8,500 soil-dependent species have just been evaluated using the official IUCN extinction criteria. The result is striking: 20% are threatened with extinction, while 40% lack sufficient data to determine their status. This first systematic assessment reveals the scale of an invisible extinction taking place beneath our feet.
The evaluation, conducted by Conservation International and published in Oryx, coincides with a Nature study that detected pesticide residues in 70% of analyzed European sites. Two converging alerts documenting the degradation of an understudied but vital ecosystem for global agriculture, at a moment when Europe is rethinking its food sovereignty.
The Essentials
- 8,500 soil-dependent species evaluated for the first time using IUCN criteria
- 20% threatened with extinction, 40% without sufficient data to determine status
- 70% of European sites studied contain pesticide residues
- Soil biodiversity represents 25% of all terrestrial biological diversity
- One teaspoon of soil harbors more organisms than humans on Earth
First Global Mapping of an Invisible World
The evaluation published in Oryx marks a methodological turning point. For the first time, Conservation International applied the rigorous criteria of the IUCN Red List to 8,500 invertebrate species dependent on soil. Earthworms, springtails, mites, nematodes, woodlice: a systematic inventory of the fauna that structures the underground ecosystem.
The finding is alarming. Of the 8,500 species analyzed, 1,700 show sufficient signs of decline to fall into the IUCN categories of “vulnerable,” “endangered,” or “critically endangered.” But the most striking aspect remains the extent of our ignorance: 3,400 species, or 40% of the total, lack basic data to assess their status. A scientific gap that reveals the magnitude of the lag in soil biodiversity knowledge.
This lack of knowledge contrasts sharply with the ecological importance of soils. A single teaspoon of soil contains more living organisms than the planet has humans. These micro-ecosystems regulate 95% of global food production, store 33% of terrestrial carbon, and filter 70% of usable fresh water. The invisibility of this biodiversity has long delayed its protection.
Intensive Agriculture Facing Its Hidden Externalities
The parallel Nature study sheds light on the pressures affecting this soil biodiversity. Researchers analyzed pesticide contamination at 340 representative agricultural sites across Europe. Result: 70% show detectable residues, with average concentrations 100 times higher than toxicity thresholds for soil invertebrates.
Neonicotinoids, banned in Europe since 2018 for their impact on pollinators, persist in 45% of analyzed samples. Their lifespan in soils reaches 3 to 5 years, creating lasting contamination that continues to affect soil fauna long after treatments stop. Herbicides like glyphosate appear in 60% of sites, irreversibly modifying the microbial composition of soils over several years.
This chemical contamination combines with physical pressures. Intensive agriculture compacts soils through repeated heavy machinery passage, reducing porosity and oxygenation. Monocultures impoverish the diversity of underground habitats. Deep plowing fragments mycelia networks that connect root ecosystems over kilometers.
Agriculture thus contributes to soil biodiversity erosion that restorative soil agriculture could correct. Soil regeneration techniques demonstrate their effectiveness in restoring soil biodiversity, but face institutional resistance.
The Geography of Underground Extinction
The assessment reveals marked geographic disparities in soil biodiversity status. Europe and North America account for 60% of species classified as threatened, despite greater research effort that should theoretically better document their status. This overrepresentation reflects the intensity of agricultural and urban pressures in these regions.
Identified extinction hotspots correspond to intensive agriculture zones: Northern European cereal plains, the American Corn Belt, Asian deltas. In these regions, the simplification of agricultural landscapes and intensive pesticide use create “underground biological deserts” where only a few generalist species survive.
Conversely, tropical regions paradoxically show fewer officially threatened species, but 70% of them lack sufficient data. This documentation gap probably masks an extinction already well underway, though silent. Amazon deforestation and palm oil expansion in Southeast Asia destroy underground ecosystems before they are even inventoried.
Ocean islands concentrate the highest extinction rates. In New Zealand, 35% of soil-endemic species are threatened by the introduction of invasive species and pastoral intensification. Hawaii has already lost 15% of its native soil fauna since humans arrived.
Innovation and Monitoring of Soil Biodiversity
Facing this documented crisis, new tools are emerging to monitor and protect soil biodiversity. DNA metabarcoding now allows identification of thousands of species in a soil sample within hours, revealing previously unsuspected diversity. This technique has multiplied the number of known species in certain ecosystems by ten.
Artificial intelligence accelerates morphological identification. Image recognition algorithms automatically process photos of soil macro-invertebrates, reducing from six months to two days the time needed to analyze a biological community’s composition. This automation makes continuous monitoring of soil biodiversity at the scale of agricultural territories conceivable.
Buried IoT sensors measure vital parameters of underground ecosystems in real time: temperature, humidity, pH, nutrient concentration. These data feed predictive models that anticipate biological community evolution based on agricultural practices. Several European regions are experimenting with these early warning systems to adapt technical practices.
Restoration initiatives are multiplying. In the United Kingdom, the “Soil Health Initiative” program pays farmers for adopting practices favorable to soil biodiversity: cover crops, reduced soil disturbance, diverse rotation. Initial results show a 40% increase in earthworm biomass within three years.
Economic Challenges of an Understudied Biodiversity
Underground biodiversity extinction generates considerable hidden costs. The FAO estimates that soil degradation costs global agriculture 40 billion dollars annually, primarily through reduced fertility and increased chemical input needs. One teaspoon of healthy soil saves the equivalent of 0.01 dollars in fertilizers and pesticides per year.
Earthworms alone represent an ecosystem service valued at 25 billion dollars annually by the OECD. Their bioturbation activity equates to the work of 50,000 tractors running continuously to aerate global agricultural soils. Their disappearance forces mechanical compensation for this natural function, increasing production costs.
Underground pollination remains largely ignored despite affecting 30% of global crops. Mycorrhizal fungi transfer nutrients and water to roots, reducing irrigation needs by 20% according to INRA. Their destruction by fungicides forces intensified water and nutrient inputs, weakening agricultural profitability against drought episodes.
The pharmaceutical industry is beginning to measure the scale of the lost resource. 40% of current antibiotics derive from molecules produced by soil micro-organisms. Each species that disappears takes unexploited therapeutic potential with it. Laboratories are now investing in preventive bio-prospecting to sequence the genomes of micro-organisms before their extinction.
Governance and Protection of an Invisible Heritage
Soil biodiversity largely escapes existing protection frameworks. Unlike charismatic species that benefit from targeted conservation programs, soil fauna remain invisible to public policies. Only 3% of world protected areas include criteria for preserving soil biodiversity.
The European Union is nevertheless preparing a revision of its Habitats Directive to integrate underground ecosystems. The project, led by the Directorate General for Environment, imposes mandatory monitoring of soil biodiversity in Natura 2000 zones. Fifteen standardized biological indicators will allow soil status comparison between member states.
France has been experimenting since 2025 with a “soil biodiversity passport” for agricultural operations. This document certifies the biological status of plots according to a common scientific framework. Certified operations access preferential interest rates for agricultural loans and benefit from exemptions on non-built land tax.
Agri-food companies are progressively integrating these issues into their supply chains. Since 2024, Danone conditions its contracts with livestock farmers on soil biodiversity objectives, measured through annual biological audits. Unilever is developing a “soil regeneration” index that influences the purchase price of its agricultural raw materials.
This scientific revelation of underground extinction arrives at a crucial moment for European agriculture. As the war in Ukraine has revived debate on food autonomy, Europe is discovering that its nutritional security depends as much on preserving this invisible biodiversity as on cultivated area. A new equation redefining the terms of agricultural sovereignty.