Bryoflora of the Itatiaia National Park along an elevation gradient: diversity and conservation

(Bryoflora of the Itatiaia National Park along an elevational gradient: diversity and conservation). Itatiaia National Park harbors a unique bryoflora due to presence of different forest formations and well-defined climatic and vegetation bands: Montane Forest, Upper Montane Forest, and High-Altitude Fields (Campos de Altitude). Analysis of bryophyte diversity was undertaken to elucidate the richness and floristic composition of the different Atlantic Forest formations and to investigate the influence of elevation gradients on the bryoflora. Data from literature, herbarium samples, and data banks of the state's flora were consulted. Ten representative elevations were examined. The bryophyte diversity was high, comprising 519 taxa in 213 genera and 81 families (57 % of the total bryophyte flora known to Rio de Janeiro State, and 34 % of the Brazilian bryoflora). Bryoflora distribution was not uniform, showing differences in both species richness and floristic composition along an elevation gradient. The Montane Forest had the highest species richness (296), and numbers of exclusive taxa (172) and the Upper Montane Forest had more endemics species (47), which could be explained by its diversity of climatic, edaphic, and physiographic parameters. The 15 families with 59 % of the total number of species are also among the most species-rich families found in tropical America inventories. The species richness of mosses and liverworts reached their peaks at the mid-altitudinal range (2100-2200 m). The numbers of threatened species increased along the elevation gradient. These results emphasize the importance of the Atlantic Forest in southeastern Brazil to the conservation of bryophyte diversity, as well as the need to give priority to the protection of Upper Montane Forests and High-Altitude Fields.