The role of fungi in maintaining tree diversity has been unraveled – a global study involving scientists from RUDN University

There are two main types of fungi involved in symbiosis with trees: ectomycorrhizal fungi (EcM) and arbuscular mycorrhizal fungi (AMF).

EcM fungi form a dense “cover” (mantle) on tree roots, but do not penetrate the plant cells. They help trees obtain water and nutrients and protect the roots from disease.

AM fungi penetrate the root cells, forming tree-like structures called arbuscules. They improve the absorption of water and minerals from the soil.

An international team, including scientists from RUDN University, conducted a large-scale study, analyzing data from 4,090 forest sites around the world. Using the GFBI global database, they studied the relationship between the proportion of trees forming symbiosis with ectomycorrhizal fungi (EcM) and forest species richness. Modern statistical methods were used for the analysis, including generalized linear models, random forest models, and structural equations, which made it possible to take into account the influence of climate, soil, and other factors.

"For the first time, we have gotten the whole picture of how mycorrhizal symbioses, these invisible underground alliances, shape the diversity of forests we see from the equator to the Arctic. The study confirmed that the role of fungal symbioses depends on climatic conditions. For example, in the tropics and humid regions, the dominance of EcM trees reduces species richness, as these fungi suppress pathogens and reduce competition. In boreal forests and arid zones, maximum diversity is achieved with a mixture of trees with different types of mycorrhiza (EcM and AM). In temperate latitudes, an intermediate variant is observed, where diversity is higher with a moderate proportion of EcM trees.

The results can be applied to forest restoration, biodiversity conservation, and predicting changes in forest ecosystems. For example, in reforestation efforts, selecting tree species based on local fungal symbioses will help create more sustainable and diverse forest ecosystems. Managing soil fungal communities could become a new tool for maintaining species richness in forests. Understanding the interaction between fungi and forests also improves the quality of predictions of changes in forest ecosystems under the influence of climate and anthropogenic factors," Dmitry Kucher, associate professor at the Institute of Environmental Engineering at the RUDN University, co-author of the study.