New DNA testing shatters ‘wild dog’ myth: most dingoes are pure

For decades, crossbreeding between dingoes and dogs has been considered the greatest threat to dingo conservation. Previous DNA studies suggested pure dingoes were virtually extinct in Victoria and New South Wales.

Reinforcing this belief, the term “wild dog” has replaced the word dingo in most legislation and policy across Australia. “Wild dog” is a coverall term defined as “any dog living in the wild, including feral dogs, dingoes and their hybrids”. It’s the term used on signs in National Parks and other lands advertising the target and presence of meat baits impregnated with the poison 1080. These baits are laid to reduce the risk of wild dogs preying on livestock.

Our new research used the latest genetic testing methods to establish the ancestry of wild dogs across Australia. Most of the 307 wild animals we tested were pure dingoes. Only a small proportion of wild dingoes had dog ancestry, probably from a great- or great-great-grandparent. There were no “first-cross” (50/50) hybrids or feral dogs in our wild-caught sample.

Essentially, all the “wild dogs” were dingoes. The results challenge public perceptions and call into question well established management practices. We argue the term “wild dog” should be removed from public language and legislation. Dingo and feral dog should be used instead. And the role of the dingo as Australia’s apex predator should be restored, for we are the greatest threat to their existence.

Better results from better tests

The dingo (Canis dingo) has been in Australia for 5,000 to 11,000 years. But while dingoes are genetically distinct from domestic dogs, they can breed with them.

Scientific support for the idea that few pure dingoes remain in eastern Australia came from skull measurement tests developed in the 1980s and a DNA test developed in the 1990s.

Applying these approaches, Victoria listed dingoes as a threatened species after finding just 1% of animals killed in pest control programs were pure dingoes. Similarly in NSW “predation and hybridisation by feral dogs (Canis familiaris)” was listed as a key threatening process in 2009.

But DNA testing methods have improved since then. When we compared old and new DNA testing methods in our study, we found the original method frequently misidentified pure dingoes as hybrids. This is because the technique used a relatively small number of DNA markers, only 23. We used 195,000 DNA markers.

A DNA marker is a genetic change that can be used to study differences between species, populations or individuals. This is the same sort of technology used for human ancestry or family tree testing. In general, more DNA markers means more information about an individual and more accurate DNA test results.

The older method was also unable to account for geographic variation in dingoes. We found evidence of at least four populations or varieties of dingo in Australia, which we call: West, East, South and Big Desert.

So when we looked at Victorian dingoes, nearly 90% of the animals we tested were pure dingoes. In NSW, over 60% of the animals we tested were pure dingoes and only two animals had less than 70% dingo DNA.

Dog ancestry was more common in NSW and Queensland dingo populations where there were intensive lethal control programs, such as aerial 1080 poison baiting, along with higher numbers of pet domestic dogs. One explanation is that lethal control programs carried out during the dingo breeding season may increase the risk of dingo-dog hybrids, as it does for wolves and coyotes in North America. Australian aerial baiting programs can kill up to 90% of the dingoes in an area, reducing the availability of mates for any remaining dingoes.

These findings have important implications for our knowledge of dingoes and how they are managed. We need to ensure public policy is built on robust, up-to-date knowledge of dingo identity and ancestry.

Wildlife managers and scientists should ensure that the DNA testing methods they use are accurate and fit for purpose. It is crucial that updated genetic surveys be carried out on dingoes, using the latest DNA methods to inform local dingo management plans.

Dingo conservation plans should consider the presence of geographic variation and the differing threats the four dingo populations may be facing.

Currently, dingoes fall into a grey area: because they are both a native animal and agricultural pest; and because their identity has become ambiguous due to the widespread adoption of the term wild dog.

Lethal control programs have been extended into conservation areas, including national parks, with the primary purpose of minimising livestock losses on neighbouring lands.

During 2020-2021, NSW dropped more than 200,000 1080 poisoned meat-baits from planes and helicopters to suppress “wild dogs”.

This year Victoria renewed its “wild dog bounty” program. It pays landholders A$120 per wild dog body part. Under the scheme, about 4,600 “wild dog” body parts have reportedly been redeemed since 2011.

Restoring an apex predator

Our study shows the term “wild dog” is a misnomer. The animals being targeted for eradication as an “invasive” pest are native dingoes.

The threat of dingo-dog hybrids has also been exaggerated. While dingoes can pose a threat to some livestock, as apex predators they play an essential role in maintaining healthy ecosystems. The dingo keeps natural systems in balance by preying on large herbivores and excluding invasive predators such as feral cats and foxes. This in turn benefits small marsupials, birds and reptiles. We need to balance managing dingo impacts on agriculture against ensuring they can perform their vital environmental functions.

The term “wild dog” should be removed from public language and legislation. Dingo and feral dog should be used instead. This change in terminology would accurately reflect the fact that a vast majority of the wild canines in Australia are pure dingoes – and the hybrids are predominantly dingo in their genetic make-up.

A name change would also align with calls from Australia’s First Nations people to respect and acknowledge the dingo as a native and culturally significant species.

Kylie M Cairns, Research fellow, UNSW Sydney; Mathew Crowther, Associate professor, University of Sydney, and Mike Letnic, Professor, Evolution and Ecology Research Centre, UNSW Sydney

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Europe has lost over half a billion birds in 40 years. The single biggest cause? Pesticides and fertilisers

A trickle of studies warning that the enormous variety of living things on Earth is diminishing has turned into a flood. The evidence for these losses within regions and globally is undeniable. But data on biodiversity, and what is causing its decline, is still patchy – restricted to some causes, some places and some species. That isn’t the case for birds in Europe, however.

Birds have long fascinated amateur and professional scientists, and close cooperation across Europe has created a deep body of knowledge about their habits, needs and numbers. Some of the longest-running datasets of their kind concern birds which live at least part of their lives in Europe.

This data paints a grim picture: an estimated 550 million birds have been lost from Europe’s total population over the last 40 years or so. It is a shocking statistic, and tells us something profound about humanity’s broken relationship with nature.

Scientists know that biodiversity is under increasing pressure, especially from rapid changes in how land is used (from forest to farmland, for instance) and rising temperatures. But how different species respond to those pressures, which of them is the most important, and how conservationists can respond to alleviate them, have all remained contentious issues.

Taking advantage of high-quality data on birds, a new paper I wrote with French researchers analysed how 170 bird species have responded to human-induced pressures in Europe, using data collected at more than 20,000 monitoring sites across 28 countries over 37 years, including data from the UK.

We found that chemicals used on farms to control insects and plants seen as weeds that might reduce crop yields are depriving many birds of their main food source, and that this is the single biggest cause of their decline across Europe.

The man-made drivers of change

We looked at four major sources of pressure on bird populations: agricultural intensification (measured by the high use of pesticides and fertilisers), climate change and its influence on temperatures, changes in forest cover, and urbanisation.

Modern farming methods were the biggest cause of decline for most bird populations – especially for those that feed on insects and other invertebrates, such as swifts, yellow wagtails, spotted flycatchers, wheatears and stonechats. How birds responded to changes in forest cover, urbanisation and climate change was much more variable and species-specific.

Between 1980 and 2016, common birds in Europe declined in abundance by a quarter. But numbers of farmland birds more than halved during this period. There were also declines in both woodland birds and urban dwellers, in northern, cold-preferring birds, and even in some southern, warm-preferring bird species – though the overall trend in this latter group of birds is one of steady growth.

One of the study’s main findings is that the large use of pesticides and fertilisers on farms in particular is the most significant driver of bird population declines across Europe, including the UK. This does not come as a great surprise – many studies have come to this conclusion. But this is the first study to look at the man-made drivers in one go, using some of the best data available and modern statistical methods. The results are clear.

Agricultural practices began to change significantly after the second world war, as countries introduced measures to increase the output of farms. Yet such efforts to increase output, including an increasing reliance on pesticides and fertilisers, have come at a significant cost to birds and other wildlife – and critically, the overall health of the environment.

A recent UK government report found that the loss of biodiversity, alongside climate change, presented the greatest medium- to long-term threat to domestic food production. Biodiversity loss has consequences for society far beyond endangered species.

We believe that birds are mainly affected by pesticides and fertilisers through the loss of food, though these chemicals may be directly affecting their health too. Pesticides are designed to kill the insects and invertebrates that birds eat. Fertilisers change what kind of plants grow in an environment, often to the detriment of a wide variety of species. Invertebrates need this vegetation for food and shelter, and birds need it too – as well as the invertebrates.

Invertebrates are an important part of the diet of many bird species, but they are rocket fuel for growing chicks, which are the engine of population growth. Invertebrates are particularly important during the breeding period for over 80% of the birds in our study. The dramatic loss of insects we often hear about appears to be having a profound impact on birds.

Nature-friendly food

The question is how best to respond. Nature is in trouble on farmland, and yet farmers can be a big part of the solution if they are supported by the right policies.

We need much greater support for nature-friendly farming practices, and a shift away from farming dominated by pesticides and inorganic fertilisers. This would be good for nature, for farmers and food production, for the climate, for consumers – and many progressive farmers are leading the way.

Our results also show the power of citizen science and cooperation across borders to advance science and better understand the natural world – and how to turn things around.

Now we need governments across the world to support land management schemes that reward nature-friendly farming, such as committing to managing at least 10% of farmland for nature, which in turn will help sustain or even boost farm yields.

But we also need wider food system reform, including nature-friendly diets. Retailers, suppliers and processors can all play their part to ensure a healthy environment that can feed us and bring back nature – with all the benefits for people this will bring.

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Richard Gregory, Honorary Professor of Genetics, Evolution & Environment, UCL

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What should happen to native forests when logging ends? Ask Victoria’s First Peoples

The end of native forest logging in Victoria announced last week was met with joy from conservationists and shock from timber industry workers.

To date, this has been how the story has been told: a win for the environment, a loss for jobs in the industry.

But there is an aspect of the story which hasn’t been told. The end of native timber harvesting is an opportunity for Victoria’s First Peoples to tend these forests again. Our voices have not been heard in this debate, but we have much to do on Forest Country.

You might think an end to logging naturally means a return to wilderness. But wilderness as an ideal is a concept which has undermined the rights of Indigenous people. For tens of thousands of years, we worked with Forest Country to ensure its health. When colonists first arrived the land was often described as resembling parklands. Colonisation took that away. In some places this change allowed wilderness to set in and some to became more fire prone.

The end of native timber harvesting gives us an opportunity to rethink what Forest Country looks like. It doesn’t have to be dense forests everywhere. We could bring back areas of open Country and reintroduce practices such as cultural burning. We urge decision-makers and the public to keep their minds open – and listen to First Peoples voices.

First Nations voices must be heard

The Victorian government’s promise to end native forest logging also included retraining and redundancy packages for workers. The government also announced an advisory panel would be formed to recommend areas for future protected areas – and for Traditional Owner management.

Conservationists are celebrating a win sought for decades. The damage done by logging on biodiversity has been significant, with once common species now endangered and mature forests now fragmented and dotted with young fire-prone regrowth.

It’s understandable this news has been framed around what it means for conservationists, nature and timber workers. As three Aboriginal Victorians, we acknowledge the important role for each of these groups in current and future forest management. But so far, the commentary has largely failed to include the voices of First Peoples in asserting their rights and obligations as they relate to Forest Country.

What form should these forests take?

When colonisers first came to the forests of Gippsland, their observations were of open forests with few but large trees. These forest systems were cared for in a way which favoured a grassy understorey and a fine-scale mosaic landscape shaped by fire used at different times. This system produced abundant resources for the land’s Traditional Custodians, while supporting abundant and diverse native wildlife.

To maintain Country in this way took regular applications of low-intensity fire. The knowledge of how to manage Country in this way was lore. Over generations, our ancestors created and maintained productive landscapes designed for comfortable and safe human habitation. Foremost in the minds of our old people was nurturing Country, passing on cultural knowledge and keeping alive the tangible and intangible cultural values of their ancestors.

With the removal of the custodians from Country, the landscape thickened. Abundant saplings quickly replaced these open forests with impassable scrub. In many places, the landscape has become more prone to wildfire.

Plantations cemented this thickening further, by favouring high density forests of straight trees of the same age and usually the same species.

Colonisation affected Country differently across Australia. But many effects are similar across the continent. European-style land management coincides with species extinctions across the continent.

The destruction of cultural landscapes has been a major contributor to the loss of biodiversity and increase in catastrophic bushfires. It’s the reason for the poor health of Country.

What would real First Nations involvement look like?

To begin the process of repair, Victoria’s First Peoples have partnered with the state government to create strategies which speak to healing Country, bringing back cultural landscapes and cultural burning.

At present, Traditional Owner groups across the state are working towards developing their own strategies to manage their Country. This is producing detailed planning and productive on-ground work. We invite the state to invest in our work planning and caring for Country.

Like the government, we agree that the end to logging doesn’t mean walking away from forest management.

Leaving our forests to themselves is not caring for Country. If we did that, it would entrench the persistent wilderness myth that all forests look after themselves. It would also be an avoidance of our responsibility to care for this land. We cannot and should not be shut out from these forests.

To return Forest Country to health doesn’t mean leaving it alone. In some cases, we may need to thin trees or use cool burns to bring back open Country. This will take careful planning and hard work. It will take people working on Country, informed by Country.

The shift will also create economic opportunities for First Peoples in taking on custodianship of these landscapes. The end to state sponsored logging is an excellent opportunity for the government to meet its commitment to self-determination of First Peoples.

When the government creates its panel of advisors on what to do with state forests post-logging, it must ensure First Peoples voices are strongly represented – and that the panel advises on tenure and ownership of the land and the future shape of these forests. We would be dismayed if these voices were not heard until after significant decisions such as new national parks had been made.

What might Victorian forests of the future look like? There’s no simple answer, because Forest Country is as diverse as the cultures of the Traditional Custodians who care for it.

But we can say that they should be shaped by the thoughtful stewardship of Victorians, with First Peoples cultural knowledge and practice at the fore. At the heart of this stewardship must be the love of Country – and care for community.

Jack Pascoe, Research fellow, The University of Melbourne; Matthew Shanks, Director, Cultural Land Management at Taungurung Land and Waters Council, Indigenous Knowledge, and Michael-Shawn Fletcher, Professor in Biogeography, The University of Melbourne

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A sustainable Australia depends on what happens in our cities – that’s why we need a national urban policy

Australia has not had a national urban policy since the Rudd government. A troika of Liberal PMs followed. Tony Abbott wasn’t interested. Malcolm Turnbull didn’t quite live up to the hype but delivered cross-governmental City Deals and the Smart Cities and Suburbs Program. Scott Morrison at best presided over a business-as-usual approach lacking any resolve, urgency or innovation.

Will this Labor government do any better? Australian cities and regions were not front and centre in the 2022 federal election campaign. But there were signs a Labor government would reinstate a concern for urban policy issues.

The federal budget confirmed the government’s focus on urban policy. It set aside funding for a “national approach for sustainable urban development” and a “cities program”. Last week the government appointed the expert members of the Urban Policy Forum announced in the budget.

These are vehicles for delivering a promised National Urban Policy. The government says this policy “will bring together a vision for sustainable growth in our cities”.

Why focus on cities?

Two in three Australians live in a capital city. Our 21 largest cities are home to 80% of the population.

Cities account for 80% of economic activity in Australia. As globally connected hubs, they are crucial sites for community, commerce, infrastructure, biodiversity, governance and democratic processes. Our cities are central to meeting the challenges of a changing climate.

Prime Minister Anthony Albanese has skin in the game. He was the minister for infrastructure and transport in the Gillard government. He oversaw the first truly national urban policy, Our Cities, Our Future, in 2011.

In 2021, Albanese declared that “cities policy has been one of the abiding passions of my time in public life”. He foreshadowed a new national policy framework.

The budget papers specifically refer to the National Cabinet agreement on April 28 on national priorities. Among these is “Better Planning for Stronger Growth reforms to support a national approach to the growth of cities, towns, and suburbs”.

The budget commits nearly A$400 million over four years in new grants and investments in “Thriving Suburbs” and “Urban Precincts and Partnerships”. Some $11 million goes to a Cities and Suburbs Unit to deliver a National Urban Policy. The policy is required to:

address urgent challenges facing our major cities – from equitable access to jobs, homes and services, to climate impacts and decarbonisation.

An overdue development

Urban development has been “undervalued in national discussion” globally, not only in Australia. But in recent years various bodies, inquiries and forums have pushed for a new-look national urban policy.

The Planning Institute of Australia has long called for a coherent governance framework for spatial plans, infrastructure, growth management and urban renewal. Without a national cities plan, a 2018 report by the institute said, “all jurisdictions will be disadvantaged when making resource allocation decisions and planning for basic enabling infrastructure”.

In the same year, a federal parliamentary inquiry into the Australian government’s role in city development called for “a national plan of settlement, providing a national vision for our cities and regions across the next 50 years”.

In 2019, Future Earth Australia, based at the Australian Academy of Sciences, advanced a ten-year national strategy for sustainable cities and regions. This strategy is aligned with the Australian achievement of the UN Sustainable Development Goals.

New ideas for Australian cities and regions

We must take seriously the economic, social and environmental impacts of long-term population growth and development. To become a more equitable and sustainable country, action on the uneven experiences of Australian cities and regions must be a government priority.

In 2021, an Australian Academy of Social Sciences workshop on Australian Urban Policy: Achievements, Failures, Challenges was undertaken jointly at the City Futures Research Centre, UNSW, and Centre for Urban Research, RMIT University. More than 50 researchers and practitioners explored the many issues competing for urban policy attention at the national level.

Key areas included water, climate change, Indigeneity, transport, migration, population settlement and new cities. Urban green space, biodiversity, digital technologies, economic productivity, social inclusion and affordable housing supply were also identified as issues that cut across national policy agendas.

Constitutional constraints mean states must play a leading role in national urban policy. Fortunately, these constraints don’t rule out inter-governmental partnerships. There are many, often poorly integrated policies, programs and initiatives across all levels of government.

There was consensus at the workshop on the need to transcend the political ideology and expediency that have led to fragmented urban policies. A different kind of national politics focused on sustainability, resilience and regeneration is required.

The “secret” to sustainability lies in an integrated national framework of policies and strategies for city-regions. All three tiers of government need to buy into it.

National urban policy redux

There is a “back to the future” quality in some of the Albanese moves. They re-invent Rudd-Gillard initiatives, and Turnbull’s City Deals remain. Action on affordable housing supply and urban inequalities has been less forceful to date.

Sitting alongside what seem like far-reaching environmental actions, including a new Net Zero Authority, the revival of urban policy at the national level is welcome. So too would be the discussion, consultation and research required to secure a resilient and sustainable future.

A national urban policy offers opportunities for cities, towns and regions. It’s also essential if Australia is to meet its national and international obligations, notably the UN’s 2030 Agenda for Sustainable Development.

Australian Urban Policy: Prospects and Pathways is a report on the UNSW-RMIT workshop edited by the authors and with over 30 contributors. It will be published by ANU Press in late 2023.

Robert Freestone, Professor of Planning, School of Built Environment, UNSW Sydney; Bill Randolph, Professor, City Futures Research Centre, Faculty of the Built Environment, UNSW Sydney, and Wendy Steele, Interim Director, Urban Futures Enabling Impact Platform, and Professor in Sustainability and Urban Policy, Centre for Urban Research, RMIT University

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It’s not just climate – we’ve already breached most of the Earth’s limits. A safer, fairer future means treading lightly

People once believed the planet could always accommodate us. That the resilience of the Earth system meant nature would always provide. But we now know this is not necessarily the case. As big as the world is, our impact is bigger.

In research released today, an international team of scientists from the Earth Commission, of which we were part, identified eight “safe” and “just” boundaries spanning five vital planetary systems: climate change, the biosphere, freshwater, nutrient use in fertilisers and air pollution. This is the first time an assessment of boundaries has quantified the harms to people from changes to the Earth system.

“Safe” means boundaries maintaining stability and resilience of our planetary systems on which we rely. “Just”, in this work, means boundaries which minimise significant harm to people. Together, they’re a health barometer for the planet.

Assessing our planet’s health is a big task. It took the expertise of 51 world-leading researchers from natural and social sciences. Our methods included modelling, literature reviews and expert judgement. We assessed factors such as tipping point risks, declines in Earth system functions, historical variability and effects on people.

Alarmingly, we found humanity has exceeded the safe and just limits for four of five systems. Aerosol pollution is the sole exception. Urgent action, based on the best available science, is now needed.

So, what did we find?

Our work builds on the influential concepts of planetary boundaries by finding ways to quantify what just systems look like alongside safety.

Importantly, the safe and just boundaries are defined at local to global spatial scales appropriate for assessing and managing planetary systems – as small as one square kilometre in the case of biodiversity. This is crucial because many natural functions act at local scales.

Here are the boundaries:

1. Climate boundary – keep warming to 1℃

We know the Paris Agreement goal of 1.5℃ avoids a high risk of triggering dangerous climate tipping points.

But even now, with warming at 1.2℃, many people around the world are being hit hard by climate-linked disasters, such as the recent extreme heat in China, fires in Canada, severe floods in Pakistan and droughts in the United States and the Horn of Africa.

At 1.5℃, hundreds of millions of people could be exposed to average annual temperatures over 29℃, which is outside the human climate niche and can be fatal. That means a just boundary for climate is nearer to 1°C. This makes the need to halt further carbon emissions even more urgent.

2. Biosphere boundaries: Expand intact ecosystems to cover 50-60% of the earth

A healthy biosphere ensures a safe and just planet by storing carbon, maintaining global water cycles and soil quality, protecting pollinators and many other ecosystem services. To safeguard these services, we need 50 to 60% of the world’s land to have largely intact natural ecosystems.

Recent research puts the current figure at between 45% and 50%, which includes vast areas of land with relatively low populations, including parts of Australia and the Amazon rainforest. These areas are already under pressure from climate change and other human activity.

Locally, we need about 20-25% of each square kilometre of farms, towns, cities or other human-dominated landscapes to contain largely intact natural ecosystems. At present, only a third of our human-dominated landscapes meet this threshold.

3. Freshwater boundaries: Keep groundwater levels up and don’t suck rivers dry

Too much freshwater is a problem, as unprecedented floods in Australia and Pakistan show. And too little is also a problem, with unprecedented droughts taking their toll on food production.

To bring fresh water systems back into balance, a rule of thumb is to avoid taking or adding more than 20% of a river or stream’s water in any one month, in the absence of local knowledge of environmental flows.

At present, 66% of the world’s land area meets this boundary, when flows are averaged over the year. But human settlement has a major impact: less than half of the world’s population lives in these areas. Groundwater, too, is overused. At present, almost half the world’s land is subject to groundwater overextraction.

4. Fertiliser and nutrient boundaries: Halve the runoff from fertilisers

When farmers overuse fertilisers on their fields, rain washes nitrogen and phosphorus runoff into rivers and oceans. These nutrients can trigger algal blooms, damage ecosystems and worsen drinking water quality.

Yet many farming regions in poorer countries don’t have enough fertiliser, which is unjust.

Worldwide, our nitrogen and phosphorus use are up to double their safe and just boundaries. While this needs to be reduced in many countries, in other parts of the world fertiliser use can safely increase.

5. Aerosol pollution boundary: Sharply reduce dangerous air pollution and reduce regional differences

New research shows differences in concentration of aerosol pollutants between Northern and Southern hemispheres could disrupt wind patterns and monsoons if pollutant levels keep increasing. That is, air pollution could actually upend weather systems.

At present, aerosol concentrations have not yet reached weather-changing levels. But much of the world is exposed to dangerous levels of fine particle pollution (known as PM 2.5) in the air, causing an estimated 4.2 million deaths a year.

We must significantly reduce these pollutants to safer levels – under 15 micrograms per cubic metre of air.

We must act

We must urgently navigate towards a safe and just future, and strive to return our planetary systems back within safe and just boundaries through just means.

To stop human civilisation from pushing the Earths’s systems out of balance, we will have to tackle the many ways we damage the planet.

To work towards a world compatible with the Earth’s limits means setting and achieving science-based targets. To translate these boundaries to actions will require urgent support from government to create regulatory and incentive-based systems to drive the changes needed.

Setting boundaries and targets is vital. The Paris Agreement galvanised faster action on climate. But we need similar boundaries to ensure the future holds fresh water, clean air, a planet still full of life and a good life for humans.

We would like to acknowledge support from the Earth Commission, which is hosted by Future Earth, and is the science component of the Global Commons Alliance

Steven J Lade, Resilience researcher at Australian National University, Australian National University; Ben Stewart-Koster, Senior research fellow, Griffith University; Stuart Bunn, Professor, Australian Rivers Institute, Griffith University; Syezlin Hasan, Research fellow, Griffith University, and Xuemei Bai, Distinguished Professor, Australian National University

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‘An exciting possibility’: scientists discover markedly different kangaroos on either side of Australia’s dingo fence

Australia’s dingo fence is an internationally renowned mega-structure. Stretching more than 5,600 kilometres, it was completed in the 1950s to keep sheep safe from dingoes. But it also inadvertently protects some native species.

This makes the fence an unintentional experiment in the relationship between predators and prey. Our new research examined how the fence affects a favourite prey of the dingo: red kangaroos.

We found young kangaroos on the side exposed to dingoes grew more quickly than their protected counterparts. This has potentially big repercussions for the health of these juveniles.

The merits of the dingo fence are hotly debated, and there have been calls to pull it down or move it. That’s why we must seek a better understanding of how the fence affects the animals that live along it.

‘Stressful’ lives

The dingo fence, formally known as the “wild dog barrier fence”, runs through Queensland, New South Wales and South Australia. It protects sheep and cattle to the southeast.

Extensive fencing can fragment habitats and disrupt ecosystems. Maintaining the fence costs about A$10 million per year. For these and other reasons, some have suggested the fence be pulled down.

But how would removing the fence affect kangaroos that have lived without dingoes for up to 70 years? Our research sought to answer this question.

We assessed 166 red kangaroos from two isolated populations on either side of the fence in far northwest NSW. We did this using data collected as part of a licensed shooting program. We compared population size, age structure, sex ratio, growth rate and skull shape.

We expected kangaroos north of the fence – those hunted by dingoes – to differ from their dingo-free cousins to the south. That’s because their lives are more stressful, especially for young kangaroos and females that are killed by dingoes more often than adult males.

What we found

As anticipated, we found more young and female kangaroos in the dingo-protected population south of the fence. But the story is more complex than that.

Young kangaroos south of the fence, up to about the age of four years, grew more slowly than those in the north. They were substantially smaller and lighter than their dingo-exposed counterparts.

This raises an exciting possibility: that the growth of kangaroos south of the fence has slowed in the absence of the dingo threat.

But maybe there was just more plant food available in the north, where there are fewer kangaroos compared to the south. Was this the reason the northern kangaroos grew more quickly?

As it turns out, no. We assessed the vegetation on each side of the fence using a decade of satellite measurements. We found there was probably less, not more, food overall for kangaroos in the north compared to the south.

More detailed investigation is needed into whether the types of plants differed on each side of the fence. But our results suggest the different growth rates were driven by predators, not food availability.

This raises important questions

The differences between populations are even more striking considering the dingo fence in the area we studied was in disrepair until 1975. Before then, dingoes and kangaroos probably moved freely. So the changes we observed could have come about in as little as 17 kangaroo generations.

This would be unusually fast for an evolutionary adaptation. Instead, we suspect it’s the result of a more immediate response to the absence of dingoes, such as lower concentrations of stress-related hormones. These affect the health of mammals, and might have affected kangaroo growth rates in this case.

After about the age of four, the protected kangaroos had caught up and were the same size as their unprotected counterparts. But the unprotected kangaroos would have invested a lot more bodily resources into growing so quickly.

This would have left less energy for the animals to develop important functions such as their immune or reproductive systems. Or they might have had less fat reserves.

Conversely, protected kangaroos might have been healthier, or more fertile, because of their slower growth rates.

Understanding the mammal response

Our study involved only a single sample at one point in time. But it’s the first to comprehensively assess differences in a dingo prey species on either side of a fence.

Our results provide an insight into how prey populations might fare if the dingo fence is removed. But the implications are potentially even broader.

We must now investigate whether other native mammal species share similar differences across the fence. If so, this could help us predict how animals elsewhere in Australia are coping with rapid environmental change.

Vera Weisbecker, Associate Professor, Flinders University; Corey J. A. Bradshaw, Matthew Flinders Professor of Global Ecology and Models Theme Leader for the ARC Centre of Excellence for Australian Biodiversity and Heritage, Flinders University; Frédérik Saltré, Research Fellow in Ecology for the ARC Centre of Excellence for Australian Biodiversity and Heritage, Flinders University, and Rex Mitchell, Postdoctoral Fellow, Flinders University

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3 little-known reasons why plastic recycling could actually make things worse

This week in Paris, negotiators from around the world are convening for a United Nations meeting. They will tackle a thorny problem: finding a globally binding solution for plastic pollution.

Of the staggering 460 million tonnes of plastic used globally in 2019 alone, much is used only once and thrown away. About 40% of plastic waste comes from packaging. Almost two-thirds of plastic waste comes from items with lifetimes of less than five years.

The plastic waste that escapes into nature persists and breaks up into smaller and smaller pieces, eventually becoming microplastics. Plastics now contaminate virtually every environment, from mountain peaks to oceans. Plastic has entered vital systems such as our food chain and even the human blood stream.

Governments and industry increasingly acknowledge the urgent need to reduce plastic pollution. They are introducing rules and incentives to help businesses stop using single-use plastics while also encouraging collection and recycling.

As a sustainability researcher, I explore opportunities to reduce plastic waste in sectors such as tourism, hospitality and meat production. I know how quickly we could make big changes. But I’ve also seen how quick-fix solutions can create complex future problems. So we must proceed with caution.

Plastic avoidance is top priority

We must urgently eliminate waste and build a so-called “circular economy”. For plastics, that means reuse or recycling back into the same type of plastic, not lower grade plastic. The plastic can be used to make similar products that then can be recycled again and again.

This means plastics should only be used where they can be captured at their end of life and recycled into a product of the same or higher value, with as little loss as possible.

Probably the only example of this to date is the recycling of PET (polyethylene terephthalate) soft-drink bottles in Norway and Switzerland. They boast recovery rates of 97% and 95% respectively.

The waste management pyramid below shows how to prioritise actions to lessen the waste problem. It is particularly relevant to single-use plastics. Our top priority, demanding the biggest investment, is prevention and reduction through redesign of products.

Where elimination is not yet achievable, reuse solutions or recycling to the same or higher-level products can be sought to make plastics circular.

Unfortunately, a lack of high-quality reprocessing facilities means plastic waste keeps growing. In Australia, plastic is largely “downcycled”, which means it is recycled into lower quality plastics.

This can seem like an attractive way to deal with waste-plastic stockpiles, particularly after the recent collapse of soft-plastics recycler RedCycle. But downcycling risks doing more harm than good. Here are three reasons why:

1. Replacing wood with recycled plastics risks contaminating our wildest natural spaces

An increasing number of benches, tables, bollards and boardwalks are being made from recycled plastic. This shift away from timber is touted as a sustainable step - but caution is warranted when introducing these products to pristine areas such as national parks.

Wood is naturally present in those areas. It has a proven record of longevity and, when degrading, does not introduce foreign matter into the natural system.

Swapping wood for plastic may introduce microplastics into the few remaining places relatively free of them. Replacing wood with downcycled plastics also risks plastic pollution through weathering or fire.

2. Taking circular plastics from their closed loop to meet recycled-content targets creates more waste

Clear PET bottles used for beverages are the most circular plastic stream in Australia, approaching a 70% recovery rate. When these bottles are recycled back into clear PET bottles, they are circular plastics.

However, the used PET bottles are increasingly being turned into meat trays, berry punnets and mayonnaise jars to help producers meet the 2025 National Packaging Target of 50% recycled content (on average) in packaging.

The problem is the current industry specifications for plastics recovery allow only downcycling of these trays, punnets and jars. This means that circular PET is removed from a closed loop into a lower-grade recovery stream. This leads to non-circular downcycling and more plastic sent to landfill.

3. Using “compostable” plastics in non-compostable conditions creates still more plastic pollution

Increasingly, plastics are labelled as compostable and biodegradable. However, well-intended use of compostable plastics can cause long-term plastic pollution.

At the right temperature with the right amount of moisture, compostable plastics breakdown into soil. But if the conditions are not “just right”, they won’t break down at all.

For example, when a landscape architect or engineer uses a “compostable” synthetic fabric instead of a natural alternative (such as coir or jute mats) they can inadvertently introduce persistent plastics into the environment. This is because the temperature is not hot enough for the synthetic mat to break down.

We must also differentiate between “home compostable” and “commercially compostable”. Commercial facilities are more effective at composting because they operate under more closely controlled conditions.

Learning from our mistakes

Clearly, we need to reduce our reliance on plastics and shift away from linear systems – including recycling into lower-grade products.

Such downcycling may have a temporary role in dealing with existing plastic in the system while circular recycling capacity is being built. But we must not develop downcycling “solutions” that need a long-term stream of plastic waste to remain viable.

What’s more, downcycling requires constantly finding new markets for their lower-grade products. Circular systems are more robust.

So, to the negotiators in Paris, yes the shift to a circular plastics economy is urgent. But beware of good intentions that could ultimately make things worse.

Pascal Scherrer, Senior Lecturer, Faculty of Business, Law and Art, Southern Cross University

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

Photos from the field: spying on Antarctic moss using drones, MossCam, smart sensors and AI

The Antarctic continent conjures visions of white ice and blue sky. But not far from Australia’s Casey Station, 3,880km due south of Perth, moss beds emerge verdant and green.

Sadly, the health of these moss beds is declining due to changing climate conditions, ozone depletion and heatwaves. Yet our understanding of the problem is limited. Conducting research in Antarctica is difficult. Periods of data collection are short, and there can be years between each research opportunity. Fortunately, new technology offers solutions.

In December 2022, we travelled to Casey Station. We spent two months in the field – combining our skills in biology, flying drones, programming and artificial intelligence – to learn more about the moss and find better ways to remotely monitor biological changes.

We mapped large moss beds and trialled a new sensor system that can deliver continuous, year-round moss data. While this research is ongoing, we’re thrilled to share the early results with you here.

Miniature forests, bustling with life

Plants need sunlight, warmth and liquid water. Antarctic plants face months of darkness, freezing temperatures and drought from frozen water – but moss has adapted to this hostile environment.

Moss is the dominant plant life in Antarctica. It provides habitat for invertebrates, microbes and fungi, which make up more than 99% of Antarctica’s land biodiversity. The moss beds resemble miniature forests, bustling with life.

Antarctic moss creates its own warm microclimate, using pigments to absorb sunlight. This warmth aids photosynthesis and helps the mosses to melt snow to obtain liquid water. The tiny hills and valleys across moss beds determine the amount of light mosses receive and creates differences in their microclimates and health.

Once we reached the moss, we’d carefully balance on rocks to take samples and place data loggers. These consisted of four sensors that measured canopy temperatures at different positions in the moss bed. We also measured photosynthesis and collected moss samples for pigment analysis, which indicates health and stress levels.

The below photo depicts a moss bed with our equipment attached. You can see the complex micro-topography and a mosaic of healthy and stressed mosses. Healthy moss is green and velvety. Stressed mosses are red and eventually turn grey.

Mosses growing just centimetres apart can experience vastly different microclimates. In the photo below, some mosses had warmed up to 19℃ (next to the red marker), while only about 30cm away the moss was at 0.6℃ (next to the white marker).

Collecting this data enables us to explore connections between the physical structure of the moss beds, microclimates and indicators of moss health.

Smart sensors, cameras and transmitters

While in Antarctica, we also tested the first prototype of an intelligent, autonomous and long-term sensing platform. It offers scientists more information than previous data-collection devices as it can collect and transmit data over an extended period outside regular summer field campaigns, including winter time.

The prototype monitored the moss bed near Casey Station for a month and a half. Its sensors captured light intensity, ambient air temperature and humidity, moss canopy temperature and, finally, energy exchanged between soil and air. A webcam, affectionately nicknamed MossCam, captured regular images of the moss bed.

We also installed the first antenna in Antarctica for the LoRaWAN wireless network. This network is low power, long range and free to use. This allowed us to send data back to Australia in near real-time and display it on a website dashboard that is visible to Australians only.

After some early bug fixes, the platform performed better than expected. We brought it home at the end of the season for further refinement and deployment next season.

Drones and hyperspectral imaging

We sent drones on 25 flights, collecting data from two Antarctic Specially Protected Areas (ASPAs 135 and 136).

Operating drones in the Antarctic presents significant challenges. The proximity to the magnetic pole disturbs the GPS navigation, and strong winds make it difficult to fly. Severe cold reduces battery life – and it’s also tough on the operator’s fingers. We customised drones with RTK (real-time kinematics, a technique to eliminate position errors) GPS, multiple redundancies and battery warmers to increase their resilience to harsh conditions.

Our drones could capture 5,000-10,000 images on each flight. They were also equipped with high-tech sensors. These sensors are programmed to record “spectral signatures”, which is a term we use to describe a kind of optical identity or visual “DNA” that differentiates landscape features like moss, rock and snow within the image.

These images will be stitched together and mapped to their ground coordinates. Using machine learning, we will train a model to identify vegetation, including moss, lichen and cyanobacteria. We will also develop vegetation and hydrology maps, 3D fly-throughs and virtual reality experiences to support decision-making around conservation and management.

One journey ends, while another is just beginning

Often while we were working, curious penguins wandered over to see what we were doing. Making friends with these locals was always the highlight of the day.

But after a couple of fantastic months in the field, it was time to pack up and head home. On the 60km journey inland to Wilkins Aerodrome we ventured into the Antarctic Circle. We waited in -20℃ to watch our plane land on the blue ice runway before boarding and flying back to Tasmania. There, it felt like we’d just woken up from a dream.

Our Antarctic adventure was over, but we all felt so grateful for the experience.

Now we’re exploring the data, to see what stories it can tell, while further developing our moss sensing platform. We hope to return to Antarctica to deploy it at the end of the year.

The authors travelled to Casey Station as part of the Australian Research Council Special Research Initiative Securing Antarctica’s Environmental Future (SAEF).

Johan Barthélemy, Developer Relations Manager, NVIDIA and Honorary Senior Research Fellow, University of Wollongong, University of Wollongong; Barbara Bollard, Professor of Computational Conservation, Auckland University of Technology; Juan Sandino, Postdoctoral research fellow, Queensland University of Technology, and Krystal Randall, Postdoctoral Research Fellow, University of Wollongong

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

A new trade deal delivers cheaper Australian beef and British sweets – but does little to avert dangerous global warming

A free trade agreement between Australia and the United Kingdom begins on Wednesday. When it was announced in 2021, then-prime ministers Boris Johnson and Scott Morrison cheerily exchanged packets of chocolate biscuits. Meanwhile, one British newspaper celebrated the prospect of cheaper steaks.

The agreement eliminates tariffs on a range of Australian exports, including beef and lamb, and makes it easier for Australians to work in the UK. British exporters of cars, whisky and confectionery will also benefit. But the deal is notable for another reason.

As our research has found, it does relatively little to tackle climate change. In the context of growing damage from climate change – internationally, in Australia and in the UK – this is a missed opportunity.

The Albanese government inherited this free trade agreement, and describes it as “gold standard”. It is not, however, gold standard on climate action. Both the Australian and UK governments must now ensure the deal does not damage efforts to keep global warming at safe limits.

Hopes were high

Trade is vital to the global economy. It is also inextricably linked to climate change.

Trade increases greenhouse gas emissions. And climate change can damage trade when severe weather disrupts supply and distribution networks.

Free trade agreements can be used to tackle climate change. For example, they can lower the cost of goods needed in the low-carbon transition, such as solar panels and bicycle parts. And trade partners can provide leadership on emissions reduction.

When the UK hosted the COP26 climate conference in 2021, it sought to establish a reputation as a global leader on climate action. The nation seemed well-placed to ensure emissions reduction was on the agenda when it negotiated a post-Brexit trade deal with Australia.

But the free trade agreement with Australia failed to put climate change at the forefront.

‘Regrettable’: the deal lacks climate ambition

The final text of the deal acknowledges each nations’ commitment to addressing climate change and notes “the role of global trade and investment in these efforts”. It also recognises the Paris Agreement.

However, a report last year by a British parliamentary committee noted the agreement’s lack of climate ambition, saying:

Given the UK’s generous tariff offer, it could have pressed [Australia] for more ambitious commitments on climate change, stronger enforcement provisions, and for an explicit reference to the Paris temperature goals.

The report also noted:

it is regrettable that the agreement did not include any references to reducing or reviewing Australia’s reliance on coal.

There was speculation that the UK government prioritised securing the agreement over holding Australia to account on climate action.

In Australia, the Department of Foreign Affairs and Trade analysed the impact of the free trade agreement with the United Kingdom and did not raise concerns over its climate ambition.

What the deal should have done

So how might the trade pact have properly addressed climate change? There are many options.

A UK-New Zealand trade deal, for example, signals that in some circumstances, it may be justifiable for climate action to affect trade. The European Union has proposed such action, in its plan to impose reporting - and potentially, a financial charge – on emissions-intensive imports.

The UK-NZ agreement also takes steps to eliminate fossil fuel subsidies, in recognition that government support for the coal, oil and gas industries distorts prices and discourages climate action.

And the pact between the European Union and Canada requires the development of climate-friendly labelling and certification standards on products.

The Australia-UK deal seeks to ensure that each nation encourages high levels of environmental protection. These provisions could be strengthened with respect to climate change – for example, by tying them to each party’s emissions-reduction commitment under the Paris Agreement.

The agreement requires Australia and the UK to promote trade and investment in environmental goods and services, such as low-emissions technologies and renewable energy infrastructure. Yet the UK-NZ deal goes further. It eliminates customs duties on listed environmental goods, such as bicycle parts and plants.

The Australia-UK deal might have had stronger climate provisions if it incorporated a wider range of public views.

Public participation is key to good environmental decision-making. But the Australia-UK trade deal has been criticised by non-government organisations for its lack of public input.

In Australia, a parliamentary committee last year examined the deal. It said while peak business groups were often satisfied with the level of consultation on free trade agreements, others – including civil society groups and unions – were frequently not.

Looking ahead

The Albanese government was elected on a platform of enhanced climate action and has since entrenched temperature targets in national legislation. While the Australia-UK trade deal was finalised when it took office, opportunities exist to strengthen its climate ambition.

The agreement establishes a working group to review and monitor environmental provisions relating to matters such as marine pollution from ships, ozone-depleting substances, illegal logging and the wildlife trade. This group could also work to better integrate the climate and trade goals of both nations.

This might involve monitoring land-use change caused by agricultural trade between the countries and exploring prospects for sustainable food systems. It could mean removing customs duties for low-emissions goods and discussing ways to constrain subsidies on fossil fuels.

Doing so would help ensure this agreement, and others to come, meet the urgent need to avert dangerous global warming.

Margaret Young, Professor, The University of Melbourne and Georgina Clough, , The University of Melbourne

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

Invasive lionfish have spread south from the Caribbean to Brazil, threatening ecosystems and livelihoods

Brazil’s coastal waters teem with a rich array of species that paint a living tapestry beneath the waves. This underwater world is particularly special because many of its species are endemic – they are found nowhere else on Earth. The southwestern Atlantic is home to 111 endemic reef fish species, each of which plays a crucial role in the intricate web of marine life.

An uninvited guest has arrived in these tropical waters: the Pacific red lionfish (Pterois volitans). Renowned for its stunning appearance and voracious appetite, the lionfish was first detected off of Florida in 1985 and has spread throughout the Caribbean, killing reef fish in large numbers.

Now it has breached a formidable obstacle: the Amazon-Orinoco river plume, which flows into the Atlantic from northeastern Brazil. This massive discharge of fresh water has long functioned as a barrier separating Caribbean fish species from those farther south along Brazil’s coastline.

Scientists and environmental managers widely agree that the lionfish invasion in Brazil is a potential ecological disaster. As a marine ecologist, I believe mitigating the damage will require a comprehensive approach that addresses the ecological, social and economic harms wrought by this predatory fish.

Tracing the lionfish’s spread

It’s easy to see why lionfish appeal to aquarium enthusiasts. Native to the warm waters of the Indo-Pacific ocean, they are 12 to 15 inches long, with red and white stripes and long, showy fins. They protect themselves with dorsal spines that deliver painful venomous stings.

Lionfish were first detected in the Atlantic Ocean in 1985 off Dania Beach, Florida, probably discarded by a tropical fish collector. Since then they have spread throughout the Caribbean Sea, the Gulf of Mexico and northward as far as Bermuda and North Carolina – one of the most successful marine invasions on record. A close relative, the common lionfish or devil firefish (Pterois miles), has invaded the Mediterranean Sea and is spreading rapidly there.

Lionfish can be eaten safely if they are properly prepared to remove their venomous spines. In Florida and the Caribbean, lionfish hunting tournaments have become popular as a control method. However, lionfish move to deeper waters as they grow, so hunting alone can’t prevent them from spreading.

Marine scientists have anticipated for years that lionfish would someday arrive along the eastern coast of South America. A single sighting in 2014, far removed from the Amazon-Orinoco plume, was likely a result of an aquarium release rather than a natural migration.

Then in December 2020, local fishermen caught a pair of lionfish on coral reefs in the mesophotic, or “twilight,” zone several hundred feet below the mighty Amazon River plume. A scuba diver also encountered a lionfish in the oceanic archipelago of Fernando de Noronha, 220 miles (350 kilometers) off Brazil’s tropical coast.

New invasion fronts have quickly opened along Brazil’s north and northeast coasts, covering eight states and diverse marine habitats. More than 350 lionfish have been tallied along a 1,720-mile (2,765-kilometer) swath of coastline.

Aggressive predators without natural enemies

Like many introduced species, lionfish in the Atlantic don’t face natural population control mechanisms such as predation, disease and parasitism that limit their numbers in the Indo-Pacific. A 2011 study found that lionfish on reefs in the Bahamas were larger and more abundant than their Pacific counterparts.

Lionfish thrive in many marine habitats, from mangroves and seagrass beds to deepwater reefs and shipwrecks. They are aggressive, persistent hunters that feed on smaller fish, including species that keep coral reefs clean and others that are food for important commercial species like snappers and groupers. In a 2008 study, when lionfish appeared on reefs in the Bahamas, populations of small juvenile reef fish declined by 80% within five weeks.

Brazil’s northeast coast, with its rich artisanal fishing activity, stands on the front line of this invasive threat. Lionfish are present in coastal mangrove forests and estuaries – brackish water bodies where rivers meet the sea. These areas serve as nurseries for important commercial fish species. Losing them would increase the risk of hunger in a region that is already grappling with substantial social inequality.

Fishers also face the threat of lionfish stings, which are not lethal to humans but can cause painful wounds that may require medical treatment.

Facing the invasion: Brazil’s challenges

Biological invasions are easiest to control in early stages, when the invader population is still growing slowly. However, Brazil has been slow to react to the lionfish incursion.

The equatorial southwestern Atlantic, where the invasion is taking place, has been less thoroughly surveyed than the Caribbean. There has been little high-resolution seabed mapping, which would help scientists identifying potential lionfish habitats and anticipate where lionfish might spread next or concentrate their populations. Understanding of the scale of the invasion is largely based on estimates, which likely underrepresent its true extent.

Moreover, turbid waters along much of Brazil’s coast make it hard for scientists to monitor and document the invasion. Despite their distinctive appearance, lionfish are difficult to spot and record in murky water, which makes it challenging for scientists, divers and fishers to keep an accurate record of their spread.

Still another factor is that from 2018 through 2022, under former President Jair Bolsonaro, Brazil’s government sharply cut the national science budget, reducing funding for field surveys. The COVID-19 pandemic further reduced field research because of lockdowns and social distancing measures.

Making up for lost time

Brazil has a history of inadequately monitoring for early detection of marine invasions. The lionfish is no exception. Actions thus far have been reactive and often initiated too late to be fully effective.

As one of many Brazilian scientists who warned repeatedly about a potential lionfish invasion over the past decade, I’m disheartened that my country missed the window to take early action. Now, however, marine researchers and local communities are stepping up.

Given the length of Brazil’s coast, traditional monitoring methods are often insufficient. So we’ve turned to citizen science and information technology to fill the gaps in our knowledge.

In April 2022, a group of academic researchers spearheaded the launch of an online dashboard, which is updated continuously with data from scientific surveys and local community self-reports. This interactive platform is maintained by a research group led by marine scientists Marcelo Soares and Tommaso Giarrizzo from the Federal University of Ceará.

The dashboard allows anyone, from fishers to recreational divers and tourists, to upload data on lionfish observations. This information supports rapid response efforts, strategic planning for preventive measures in areas still free from lionfish, and the development of localized lionfish removal programs.

I believe lionfish are here to stay and will integrate over time into Brazil’s marine ecosystems, much as they have in the Caribbean. Given this reality, our most pragmatic and effective strategy is to reduce lionfish populations below levels that cause unacceptable ecological harm.

Regions along the coast that are still lionfish-free might benefit from early and preventive actions. Comprehensive surveillance plans should include environmental education programs about exotic species; early detection approaches, using techniques such as analyzing environmental DNA; citizen science initiatives to monitor and report lionfish sightings, participate in organized culls and help collect research data; and genetic surveys to identify patterns of connectivity among lionfish populations along Brazil’s coast and between Brazilian and Caribbean populations.

Brazil missed its initial opportunity to prevent the lionfish invasion, but I believe that with strategic, swift action and international collaboration, it can mitigate the impacts of this invasive species and safeguard its marine ecosystems.

This article has been updated to reflect that the correct number of endemic reef fish species in the southwestern Atlantic is 111.

Osmar J. Luiz, Senior Research Fellow in Aquatic Ecology, Charles Darwin University

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

Why 40°C is bearable in a desert but lethal in the tropics

This year, even before the northern hemisphere hot season began, temperature records were being shattered. Spain for instance saw temperatures in April (38.8°C) that would be out of the ordinary even at the peak of summer. South and south-east Asia in particular were hammered by a very persistent heatwave, and all-time record temperatures were experienced in countries such as Vietnam and Thailand (44°C and 45°C respectively). In Singapore, the more modest record was also broken, as temperatures hit 37°C. And in China, Shanghai just recorded its highest May temperature for over a century at 36.7°C.

We know that climate change makes these temperatures more likely, but also that heatwaves of similar magnitudes can have very different impacts depending on factors like humidity or how prepared an area is for extreme heat. So, how does a humid country like Vietnam cope with a 44°C heatwave, and how does it compare with dry heat, or a less hot heatwave in even-more-humid Singapore?

Weather and physiology

The recent heatwave in south-east Asia may well be remembered for its level of heat-induced stress on the body. Heat stress is mostly caused by temperature, but other weather-related factors such as humidity, radiation and wind are also important.

Our bodies gain heat from the air around us, from the sun, or from our own internal processes such as digestion and exercise. In response to this, our bodies must lose some heat. Some of this we lose directly to the air around us and some through breathing. But most heat is lost through sweating, as when the sweat on the surface of our skin evaporates it takes in energy from our skin and the air around us in the form of latent heat.

Meteorological factors affect all this. For example, being deprived of shade exposes the body to heat from direct sunlight, while higher humidity means that the rate of evaporation from our skin will decrease.

It’s this humidity that meant the recent heatwave in south-east Asia was so dangerous, as it’s already an extremely humid part of the world.

The limit of heat stress

Underlying health conditions and other personal circumstances can lead to some people being more vulnerable to heat stress. Yet heat stress can reach a limit above which all humans, even those who are not obviously vulnerable to heat risk – that is, people who are fit, healthy and well acclimatised – simply cannot survive even at a moderate level of exertion.

One way to assess heat stress is the so-called Wet Bulb Globe Temperature. In full sun conditions, that is approximately equivalent to 39°C in temperature combined with 50% relative humidity. This limit will likely have been exceeded in some places in the recent heatwave across south-east Asia.

In less humid places far from the tropics, the humidity and thus the wet bulb temperature and danger will be much lower. Spain’s heatwave in April with maximum temperatures of 38.8°C had WBGT values of “only” around 30°C, the 2022 heatwave in the UK, when temperatures exceeded 40°C, had a humidity of less than 20% and WBGT values of around 32°C.

Two of us (Eunice and Dann) were part of a team who recently used climate data to map heat stress around the world. The research highlighted regions most at risk of exceeding these thresholds, with literal hotspots including India and Pakistan, south-east Asia, the Arabian peninsula, equatorial Africa, equatorial South America and Australia. In these regions, heat stress thresholds are exceeded with increased frequency with greater global warming.

In reality, most people are already vulnerable well below the survivability thresholds, which is why we can see large death tolls in significantly cooler heat waves. Furthermore, these global analyses often do not capture some very localised extremes caused by microclimate processes. For example a certain neighbourhood in a city might trap heat more efficiently than its surroundings, or might be ventilated by a cool sea breeze, or be in the “rain shadow” of a local hill, making it less humid.

Variability and acclimatisation

The tropics typically have less variable temperatures. For example, Singapore sits almost on the equator and its daily maximum is about 32°C year round, while a typical maximum in London in mid summer is just 24°C. Yet London has a higher record temperature (40°C vs 37°C in Singapore).

Given that regions such as south-east Asia consistently have high heat stress already, perhaps that suggests that people will be well acclimatised to deal with heat. Initial reporting suggests the intense heat stress of the recent heatwave lead to surprisingly few direct deaths – but accurate reporting of deaths from indirect causes is not yet available.

On the other hand, due to the relative stability in year-round warmth, perhaps there is less preparedness for the large swings in temperature associated with the recent heatwave. Given that it is not unreasonable, even in the absence of climate change, that natural weather variability can produce significant heatwaves that break local records by several degrees Celsius, even nearing a physiological limit might be a very risky line to tread.

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Alan Thomas Kennedy-Asser, Research Associate in Climate Science, University of Bristol; Dann Mitchell, Professor of Climate Science, University of Bristol, and Eunice Lo, Research Fellow in Climate Change and Health, University of Bristol

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

Plastic recycling is failing – here’s how the world must respond

Recycling was once considered the obvious solution to the excessive amount of new (or virgin) plastic produced each year. This is no longer realistic. Global recycling capacity simply cannot keep up with the taking, making and wasting of natural resources.

Growing mountains of plastic waste are accumulating in the poorest countries as affluent nations such as the UK ship their recycling overseas. But some nations are importing far more plastic waste than they can possibly recycle.

The recycling process itself also creates problems. A new report by Greenpeace and the International Pollutants Elimination Network has revealed how plastics which are made with or come into contact with toxic chemicals, such as flame retardants, can contaminate the recycling process by spreading these toxins through subsequent batches of plastic waste. Another recent study showed that recycling facilities can release hundreds of tonnes of microplastics into the environment each year.

Only 6-9% of all plastic ever produced has been sent for recycling. Although plastic and other waste is collected for recycling in most countries, the amount of material that is remade into the same or similar products (what is called closed-loop recycling) is extremely low. Only 2% of plastic waste is recycled in a closed loop and not turned into something of lower quality, which is called downcycling. Recycling can not fully replace virgin material as it can only be recycled twice before losing necessary properties, and so most recycling results in a downgraded material that cannot be used for the same purpose.

A more sustainable approach would prioritise preventing plastic waste by taking action at earlier stages of a plastic product’s lifecycle: reducing how much plastic is ultimately made, reusing what exists and replacing plastic with alternative materials where appropriate.

Reduce

Manufacturers must stop making so much unnecessary plastic to reduce the amount entering the economy. There is no case for making plastics that are impossible to collect, reuse or recycle, or are toxic. Yet they are abundant: think multilayered sachets, thin films and wrappers. These should be phased out as a priority.

Global caps on plastic production could restrict its use to reusable products and packaging, reducing the pressure on recycling systems.

You can refuse single-use packaging when shopping if alternatives are available and affordable. Choose loose vegetables, or products wrapped in packaging that can be refilled.

Reuse

Using the plastic you already have for as long as possible reduces the amount of new products and packaging that need to be made and how much waste is ultimately sent for recycling.

Roughly 250 billion single-use coffee cups are used worldwide every year – a figure that could be slashed by governments setting national mandates for reusable cups and bottles. This might involve shops, cafés and other venues providing reusable packaging for any products they sell and ensuring each one is used, tracked, washed, returned and replenished for the next consumer cycle.

Substitute

Metals, glass, or paper can be used instead of plastic, but there is no universal sustainable alternative. The most appropriate material depends on the item’s use.

The environmental consequences of any material should be rigorously assessed across its entire life cycle – from production to use and disposal – to ensure it does more good than harm. And such assessments must consider all social, environmental and economic costs.

The true cost of making, distributing and disposing of plastic is estimated to be more than ten times greater than what the customer pays for the product. Including the hidden costs of environmental damage and human misery arising from pollution in the price of virgin plastic, by taxing manufacturers or retailers for instance, could boost the economic case for alternatives.

Recycling can still be useful

Not all plastics can be reused, especially medical devices. When all alternatives have been exhausted, recycling keeps material in the economy and temporarily delays the need for more virgin plastic. But the existence of recycling shouldn’t justify making more plastic.

Recycling must not pollute. Manufacturers should only make plastics which can be recycled via methods proven to be safe and clean, and ban toxic additives. Simple labelling can help consumers make informed decisions about how, where and what to either reuse or recycle, which would help prevent recycling loads becoming contaminated with non-recyclable waste and toxins.

Plastics sent for recycling should be treated in the most socially and environmentally responsible way. High-income countries which export waste to poorer countries for cheap recycling do so without guarantees that infrastructure exists to manage this waste where it ends up. The result is waste leaking into the environment, and toxic plastic blocking drainage channels and causing floods. Some of this is burned outdoors, which comes with its own risks to health and the environment. Banning or restricting exports would help.

Precarious workers in the informal waste sector collect, sort and sell recyclable materials and carry out 60% of global recycling. Waste reclaimers endure poor health and low pay but their extensive knowledge is invaluable and must be acknowledged. Policies to protect their rights and improve their livelihoods are needed.

Countries meeting in Paris for the second of five rounds of negotiations for an international treaty to end plastic pollution will discuss all areas of the plastic lifecycle - from the extraction of material to manufacturing, use and disposal. Banning unnecessary plastics, toxic additives and waste exports should be high on the agenda, along with schemes to encourage reuse and repair.

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Cressida Bowyer, Senior Research Fellow and Deputy Director, Revolution Plastics, University of Portsmouth; Keiron Roberts, Senior Lecturer in Sustainability and the Built Environment, University of Portsmouth, and Stephanie Northen, Research Associate, Revolution Plastics, University of Portsmouth

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The secret world of moss, ancient ancestor of all plants and vital for the health of the planet

When people consider extraordinary plants, most probably don’t spare a thought for moss. It blends in against the green background of plant life, and seems to grow everywhere – whether you want it to or not.

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But this group of plants, which actually comprises between 12,000 and 15,000 species, is astonishing. Their almost unique resilience allows them to grow practically everywhere on Earth. They are helping scientists understand the evolution of life, and are one of the most ancient plant groups alive today.

A recent study by an Australian research team found that mosses are the lifeblood of habitats around the world, with plants and soil in better shape almost everywhere they grow.

Despite their importance, mosses are often overlooked due to their diminutive size. The smallest mosses, known as micromosses, measure only a few millimetres in length. Even the largest moss, Dawsonia superba, a species native to Australia, New Zealand and the Pacific Islands, only reaches heights of up to 50cm – a giant among mosses, yet still smaller than the average houseplant.

But in fact, mosses help hold up entire ecosystems.

Many people think of plants as nice-looking greens. Essential for clean air, yes, but simple organisms. A step change in research is shaking up the way scientists think about plants: they are far more complex and more like us than you might imagine. This blossoming field of science is too delightful to do it justice in one or two stories. This article is part of a series, Plant Curious, exploring scientific studies that challenges the way you view plantlife.

Drivers of critical ecosystem services

The contributions of mosses to the structure and function of modern ecosystems is often overlooked, lagging behind our understanding of more complex plants. The Australian study examined mosses’ relationship to their habitats in detail, and found they are critical to soil health.

The researchers collected moss samples from ecosystems around the globe – from tropical rainforest to polar landscapes through to arid deserts. Combining their findings from these samples with an analysis of previous research, their results showed that mosses are key players in every habitat in which they are found. Mosses store huge amounts of carbon, help the soil nutrient cycle, and also the decomposition of organic matter.

Mosses can even come to the rescue in disturbed ecosystems. Research examining the area around the Mount St. Helens volcano following a devastating eruption in the early 1980s found mosses were among the first forms of life to reappear.

Some types of moss, including the Sphagnum species, absorb and hold water in their tissues. This regulates water flow in the area, preventing flooding and creating peatland habitats which are home to rare plants and animals.

Mosses also provide unique habitats for microscopic life. Tardigrades, eight-legged micro-animals, are also known as moss piglets or bears of moss, thanks to their habit of clambering through moss “jungles” in search of their next meal. Moss piglets are nearly indestructible and can even survive in outer space, by entering a death-like state called cryptobiosis.

Ancient ancestors

Mosses, along with liverworts and hornworts, are part of a group of plants known as bryophytes. These evolved more than 400 million years ago and still share many characteristics with the first plants to have emerged on to the Earth’s land surfaces – their small size and lack of true roots, for example. And while most plants have a continuous column of water which flows inside them via a xylem and phloem, mosses don’t – just like some of the most ancient plants in Earth’s history.

Instead, these tiny plants have their own conducting systems to move substances around their bodies. They absorb water and nutrients from rainwater and dust deposits across their surfaces. Their hair-like “roots”, known as rhizoids, anchor mosses to the surface they are growing on.

Mosses are almost unparalleled in their ability to survive harsh environments. This makes them excellent for studying the evolution of plants, much of which occurred during challenging conditions on Earth.

The study of modern mosses’ and other bryophytes’ genetics and physiology has given researchers insights into the adaptations that allowed plants to transition from water to land – for example, the formation of partnerships with fungi to access soil nutrients. Their incredible resistance to environmental stress such as drought and UV radiation was also crucial to their ability to evolve on land.

One of the most critical features of land mosses is their desiccation tolerance, which is the ability to survive near-complete drying out. When water is scarce, mosses can enter a state of suspended animation where they greatly reduce their metabolic activity, allowing them to survive until conditions improve. Some species, such the desert moss Syntrichia caninervis, can survive a hundred years in this dormant state and revive within hours of rewetting.

Studying the mechanisms of this ability in modern plants helps scientists understand how ancient plants might have adapted to land. It is possible that studying desiccation tolerance in mosses could help scientists discover new ways to protect crops from extreme drought in the future.

These little plants are also entwined with human history. From exploiting the antiseptic properties of moss for wound healing to using broom moss (Dicranium scoparium) for relief of constipation, mosses have played a substantial role in relieving human suffering.

So, perhaps we should think twice before raking out mosses from the lawn. Instead, take a moment to consider the natural beauty of their delicate green tendrils – and their history as some of the most intrepid explorers in Earth’s history.

Katie Field, Professor in Plant-Soil Processes, University of Sheffield and Silvia Pressel, Senior Researcher Lead in Life Sciences, Natural History Museum

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Atlantic hurricane season 2023: El Niño and extreme Atlantic Ocean heat are about to clash

The Atlantic hurricane season starts on June 1, and forecasters are keeping a close eye on rising ocean temperatures, and not just in the Atlantic.

Globally, warm sea surface temperatures that can fuel hurricanes have been off the charts in the spring of 2023, but what really matters for Atlantic hurricanes are the ocean temperatures in two locations: the North Atlantic basin, where hurricanes are born and intensify, and the eastern-central tropical Pacific Ocean, where El Niño forms.

This year, the two are in conflict – and likely to exert counteracting influences on the crucial conditions that can make or break an Atlantic hurricane season. The result could be good news for the Caribbean and Atlantic coasts: a near-average hurricane season. But forecasters are warning that that hurricane forecast hinges on El Niño panning out.

Ingredients of a hurricane

In general, hurricanes are more likely to form and intensify when a tropical low-pressure system encounters an environment with warm upper-ocean temperatures, moisture in the atmosphere, instability and weak vertical wind shear.

Warm ocean temperatures provide energy for a hurricane to develop. Vertical wind shear, or the difference in the strength and direction of winds between the lower and upper regions of a tropical storm, disrupts the organization of convection – the thunderstorms – and brings dry air into the storm, inhibiting its growth.

The Atlantic Ocean’s role

The Atlantic Ocean’s role is pretty straightforward. Hurricanes draw energy from warm ocean water beneath them. The warmer the ocean temperatures, the better for hurricanes, all else being equal.

Tropical Atlantic Ocean temperatures were unusually warm during the most active Atlantic hurricane seasons on recent record. The 2020 Atlantic hurricane season produced a record 30 named tropical cyclones, while the 2005 Atlantic hurricane season produced 28 named storms, a record 15 of which became hurricanes, including Katrina.

How the Pacific Ocean gets involved

The tropical Pacific Ocean’s role in Atlantic hurricane formation is more complicated.

You may be wondering, how can ocean temperatures on the other side of the Americas influence Atlantic hurricanes? The answer lies in teleconnections. A teleconnection is a chain of processes in which a change in the ocean or atmosphere in one region leads to large-scale changes in atmospheric circulation and temperature that can influence the weather elsewhere.

One recurring pattern of tropical Pacific climate variability that initiates teleconnections is the El Niño-Southern Oscillation.

When the tropical eastern-central Pacific Ocean is unusually warm, El Niño can form. During El Niño events, the warm upper-ocean temperatures change the vertical and east-west atmospheric circulation in the tropics. That initiates a teleconnection by affecting the east-west winds in the upper atmosphere throughout the tropics, ultimately resulting in stronger vertical wind shear in the Atlantic basin. That wind shear can tamp down hurricanes.

That’s what forecasters are expecting to happen this summer. The latest forecasts show a 90% likelihood that El Niño will develop by August and stay strong through the fall peak of the hurricane season.

A tug of war between Atlantic and Pacific influences

My research and work by other atmospheric scientists has shown that a warm Atlantic and a warm tropical Pacific tend to counteract each other, leading to near-average Atlantic hurricane seasons.

Both observations and climate model simulations have shown that outcome. The National Oceanic and Atmospheric Administration’s 2023 forecast calls for a near-average 12 to 17 named storms, five to nine hurricanes and one to four major hurricanes. An earlier outlook from Colorado State University forecasters anticipates a slightly below-average season, with 13 named storms, compared with a climatological average of 14.4.

The wild cards to watch

Although tropical Atlantic and Pacific Ocean temperatures often inform skillful seasonal hurricane forecasts, there are other factors to consider and monitor.

First, will the forecast El Niño and Atlantic warming pan out? If one or the other does not, that could tip the balance in the tug of war between the influences.

The Atlantic Coast should be rooting for El Niño to develop as forecast, since such events often reduce hurricane impacts there. If this year’s expected Atlantic Ocean warming were instead paired with La Niña – El Nino’s opposite, characterized by cool tropical Pacific waters – that could have led to a record-breaking active season instead.

Two other factors are also important. The Madden-Julian Oscillation, a pattern of clouds and rainfall that travels eastward through the tropics on a time scale of 30 to 90 days, can either encourage or suppress tropical storm formation. And dust storms from the Saharan air layer, which contains warm, dry and dusty air from Africa, can suppress tropical cyclones.

Christina Patricola, Assistant Professor of Atmospheric Sciences, Iowa State University

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