Anika Lehmann, a researcher in the Rillig Lab at Freie Universität Berlin, carefully lifts a soil sample from a growth chamber, its surface threaded with delicate white filaments—living strands of fungi that, though invisible to most, are quietly shaping the fate of ecosystems worldwide. For over a decade, this lab has been unraveling the hidden world beneath our feet, revealing how soil fungi are not just silent partners in nature but central players in carbon storage, crop resilience, and planetary health. In a comprehensive review published in Nature Reviews Microbiology, Professor Matthias C. Rillig synthesizes years of global research, underscoring that fungal networks are as foundational to terrestrial life as roots or leaves.
These organisms form vast underground alliances with plants—mycorrhizal relationships that allow crops and wild flora alike to access essential nutrients like phosphorus and nitrogen, often increasing plant growth by up to 70% in nutrient-poor soils. At the same time, fungi act as nature’s recyclers, decomposing organic matter and channeling carbon deep into the soil, where it can remain sequestered for decades. With more than 120,000 known fungal species—and estimates suggesting over 2.2 million may exist—this biological frontier remains largely uncharted, yet its implications are immediate. As climate change accelerates and land use intensifies, fungal communities are shifting, sometimes collapsing, with cascading effects on food security and ecosystem stability.
Rillig’s work highlights that fungi sit at the base of the soil food web, making them especially vulnerable to human impacts like chemical pollution, deforestation, and rising temperatures. Even small disruptions in fungal diversity can reduce soil aggregation by up to 50%, increasing erosion and diminishing water retention. Alarmingly, some fungi are also emerging as resistant pathogens, threatening both crops and human health—antifungal resistance is now a growing concern in medicine, with agricultural overuse of fungicides potentially accelerating the crisis. Yet, despite their dual roles as both guardians and threats, fungi remain underrepresented in global biodiversity policies and One Health frameworks.
The message is clear: to safeguard ecosystems and human well-being, we must look downward. "Fungi are the invisible cornerstone of many ecosystems," says Rillig. "The better we understand their diversity and functions, the better we can predict the consequences of global environmental change." From enhancing sustainable agriculture to mitigating climate change, the solutions may lie not in high-tech labs alone, but in the intricate, living web beneath our feet. As research expands, so too does the hope that these overlooked organisms will finally receive the attention—and protection—they deserve.