Abstract Phylogenetic structures, the relatedness of species based on evolutionary traits, are still hardly studied. Several studies in the last three decades have been performed to examine taxonomic structures in forest and non-forest areas. Based on recent studies of phylogenetic structures in the Amazon forest, we aimed to explore the phylogenetic structure of non-forest areas in tropical South-America. We focused on mechanisms, such as environmental filtering and dispersal on the species composition and phylogenetic structure in these types of regions. We selected two of these non-forest areas, namely Guiana Shield (sandstone plateau in the Amazon) and Páramo (Andean). Vegetation and location data of both areas were analyzed. Our results suggested that these mechanisms play a crucial role in the phylogenetic structure in both regions. A significant negative correlation has been found between phylogenetic similarity and geographical (Euclidean) distance in Guiana Shield and Páramo. An NMDS-ordination showed the similarity between the different communities and substantiate the correlation found. Based on the positive values of the NRI and NTI, both regions were phylogenetically clustered. We concluded that mechanisms of environmental filtering and dispersal are important historical drivers that influence the phylogenetic structure, similarity and clustering in both these non-forest ecosystems.

Phylogenetic structure, phylogenetic similarity, dispersal, environmental filtering, non-forest areas, Guiana Shield, Páramo, Tropical South America