Developing strategies and tools for the monitoring of aquatic fungal biodiversity

The biodiversity of aquatic fungi remains vastly underexplored, including the taxonomy and biogeography of species and their responses to environmental changes. Aquatic fungi contribute substantially to ecosystem processes and services, and interact with other organisms in aquatic food webs, as decomposers, symbionts, pathogens, and parasites. All these roles depend on different facets of aquatic fungal biodiversity. Despite increasing recognition of their importance for ecosystems and societies, aquatic fungi are not included in routine biodiversity monitoring programs, unlike other key aquatic organism groups, such as fish and macroinvertebrates. These gaps in knowledge and policy impede effective management and conservation of aquatic fungi and of the crucial ecosystem processes and services they provide. Through MoSTFun, a Biodiversa+ project, we aim to develop the conceptual foundation, methodologies, and experience needed to include aquatic fungi in routine biodiversity monitoring programs. We leverage and add value to existing biodiversity monitoring programs and networks designed for other organism groups by reanalyzing their data or samples, either from publicly available archives or previous sampling efforts. Additionally, we are evaluating the procedures and experiences of existing biodiversity monitoring programs to determine how aquatic fungal biodiversity could be added to them. To facilitate this uptake, we use existing monitoring concepts such as Essential Biodiversity Variables but advance them to account for aquatic fungal biology and ecology. This approach is possible thanks to increasingly efficient, and accessible molecular tools and public databases that contain rapidly growing volumes of molecular data of different types. While the project develops and focuses on examples on the European scale, we will generate scalable knowledge and recommendations, potentially transferable to other regions. This knowledge transfer is ensured through close collaboration with relevant stakeholder groups and will be developed into a Knowledge-to-Action Hub for aquatic fungi. This will also allow for collaboration with other ongoing initiatives on the monitoring and conservation of aquatic fungal biodiversity and ensure the continuation of our efforts after the project’s lifetime.