I co-authored this week’s Instigator with Toby Kiers, Professor of Evolutionary Biology and University Research Chair at Vrije Universiteit Amsterdam and the Executive Director of the Society for the Protection of Underground Networks (SPUN). I serve as the Chair of SPUN’s Board of Directors.

SPUN’s mission is to protect and harness the mycorrhizal networks that regulate the Earth’s climate and ecosystems. You can help us by sharing this with anyone who may be interested.

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Every day across the world, an area roughly the size of 1,000 football fields is paved over to make way for freeways, parking lots and construction sites. This activity seals and traps hidden underground ecosystems and their carbon-capturing capabilities.

Soils store 75% of all terrestrial carbon. Every acre lost to pavement, erosion, pollution and agricultural expansion is a dent in the planet’s climate-regulating toolbox. An astonishing 25% of all species live underground. Some analyses suggest that soils are the most diverse ecosystem on Earth, containing more species than all the plants and animals in the world’s tropical forests combined. Yet efforts to limit climate change and protect biodiversity fail to include underground organisms. This is a mistake.

The subterranean superheroes include mycorrhizal fungi, a network-forming fungus that has been evolving an underground economy with plant roots for over 400 million years. Plants and fungi work together in a highly choreographed - and intimate - trade symbiosis. Plant roots feed the fungi sugars and fats; in return the fungi provide phosphorus and nitrogen.

As a result of this invisible market, plants compete to pump carbon into mycorrhizal networks to get access to valuable phosphorous and nitrogen. This exchange helps draw millions of tons of carbon dioxide into the soil. Researchers are starting to visualise and quantify these complex streams of carbon and nutrients to better understand the Earth’s underground circulatory system and flow patterns.

Researchers have dubbed soil organisms “canaries in the coal mine” because their deterioration is the first warning that ecosystems will start to underperform. The economic cost of soil degradation already underway is staggering. The United Nations Campaign to Combat Desertification estimates that about $44 trillion of annual economic output – more than half of global GDP – depends on natural capital. The loss of soil biodiversity therefore has the potential to induce a shocking chain reaction for the climate and for the planet.

This month parties to the UN Convention on Biological Diversity (CBD) will release new goals working toward the protection of 30% of all land and ocean by 2030. Countries have the opportunity to demonstrate leadership by specifically including underground organisms in these targets. But they need to act fast.

The protection of soil biodiversity – and its unrivalled power at sequestering carbon – is currently a coincidental product of other objectives. Underground ecosystems and the microscopic rainforests they contain remain largely unprotected.

Policymakers often assume that current conservation targets already protect the most important habitats on Earth. This may be due to the common misconception that hotspots of biodiversity above and below ground are in the same places. However, this has been disproven. Biodiversity above ground does not effectively predict the same conditions below ground for at least a third of the world’s ecosystems.

A recent estimate published by Nature found that more than 70% of the Earth’s known soil biodiversity hotspots are unprotected by current conservation schemes. These include tundra, boreal forests and especially drylands, which cover approximately 45% of the Earth’s land surface.

Scientists now recognise that when fungal networks are degraded, ecosystems above ground also deteriorate, and biodiversity protection disappears. That’s why organisations like the Society for the Protection of Underground Networks (SPUN), GlobalFungi and the Fungi Foundation have launched global sampling efforts to create maps of Earth’s mycorrhizal networks.

Underground conservation requires a shift to acknowledge that the biodiversity we have historically cherished - plants, mammals, birds, amphibians, reptiles - is generated and maintained by complex and unseen interactions that also need targeted protection. The first step is to incorporate underground ecosystems into global conservation and climate schemes. We should also begin systematically mapping and monitoring underground biodiversity hotspots across the Earth.

Most fundamental, however, is encouraging the public to start valuing hidden biodiversity. To do so, we can deploy our senses to smell and even taste soils. Soils also make sounds. Elaborate acoustic displays of organisms in soils reveal hidden and intricate lives. Researchers are starting to record, analyse and use soundscapes to identify underground biodiversity hotspots. Conservationists have been sounding the alarm about the loss of biodiversity for centuries. It’s now time to recognise what has been missed by looking under the ground, as well as above it.

Happy holidays to all of our readers. Thank you for all of your support. We’ll be back early in the new year. But we’d love to keep hearing from you in the meantime.

Please keep sharing your views with us. Suggest topics we should cover. Let us know if we’re getting anything wrong. Point out the bright spots you see on the environmental front.

Onward,

The Instigator

Protecting Earth’s Underground Heroes