A landmark IUCN and Conservation International study reveals that the organisms keeping Earth’s soils alive are vanishing — and we barely know they exist.
📅 April 15, 2026 🔬 Source: Conservation International / IUCN / Oryx Journal / Mongabay
What the study found
There’s an entire world beneath the surface of the ground — one that most people never think about and science has barely begun to understand. A major new report, published in the journal Oryx on April 15, 2026, by a team of 44 scientists led by Conservation International and IUCN, has assessed the extinction risk of soil-dependent species for the first time at a global scale.
The findings are alarming: of more than 8,500 soil-dependent species evaluated against the IUCN Red List criteria, over 40% are either threatened with extinction or so poorly studied that their status is entirely unknown — classified as Data Deficient. One in five of the assessed species is already globally threatened.
🌍 Why soil matters — the numbers: 95% of all food consumed by humans depends on healthy soil. Soil could store up to 27% of the carbon needed to keep global warming below 2°C. Approximately 59% of all known species on Earth live exclusively in soil.
What lives in soil?
When most people think of soil, they picture dirt. What actually lives there is closer to a civilization. Soil hosts an extraordinary diversity of life: fungi that form networks connecting tree roots across entire forests, nematodes that regulate nutrient cycling, arthropods that physically break down organic matter, earthworms that aerate and restructure the earth, and microbial communities of bacteria and archaea so dense that a single teaspoon of healthy forest soil can contain more organisms than there are people on Earth.
These organisms don’t just live in the soil — they create it. Without them, the soil loses structure, loses fertility, and loses its ability to hold water. Agricultural productivity collapses. Carbon storage is compromised. The hydrological cycle breaks down. The study authors are blunt about the implications: losing soil biodiversity doesn’t just threaten the organisms themselves. It threatens the biological foundation of human food systems.
Why don’t we know more?
The honest answer is that soil biology has been chronically underfunded and understudied compared to more visible ecosystems. Most soil organisms are microscopic, difficult to identify, poorly catalogued, and lack the charisma of pandas or tigers. Thousands of soil-dependent species aren’t even listed on the IUCN Red List yet — their extinction risk has simply never been evaluated.
As lead author Neil Cox noted, this represents a ‘big, glaring hole’ in our understanding of global biodiversity. These organisms are hugely underrepresented in conservation policy, research funding, and public awareness — despite being more essential to human survival than virtually any visible species on Earth.
🚨 What researchers are calling for: Establishment of an IUCN SSC Soil Biota Working Group; stronger coordination between global soil science organizations; and urgent public investment in soil biodiversity research before we lose species we haven’t even named yet.
The agricultural connection
The threat isn’t hypothetical. When soil biodiversity declines — whether through overuse of pesticides and synthetic fertilizers, compaction from heavy machinery, or conversion of natural land to monocultures — the first visible sign is often reduced crop yields. Farmers compensate by adding more agrochemicals, which further reduces soil biodiversity, which further reduces fertility. It’s a downward spiral that is already playing out in agricultural regions worldwide.
The science is clear: investing in soil biology conservation is not just an environmental issue. It is, quite directly, a food security issue for every person on the planet. The organisms doing the work are invisible — but their absence will be anything but.