Temporal changes in the taxonomic and functional structure of bryophyte assemblages warn about the conservation status of biological refuges

Tropical rainforests are subject to changes over time, further accelerated under anthropic pressure. We investigated the influence of anthropogenic disturbances and vegetation cover on the taxonomic and functional structure of assemblages of bryophytes in three rainforests in Brazil. The parameters analyzed were richness, composition and beta diversity. Temporal changes in floristic dissimilarity were explained by species turnover, while those in functional dissimilarity by were explained nestedness and turnover. Only the increase in species richness was significantly influenced by the increase in matrix forest cover and changes in the degree of chronic anthropogenic disturbance. In scenarios of slight increase in matrix forest cover associated with increase in anthropogenic disturbances, we found a loss of functional diversity due to the loss of moisture- and shade-demanding species, which were replaced with species that are generalist as to light requirements and species with high reproductive capacity (monoicous). In turn, in scenarios of increase in forest cover and decrease in chronic disturbances, there was an increase in demanding species, implying greater functional diversity. Thus, efforts to increase the vegetation cover and decrease anthropogenic pressures, especially chronic disturbances, can improve the environmental quality and favor the conservation of the diversity of more demanding species.