Does genotypic and species diversity of mycorrhizal plants and fungi affect ecosystem function?

Contents Summary 1122 I. Introduction 1122 II. Are there consistent patterns in diversity of mycorrhizal fungal genotypes and species across space? 1125 III. What is the variation in functional traits and genes of mycorrhizal fungi at different taxonomic scales? 1125 IV. How will environmental change impact the relationships between genotypic and species diversity of mycorrhizal fungi and ecosystem function? 1126 V. Conclusions: considerations for future MEF research 1127 Acknowledgements 1127 References 1127 SUMMARY: Both genotypes and species of mycorrhizal fungi exhibit considerable variation in traits, and this variation can result in their diversity regulating ecosystem function. Yet, the nature of mycorrhizal fungal diversity-ecosystem function (MEF) relationships for both genotypes and species is currently poorly defined. New experiments should reflect the richness of genotypes and species in nature, but we still lack information about the extent to which fungal populations in particular are structured. Sampling designs should quantify the diversity of mycorrhizal fungal genotypes and species at three key broad spatial scales (root fragment, root system and interacting root systems) in order to inform manipulation experiments and to test how mycorrhizal fungal diversity both responds, and confers resilience to, environmental drivers.