Land-use history alters the diversity, community composition and interaction networks of ectomycorrhizal fungi in beech forests

Forests have expanded across Europe over the last centuries as a consequence of farmland (agricultural and pasture) abandonment. Agricultural practices usually increase soil fertility and reduce the diversity and abundance of ectomycorrhizal (ECM) fungi, essential mutualists of many woody species in temperate and Mediterranean forests. The recovery of this biotic interaction after the cessation of human activities is, thus, crucial for the re-establishment of functional forest ecosystems.

Here we addressed the legacies of past land use and the recovery of the mutualism between ECM fungi and Fagus sylvatica trees in recent beech forests (< 50 years) in Northeast Spain. Soil and root samples were collected in 6 long-established and 8 recent beech forests to analyse soil abiotic properties and the ECM fungi associated with beech roots (Illumina DNA metabarcoding of ECM tips).

Up to 609 amplicon sequence variants (ASV) of ECM fungi were identified, with 220 ASV found in both forest...