Tree Species Richness and Neighborhood Effects on Ectomycorrhizal Fungal Richness and Community Structure in Boreal Forest.

Eveli Otsing,Julia Koricheva,Leho Tedersoo,Sten Anslan,Elia Ambrosio

doi:10.3389/fmicb.2021.567961

Abstract

Tree species identity is one of the key factors driving ectomycorrhizal (EcM) fungal richness and community composition in boreal and temperate forest ecosystems, but little is known about the influence of tree species combinations and their neighborhood effects on EcM communities. To advance our understanding of host plant effects on EcM fungi, the roots of silver birch, Scots pine, and Norway spruce were analyzed using high-throughput sequencing across mature boreal forest exploratory plots of monocultures and two- and three-species mixtures in Finland. Our analyses revealed that tree species identity was an important determinant of EcM fungal community composition, but tree species richness had no significant influence on EcM fungal richness and community composition. We found that EcM fungal community composition associated with spruce depends on neighboring tree species. Our study suggests that at a regional-scale tree species identity is the primary factor determining community composition of root-associated EcM fungi alongside with tree species composition effects on EcM fungal community of spruce in mixed stands.

Highlights

Effects of aboveground diversity on belowground diversity and vice versa are context-dependent and difficult to predict (Wardle et al, 2004)
2,079,719 high-quality sequences from 191 samples were clustered to 5,739 operational taxonomic units (OTUs), of which 5,489 OTUs were considered to be fungi
Our results provide no evidence for a positive relationship between tree species richness and EcM fungal richness on a regional scale in boreal forest stands, which contrasts our first hypothesis

Summary

Introduction

Effects of aboveground diversity on belowground diversity and vice versa are context-dependent and difficult to predict (Wardle et al, 2004). Microbial interactions can drive ecosystem functions, such as plant biodiversity, productivity, and variability as shown by van der Heijden et al (1998, 2008) based on arbuscular mycorrhizal fungal communities. It is known that plant diversity and productivity increase with increasing diversity of ectomycorrhizal (EcM) fungi (Baxter and Dighton, 2001; Jonsson et al, 2001; Kernaghan et al, 2003). EcM fungal communities have a major part in driving forest soil processes, such as soil organic matter decomposition, nutrient cycling, and carbon (C) sequestration (Read and PerezMoreno, 2003; Clemmensen et al, 2015; Lindahl and Tunlid, 2015). Plant-fungus interactions play an important role in ecosystem functioning, but plant diversity effects on microbial communities in forest ecosystems are not well-understood

Objectives

Methods

Results

Conclusion