The nature of threat category changes in three Mediterranean biodiversity hotspots

Threats originating from human activities represent more than 80% of all threat types. The most frequently reported threats in California and Spain are related to population density, whereas in Western Australia threat types are modulated by human presence rather than human abundance. A strong relationship between increasing risk (upgrading in threat categories) and threats derived from human activities was found only for Spanish plants. Nevertheless, when conservation reasons are the cause for a category to change, they are associated with direct upgrading of species in Spain and Western Australia.