Height From the Ground and Phytotelm pH Affect Prokaryotic Diversity in Epiphytic Bromeliads

Tank bromeliads in the neotropics harbour complex communities of invertebrates and even provide food, water and shelter to various vertebrate species. However, few studies have sequenced the microbial communities within epiphytic bromeliad phytotelmata. We sequenced the 16S rRNA subunit extracted from swabs rubbed at the base within the central phytotelm of the epiphytic bromeliads Aechmea hoppii and A. nidularioides. We tested factors that we suspected could influence the alpha diversity and beta-diversity of prokaryotic communities in bromeliads. Height on the tree and size of the bromeliad influenced the alpha-diversity within plants. Height from the ground and pH of the phytotelm explained small proportions of the variation among communities, regardless of whether quantitative or qualitative distances were calculated. We used FAPROTAX to assign taxa to functional groups and found that a complex picture of correlations between function and variables emerged, with height on the tree, pH, plant size and species, forest type and sampling season correlating with different functional groups. This relatively large metabarcoding study of bromeliad phytotelmata prokaryotes contributes to the growing knowledge of these highly diverse and complex systems.