Red List Index application for vascular flora along an altitudinal gradient

High mountain habitats are particularly susceptible to climate changes, which have been classified as the key drivers of biodiversity extinction. Plant species have proved to be a suitable surrogate for estimating the state of an area’s total biodiversity, and the Red List Index (RLI) is one of the key global Convention on Biological Diversity Indicators. The main aim of this study was to analyse the changes in the categories of threatened flora in a specific region along an altitudinal gradient, and to determine possible relationships between threat categories, altitudinal ranges and global change effects, through RLI application. The study of the trends of threatened flora in Andalusia reveals a general decline in the species’ conservation status. Altitudinal ranges above 3000 m present greater deterioration of the threat categories. Thus, the Mediterranean high-mountain flora is confirmed as being highly sensitive to habitat alterations and as suffering the most severe threats. However, the study did not highlight the global change threat factor from the studied Red Lists. Therefore, the use of the RLI in the study of the conservation status of the vascular flora along an altitudinal gradient could represent a novel and remarkable advance as an indicator of the global change threat factor on a detailed scale.