Monitoring ectomycorrhizal fungi at large scales for science, forest management, fungal conservation and environmental policy

Key message: The ICP Forests network can be a platform for large-scale mycorrhizal studies. Mapping and monitoring of mycorrhizas have untapped potential to inform science, management, conservation and policy regarding distributions, diversity hotspots, dominance and rarity, and indicators of forest changes. Context: A dearth of information about fungi at large scales has severely constrained scientific, forest management, fungal conservation and environmental policy efforts worldwide. Nonetheless, fungi fulfil critical functional roles in our changing environments and represent a considerable proportion of terrestrial biodiversity. Mycorrhizal fungi are increasingly viewed as a major functional guild across forest ecosystems, and our ability to study them is expanding rapidly. Aims: This study aimed to discuss the potential for starting a mycorrhizal monitoring programme built upon the existing forest monitoring network, raise questions, propose hypotheses and stimulate further discussion. Results: An overview of the state-of-the-art regarding forest ectomycorrhizal ecology raises questions and recommendations for scaling up mycorrhizal assessments aimed at informing a variety of stakeholders, with a new focus on conservation and policy. Conclusion: Fungal research and conservation are areas that can be informed by ICP Forests and may lead to useful spin-offs; research linked to long-term forest monitoring plots will enhance the relevance of science and conservation.