Ectomycorrhizal fungi in wood-pastures : Communities are determined by trees and soil properties, not by grazing

Abstract

Traditional rural biotopes such as wood-pastures are species-rich environments that have been created by low-intensity agriculture. Their amount has decreased dramatically during the 20th century in whole Europe due to the intensification of agriculture. Wood-pastures host some fungal species that prefer warm areas and are adapted to semi-open conditions, but still very little is known about fungi in these habitats. We studied how management, historical land-use intensity, present grazing intensity, time since abandonment, and stand conditions affect the species richness and community composition of ectomycorrhizal fungi. We surveyed fruit bodies on three 10 m × 10 m study plots in 36 sites and repeated the surveys three times. Half of the sites were currently unmanaged but had a grazing history. We measured soil pH, soil moisture and the basal area of different tree species, and interviewed landowners about grazing history. We found that the proportion of broadleaved trees, soil pH, and soil moisture are the major drivers of the communities of ectomycorrhizal fungi in boreal wood-pastures. Management or grazing intensity did not have significant effects on fungal species richness, whereas historical land-use intensity seemed to have a negative effect on species richness. To conclude, present stand conditions are the most important factors to evaluate when planning the conservation of ectomycorrhizal fungi living in semi-open forest habitats.