Linking taxonomic and molecular databases: a pilot study by the Freshwater Animal Diversity Assessment (FADA) for Catalogue of Life (CoL)

Freshwater biodiversity is among the most diverse yet most threatened components of the biosphere. Despite its ecological importance, freshwater species remain underrepresented in global biodiversity databases, and taxonomic, ecological and molecular information are often maintained in separate systems. Building on the Freshwater Animal Diversity Assessment (FADA), which currently provides a global taxonomic reference for more than 125,000 freshwater animal species, FADAmol aims to establish a pilot framework linking taxonomic and molecular biodiversity information for the Catalogue of Life and other international biodiversity infrastructures. The project will expand FADA by integrating habitat information and linking species to the freshwaterecology.info database, thereby connecting taxonomy with ecological knowledge. It will further incorporate parasitic freshwater animals, including host–parasite relationships and links to published DNA sequence repositories, improving the representation of parasite diversity and supporting One Health applications. Finally, FADAmol will address cryptic ("dark") species by systematically documenting published genetic lineages and linking molecular evidence to formally described taxa. By connecting taxonomic, ecological and molecular information within a single interoperable framework, FADAmol will improve the discoverability, integration and reuse of freshwater biodiversity data. The project will strengthen biodiversity monitoring, facilitate DNA-based species identification, and provide an important contribution to international biodiversity infrastructures supporting the Kunming–Montreal Global Biodiversity Framework and the WHO One Health approach.