Forest canopy cover composition and landscape influence over bryophytes communities in Nothofagus forests of southern Patagonia

Understanding the influence environmental drivers on understory vegetation is important for conservation efforts under climate change. Bryophytes are one of the most diverse groups in temperate forests but also the least known. In addition, the environmental drivers (e.g., forest structure, microclimate, soil conditions or substrate) influencing over bryophyte community among Nothofagus forest types are poorly known. The aim of this study was to evaluate the influence of forest canopy-layer composition on the structure (cover) and the composition (richness and diversity) of bryophyte communities (mosses and liverworts) in two contrast landscape types (coast and mountain) in southern Patagonia. Three natural Nothofagus forest types (pure deciduous, pure evergreen, and mixed deciduous-evergreen) in two landscapes (coast 400 m.a.s.l.) were selected (N = 60 plots). In each forest plot, we established one linear transect (10 m length) to measure bryophyte cover (point-intercept method). The data were evaluated using ANOVAs, Chi-square test and multivariate analyses. The mosses were mostly austral-antarctic origin, and the liverworts were all endemics. The principal substrates for the bryophytes development in the forest floor were litter and decaying woods. Moreover, many bryophytes species act as a substrate for natural tree regeneration. The forest structure was the main driver of bryophytes community in the coast landscape, while the slope was the principal driver of bryophytes in the mountain landscape. These differences were mainly explained for the microclimate into the forests (e.g., soil moisture and air temperature), and for the regional climate in the landscapes (e.g., air temperature and soil conditions). Notably, the mixed forest, mainly in the coast, presented exclusive species that were not present in the deciduous and evergreen pure forests. The conservation efforts should include management considerations both the stand and landscape levels based on the potential climate-change impact over bryophyte communities.