Ecology of Ectomycorrhizal‐Basidiomycete Communities on a Local Vegetation Gradient

Abstract

To understand the factors that structure ectomycorrhizal—basidiomycete communities at a local scale, we measured the strength of the relations among the fungal communities, the tree communities, and the environment of a series of forest ecosystems in southern Quebec. We collected fruit bodies belonging to ectomycorrhizal—basidiomycete families and genera, sampled the woody vegetation, and described soils and landforms at 11 permanent sampling stations. We first calculated similarity matrices among stations, one for each descriptor (fungal species abundance, woody species abundance, and abiotic variables). We then explored the dependence among these matrices using Mantel and partial Mantel tests, path analysis, and comparisons of ordinations and classifications. Similarity among ectomycorrhizal fungus communities was strongly and significantly correlated with tree community similarity, even when controlling for the effect of environmental similarity. When the tests were made with a similarity matrix based on those tree species that are known to be hosts of ectomycorrhizal fungi, abiotic similarity explained a significant portion of the residual variation in the similarity among fungus communities. To explore this complex relationship further, we analyzed species associations. The preference of fungus associations for different sets of abiotic conditions showed that some factors affecting fungal species distribution were different from those affecting the distribution of their tree hosts. Direct and indirect gradient analyses showed that humus characteristics seemed to be important niche dimensions of ectomycorrhizal fungi. The continuum concept was useful to interpret the complex relations among symbiotic species. Trees were the main component of the realized niche of ectomycorrhizal Basidiomycetes, but the fungal symbionts of a particular tree species followed that tree species for only a part of the abiotic gradients over which the host tree was found. This type of distribution predicts that beta diversity of fungi would be generally higher than beta diversity of ectomycorrhizae—forming trees. It also means that the ratio of fungus species richness to woody species richness would be high for most community gradients. Our results and those of previous mycosynecological studies agree with these predictions. The results have implications for the conservation of biodiversity: site selection for conservation based on vegetation classification or mapping, or on distribution of tree species, may miss important fungal species.

Exploring the relationship between macrofungi diversity, abundance, and vascular plant diversity in semi‐natural and managed forests in north‐east Hungary

“…The old-growth beech forests, rich in arboreal species, showed greater evenness but low abundance of macrofungi. In most unmanaged beech forest plots, besides highly productive and frequent species such as the lignicolous Bisporella citrina, Trametes hirsuta, Micromphale foetidum, Schizophyllum commune, the more rare ectomycorrhizal fungi with low abundance such as Cortinarius alboviolaceus, C. terpsichores, Inocybe asterospora, I. furfurea, Lactarius flavidus, Russula fellea and Thelephora palmata can be found in greater proportion, presumably because of the host trees and forest structure (Bujakiewicz 1992;Pál-Fám et al 2007) as well as the physical and chemical properties of the humus (Nantel and Neumann 1992). The abandoned oak wood-pasture is the richest in vascular plants, but fungal abundance is low there.…”

Response of fungal and actinobacterial communities to water-level drawdown in boreal peatland sites

“…This pattern may reflect the variation in substrate quality and heterogeneity: saprobes differ in their ability to utilize different compounds as C sources (Thormann et al, 2001(Thormann et al, , 2002 and may affiliate with different litter types according to their chemical composition (Thormann, 2004). Plant community composition also has implications for fungal mycorrhizal associations (Natel and Neumann, 1992).…”

The composition and structure of macrofungus communities in boreal upland type forests and peatlands in North Karelia, Finland

“…The structure of fungal populations and fungal communities on mineral soil forest sites has been studied in Sweden by Dahlberg & Stenlid (1990), Dahlberg (1991) and Dahlberg & Stenstrom (1991). In Canada, Nantel & Neumann (1992) used two canonical correspondence analyses and principal coordinates analysis to clarify the structure of tree and ectomycorrhizalbasidiomycete communities.…”