Quantifying and mapping angiosperm endemism in the Araucaria Forest.

Neotropical forests are home to exceptional biodiversity, especially along the eastern coast of tropical and subtropical South America. In the Atlantic Forest, the subtropical Araucaria Forest harbours both tropical and temperate plant lineages. Is the presence of Araucaria angustifolia the only attribute characterizing the south-eastern South American Araucaria Forest, or is this formation also defined by the co-occurrence of other endemic species? To answer this question, we revisited the history of this vegetation from published lists and from the current distribution data of angiosperm species. We aimed to identify species endemic to the Araucaria Forest, and to analyse areas of endemism, species richness and occurrence records across the study area. The taxa reported were classified as endemic, near-endemic or non-endemic. A list of 52 endemic taxa and 28 near-endemics was built from public databases and refined. Our results indicate that the eastern region of the southern plateau between the states of Rio Grande do Sul and Santa Catarina has the highest endemism diversity. We suggest that complex interactions are involved in the origin of endemism and that lineages represented in the list of endemic species may contain key taxa for future understanding these drivers in space and time.