Angiosperm flora and biogeography of the páramo region of Colombia, Northern Andes

Páramo is the neotropical high elevation ecosystem in the northern Andes and Central America consisting of multiple dissected open areas above 3000 m a.s.l. Complex evolutionary processes that occurred within these ecosystems gave rise to a unique tropical Andean flora. Previous phytogeographical classifications for Colombian páramos have been based on subjective assessments of species distributions. However, a detailed floristic analysis highlighting affinities between páramo regions in Colombia has not yet been proposed. The aim of this study is to provide an analytical scenario for the patterns of regional plant diversity in a hierarchical framework based on the biogeographical history of the páramos, based on 30 localities of the Colombian páramos. Parsimony analysis of endemicity (PAE) and Jaccard similarity indices were applied to a presence/absence data matrix of páramo angiosperm species. Altitudinal distribution of species was used to determine the percentage of the páramo flora endemic to this ecosystem. Genera are shared among páramos, whereas species composition is highly endemic. 86% of the páramo angiosperm plant species is endemic to this ecosystem. The Colombian Páramo areas can be grouped using PAE into five biogeographical units, based on angiosperm species composition. These are: (1) Páramos de la Cordillera Oriental; (2) Páramos de la Cordillera Central and Macizo Colombiano; (3) Páramos de Antioquia; (4) Páramos del Norte; (5) Páramos de la Cordillera Occidental.