Biogeography of epiphytic Angiosperms in the Brazilian Atlantic forest, a world biodiversity hotspot

This study aims to analyse the available distributional data about epiphytic Angiosperms of the Brazilian Atlantic forest (BAF) in order to define geographic distribution patterns, areas of higher species richness and endemism, and locate knowledge gaps regarding the epiphytic flora. Thus, we seek to enhance the knowledge of the biogeography of these species and highlight priority areas for their conservation. Distribution data from literature and collections housed in 51 herbaria were compiled and submitted to analyses of richness (species count per distribution grid), similarity and parsimony analysis of endemicity. The regions of higher richness and endemism, chiefly in Rio de Janeiro and Espirito Santo, overlap with those found for trees and animal groups, while the location of some areas of endemism coincide with the supposed existence of Pleistocene forest refuges in Brazil's Northeastern and Southeastern regions. The Doce River seems to be responsible for the division of the Angiosperm epiphytic flora into north and south sectors of the BAF. In addition, the existence of a discontinuity named here as 'Falha de Conde' (Conde's Gap) situated in the northern corner of the State of Bahia was highlighted. Such gap divides the north sector of the BAF into two segments. It was also found that the hydrographic basins influence the delimitation of those areas. Subsampling of parts of the range leads to information gaps that need to be addressed by further data collection to ensure an improved understanding of the biogeographic relation between some of the regions, and also to fully clarify their delimitation.