The sheer scale and intensity of the Australian bushfire crisis have led to apocalyptic scenes making the front pages of newspapers the world over. An estimated 10 million hectares (100,000 sq km) of land have burned since 1 July 2019. At least 28 people have died. And over a billion animals are estimated to have been killed to date. Of course, the actual toll will be much higher if major animal groups, such as insects, are included in these estimates.

The impacts of climate change – in particular, the consequences of the increasing frequency of extreme weather events on all life should be abundantly clear. People finally seem to be taking this seriously, but there is an undercurrent of opinion about the “naturalness” of wildfires. Some are still questioning the role of climate change in driving the Australian bushfires.

It is true that wildfires naturally occur in many parts of the world, and benefit plants and animals in ecosystems that have been uniquely shaped by fire over evolutionary time. And people have been using fire to manage ecosystems for thousands of years. We could learn a thing or two from Aboriginal people and the techniques they have traditionally used to prevent bushfires.

But make no mistake, the scientific evidence shows that human-caused climate change is a key driver of the rapid and unprecedented increases in wildfire activity. What is particularly worrying is the extent to which this is eroding the resilience of ecosystems across wide regions. Yes, it is plausible to expect most plants and animals that have adapted to fire will recover. But the ecological costs of huge, repetitive, high-severity wildfires on ecosystems could be colossal.

Out of control

And it’s unclear how much the natural world can tolerate such dramatic disturbance. Wildfires are increasing in severity around the world. The Australian bushfires are larger than some of the deadliest recorded. Incidences are also increasing in ecosystems where wildfires are uncommon, such as the UK uplands. Not to mention the widespread deliberate burning of areas of high conservation value for agriculture, as has been recently reported in large parts of the Brazilian Amazon for beef production and in Indonesia for palm oil.

Unsurprisingly, given the shocking numbers of animals that must have perished as a result of these wildfires, many are questioning whether burned ecosystems can recover from such dramatic losses of biodiversity. In Australia, for example, some estimate that the fires could drive more than 700 insect species to extinction.

The world’s biodiversity is already severely struggling – we are in the midst of what scientists describe as the sixth mass extinction. A recent report has highlighted that about a quarter of assessed species are threatened with extinction. Australia already has the highest rate of mammal loss for any region in the world, signalling the fragility of existing ecosystems that might struggle to function in a warming, fire prone world.

Fears for familiar and charismatic animals affected by the bushfires, such as koala, have been expressed by conservationists. The outlook for already critically endangered species, such as the regent honeyeater and western ground parrot, meanwhile, is uncertain. But to establish the true ecological costs of wildfires it is important to consider biodiversity in terms of networks, not particular species or numbers of animals.

All species are embedded in complex networks of interactions where they are directly and indirectly dependent on each other. A food web is a good example of such networks. The simultaneous loss of such large numbers of plants and animals could have cascading impacts on the ways species interact – and hence the ability of ecosystems to bounce back and properly function following high-severity wildfires.

A fragile system

And so it’s key that we consider biodiversity loss due to wildfires in terms of entire networks of interacting organisms, including humans, rather than simply one or two charismatic animals. I have studied and recently published research about the loss of plants and animals due to wildfires in Portugal, using new methods in ecology that can examine the resilience of ecosystems to species extinctions. My team found that networks of interacting plants and animals at burned sites became fragile and more prone to species extinctions.

Our study looked at the impacts of a large wildfire in 2012 on one of the many ecological interactions that keep ecosystems healthy – insect pollination. We examined the responses of moths, which are important but often overlooked pollinators, to wildfire by comparing those we caught in burned and neighbouring unburned areas.

By collecting, counting and identifying the thousands of pollen grains they were carrying, we were able to decipher the plant-insect network of interacting species. In this way, it was possible to examine not only the responses of the plants and animals to wildfire, but crucially the impacts on pollination processes.

We then used these networks to model the resilience of the ecosystem more generally. We found that burned areas had significantly more abundant flowers (due to a flush of plants whose seeds and roots survived in the soil) but less abundant and species‐rich moths. The total amount of pollen being transported by the moths in burned areas was just 20% of that at unburned areas.

Our analysis revealed important differences in the way these species interacted as a result of the wildfire. Although the study was only a snapshot in time, we were able to show that plant-insect communities at burned sites were less able to resist the effects of any further disturbances without suffering species extinctions.

And so as people start rebuilding their homes, livelihoods and communities in Australia following the devastating bushfires, it is crucial that governments and land managers around the world take sensible decisions that will build resilience into ecosystems. To do this, ecological interaction networks need to be considered, rather than specific species. Cutting-edge network approaches that examine the complex ways in which entire communities of species interact can and should help with this.

Over 45 years ago, the American evolutionary ecologist and conservationist Dan Janzen wrote: “There is a much more insidious kind of extinction: the extinction of ecological interactions.” We should all be concerned not just about the loss of animals, but about the unravelling of species interactions within ecosystems on which we all depend for our survival.

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Darren Evans, Reader in Ecology and Conservation, Newcastle University

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

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Bonus Video added by Informed Comment:

Nine News Australia: “Victoria Bushfires: Retired captain protects others’ homes | Nine News Australia”

Around 66 million years ago, a giant asteroid struck the Earth, causing the extinction of the dinosaurs, ammonites, and many other species.

The asteroid was equally devastating at a microscopic level, driving ocean plankton to near-extinction. This crippled the base of the marine food chain and shut down important ocean functions, such as the absorption and delivery of carbon dioxide from the atmosphere to the ocean floor.

Given the real threat of a sixth mass extinction event brought about by human-caused climate breakdown and habitat disruption, we wanted to find out how long the ocean ecosystem took to reboot after the last one. What we found has grave implications for the long-term outlook of marine ecosystems should we tip the critical base of its food chain over the threshold of extinction.

The nannoplankton almost totally wiped out 66m years ago – also known as coccolithophores – are now widespread once more in the sunlit upper oceans. Although roughly 100 times smaller than a grain of sand, they are so abundant that they are visible from space as swirling blooms in the ocean surface.

When these microscopic plankton die, they leave behind exquisite armoured exoskeletons known as coccospheres made from the mineral calcite, composed of bonded calcium and carbon. Along with the dead plankton cells, these skeletons slowly fall to the ocean floor, forming a muddy calcium and carbon-rich sediment. As this sediment compacts, it forms chalk and limestone, leaving us with iconic landscapes such as white chalk cliffs – the shallow sea floor of a forgotten age, since lifted up by tectonic activity.

Conserved within this compacted sediment is a continuous fossil record stretching back 220m years. It is this fossil record – the most abundant on the planet – that can tell us how ecosystems responded to the extinction of nannoplankton. Changes in the diversity and abundance of the plankton that once lived in the ocean above reflect the environmental changes that played out in the millennia after the giant asteroid hit.

We extracted a continuous core of deep-sea sediment from the Pacific Ocean. For the first 13m years after the mass extinction event, we took a sample of the fossil record at intervals of 13,000 years. We measured fossil abundance, diversity and cell sizes from over 700,000 specimens, producing probably the largest fossil dataset ever produced from a single site.

2m years for stability, 10m for diversity

These fossil data revealed that the plant-like, photosynthetic plankton bounced back almost immediately – probably within a few thousand years after the mass extinction. However, the earliest communities were highly unstable and made up of just a handful of species with unusually small cell sizes, as the figure above shows.

While the calcite skeletons of larger plankton cells can sink to the sea floor, the skeletons of these smaller organisms descend much less often, instead getting “recycled” in the upper ocean by hungry plankton. Communities with larger cell sizes were not reestablished until two million years later, restoring their critical transfer of carbon to the ocean floor to pre-extinction levels.

By this time, the number of different plankton species had also increased. This genetic diversity allowed them to expand into a greater range of ocean habitats, providing greater resilience to environmental change, and a secure foundation at the base of the ocean food web.

This stability then supported expansion in the abundance and diversity of larger plankton, fish, mammals, and birds dependent on these food sources. But although stable and resilient ecosystems had returned by two million years after the mass extinction, it took a further eight million years for species numbers to fully recover to their previous levels.

A warning from the past

Today’s marine ecosystems are still just as dependent on the plankton at their base as they were in the past. Studies show that populations of modern-day plankton have already declined by as much as 40%, and that 70% of species are migrating towards the poles. We still don’t fully understand how plankton species might finally be driven to extinction, but the fossil record shows us that extinction is strongly shaped by climate change.

If we carry on emitting carbon and interfering with marine ecosystems, we run the risk of losing one of its critical carbon-storing and food-providing players. Research shows that that could take nature millions of years to reverse.

Click here to subscribe to our climate action newsletter. Climate change is inevitable. Our response to it isn’t.

Paul Bown, Professor of Micropalaeontology, UCL; Samantha Gibbs, Lecturer, National Oceanography Centre, University of Southampton, and Sarah Alvarez, Lecturer in Life and Earth Sciences, University of Gibraltar

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

We are witnessing the loss of biodiversity at rates never before seen in human history. Nearly a million species face extinction if we do not fundamentally change our relationship with the natural world, according to the world’s largest assessment of biodiversity.

Last week, in the culmination of a process involving 500 biodiversity experts from over 50 countries, and 134 governments negotiated the final form of the Global Assessment of the Intergovernmental Science-Policy Platform for Biodiversity and Ecosystem Services (IPBES).

IPBES aims to arm policy-makers with the tools to address the relationships between biodiversity and human well-being. It synthesises evidence on the state of biodiversity, ecosystems and natures’ contributions to people on a global scale.

The IPBES Global Assessment provides unequivocal evidence that we need biodiversity for human survival and well-being. To stem unprecedented species decline the assessment sets out the actions governments, the private sector and individuals can take.

Importantly, a whole chapter of the Global Assessment (about one-sixth of the assessment) is dedicated to examining whether existing biodiversity law and policy is adequate. This chapter also outlines ways to address the vortex of biodiversity decline.

If we are to halt the continued loss of nature, then the world’s legal, institutional and economic systems must be reformed entirely. And this change needs to happen immediately.

What makes IPBES Assessments special?

IPBES is the biodiversity equivalent to the Intergovernmental Panel on Climate Change (IPCC). Assessments are a fundamental part of IPBES’s work.

IPBES Assessments review thousands of biodiversity studies to identify broad trends and draw authoritative conclusions. In the case of the Global Assessment, IPBES authors reviewed more than 15,000 publications from scientific and governments sources.

Governments and stakeholders give feedback on the draft text, and experts respond meticulously to the thousands of comments before revising and clarifying the draft. A final summary of key findings is then negotiated with member states at plenary meetings – these meetings concluded on Saturday.

What did the Global Assessment find?

Human activity severely threatens biodiversity and ecosystem functions worldwide. About 1 million species are facing extinction. If nothing changes many of these could be gone within just decades.

But nature is vital to all aspects of human health. We rely on natural systems, not only for food, energy, medicine and genetic resources, but also for inspiration, learning and culture.

The report also reveals the loss of biodiversity and ecosystem function is much less pronounced on lands managed by Indigenous peoples and local communities. It also recognises the significant role of Indigenous knowledge, governance systems and culturally-specific worldviews which adopt a stewardship approach to managing natural systems.

The report identified agriculture, forestry and urbanisation as the number one reason for biodiversity loss in land-based ecosystems and rivers. In the sea, fishing has had the greatest impact on biodiversity and is exacerbated by changes in the use of the sea and coastal lands.

This is followed closely by:

• the direct use of species (primarily through harvesting, logging, hunting and fishing)

• climate change

• pollution

• the invasion of non-native species.

These factors are aggravated by underlying social values, such as unsustainable consumption and production, concentrated human populations, trade, technological advances, and governance at multiple scales.

The Global Assessment concludes that current biodiversity laws and policies have been insufficient to address the threats to the natural world.

What’s more, if nothing changes, neither the Convention on Biological Diversity’s Aichi Targets nor the United Nations’ Sustainable Development Goals are likely to be met.

And yet, the Global Assessment has an optimistic outlook. It emphasises that if the world’s legal, institutional and economic systems are transformed then it is possible to achieve a better future for biodiversity and human well-being in the next 30 years.

But this is only possible if reform happens immediately, as incremental change will be insufficient.

What must be done?

The Global Assessment puts forward these next, urgent steps:

• we need to redefine human well-being beyond its narrow basis on economic growth

• engage multiple public and private actors

• link sustainability efforts across all governance scales

• elevate Indigenous and local knowledge and communities.

The report also recommends strengthening environmental laws and taking serious precautionary measures in public and private endeavours. Governments must recognise indivisibility of society and nature, and govern to strengthen rather than weaken the natural world.

What can I do?

Produce and consume sustainably

Individuals can make meaningful change through what we produce and what we buy. Our food is an important starting point. You could, for instance, choose local or sustainably produced meals and reduce your food waste.

Champion the inclusion of Indigenous peoples and local communities

Indigenous and local communities need to be included and supported more than ever before. The Global Assessment provides clear evidence that lands managed by Indigenous and local communities are performing better in terms of biodiversity. Still, these lands face serious threats, and Indigenous communities continue to be marginalised around the world.

Provoke governments to do better

Current biodiversity laws and policies don’t adequately address the threats to the natural world. The report recommends the world include biodiversity considerations across all sectors and jurisdictions to prevent further degradation of natural systems. We have an important role in rallying our governments to ensure this occurs.

We are losing biodiversity at record-breaking rates. The majesty of the natural world is disappearing and with it that which makes life worth living. We are also undermining the capacity of the Earth to sustain thriving human societies. We have the power to change this – but we need to act now.

Michelle Lim, Lecturer, Adelaide Law School, University of Adelaide

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

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Bonus video added by Informed Comment:

PBS NewsHour: “Humans pushing 1 million species to brink of extinction, says UN report”