the alien invaders: pest plants and animals leave a frightening $1.7 trillion bill

19 04 2021

Shutterstock


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 attacking a gecko
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.

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One trillion dollars!

1 04 2021

Or thereabouts.

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.

While the database itself has already been published, today we are pleased to announce the publication in Nature of the main results — High and rising economic costs of biological invasions worldwide — led by Christophe Diagne (one of the nicest people I’ve ever met), and co-authored by Boris Leroy, Anne-Charlotte Vaissière, Rodolphe Gozlan, David Roiz, Ivan Jarić, Jean-Michel Salles, me, and Franck Courchamp (of course).

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.

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A perfect storm of global ineptitude

18 03 2021

Given the ‘success’ (i.e., a lot of people seem to be reading it) of our recent Ghastly Future paper, I thought it would be interesting to go back and have a look at what we wrote in our 2015 book Killing the Koala on the subject. I think you’ll find that if anything we were probably overly optimistic.

An updated digest of that material follows.


When your accountant tells you to reduce expenditure, you do it or risk bankruptcy; when your electrician tells you the wiring in your house is dodgy, you replace it or risk your family dying in an avoidable fire; when your doctor tells you your cholesterol is too high, you cut back fat intake (and/or take cholesterol-reducing drugs) or risk a heart attack.

Yet few with any real political or financial power heed the warnings of environmental scientists. It is not just a few of us either — globally, ecologists, conservation biologists and environmental scientists are united in telling the world (for decades now) that growth in population and consumption cannot go on forever. They have been united in telling us if we do not clean up our planet, our life-support systems could ultimately fail.

There are now nearly eight billion people on Earth, and median projections suggest that the population will grow to ten billion or more by the end of the century. Some analyses indicate that with present technologies, Earth could only sustainably support indefinitely some 5 billion people under best-case scenarios, but assuming similar proportions of poverty and suffering as we have today. Others imply that 5 billion could be many too many.

As a result, humanity is entering that near-perfect storm of problems driven by overpopulation, overconsumption, gross inequalities, and the use of needlessly environmentally damaging technologies. The problems include the intertwined dilemmas of loss of the biodiversity that runs human life-support systems, climate disruption, energy shortages, global toxification, alteration of critical biogeochemical cycles, shortages of water, soil, mineral resources and farmland, and increasing probability of vast epidemics (as COVID-19 poignantly exemplifies).

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Conservation paradox – the pros and cons of recreational hunting

20 02 2021
The recovery of species such as mountain zebra (Equus zebra) was partly supported by the economic benefits generated by trophy hunting. © Dr Hayley Clements

Through the leadership of my long-time friend and collaborator, Enrico Di Minin of the Helsinki Lab of Interdisciplinary Conservation Science, as well as the co-leadership of my (now) new colleague, Dr Hayley Clements, I’m pleased to report our new paper in One Earth — ‘Consequences of recreational hunting for biodiversity conservation and livelihoods‘.


My father was a hunter, and by proxy so was I when I was a lad. I wasn’t really a ‘good’ hunter in the sense that I rarely bagged my quarry, but during my childhood not only did I fail to question the morality of recreational hunting, I really thought that in fact it was by and large an important cultural endeavour.

It’s interesting how conditioned we become as children, for I couldn’t possibly conceive of hunting a wild, indigenous species for my own personal satisfaction now. I find the process not only morally and ethically reprehensible, I also think that most species don’t need the extra stress in an already environmentally stressed world.

I admit that I do shoot invasive European rabbits and foxes on my small farm from time to time — to reduce the grazing and browsing pressure on my trees from the former, and the predation pressure on the chooks from the latter. Of course, we eat the rabbits, but I tend just to bury the foxes. My dual perspective on the general issue of hunting in a way mirrors the two sides of the recreational hunting issue we report in our latest paper.

Wild boar (Sus scrofus). Photo: Valentin Panzirsch, CC BY-SA 3.0 AT, via Wikimedia Commons

I want to be clear here that our paper focuses exclusively on recreational hunting, and especially the hunting of charismatic species for their trophies. The activity is more than just a little controversial, for it raises many ethical and moral concerns at the very least. Yet, recreational hunting is frequently suggested as a way to conserve nature and support local people’s livelihoods. 

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