Understanding and Protecting Aquatic Fungal Diversity

Aquatic ecosystems and biodiversity are highly threatened due to human activities. Despite efforts to reduce biodiversity loss, approximately 22% of the aquatic species that have been investigated for the International Union for the Conservation of Nature (IUCN) Red List are threatened with extinction. This estimate is based almost entirely on data from plants and animals; however, the ecologically important fungi that live in water are subjected to the same environmental challenges.

Currently, we know little about how aquatic fungi adapt and respond to threats to aquatic biodiversity or about how diversity in these fungi is distributed. As a result, we are limited in our ability to protect ecologically important biodiversity and to predict changes due to environmental challenges including climate change. My research focuses on building the knowledge and networks to overcome these limitations.

Aquatic fungi depend on aquatic habitats for at least part of their life cycle and include representatives from across the fungal tree of life. Most aquatic fungi are microscopic. Although tiny in size, these fungi are important for ecosystem health and functioning through their roles as symbionts, pathogens, and decomposers.

Studying the diversity and distributions of aquatic fungi through direct observation is difficult. However, by studying DNA from water samples collected from across Europe and from historical archives together with climate and environmental data it is now possible to map distributions of different species, see patterns and identify the factors that influence distributions at large geographic scales, and to predict future changes. 

When we think about biodiversity, we often think about species diversity, as above. However, genetic diversity within a species is an important and protected element of biodiversity. It is therefore necessary to understand aspects of the biology of aquatic fungi that impact genetic diversity. Although previously underappreciated, some “aquatic” fungi can also live on land.

Depending on connectivity between terrestrial and aquatic habitats, dual-niche fungi may realize very large population sizes and potentially higher genetic diversity than those that only live in water. Similarly, fungi that reproduce sexually, even rarely, may have an enhanced ability to generate genetically variable offspring. Both large population sizes and sexual reproduction can support the maintenance of genetic variation in populations which positively impacts the ability of species to adapt to new or challenging conditions. 

In this talk, I will briefly introduce the aquatic fungi and their ecological importance. I will discuss my ongoing independent and collaborative projects aimed at mapping and monitoring aquatic fungal diversity, identifying the drivers that shape the levels and distributions of that diversity, and investigate the biological factors that influence potential adaption to new and challenging environments.

I will also discuss next-steps and long-term goals for my research and place my work in the context of growing global interest and opportunities for inclusion of aquatic fungi in main-stream conservation thinking.