El inventario de 384 parcelas sobre 64 árboles, en cuatro localidades de la región amazónica de Colombia (Amazonas, Caquetá, Putumayo, Vaupés), produjo 160 especies de briófitos epífitos (116 hepáticas, 44 musgos), distribuidas en 64 géneros y 26 familias. El muestreo se llevó a cabo en cuatro bosques no inundables de la selva tropical (Terra Firme). Los briofitos epífitos fueron recolectados desde la base hasta el dosel exterior de 16 árboles, en cada una de las localidades. La flora se caracterizó por la dominancia de hepáticas, particularmente de la familia Lejeuneaceae. Las familias con mayor número de registros fueron Lejeuneaceae (55%), Calymperaceae (10%), Lepidoziaceae (8%), Octoblepharaceae (6%) y Sematophyllaceae (5%). Los géneros con mayor número de registros fueron Cheilolejeunea (11%), Pycnolejeunea (8%), Archilejeunea (8%) Ceratolejeunea (8%) y Syrrhopodon (7%). Syrropodon y Lejeunea fueron los géneros más diversos, seguidos por Ceratolejeunea y Cheilolejeunea. El promedio de especies por localidad fue de 102. En términos de riqueza y composición de especies, no hubo diferencias significativas entre las cuatro localidades.

An inventory of 384 plots on 64 trees, in four localities across the Colombian Amazon region (Amazonas, Caquetá, Putumayo, Vaupés), yielded 160 species of epiphytic bryophytes (116 of liverworts, 44 of mosses), in 64 genera and 26 families. Sampling was carried out in four non-seasonally flooded forests (Terra Firme), where bryophytes where collected from the base to the outer canopy, of 16 trees per locality. The flora is characterized by dominance of liverworts, especially Lejeuneaceae. The families with the highest number of records were Lejeuneaceae (55%), Calymperaceae (10%), Lepidoziaceae (8%), Octoblepharaceae (6%) and Sematophyllaceae (5%). The most common genera in number of records were Cheilolejeunea (11%), Pycnolejeunea (8%), Archilejeunea (8%) Ceratolejeunea (8%) and Syrrhopodon (7%).Syrropodon and Lejeunea were the most species-rich genera, followed by Ceratolejeunea and Cheilolejeunea. In average, the localities had 102 species in sixteen phorophytes. In terms of species richness and composition there were no significant differences between the four localities.

Epiphytic bryophyte communities in terra firme forests of the Amazon region were investigated for the first time through standardized sampling across the Amazon basin. The sampling was carried out at nine localities, where bryophytes were collected in five height zones, from the forest floor to the canopy of eight canopy trees per locality. The sampling generated 3104 records, identifying 222 species and 39 morphospecies, within 29 families. The most common families were Lejeuneaceae (in 55%), Calymperaceae (in 8%), Leucobryaceae (in 4%) and Sematophyllaceae (in 4%). Richness and species composition did not show any geographical gradient. The bryoflora was significantly richer in the localities of Saül, in French Guiana, and Tiputini, in Ecuador, than in the other localities, probably due to differences in local climatic conditions. Among the 155 species recorded for more than one locality, 57 were classified as specialists. A total of 29 species (among which 3 were unidentified) were sampled only in the canopy, which reinforces the importance of canopy sampling for the study of epiphytic bryophytes in the Amazon.

A vasta extensão e a alta diversidade de árvores das florestas na Amazônia desafiam a nossa compreensão sobre como variam a composição e abundância de espécies arbóreas ao longo desta região. Informações sobre estes parâmetros, geralmente obtidas a partir de inventários florísticos, são fundamentais para análises sobre padrões de diversidade. Embora inúmeros inventários florísticos tenham sido estabelecidos na Amazônia, a composição de espécies e a diversidade de árvores das florestas de campinarana e de terra-firme, na região do alto Rio Negro, permanecem ainda pouco conhecidas. Aqui, apresentamos dados de inventários florísticos de oito parcelas de um hectare estabelecidas em florestas de campinarana e de terra-firme do alto Rio Negro. Ao todo, registramos 4.703 indivíduos com diâmetro à altura do peito > 10 cm pertencentes a 49 famílias, 215 gêneros e 603 espécies. As comunidades de árvores das florestas de campinarana e terra-firme do alto Rio Negro diferem entre si, sendo que as florestas de campinaranas são mais similares e menos diversas que as florestas de terra-firme. Sugerimos que os mecanismos que causam diferenças entre as comunidades arbóreas das florestas de campinarana e terra-firme são principalmente relacionados a diferenças do tamanho do habitat, isto porque o tamanho da área do habitat influencia processos evolutivos que ocorrem em grande escala temporal e espacial.

The high tree diversity and vast extent of Amazonian forests challenge our understanding of how tree species abundance and composition varies across this region. Information about these parameters, usually obtained from tree inventories plots, is essential for revealing patterns of tree diversity. Numerous tree inventories plots have been established in Amazonia, yet, tree species composition and diversity of white-sand and terra-firme forests of the upper Rio Negro still remain poorly understood. Here, we present data from eight new one-hectare tree inventories plots established in the upper Rio Negro; four of which were located in white-sand forests and four in terra-firme forests. Overall, we registered 4703 trees > 10 cm of diameter at breast height. These trees belong to 49 families, 215 genera, and 603 species. We found that tree communities of terra-firme and white-sand forests in the upper Rio Negro significantly differ from each other in their species composition. Tree communities of white-sand forests show a higher floristic similarity and lower diversity than those of terra-firme forests. We argue that mechanisms driving differences between tree communities of white-sand and terra-firme forests are related to habitat size, which ultimately influences large-scale and long-term evolutionary processes.