How fungi’s knack for networking boosts ecological recovery after bushfires



Doug Beckers/Flickr, CC BY-SA

Adam Frew, University of Southern Queensland; Andy Le Brocque, University of Southern Queensland; Dale Nimmo, Charles Sturt University; Eleonora Egidi, Western Sydney University; Jodi Price, Charles Sturt University, and Leanne Greenwood, Charles Sturt University

The unprecedented bushfires that struck the east coast of Australia this summer killed an estimated one billion animals across millions of hectares.

Scorched landscapes and animal corpses brought into sharp relief what climate-driven changes to wildfire mean for Australia’s plants and animals.

Yet the effects of fire go much deeper, quite literally, to a vast and complex underground world that we know stunningly little about, including organisms that might be just as vulnerable to fire, and vital to Australia’s ecological recovery: the fungi.

Fungi play a crucial role in ecosystems around the world. Amanita sp, Geastrum sp and Aseroe sp.
Adam Frew

Plants and fungi: a match made underground

The aftermath of wildfires can make landscapes appear devoid of life. Yet under the ash beds lies a vast living network of fungi.

One group of fungi, called arbuscular mycorrhizal (AM) fungi, form symbiotic relationships with most of the world’s land plants. This means most plants and AM fungi rely on each other to grow and thrive.

Fungi provide access to nutrients such as phosphorus, and plants provide carbon as sugar and fats.
Adam Frew via BioRender

Extensive networks of AM fungal mycelium (a vegetative part of a fungus, akin to plant roots) explore the soil to access nutrients beyond the reach of their plant partners. The mycelium forms a fungal underground highway, transporting the valuable nutrients back to the plants.




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Beyond nutrients, AM fungi can influence all aspects of plant ecology, such as seedling establishment, plant growth, defence against herbivores, and competition between different plant species. In fact, the number of species and abundance of AM fungi determine the success and diversity of plants.

In return for the nutrients they provide, AM fungi receive sugar made by plants through photosynthesis. For many species, this means without a plant host the fungi won’t last.

The responses of plants and AM fungi to fire are therefore deeply intertwined: the recovery of one is dependent on the other. Yet ecologists are only beginning to learn how fire affects fungi and what role they might have in hastening ecosystem recovery following wildfires.

Arbuscular mycorrhizal fungi colonising a plant root.
Adam Frew

Fungi and fire: what do we know?

Studies have shown fungi living near the soil surface are particularly susceptible to fire, often killed by high soil temperatures as the fire passes over. Fungi further below the surface are relatively more protected, and may provide the nuclei for recovery.

But, as with animals, surviving fire is only half the battle. When fire removes vegetation, it suddenly halts sugar and fats plants produce, delivered to the fungi below-ground.




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Another challenge is the ways fire influences the underground world, such as changes in soil acidity, soil carbon, nutrient dynamics, and soil water. For instance, soils with more acidity tend to have less diversity of AM fungi.

How exactly fungi and fire interact remains an ecological mystery. Coprinus sp.
Adam Frew

The combination of high temperatures and changed conditions appear to take a toll on fungi: a 2017 meta-analysis of 29 studies found fire reduces the number of fungal species by about 28%. And given the severity of last summer’s bushfires, we can expect that many fungal communities below the surface have been lost, too.

Lose fungi, lose function

When fire hits, the community of AM fungi may lose less resistant species. This is important because studies show different species of AM fungi are better at supporting their plant partners in different ways. Some are better at providing nutrients, while others are more helpful with defending plants from disease and herbivores.

Changes in the number and types of AM fungal species can strongly determine how well plants recover, and can influence the whole ecosystem after fire. For example, plants could be left more vulnerable to disease if fungi supporting native plant chemical or physical defences are reduced by fire.

Amanita muscaria (Fly agaric)
Adam Frew

Since we know fungi are particularly important to plants in times of ecological stress, their role may be paramount in harsh post-fire landscapes. But while firefighters and wildlife carers have gone to inspiring lengths to protect plants and animals, we know little about how to help AM fungi recovery from the bushfires, or if help is even necessary.

Helping fungi help ecosystems

Research from last year showed reintroducing AM fungal communities (usually as an inoculant or biofertiliser) to degraded and disturbed landscapes can increase plant diversity by around 70%, encourage recovery of native plants, and suppress invasive weeds.

Fire tends to change what species of arbuscular mycorrhizal fungi are present in the soil as ecosystems recovery.
Adam Frew via BioRender

Taking a similar approach and actively putting fungi back into fire-affected environments could ensure more rapid or more complete recovery of native vegetation, including the survival of endangered plant species threatened by the fires.

However, it’s important to consider which AM fungi are reintroduced. They should be species normally present in the local area, and suited to support recovering plant communities.




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So as climate change leads to more frequent and intense bushfires, could fungi form a fundamental component of fire recovery efforts? Maybe.

But there is so much we’re yet to learn about these ancient and complex relationships. We’re only beginning to scratch the surface.The Conversation

Adam Frew, Lecturer, University of Southern Queensland; Andy Le Brocque, Associate Professor, University of Southern Queensland; Dale Nimmo, Associate Professor in Ecology, Charles Sturt University; Eleonora Egidi, Researcher, Western Sydney University; Jodi Price, Senior Lecturer in Vegetation Ecology, Charles Sturt University, and Leanne Greenwood, PhD candidate, Charles Sturt University

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

Victoria quietly lifted its gas exploration pause but banned fracking for good. It’s bad news for the climate


Samantha Hepburn, Deakin University

Amid coronavirus chaos, the Victorian government announced its decision earlier this week to lift the ban on onshore gas exploration, but also to make the temporary state-wide ban on fracking permanent.

This decision was made three years after an investigation found gas reserves in the state could be extracted without any environmental impacts, and new laws will be introduced to parliament for drilling to start in July next year.




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The state government first introduced the moratorium (temporary ban) on onshore conventional and unconventional gas production in 2017, enshrined in the Mineral Resources (Sustainable Development) Act 1990. It effectively made it an offence to either conduct coal seam gas exploration or hydraulic fracturing (fracking) until June 2020.

The ban was originally imposed amid strong concerns about the environmental, climate and social impacts of onshore gas expansion. But lifting the ban to allow conventional gas exploration while banning fracking and unconventional gas (coal seam gas), doesn’t remove these concerns.

The fracking ban isn’t so permanent

The new laws seek to do two things: lift the ban on conventional onshore gas production, and to entrench a ban on fracking and coal seam gas exploration into the state constitution.

The government has stated it wants to make it difficult for future governments to remove the fracking ban. But this is highly unlikely to be legally effective. Unlike the federal constitution, the Victorian constitution is an ordinary act, and so it can be amended by another legal act.

The only way entrenching an amendment in the state constitution so that it is permanent and unchangeable is if it relates to the operation and procedure of parliament. And fracking does not do this.

This raises the spectre of a future government removing the fracking ban in line with an accelerating onshore gas framework.

Conventional vs unconventional gas

The main difference between conventional gas and unconventional gas (coal seam gas) lies in their geology.

Conventional gas can generally be extracted without the need to frack, as gas can move to the surface through gas wells. To release unconventional gas, particularly shale gas, fracking is always required.




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Fracking technologies risk water quality from ground disturbances, spills, the release of chemicals and other fluids, and the underground migration of gases and chemicals.

So lifting the conventional onshore gas ban while keeping the fracking ban will mean less risk to the environment. But extracting conventional gas is still risky.

Greenhouse gas leaks

Extracting conventional gas risks fugitive emissions. This refers to greenhouse gases, such as methane, that can escape into the atmosphere during mining fossil fuels, such as from equipment leaks, deliberate or accidental venting, or from gas flaring.

Precise measurements of the fugitive emissions from onshore conventional gas production are difficult to predict, but their effect on climate change is alarming.

The latest estimates indicate fugitive emissions account for approximately 6% of Australia’s national greenhouse gas emissions. Fugitive emissions also have about 27 times the greenhouse harming potential of carbon dioxide.

In 2017, the Australian Gas Industry argued well managed sites produce little fugitive emissions, and poorly managed sites were responsible for 75% of fugitive emissions.

This means any expansion of onshore conventional gas must be accompanied by strict management and regulation. But there’s no industry-wide code of practice in Victoria focused on reducing this emissions risk.

Increasing annual emissions

Even in the unlikely scenario of zero or limited fugitive emissions, expanding conventional gas exploration will still add to Victoria’s annual greenhouse gas emissions.

The proposed laws follow the conclusions of a three-year study that reviewed the climate, environmental, economic and social impacts of gas exploration in Victoria.

The report suggested a slight increase in absolute annualised greenhouse gas emissions. In other words, Victoria’s annual greenhouse gas emissions would be proportionately increased by lifting the ban.

It also suggested expanding gas development would contribute between only 0.1% and 0.2% of Victoria’s annual greenhouse gas emissions, and that this wouldn’t affect Victoria’s 2050 net-zero target.

But 0.1% to 0.2% still amounts to releasing an additional 122,000 to 329,000 tonnes of CO₂ equivalent into the atmosphere.

What’s more, this assessment completely ignores emissions released through increased gas usage within the community. Globally, CO₂ emissions from natural gas use rose almost 200 million metric tons in 2019 and were responsible for two-thirds of the global emissions increase.

What it means for the community

The report predicts 242 jobs, A$312 million in gross regional product and A$43 million in royalties for Victoria. But overall, gas prices in the east coast market won’t change.




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The additional 128-830 petajoules (a joule is a measure of thermal energy and a petajoule is a million billion joules) that is potentially capable of being produced by lifting the moratorium will not be enough to address the forecast shortfall.

For the communities around the gas exploration sites, the report indicates the social impact of lifting the moratorium would be manageable.

The report indicates that 80% of the south-west and Gippsland communities – from more than 800 engagements with industry, farmers, local school students, and environmental community groups – either supported or tolerated onshore conventional gas development if noise or disturbances were appropriately addressed through regulation. But industry wide codes of behaviour are yet to be implemented.




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At what cost?

Lifting the ban on onshore conventional gas in Victoria comes at a time when the need to reduce greenhouse gas emissions is profoundly important.

Climate change is accelerating. While gas may be an important resource as we transition to renewable energy, accelerating its production, particularly in the absence of stringent regulatory controls, comes at a very high price.The Conversation

Samantha Hepburn, Director of the Centre for Energy and Natural Resources Law, Deakin Law School, Deakin University

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