Research by Scheele et al into the global effect chytrid fungus – on 501 frog species. Each bar represents a species; colours show the extent of population declines. The researchers say their decline estimates are conservative for a number of reasons. They point to the large number of currently undescribed species in remote tropical ecosystems; their exclusion of species with documented declines but with no direct evidence linking that decline to chytrid; and a lack of data about many frogs’ full range.