Diversity patterns and knowledge gaps of Atlantic Forest epiphyllous bryophytes: a highly neglected group.

Background: Epiphyllous bryophytes are a group of plants with complex adaptations to colonize the leaves of vascular plants and are considered one of the most specialized and sensitive groups to environmental changes. Despite their specificity and ecological importance, these plants represent a largely neglected group in relation to scientific research and ecological data. This lack of information directly affects our understanding of biodiversity patterns and compromises the conservation of this group in threatened ecosystems.

Scope: Based on the compilation of data from a systematic review and virtual herbarium databases, we provide the first biogeographic assessment of diversity patterns of epiphyllous bryophytes in the Atlantic Forest hotspot. We also identify their phorophytes and assess sampling bias, knowledge gaps, and the current conservation state of epiphyllous bryophytes.

Conclusions: The state of knowledge about epiphyllous bryophytes in the Atlantic Forest is still incipient and taxonomic and geographically biased. Sampling effort and climate variation highly influenced species richness patterns. Notably, Bromeliophila natans, a threatened and endemic species, has not been recorded in the past 20 years, possibly indicating extinction due to anthropogenic activities such as habitat loss. We found that the occurrence information, distributed across the domain, was positively influenced by the presence of protected areas, forest cover and density of cities, whereas it was negatively influenced by distance to access roads and research centers. More fieldwork and taxonomic and molecular studies are urgently needed to uncover biodiversity patterns and conservation priorities of this sensitive group. Without an increased collection effort, we may lose important species and their contributions to people.