Species richness and nitrogen supply regulate the productivity and respiration of ectomycorrhizal fungi in pure culture

Anna Wilkinson,Ian Alexander,David Johnson,Martin Solan

doi:10.1016/j.funeco.2011.08.007

Anna Wilkinson, Ian Alexander + Show 2 more

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https://doi.org/10.1016/j.funeco.2011.08.007

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Abstract

Abstract The effects of biodiversity of aboveground organisms have been widely investigated in a range of ecosystems, yet whether similar responses are also seen in belowground microbial communities, such as ectomycorrhizal (EM) fungi, are little understood. We investigated, in vitro , the effects of a gradient of 1–8 species of EM fungi interacting with substratum carbon:nitrogen (C:N) ratio on biomass production and CO 2 efflux. The model experimental systems enabled us to recover and measure biomass of individuals within communities and calculate net selection and complementarity effects. Both biomass and CO 2 efflux increased with species richness particularly under high N concentrations. Moreover, net biodiversity effects were largely positive, driven by both selection and complementarity effects. Our results reveal, in pure culture, the implications of EM species richness on community productivity and C cycling, particularly under high N conditions, and constitute the basis for future experiments under natural conditions.

Highlights

There is growing concern that reductions in biodiversity will be detrimental to ecosystem functioning (Ehrlich & Wilson 1991; Chapin III et al 1997; Costanza et al 1997; Vitousek et al 1997), and so the effects of diversity have been investigated in a wide range of terrestrial and marine ecosystems worldwide
In many studies it has been proposed that more species-diverse ecosystems are more productive than those that support fewer species (Tilman et al 1996; Engelhardt & Ritchie 2001; Hooper et al 2005). Whether such biodiversity effects can be seen in belowground microbial systems is less well understood, despite the key roles that soil microorganisms play both in belowground nutrient cycling (Finlay & So€derstro€m 1992) and aboveground productivity and diversity (Setala & Huhta 1991; Moore et al 2003; Smith & Read 2008; van der Heijden et al 2008)
The 10:1 ratio produced increasingly higher amounts of biomass as species richness increased in comparison with the other C:N ratio treatments

Summary

Introduction

There is growing concern that reductions in biodiversity will be detrimental to ecosystem functioning (Ehrlich & Wilson 1991; Chapin III et al 1997; Costanza et al 1997; Vitousek et al 1997), and so the effects of diversity have been investigated in a wide range of terrestrial and marine ecosystems worldwide. In many studies it has been proposed that more species-diverse ecosystems are more productive than those that support fewer species (Tilman et al 1996; Engelhardt & Ritchie 2001; Hooper et al 2005) Whether such biodiversity effects can be seen in belowground microbial systems is less well understood, despite the key roles that soil microorganisms play both in belowground nutrient cycling (Finlay & So€derstro€m 1992) and aboveground productivity and diversity (Setala & Huhta 1991; Moore et al 2003; Smith & Read 2008; van der Heijden et al 2008). Using a more sophisticated design, Jonsson et al (2001) found that species richness of fungi colonising Pinus sylvestris and Betula pendula increased productivity, but this was apparent only under certain nutrient availabilities

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