The Martírios-Andorinhas Mountain Ridge, in southeastern Pará, is located in a transition zone between two important biomes in Tropical America, Amazonia and the Brazilian Cerrado. The aim of this study was to inventory the bryophyte flora in different vegetation formations of the Martírios-Andorinhas Mountain Ridge, as a contribution to the evaluation of the environmental conservation status of the area. A total of 1784 specimens (1093 of mosses, 691 of liverworts) were gathered, with a prevalence of mosses over liverworts. In terms of species richness, however, liverworts (65 spp.) were as diverse as mosses (65). The number of specimens was higher in secondary forest (799), followed by gallery forest (670), riparian forest (208), and savanna (107). In turn, in number of species, gallery forest (88 spp./25 exclusive) surpassed secondary forest (75/17), riparian forest (64/8), and savanna (32/1). Bryophyte composition and richness reflects the environmental conditions in each vegetation type. Six species are new occurrences for the state of Pará, four for the northern region, and one for Brazil. The great majority (95 %) of the species were already recorded from the Amazonian domain, while 76 % were known from the Cerrado domain. The high percentage of species recorded from Amazonia can be explained by the presence of humid lowland forests in the study area, promoting the establishment of Amazonian species including many Lejeuneaceae.
Mosses, liverworts, conservation unit, Amazonia, Brazilian Planalto