Applying IUCN red-listing criteria for assessing and reporting on the conservation status of fungal species

With its strict criteria, required documentation and coverage of all groups of multicellular organisms, the red-listing system of IUCN is recognized as the most authoritative guide to the status of biological diversity. The aim of red-listing sensu IUCN is to evaluate the risk of extinction of a species using a comparable, revisable, transparent and objective assessment method. The evaluation estimates the potential change in the species’ population size over time, aiming to infer extinction risk. Both extremely rare species and more common ones experiencing ongoing decline may be at risk of extinction. Red-listing is an assessment of conservation status, directing awareness and providing a scientific basis for management and decision-making. The IUCN criteria were originally designed for global assessments. However, they can be, and are, commonly applied at the national or regional level. This paper summarizes the basic aspects and usefulness of red-listing in a mycological context, and suggests methods for fungal red-listing that are applicable to most fungal groups, even with limited information on the species being considered. The suggested methods are based on the accumulated experience of national fungal red-listing throughout the world, coupled with recently published research on fungal diversity, distributions, and population biology.