Niche-based processes structure tropical bryophyte assemblages in phytogeographic domains of Brazil

Abstract In forest enclaves known as Brejos de Altitude (forest refuges) in northeastern Brazil, floristic affinities are generally explained by historical processes of vicariance. However, for poikilohydric plants with long distance dispersal such as bryophytes, the present work predicts that floristic similarities result from environmental affinities between areas. The floristic relationships of forest refuges with different phytogeographic domains of Brazil were investigated based on the current distribution of bryophytes, and the processes that explain the distribution of species were discussed. A floristic database of 863 bryophyte species from 108 areas, including geoclimatic data, was used in the analysis. The floristic similarity between areas and their relationships with environmental and spatial variables were analyzed. The species composition was found to be distinct between biomes and phytogeographic domains. The floristic difference between the domains was mainly explained by turnover of species. Variables associated with water availability, i.e. aridity and water vapor pressure, drive the bryophyte assembly, leading to the conclusion that niche-based processes explain the distribution of bryophyte species in Brazilian biological refuges and tropical forests.