The underground fungal networks that support life on Earth require urgent political action to protect them, according to new research.

Scientists from the Society for the Protection of Underground Networks (Spun) have produced the first high-resolution biodiversity maps of mycorrhizal fungi – microscopic organisms living on plant roots that regulate ecosystems and help absorb more than 13bn tonnes of CO₂ into soils each year, roughly one-third of global fossil fuel emissions.

Published in Nature, the study found that 90% of mycorrhizal biodiversity hotspots lie outside protected areas, leaving them vulnerable to destruction. Loss of these ecosystems could reduce carbon storage, crop yields, and resilience to extreme weather. Ghana’s coastline was identified as a key hotspot, but with erosion advancing by 2 metres a year, researchers warn vital biodiversity risks being lost to the sea.

Mycorrhizal fungi have “remained in the dark, despite the extraordinary ways they sustain life on land”, said Dr Toby Kiers, the executive director of Spun.

“They cycle nutrients, store carbon, support plant health, and make soil. When we disrupt these critical ecosystem engineers, forest regeneration slows, crops fail and biodiversity above ground begins to unravel … 450m years ago, there were no plants on Earth and it was because of these mycorrhizal fungal networks that plants colonised the planet and began supporting human life.

“If we have healthy fungal networks, then we will have greater agricultural productivity, bigger and beautiful flowers, and can protect plants against pathogens.”

Using machine learning on 2.8bn fungal DNA sequences from 130 countries, scientists mapped fungal diversity at a 1km² scale. Only 9.5% of hotspots fell within protected zones, revealing significant conservation gaps.

Spun, launched in 2021 with partners including GlobalFungi and the Fungi Foundation, is urging governments to integrate fungi into environmental policy. Dr Michael Van Nuland, the study’s lead author, said that the maps “are more than scientific tools – they can help guide the future of conservation”.

“Given the impact of these fungal symbioses on the health and functioning of Earth’s ecosystems, continuing to ignore them could be a hugely missed opportunity.”

He warned that mycorrhizal fungi are sensitive to human pressures and their decline could undermine natural climate solutions.

Land use is a significant cause of mycorrhizal fungal degradation, and it is “frustrating that no action has been taken to prioritise conservation of it”, said Kiers. “The fungi are needed for agricultural productivity and human health.”

These fungal ecosystems were largely invisible in law and policy, said César Rodríguez-Garavito, a professor of law and the faculty director of the More-Than-Human Life (Moth) programme at NYU’s School of Law. “[The data is] incredibly important in strengthening law and policy on climate change and biodiversity loss across all of Earth’s underground ecosystems.”

The data is available through Spun’s online “underground atlas” for use by conservationists, researchers, and policymakers.

The organisation’s 400-strong international team is sampling remote underground ecosystems from Mongolia to Bhutan, and is seeking new collaborators and funding to expand its maps – which currently cover just 0.001% of the planet’s surface.

Protecting mycorrhizal fungi, said WWF chief scientist Dr Rebecca Shaw, could help address biodiversity loss, climate change, and declining food productivity – with direct benefits for people.

 

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