Does the stage of decomposition of fallen logs influence the bryophyte community? Understanding the epixylic bryophytes in a Nebular Forest in Southeastern Brazil

Epixylic bryophytes - colonizers of decaying logs - are the third most endangered group of these plants, but few studies have been focused on them. Thirty logs in the proximity of three trails in a nebular forest in the Serra da Bocaina National Park in the state of Sao Paulo, Brazil, were sampled. Our objective was to study and compare the composition of the communities in three levels of decomposition (10 plots per level): X = initial (solid wood and intact cortex); Y = intermediate (partially soft wood with cracks) and Z = advanced (completely soft wood with undefined shape). To compare the floristic relationships among plots, we used Sorensen's similarity coefficient and phytosociological parameters. We found 74 species of bryophytes (40 genera and 24 families), 80% of which were pleurocarpous mosses. The results showed no preference of the species for any level of decomposition and no spatial structure (similarity x distance). We conclude that epixylic bryophyte species in Atlantic Forest are generalists and colonize different types of environments and substrates.