Riqueza, composição e distribuição de briófitas epífitas em florestas de igapó de água preta da Amazônia Central

Abstract

The Amazon rainforest is the second biome with the highest number of bryophyte species in Brazil; however, the number of inventories is still limited compared to other environments, and ecological aspects regarding this plant community are still poorly studied, especially concerning epiphytic bryophytes. It is already understood that in the Amazon, epiphytic bryophytes behave as a set of local communities linked by the dispersal of multiple species potentially interacting with each other, indicating high similarity in the distribution of these plants' composition. Considering these findings, the aim of this study was to analyze the richness, composition, and floristic similarity of epiphytic bryophytes in different blackwater floodplain forests along the Rio Negro in Central Amazonia. Collections were made during the dry season in five locations within three reserves along the Rio Negro. A total of 180 samples were collected and subsequently identified at the Cryptogamic Laboratory of the National Institute of Amazonian Research. A total of 291 occurrences were recorded in the five sampled locations along the Rio Negro, identifying 39 species distributed among 9 families and 27 genera, including liverworts and mosses. Liverworts were predominant, with Lejeuneaceae Cavers being the most representative family. Our results revealed low epiphytic bryophyte richness in the floodplain forests compared to other flooded forests in the Amazon, but with a distinct species composition. A high similarity was found along the horizontal gradient, indicating significant species sharing among locations and macrohabitats of the floodplain forest, possibly due to the great dispersal capacity of epiphytic bryophytes between locations. In our study, vertical composition was more homogeneous in the floodplain forests, with high similarity between zones; however, the canopy stood out for its greater species richness but did not show a marked vertical zoning. Given the importance of floodplain forests in the Amazon region, understanding the distribution and patterns of epiphytic bryophytes becomes essential for awareness and conservation strategies. Our results enhance knowledge about the epiphytic bryophyte community in floodplain forests in Central Amazonia and provide essential information about species composition and distribution patterns. Our findings can support conservation strategies for these species as well as future ecological studies involving epiphytic bryophytes.