Photo: IICG image bank
Every November 1st, World Ecology Day is celebrated, a date dedicated to recognizing the importance of understanding the interactions that make life possible on our planet. Ecology not only studies living beings individually, but also the relationships that connect them to each other and to their environment. And these connections are deeper—and more invisible—than we imagine.
When we walk through the forest, we usually focus on the trees, their leaves, or the water flowing in a nearby river. However, we rarely think about what’s happening beneath our feet: roots and microscopic fungi intertwine, forming an underground network capable of exchanging water, nutrients, and chemical information between the trees. This network is called the “Wood Wide Web”, or in Spanish, la red subterránea del bosque. Through it, trees cooperate to survive, especially in environments where resources are limited.
At the Institute for Global Change Research at Rey Juan Carlos University (IICG-URJC) we study how these connections work in semi-arid Mediterranean ecosystems, where plants coexist with drought and different forms of environmental stress.
An international team led by scientists from the IICG-URJC has revealed the ecological factors that determine the distribution of arbuscular mycorrhizal fungi in these scrublands. These fungi, essential for the absorption of water and nutrients by plants, are key to the resilience of dry ecosystems.
The study, titled Ecological drivers of fine-scale distribution of arbuscular mycorrhizal fungi in a semiarid Mediterranean scrubland and published in Annals of Botany, combined DNA sequencing techniques and detailed spatial sampling to analyze the diversity and composition of arbuscular mycorrhizal fungi and plant communities, both on the soil and in the roots.
The results show that visible vegetation is a good indicator of mycorrhizal associations, although roots and soil physicochemical properties also have a significant influence. Furthermore, a phylogenetic signal was identified in plant-fungal associations, suggesting that related species tend to associate with similar fungi. This finding provides new insights into the evolutionary mechanisms governing these symbioses. The study highlights the importance of simultaneously considering aboveground vegetation, roots, and soil to understand and predict the structure of arbuscular mycorrhizal fungal communities, which are fundamental to the health of dryland ecosystems.
These findings are reinforced by Angela Illuminati’s doctoral thesis (2022), developed at URJC, which demonstrates that root functional traits and nutrient use strategies are closely linked to mycorrhizal associations. Her research reveals that plants with more acquisitive strategies—that is, those that invest in rapid growth and efficient resource uptake—tend to establish more active mycorrhizal relationships. These links influence not only the development of juvenile plants, but also the structure and dynamics of plant communities in arid ecosystems.
Thus, understanding what happens underground becomes essential to anticipating how ecosystems evolve in the face of increasingly extreme environmental conditions.
On World Ecology Day, the IICG-URJC invites you to recognize the value of these invisible connections that sustain life on our planet. Because life thrives when it is connected.