Bryophyte communities across the ecological succession process in the Caxiuanã National Forest, Pará, Brazil.

Bryophytes play an important role in the process of ecological succession: conditioning the environment favourably for the emergence of subsequent groups. The objective of this study was to investigate the distribution of bryophyte communities in a cronossequence in the Caxiuanã National Forest, Pará, Brazil. To this end, biological material was collected in forest remnants with different successional stages based on regeneration age: Stage I (0 - 10 years), Stage II (10 - 25), Stage III (> 25) and Stage IV (primary forests). Density, richness and composition of species were compared between successional stages and the occurrence of possible indicator-species was investigated. The identified taxa were also classified by guilds of tolerance to solar radiation and colonized substrate. Composition of species was the variable that most contributed to understanding the distribution of bryophyte communities throughout successional stages, with eight species identified as potential indicators of some successional stages. Generalist species predominated in all stages. The richness of sun tolerants, in turn, decreased with the progress of succession, while shade tolerants increased. The land use history and land cover can influence the availability and quality of substrates and consequently their colonization by bryophytes in the different stages.